[med-svn] [libtabixpp] 01/01: Imported Upstream version 0.0.20141119

Andreas Tille tille at debian.org
Sun Feb 1 13:53:49 UTC 2015


This is an automated email from the git hooks/post-receive script.

tille pushed a commit to branch master
in repository libtabixpp.

commit f6dfb9c42af26fbe1e872da71df5f039afef23d3
Author: Andreas Tille <tille at debian.org>
Date:   Sun Feb 1 14:53:24 2015 +0100

    Imported Upstream version 0.0.20141119
---
 .gitignore            |   5 +
 ChangeLog             | 593 ++++++++++++++++++++++++++++++
 Makefile              |  71 ++++
 NEWS                  | 126 +++++++
 README                |   6 +
 TabixReader.java      | 395 ++++++++++++++++++++
 bam_endian.h          |  42 +++
 bedidx.c              | 156 ++++++++
 bgzf.c                | 714 ++++++++++++++++++++++++++++++++++++
 bgzf.h                | 157 ++++++++
 bgzip.c               | 206 +++++++++++
 example.gtf.gz        | Bin 0 -> 3778 bytes
 example.gtf.gz.tbi    | Bin 0 -> 259 bytes
 index.c               | 998 ++++++++++++++++++++++++++++++++++++++++++++++++++
 khash.h               | 486 ++++++++++++++++++++++++
 knetfile.c            | 632 ++++++++++++++++++++++++++++++++
 knetfile.h            |  75 ++++
 kseq.h                | 227 ++++++++++++
 ksort.h               | 271 ++++++++++++++
 kstring.c             | 165 +++++++++
 kstring.h             |  68 ++++
 main.c                | 290 +++++++++++++++
 main.cpp              |  47 +++
 perl/MANIFEST         |   8 +
 perl/Makefile.PL      |   8 +
 perl/Tabix.pm         |  76 ++++
 perl/Tabix.xs         |  71 ++++
 perl/TabixIterator.pm |  41 +++
 perl/t/01local.t      |  28 ++
 perl/t/02remote.t     |  28 ++
 perl/typemap          |   3 +
 python/setup.py       |  55 +++
 python/tabixmodule.c  | 408 +++++++++++++++++++++
 python/test.py        |  91 +++++
 tabix.1               | 132 +++++++
 tabix.cpp             |  89 +++++
 tabix.h               | 145 ++++++++
 tabix.hpp             |  31 ++
 tabix.py              |  87 +++++
 tabix.tex             | 121 ++++++
 40 files changed, 7152 insertions(+)

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c92e3d2
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+*.a
+*.o
+tabix
+tabix++
+bgzip
diff --git a/ChangeLog b/ChangeLog
new file mode 100644
index 0000000..fd335b8
--- /dev/null
+++ b/ChangeLog
@@ -0,0 +1,593 @@
+------------------------------------------------------------------------
+r942 | lh3lh3 | 2011-03-31 16:39:50 -0400 (Thu, 31 Mar 2011) | 2 lines
+Changed paths:
+   M /trunk/tabix/main.c
+
+update version number
+
+------------------------------------------------------------------------
+r940 | lh3lh3 | 2011-03-31 16:38:03 -0400 (Thu, 31 Mar 2011) | 2 lines
+Changed paths:
+   M /trunk/tabix/bedidx.c
+   M /trunk/tabix/main.c
+
+fixed two bugs due to recent changes
+
+------------------------------------------------------------------------
+r939 | lh3lh3 | 2011-03-31 16:12:21 -0400 (Thu, 31 Mar 2011) | 2 lines
+Changed paths:
+   M /trunk/tabix/bgzf.c
+   M /trunk/tabix/bgzf.h
+   M /trunk/tabix/main.c
+
+update to the latest bgzf.*
+
+------------------------------------------------------------------------
+r938 | lh3lh3 | 2011-03-31 16:02:21 -0400 (Thu, 31 Mar 2011) | 2 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.h
+
+BED support
+
+------------------------------------------------------------------------
+r937 | lh3lh3 | 2011-03-31 15:03:49 -0400 (Thu, 31 Mar 2011) | 2 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   A /trunk/tabix/bedidx.c
+   M /trunk/tabix/example.gtf.gz.tbi
+   M /trunk/tabix/index.c
+   A /trunk/tabix/kseq.h
+   M /trunk/tabix/tabix.h
+
+restructure get_intv() for BED support
+
+------------------------------------------------------------------------
+r919 | petulda | 2011-02-24 10:14:14 -0500 (Thu, 24 Feb 2011) | 1 line
+Changed paths:
+   M /trunk/tabix/bgzf.c
+   M /trunk/tabix/bgzf.h
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+New -r (reheader) option for efficient header replacement.
+------------------------------------------------------------------------
+r915 | lh3lh3 | 2011-02-22 09:50:57 -0500 (Tue, 22 Feb 2011) | 2 lines
+Changed paths:
+   A /trunk/tabix/python
+   A /trunk/tabix/python/setup.py (from /trunk/tabix/setup.py:914)
+   A /trunk/tabix/python/tabixmodule.c (from /trunk/tabix/tabixmodule.c:914)
+   A /trunk/tabix/python/test.py (from /trunk/tabix/test.py:914)
+   D /trunk/tabix/setup.py
+   D /trunk/tabix/tabixmodule.c
+   D /trunk/tabix/test.py
+
+move to a new python/ directory
+
+------------------------------------------------------------------------
+r914 | lh3lh3 | 2011-02-22 09:49:35 -0500 (Tue, 22 Feb 2011) | 2 lines
+Changed paths:
+   A /trunk/tabix/setup.py
+   A /trunk/tabix/tabixmodule.c
+   A /trunk/tabix/test.py
+
+CPython C-API by Hyeshik Chang
+
+------------------------------------------------------------------------
+r904 | petulda | 2011-01-28 08:06:27 -0500 (Fri, 28 Jan 2011) | 1 line
+Changed paths:
+   M /trunk/tabix/index.c
+
+Check the number of fields on each line and exit nicely without segfault
+------------------------------------------------------------------------
+r901 | petulda | 2011-01-21 06:45:37 -0500 (Fri, 21 Jan 2011) | 1 line
+Changed paths:
+   M /trunk/tabix/main.c
+
+Fix: Complain only when VCF is newer, not newer or same mtime
+------------------------------------------------------------------------
+r900 | petulda | 2011-01-21 04:23:04 -0500 (Fri, 21 Jan 2011) | 1 line
+Changed paths:
+   M /trunk/tabix/main.c
+
+Prevent the common user mistake and check the timestamps of the vcf and index file
+------------------------------------------------------------------------
+r876 | lh3lh3 | 2010-12-08 12:38:45 -0500 (Wed, 08 Dec 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/ChangeLog
+   M /trunk/tabix/NEWS
+   M /trunk/tabix/main.c
+
+Release tabix-0.2.3
+
+------------------------------------------------------------------------
+r875 | lh3lh3 | 2010-12-08 12:28:35 -0500 (Wed, 08 Dec 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/ChangeLog
+   M /trunk/tabix/index.c
+
+Fixed a minor bug in generating index
+
+------------------------------------------------------------------------
+r855 | petulda | 2010-11-25 11:50:13 -0500 (Thu, 25 Nov 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/main.c
+
+Disable "unknown target name or minus interval" warning.
+------------------------------------------------------------------------
+r775 | petulda | 2010-10-26 15:02:30 -0400 (Tue, 26 Oct 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/main.c
+
+Added -h option to print header lines
+------------------------------------------------------------------------
+r742 | jmarshall | 2010-09-27 06:47:23 -0400 (Mon, 27 Sep 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix
+
+Add svn:ignore properties for intermediate and generated files.
+
+------------------------------------------------------------------------
+r725 | lh3lh3 | 2010-09-15 13:01:53 -0400 (Wed, 15 Sep 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/bgzip.c
+
+patches by Peter Chines
+
+------------------------------------------------------------------------
+r714 | lh3lh3 | 2010-09-07 10:13:25 -0400 (Tue, 07 Sep 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/TabixReader.java
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+fixed a bug in C/Java when n_off == 0
+
+------------------------------------------------------------------------
+r712 | lh3lh3 | 2010-09-03 09:21:23 -0400 (Fri, 03 Sep 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/TabixReader.java
+
+fixed a bug in parsing region strings
+
+------------------------------------------------------------------------
+r700 | petulda | 2010-08-25 10:42:37 -0400 (Wed, 25 Aug 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/main.c
+
+Fix: Exit with an error rather than segfault when index is not present and region is queried
+------------------------------------------------------------------------
+r696 | petulda | 2010-08-24 10:24:12 -0400 (Tue, 24 Aug 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/bgzf.c
+   M /trunk/tabix/bgzf.h
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+Complain about not-bgzipped files and check for noncontinuous chromosome blocks
+------------------------------------------------------------------------
+r603 | lh3lh3 | 2010-06-28 10:49:39 -0400 (Mon, 28 Jun 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/NEWS
+   M /trunk/tabix/TabixReader.java
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+Release tabix-0.2.2
+
+------------------------------------------------------------------------
+r597 | lh3lh3 | 2010-06-13 21:08:29 -0400 (Sun, 13 Jun 2010) | 3 lines
+Changed paths:
+   M /trunk/tabix/index.c
+
+Change the namespace of sorting, to avoid function name collision with samtools.
+
+
+------------------------------------------------------------------------
+r582 | lh3lh3 | 2010-06-03 10:40:25 -0400 (Thu, 03 Jun 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/NEWS
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.py
+
+Release tabix-0.2.1
+
+------------------------------------------------------------------------
+r581 | lh3lh3 | 2010-05-24 14:24:24 -0400 (Mon, 24 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/tabix.py
+
+OOP interface with the help from Aaron Quinlan
+
+------------------------------------------------------------------------
+r580 | lh3lh3 | 2010-05-23 23:36:05 -0400 (Sun, 23 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/tabix.py
+
+minor change
+
+------------------------------------------------------------------------
+r579 | lh3lh3 | 2010-05-23 23:25:24 -0400 (Sun, 23 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/tabix.py
+
+For Snow Leopard compatibility
+
+------------------------------------------------------------------------
+r575 | lh3lh3 | 2010-05-12 19:31:27 -0400 (Wed, 12 May 2010) | 4 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/index.c
+   M /trunk/tabix/tabix.h
+   A /trunk/tabix/tabix.py
+
+ * optionally generate shared library for Mac and Linux
+ * added a python script that directly calls the shared library
+ * added a new API for easy python access
+
+------------------------------------------------------------------------
+r574 | lh3lh3 | 2010-05-11 12:14:27 -0400 (Tue, 11 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/ChangeLog
+   M /trunk/tabix/NEWS
+   M /trunk/tabix/perl/Tabix.pm
+   M /trunk/tabix/perl/TabixIterator.pm
+   M /trunk/tabix/tabix.1
+
+Release tabix-0.2.0
+
+------------------------------------------------------------------------
+r573 | lh3lh3 | 2010-05-11 12:08:30 -0400 (Tue, 11 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+
+Added -fPIC
+
+------------------------------------------------------------------------
+r572 | lh3lh3 | 2010-05-11 11:59:07 -0400 (Tue, 11 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/perl/MANIFEST
+
+update
+
+------------------------------------------------------------------------
+r571 | lh3lh3 | 2010-05-11 11:56:54 -0400 (Tue, 11 May 2010) | 4 lines
+Changed paths:
+   A /trunk/tabix/example.gtf.gz
+   A /trunk/tabix/example.gtf.gz.tbi
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/perl/MANIFEST
+   M /trunk/tabix/perl/Tabix.pm
+   M /trunk/tabix/perl/Tabix.xs
+   A /trunk/tabix/perl/TabixIterator.pm
+   A /trunk/tabix/perl/t
+   A /trunk/tabix/perl/t/01local.t
+   A /trunk/tabix/perl/t/02remote.t
+   M /trunk/tabix/tabix.1
+   M /trunk/tabix/tabix.h
+
+ * improved C/Perl APIs
+ * added test for Perl
+ * added an tiny example
+
+------------------------------------------------------------------------
+r570 | lh3lh3 | 2010-05-11 01:04:21 -0400 (Tue, 11 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/TabixReader.java
+
+fixed the same issue in java
+
+------------------------------------------------------------------------
+r569 | lh3lh3 | 2010-05-11 01:03:24 -0400 (Tue, 11 May 2010) | 3 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/perl/Tabix.pm
+   M /trunk/tabix/perl/Tabix.xs
+
+ * fixed a potential issue in index.c
+ * improve perl APIs
+
+------------------------------------------------------------------------
+r568 | lh3lh3 | 2010-05-10 23:46:21 -0400 (Mon, 10 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/perl/Tabix.xs
+
+return an array from get_names()
+
+------------------------------------------------------------------------
+r567 | lh3lh3 | 2010-05-10 23:38:46 -0400 (Mon, 10 May 2010) | 4 lines
+Changed paths:
+   M /trunk/tabix/TabixReader.java
+   M /trunk/tabix/index.c
+   A /trunk/tabix/perl
+   A /trunk/tabix/perl/MANIFEST
+   A /trunk/tabix/perl/Makefile.PL
+   A /trunk/tabix/perl/Tabix.pm
+   A /trunk/tabix/perl/Tabix.xs
+   A /trunk/tabix/perl/typemap
+   M /trunk/tabix/tabix.h
+
+ * added the initial perl binding. The interface needs to be improved.
+ * added a new API for perl binding
+ * fixed a potential bug in java.
+
+------------------------------------------------------------------------
+r565 | lh3lh3 | 2010-05-09 23:24:35 -0400 (Sun, 09 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/main.c
+
+Release tabix-0.1.6
+
+------------------------------------------------------------------------
+r564 | lh3lh3 | 2010-05-09 23:01:49 -0400 (Sun, 09 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/index.c
+
+fixed a typo
+
+------------------------------------------------------------------------
+r563 | lh3lh3 | 2010-05-09 22:58:26 -0400 (Sun, 09 May 2010) | 2 lines
+Changed paths:
+   A /trunk/tabix/ChangeLog
+   M /trunk/tabix/NEWS
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.h
+
+If nothing bad happens, this will become 0.1.6
+
+------------------------------------------------------------------------
+r562 | lh3lh3 | 2010-05-09 19:43:56 -0400 (Sun, 09 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/index.c
+
+Fixed a bug
+
+------------------------------------------------------------------------
+r560 | lh3lh3 | 2010-05-05 10:59:09 -0400 (Wed, 05 May 2010) | 3 lines
+Changed paths:
+   A /trunk/tabix/NEWS
+   M /trunk/tabix/TabixReader.java
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.1
+   M /trunk/tabix/tabix.h
+
+ * Release tabix-0.1.5 (r560)
+ * Improve seeking efficiency. Index file needs to be rebuilt.
+
+------------------------------------------------------------------------
+r559 | lh3lh3 | 2010-05-04 23:11:42 -0400 (Tue, 04 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/main.c
+
+Release tabix-0.1.4 (r559)
+
+------------------------------------------------------------------------
+r558 | lh3lh3 | 2010-05-01 12:48:01 -0400 (Sat, 01 May 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/TabixReader.java
+
+implement SAM/VCF support; NOT tested yet
+
+------------------------------------------------------------------------
+r557 | lh3lh3 | 2010-05-01 00:42:34 -0400 (Sat, 01 May 2010) | 2 lines
+Changed paths:
+   A /trunk/tabix/TabixReader.java
+
+The Java implementation of tabix.
+
+------------------------------------------------------------------------
+r556 | lh3lh3 | 2010-04-30 22:34:07 -0400 (Fri, 30 Apr 2010) | 4 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/knetfile.c
+   M /trunk/tabix/main.c
+
+ * tabix-0.1.3-3 (r556)
+ * fixed a small memory leak in knetfile
+ * fixed a minor bug for remote downloading
+
+------------------------------------------------------------------------
+r555 | lh3lh3 | 2010-04-30 22:15:12 -0400 (Fri, 30 Apr 2010) | 4 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+ * tabix-0.1.3-2 (r555)
+ * do not overwrite index file by default
+ * a little code cleanup
+
+------------------------------------------------------------------------
+r554 | lh3lh3 | 2010-04-30 21:44:31 -0400 (Fri, 30 Apr 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/index.c
+
+fixed a potential bug for UCSC-like coordinate
+
+------------------------------------------------------------------------
+r553 | lh3lh3 | 2010-04-28 17:43:41 -0400 (Wed, 28 Apr 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/tabix.tex
+
+minor clarification to the format spec
+
+------------------------------------------------------------------------
+r552 | lh3lh3 | 2010-04-28 16:33:07 -0400 (Wed, 28 Apr 2010) | 3 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/bgzip.c
+   A /trunk/tabix/tabix.tex
+
+ * added the format specification
+ * fixed a typo in bgzip
+
+------------------------------------------------------------------------
+r550 | petulda | 2010-04-22 11:03:24 -0400 (Thu, 22 Apr 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/bgzip.c
+
+The behaviour changed slightly to mimic gzip. Detect if std descriptors are connected to the terminal.
+------------------------------------------------------------------------
+r549 | petulda | 2010-04-22 09:46:10 -0400 (Thu, 22 Apr 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/bgzip.c
+
+Fix in src/dst file detection and slight change of behaviour
+------------------------------------------------------------------------
+r548 | petulda | 2010-04-19 04:39:46 -0400 (Mon, 19 Apr 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/index.c
+
+Close file descriptor in ti_list_chromosomes
+------------------------------------------------------------------------
+r547 | petulda | 2010-04-16 09:27:11 -0400 (Fri, 16 Apr 2010) | 1 line
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.h
+
+Added the -l option for listing chromosomes
+------------------------------------------------------------------------
+r544 | lh3lh3 | 2010-03-29 10:58:48 -0400 (Mon, 29 Mar 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/main.c
+
+removed a line of debugging code
+
+------------------------------------------------------------------------
+r543 | lh3lh3 | 2010-03-19 12:29:16 -0400 (Fri, 19 Mar 2010) | 3 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.1
+
+ * tabix-0.1.3 (r543)
+ * fixed another off-by-one bug
+
+------------------------------------------------------------------------
+r542 | lh3lh3 | 2010-03-16 22:35:52 -0400 (Tue, 16 Mar 2010) | 2 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.1
+
+Release tabix-0.1.1
+
+------------------------------------------------------------------------
+r506 | lh3lh3 | 2009-11-02 23:20:12 -0500 (Mon, 02 Nov 2009) | 2 lines
+Changed paths:
+   M /trunk/tabix/main.c
+
+Release tabix-0.1.0
+
+------------------------------------------------------------------------
+r505 | lh3lh3 | 2009-11-02 23:15:49 -0500 (Mon, 02 Nov 2009) | 2 lines
+Changed paths:
+   A /trunk/tabix/tabix.1
+
+documentation
+
+------------------------------------------------------------------------
+r504 | lh3lh3 | 2009-11-02 11:08:18 -0500 (Mon, 02 Nov 2009) | 5 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/bgzip.c
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.h
+
+ * tabix-0.0.0-5 (r504)
+ * fixed a critical bug in fetching data (a typo in fact)
+ * support SAM (tested on ex1.sam) and VCF (not tested)
+ * improve the command-line interface
+
+------------------------------------------------------------------------
+r503 | lh3lh3 | 2009-11-02 10:04:43 -0500 (Mon, 02 Nov 2009) | 3 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+ * tabix-0.0.0-4 (r503)
+ * index files are bgzf compressed
+
+------------------------------------------------------------------------
+r502 | lh3lh3 | 2009-11-02 09:47:25 -0500 (Mon, 02 Nov 2009) | 4 lines
+Changed paths:
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+   M /trunk/tabix/tabix.h
+
+ * tabix-0.0.0-3 (r502)
+ * support meta lines (not tested)
+ * I am going to make the index file in the BGZF format
+
+------------------------------------------------------------------------
+r501 | lh3lh3 | 2009-11-01 22:03:07 -0500 (Sun, 01 Nov 2009) | 3 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/bgzf.h
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+ * tabix-0.0.0-2 (r501)
+ * accelerate ti_readline()
+
+------------------------------------------------------------------------
+r500 | lh3lh3 | 2009-11-01 20:49:52 -0500 (Sun, 01 Nov 2009) | 3 lines
+Changed paths:
+   M /trunk/tabix/Makefile
+   M /trunk/tabix/bgzip.c
+   M /trunk/tabix/index.c
+   M /trunk/tabix/main.c
+
+ * tabix-0.0.0-1 (r500)
+ * apparently working
+
+------------------------------------------------------------------------
+r499 | lh3lh3 | 2009-11-01 14:04:52 -0500 (Sun, 01 Nov 2009) | 2 lines
+Changed paths:
+   D /trunk/tabix/parser.c
+
+obsolete file
+
+------------------------------------------------------------------------
+r498 | lh3lh3 | 2009-11-01 14:04:08 -0500 (Sun, 01 Nov 2009) | 2 lines
+Changed paths:
+   M /trunk/tabix/bgzip.c
+
+bgzip is more like gzip in its command-line interface
+
+------------------------------------------------------------------------
+r497 | lh3lh3 | 2009-11-01 13:43:35 -0500 (Sun, 01 Nov 2009) | 2 lines
+Changed paths:
+   A /trunk/tabix/Makefile
+   A /trunk/tabix/bam_endian.h
+   A /trunk/tabix/bgzf.c
+   A /trunk/tabix/bgzf.h
+   A /trunk/tabix/bgzip.c
+   A /trunk/tabix/index.c
+   A /trunk/tabix/khash.h
+   A /trunk/tabix/knetfile.c
+   A /trunk/tabix/knetfile.h
+   A /trunk/tabix/ksort.h
+   A /trunk/tabix/kstring.c
+   A /trunk/tabix/kstring.h
+   A /trunk/tabix/main.c
+   A /trunk/tabix/parser.c
+   A /trunk/tabix/tabix.h
+
+initial source code. It is BUGGY!
+
+------------------------------------------------------------------------
+r496 | lh3lh3 | 2009-11-01 13:42:39 -0500 (Sun, 01 Nov 2009) | 2 lines
+Changed paths:
+   A /trunk/tabix
+
+A generic indexer for TAB-delimited genome position files
+
+------------------------------------------------------------------------
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..0702ed3
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,71 @@
+CC=			gcc
+CPP= 		g++
+CFLAGS=		-g -Wall -O2 -fPIC #-m64 #-arch ppc
+DFLAGS=		-D_FILE_OFFSET_BITS=64 -D_USE_KNETFILE
+LOBJS=		bgzf.o kstring.o knetfile.o index.o bedidx.o
+AOBJS=		main.o
+PROG=		tabix bgzip tabix++
+INCLUDES=
+SUBDIRS=	.
+LIBPATH=
+LIBCURSES=	
+
+.SUFFIXES:.c .o
+
+.c.o:
+		$(CC) -c $(CFLAGS) $(DFLAGS) $(INCLUDES) $< -o $@
+
+all-recur lib-recur clean-recur cleanlocal-recur install-recur:
+		@target=`echo $@ | sed s/-recur//`; \
+		wdir=`pwd`; \
+		list='$(SUBDIRS)'; for subdir in $$list; do \
+			cd $$subdir; \
+			$(MAKE) CC="$(CC)" DFLAGS="$(DFLAGS)" CFLAGS="$(CFLAGS)" \
+				INCLUDES="$(INCLUDES)" LIBPATH="$(LIBPATH)" $$target || exit 1; \
+			cd $$wdir; \
+		done;
+
+all:$(PROG)
+
+lib:libtabix.a
+
+libtabix.so.1:$(LOBJS)
+		$(CC) -shared -Wl,-soname,libtabix.so -o $@ $(LOBJS) -lc -lz
+
+libtabix.1.dylib:$(LOBJS)
+		libtool -dynamic $(LOBJS) -o $@ -lc -lz
+
+libtabix.a:$(LOBJS)
+		$(AR) -cru $@ $(LOBJS)
+		ranlib $@
+
+tabix:lib $(AOBJS)
+		$(CC) $(CFLAGS) -o $@ $(AOBJS) -lm $(LIBPATH) -L. -ltabix -lz
+
+tabix.o: tabix.hpp tabix.cpp
+		$(CPP) $(CFLAGS) -c tabix.cpp
+
+tabix++:lib tabix.o main.cpp
+		$(CPP) $(CFLAGS) -o $@ main.cpp tabix.o bgzf.o -lm $(LIBPATH) -L. -ltabix -lz
+
+bgzip:bgzip.o bgzf.o knetfile.o
+		$(CC) $(CFLAGS) -o $@ bgzip.o bgzf.o knetfile.o -lz
+
+TabixReader.class:TabixReader.java
+		javac -cp .:sam.jar TabixReader.java
+
+kstring.o:kstring.h
+knetfile.o:knetfile.h
+bgzf.o:bgzf.h knetfile.h
+index.o:bgzf.h tabix.h khash.h ksort.h kstring.h
+main.o:tabix.h kstring.h bgzf.h
+bgzip.o:bgzf.h
+bedidx.o:kseq.h khash.h
+
+tabix.pdf:tabix.tex
+		pdflatex tabix.tex
+
+cleanlocal:
+		rm -fr gmon.out *.o a.out *.dSYM $(PROG) *~ *.a tabix.aux tabix.log tabix.pdf *.class libtabix.*.dylib libtabix.so*
+
+clean:cleanlocal-recur
diff --git a/NEWS b/NEWS
new file mode 100644
index 0000000..d230541
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,126 @@
+Release 0.2.4 (10 April, 2011)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Give an error if the index file is older than the data file.
+
+ * Avoid a segfault given flawed input.
+
+ * Added Python APIs contributed by Hyeshik Chang. The new APIs do not bind to
+   the dynamic library and are reported to be faster. Pysam also comes with a
+   tabix binding.
+
+ * Added option "-r" for efficient header replacement.
+
+ * Added BED support.
+
+ * Synchronized the BGZF library between tabix and samtools.
+
+(0.2.4: 10 April 2011, r949)
+
+
+
+Beta Release 0.2.3 (8 December, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Fixed a minor bug where the first record in a headerless file may be
+   missed.
+
+ * Added an option to print header lines.
+
+ * Fixed a rare bug which may occasionally happen when retrieving data
+   from a region without any records.
+
+ * Enhanced error reporting.
+
+ * Fixed a bug in bgzip which may delete the original file even if not
+   intended.
+
+(0.2.3: 8 December 2010, r876)
+
+
+
+Beta Release 0.2.2 (28 June, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Dropped the VCF3 support. Added VCF4 support.
+
+ * Avoided the function name collision with samtools.
+
+(0.2.2: 28 June 2010, r603)
+
+
+
+Beta Release 0.2.1 (3 June, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Allow shared library to be compiled. Added python binding to the
+   shared library.
+
+(0.2.1: 3 June 2010, r582)
+
+
+
+Beta Release 0.2.0 (11 May, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Fixed an issue for random access given an interval end larger than
+   2^29.
+
+ * Updated the Java binding.
+
+ * Added a Perl module using XS.
+
+ * Improved the C APIs.
+
+(0.2.0: 11 May 2010, r574)
+
+
+
+Beta Release 0.1.6 (9 May, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Improved backward compatibility. Release 0.1.5 does not work with the
+   buggy index file generated by 0.1.2.
+
+ * Fixed a bug in building linear index. The bug does not affect the
+   results, only affects efficiency in rare cases.
+
+ * Reduced the number of seek calls given an index generated by old
+   version of tabix.
+
+ * Added new APIs for retrieving data via an iterator. The old callback
+   APIs are not changed, although internally it uses iterator to
+   retrieve data.
+
+I am trying to freeze tabix. I just hope I am committing new bugs.
+
+(0.1.6: 9 May 2010, r563)
+
+
+
+Beta Release 0.1.5 (5 May, 2010)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Notable changes:
+
+ * Clarified that tabix is released under MIT/X11.
+
+ * Improved the robustness of indexing and retrieval.
+
+ * Reduced the number of seek calls when the specified region starts
+   from a 16kb block with no data. The index format is the same, but the
+   content is changed a little.
+
+(0.1.5: 5 May 2010, r560)
diff --git a/README b/README
new file mode 100644
index 0000000..966660e
--- /dev/null
+++ b/README
@@ -0,0 +1,6 @@
+This is a fork of the tabix project [1] which includes a C++ class wrapper for
+reading tabix-indexed files.
+
+Author: Erik Garrison <erik.garrison at bc.edu>
+
+[1] http://samtools.sourceforge.net/tabix.shtml
diff --git a/TabixReader.java b/TabixReader.java
new file mode 100644
index 0000000..5874202
--- /dev/null
+++ b/TabixReader.java
@@ -0,0 +1,395 @@
+/* The MIT License
+
+   Copyright (c) 2010 Broad Institute.
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <hengli at broadinstitute.org> */
+
+import net.sf.samtools.util.BlockCompressedInputStream;
+
+import java.io.*;
+import java.nio.*;
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.lang.StringBuffer;
+
+public class TabixReader
+{
+	private String mFn;
+	private BlockCompressedInputStream mFp;
+
+	private int mPreset;
+	private int mSc;
+	private int mBc;
+	private int mEc;
+	private int mMeta;
+	private int mSkip;
+	private String[] mSeq;
+
+	private HashMap<String, Integer> mChr2tid;
+
+	private static int MAX_BIN = 37450;
+	private static int TAD_MIN_CHUNK_GAP = 32768;
+	private static int TAD_LIDX_SHIFT = 14;
+
+	private class TPair64 implements Comparable<TPair64> {
+		long u, v;
+		public TPair64(final long _u, final long _v) {
+			u = _u; v = _v;
+		}
+		public TPair64(final TPair64 p) {
+			u = p.u; v = p.v;
+		}
+		public int compareTo(final TPair64 p) {
+			return u == p.u? 0 : ((u < p.u) ^ (u < 0) ^ (p.u < 0))? -1 : 1; // unsigned 64-bit comparison
+		}
+	};
+
+	private class TIndex {
+		HashMap<Integer, TPair64[]> b; // binning index
+		long[] l; // linear index
+	};
+	private TIndex[] mIndex;
+
+	private class TIntv {
+		int tid, beg, end;
+	};
+
+	private static boolean less64(final long u, final long v) { // unsigned 64-bit comparison
+		return (u < v) ^ (u < 0) ^ (v < 0);
+	}
+
+	/**
+	 * The constructor
+	 *
+	 * @param fn File name of the data file
+	 */
+	public TabixReader(final String fn) throws IOException {
+		mFn = fn;
+		mFp = new BlockCompressedInputStream(new File(fn));
+		readIndex();
+	}
+
+	private static int reg2bins(final int beg, final int _end, final int[] list) {
+		int i = 0, k, end = _end;
+		if (beg >= end) return 0;
+		if (end >= 1<<29) end = 1<<29;
+		--end;
+		list[i++] = 0;
+		for (k =    1 + (beg>>26); k <=    1 + (end>>26); ++k) list[i++] = k;
+		for (k =    9 + (beg>>23); k <=    9 + (end>>23); ++k) list[i++] = k;
+		for (k =   73 + (beg>>20); k <=   73 + (end>>20); ++k) list[i++] = k;
+		for (k =  585 + (beg>>17); k <=  585 + (end>>17); ++k) list[i++] = k;
+		for (k = 4681 + (beg>>14); k <= 4681 + (end>>14); ++k) list[i++] = k;
+		return i;
+	}
+
+	public static int readInt(final InputStream is) throws IOException {
+		byte[] buf = new byte[4];
+		is.read(buf);
+		return ByteBuffer.wrap(buf).order(ByteOrder.LITTLE_ENDIAN).getInt();
+	}
+
+	public static long readLong(final InputStream is) throws IOException {
+		byte[] buf = new byte[8];
+		is.read(buf);
+		return ByteBuffer.wrap(buf).order(ByteOrder.LITTLE_ENDIAN).getLong();
+	}
+
+	public static String readLine(final InputStream is) throws IOException {
+		StringBuffer buf = new StringBuffer();
+		int c;
+		while ((c = is.read()) >= 0 && c != '\n')
+			buf.append((char)c);
+		if (c < 0) return null;
+		return buf.toString();
+	}
+
+	/**
+	 * Read the Tabix index from a file
+	 *
+	 * @param fp File pointer
+	 */
+	public void readIndex(final File fp) throws IOException {
+		if (fp == null) return;
+		BlockCompressedInputStream is = new BlockCompressedInputStream(fp);
+		byte[] buf = new byte[4];
+
+		is.read(buf, 0, 4); // read "TBI\1"
+		mSeq = new String[readInt(is)]; // # sequences
+		mChr2tid = new HashMap<String, Integer>();
+		mPreset = readInt(is);
+		mSc = readInt(is);
+		mBc = readInt(is);
+		mEc = readInt(is);
+		mMeta = readInt(is);
+		mSkip = readInt(is);
+		// read sequence dictionary
+		int i, j, k, l = readInt(is);
+		buf = new byte[l];
+		is.read(buf);
+		for (i = j = k = 0; i < buf.length; ++i) {
+			if (buf[i] == 0) {
+				byte[] b = new byte[i - j];
+				System.arraycopy(buf, j, b, 0, b.length);
+				String s = new String(b);
+				mChr2tid.put(s, k);
+				mSeq[k++] = s;
+				j = i + 1;
+			}
+		}
+		// read the index
+		mIndex = new TIndex[mSeq.length];
+		for (i = 0; i < mSeq.length; ++i) {
+			// the binning index
+			int n_bin = readInt(is);
+			mIndex[i] = new TIndex();
+			mIndex[i].b = new HashMap<Integer, TPair64[]>();
+			for (j = 0; j < n_bin; ++j) {
+				int bin = readInt(is);
+				TPair64[] chunks = new TPair64[readInt(is)];
+				for (k = 0; k < chunks.length; ++k) {
+					long u = readLong(is);
+					long v = readLong(is);
+					chunks[k] = new TPair64(u, v); // in C, this is inefficient
+				}
+				mIndex[i].b.put(bin, chunks);
+			}
+			// the linear index
+			mIndex[i].l = new long[readInt(is)];
+			for (k = 0; k < mIndex[i].l.length; ++k)
+				mIndex[i].l[k] = readLong(is);
+		}
+		// close
+		is.close();
+	}
+
+	/**
+	 * Read the Tabix index from the default file.
+	 */
+	public void readIndex() throws IOException {
+		readIndex(new File(mFn + ".tbi"));
+	}
+
+	/**
+	 * Read one line from the data file.
+	 */
+	public String readLine() throws IOException {
+		return readLine(mFp);
+	}
+
+	private int chr2tid(final String chr) {
+		if (mChr2tid.containsKey(chr)) return mChr2tid.get(chr);
+		else return -1;
+	}
+
+	/**
+	 * Parse a region in the format of "chr1", "chr1:100" or "chr1:100-1000"
+	 *
+	 * @param reg Region string
+	 * @return An array where the three elements are sequence_id,
+	 *         region_begin and region_end. On failure, sequence_id==-1.
+	 */
+	public int[] parseReg(final String reg) { // FIXME: NOT working when the sequence name contains : or -.
+		String chr;
+		int colon, hyphen;
+		int[] ret = new int[3];
+		colon = reg.indexOf(':'); hyphen = reg.indexOf('-');
+		chr = colon >= 0? reg.substring(0, colon) : reg;
+		ret[1] = colon >= 0? Integer.parseInt(reg.substring(colon+1, hyphen >= 0? hyphen : reg.length())) - 1 : 0;
+		ret[2] = hyphen >= 0? Integer.parseInt(reg.substring(hyphen+1)) : 0x7fffffff;
+		ret[0] = chr2tid(chr);
+		return ret;
+	}
+
+	private TIntv getIntv(final String s) {
+		TIntv intv = new TIntv();
+		int col = 0, end = 0, beg = 0;
+		while ((end = s.indexOf('\t', beg)) >= 0 || end == -1) {
+			++col;
+			if (col == mSc) {
+				intv.tid = chr2tid(s.substring(beg, end));
+			} else if (col == mBc) {
+				intv.beg = intv.end = Integer.parseInt(s.substring(beg, end));
+				if ((mPreset&0x10000) != 0) ++intv.end;
+				else --intv.beg;
+				if (intv.beg < 0) intv.beg = 0;
+				if (intv.end < 1) intv.end = 1;
+			} else { // FIXME: SAM supports are not tested yet
+				if ((mPreset&0xffff) == 0) { // generic
+					if (col == mEc)
+						intv.end = Integer.parseInt(s.substring(beg, end));
+				} else if ((mPreset&0xffff) == 1) { // SAM
+					if (col == 6) { // CIGAR
+						int l = 0, i, j;
+						String cigar = s.substring(beg, end);
+						for (i = j = 0; i < cigar.length(); ++i) {
+							if (cigar.charAt(i) > '9') {
+								int op = cigar.charAt(i);
+								if (op == 'M' || op == 'D' || op == 'N')
+									l += Integer.parseInt(cigar.substring(j, i));
+							}
+						}
+						intv.end = intv.beg + l;
+					}
+				} else if ((mPreset&0xffff) == 2) { // VCF
+					String alt;
+					alt = end >= 0? s.substring(beg, end) : s.substring(beg);
+					if (col == 4) { // REF
+						if (alt.length() > 0) intv.end = intv.beg + alt.length();
+					} else if (col == 8) { // INFO
+						int e_off = -1, i = alt.indexOf("END=");
+						if (i == 0) e_off = 4;
+						else if (i > 0) {
+							i = alt.indexOf(";END=");
+							if (i >= 0) e_off = i + 5;
+						}
+						if (e_off > 0) {
+							i = alt.indexOf(";", e_off);
+							intv.end = Integer.parseInt(i > e_off? alt.substring(e_off, i) : alt.substring(e_off));
+						}
+					}
+				}
+			}
+			if (end == -1) break;
+			beg = end + 1;
+		}
+		return intv;
+	}
+
+	public class Iterator {
+		private int i, n_seeks;
+		private int tid, beg, end;
+		private TPair64[] off;
+		private long curr_off;
+		private boolean iseof;
+
+		public Iterator(final int _tid, final int _beg, final int _end, final TPair64[] _off) {
+			i = -1; n_seeks = 0; curr_off = 0; iseof = false;
+			off = _off; tid = _tid; beg = _beg; end = _end;
+		}
+
+		public String next() throws IOException {
+			if (iseof) return null;
+			for (;;) {
+				if (curr_off == 0 || !less64(curr_off, off[i].v)) { // then jump to the next chunk
+					if (i == off.length - 1) break; // no more chunks
+					if (i >= 0) assert(curr_off == off[i].v); // otherwise bug
+					if (i < 0 || off[i].v != off[i+1].u) { // not adjacent chunks; then seek
+						mFp.seek(off[i+1].u);
+						curr_off = mFp.getFilePointer();
+						++n_seeks;
+					}
+					++i;
+				}
+				String s;
+				if ((s = readLine(mFp)) != null) {
+					TIntv intv;
+					char[] str = s.toCharArray();
+					curr_off = mFp.getFilePointer();
+					if (str.length == 0 || str[0] == mMeta) continue;
+					intv = getIntv(s);
+					if (intv.tid != tid || intv.beg >= end) break; // no need to proceed
+					else if (intv.end > beg && intv.beg < end) return s; // overlap; return
+				} else break; // end of file
+			}
+			iseof = true;
+			return null;
+		}
+	};
+
+	public Iterator query(final int tid, final int beg, final int end) {
+		TPair64[] off, chunks;
+		long min_off;
+		TIndex idx = mIndex[tid];
+		int[] bins = new int[MAX_BIN];
+		int i, l, n_off, n_bins = reg2bins(beg, end, bins);
+		if (idx.l.length > 0)
+			min_off = (beg>>TAD_LIDX_SHIFT >= idx.l.length)? idx.l[idx.l.length-1] : idx.l[beg>>TAD_LIDX_SHIFT];
+		else min_off = 0;
+		for (i = n_off = 0; i < n_bins; ++i) {
+			if ((chunks = idx.b.get(bins[i])) != null)
+				n_off += chunks.length;
+		}
+		if (n_off == 0) return null;
+		off = new TPair64[n_off];
+		for (i = n_off = 0; i < n_bins; ++i)
+			if ((chunks = idx.b.get(bins[i])) != null)
+				for (int j = 0; j < chunks.length; ++j)
+					if (less64(min_off, chunks[j].v))
+						off[n_off++] = new TPair64(chunks[j]);
+		if (n_off == 0) return null;
+		Arrays.sort(off, 0, n_off);
+		// resolve completely contained adjacent blocks
+		for (i = 1, l = 0; i < n_off; ++i) {
+			if (less64(off[l].v, off[i].v)) {
+				++l;
+				off[l].u = off[i].u; off[l].v = off[i].v;
+			}
+		}
+		n_off = l + 1;
+		// resolve overlaps between adjacent blocks; this may happen due to the merge in indexing
+		for (i = 1; i < n_off; ++i)
+			if (!less64(off[i-1].v, off[i].u)) off[i-1].v = off[i].u;
+		// merge adjacent blocks
+		for (i = 1, l = 0; i < n_off; ++i) {
+			if (off[l].v>>16 == off[i].u>>16) off[l].v = off[i].v;
+			else {
+				++l;
+				off[l].u = off[i].u;
+				off[l].v = off[i].v;
+			}
+		}
+		n_off = l + 1;
+		// return
+		TPair64[] ret = new TPair64[n_off];
+		for (i = 0; i < n_off; ++i) ret[i] = new TPair64(off[i].u, off[i].v); // in C, this is inefficient
+		return new TabixReader.Iterator(tid, beg, end, ret);
+	}
+	
+	public Iterator query(final String reg) {
+		int[] x = parseReg(reg);
+		return query(x[0], x[1], x[2]);
+	}
+
+	public static void main(String[] args) {
+		if (args.length < 1) {
+			System.out.println("Usage: java -cp .:sam.jar TabixReader <in.gz> [region]");
+			System.exit(1);
+		}
+		try {
+			TabixReader tr = new TabixReader(args[0]);
+			String s;
+			if (args.length == 1) { // no region is specified; print the whole file
+				while ((s = tr.readLine()) != null)
+					System.out.println(s);
+			} else { // a region is specified; random access
+				TabixReader.Iterator iter = tr.query(args[1]); // get the iterator
+				while (iter != null && (s = iter.next()) != null)
+					System.out.println(s);
+			}
+		} catch (IOException e) {
+		}
+	}
+}
diff --git a/bam_endian.h b/bam_endian.h
new file mode 100644
index 0000000..0fc74a8
--- /dev/null
+++ b/bam_endian.h
@@ -0,0 +1,42 @@
+#ifndef BAM_ENDIAN_H
+#define BAM_ENDIAN_H
+
+#include <stdint.h>
+
+static inline int bam_is_big_endian()
+{
+	long one= 1;
+	return !(*((char *)(&one)));
+}
+static inline uint16_t bam_swap_endian_2(uint16_t v)
+{
+	return (uint16_t)(((v & 0x00FF00FFU) << 8) | ((v & 0xFF00FF00U) >> 8));
+}
+static inline void *bam_swap_endian_2p(void *x)
+{
+	*(uint16_t*)x = bam_swap_endian_2(*(uint16_t*)x);
+	return x;
+}
+static inline uint32_t bam_swap_endian_4(uint32_t v)
+{
+	v = ((v & 0x0000FFFFU) << 16) | (v >> 16);
+	return ((v & 0x00FF00FFU) << 8) | ((v & 0xFF00FF00U) >> 8);
+}
+static inline void *bam_swap_endian_4p(void *x)
+{
+	*(uint32_t*)x = bam_swap_endian_4(*(uint32_t*)x);
+	return x;
+}
+static inline uint64_t bam_swap_endian_8(uint64_t v)
+{
+	v = ((v & 0x00000000FFFFFFFFLLU) << 32) | (v >> 32);
+	v = ((v & 0x0000FFFF0000FFFFLLU) << 16) | ((v & 0xFFFF0000FFFF0000LLU) >> 16);
+	return ((v & 0x00FF00FF00FF00FFLLU) << 8) | ((v & 0xFF00FF00FF00FF00LLU) >> 8);
+}
+static inline void *bam_swap_endian_8p(void *x)
+{
+	*(uint64_t*)x = bam_swap_endian_8(*(uint64_t*)x);
+	return x;
+}
+
+#endif
diff --git a/bedidx.c b/bedidx.c
new file mode 100644
index 0000000..722877d
--- /dev/null
+++ b/bedidx.c
@@ -0,0 +1,156 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include <zlib.h>
+
+#include "ksort.h"
+KSORT_INIT_GENERIC(uint64_t)
+
+#include "kseq.h"
+KSTREAM_INIT(gzFile, gzread, 8192)
+
+typedef struct {
+	int n, m;
+	uint64_t *a;
+	int *idx;
+} bed_reglist_t;
+
+#include "khash.h"
+KHASH_MAP_INIT_STR(reg, bed_reglist_t)
+
+#define LIDX_SHIFT 13
+
+typedef kh_reg_t reghash_t;
+
+int *bed_index_core(int n, uint64_t *a, int *n_idx)
+{
+	int i, j, m, *idx;
+	m = *n_idx = 0; idx = 0;
+	for (i = 0; i < n; ++i) {
+		int beg, end;
+		beg = a[i]>>32 >> LIDX_SHIFT; end = ((uint32_t)a[i]) >> LIDX_SHIFT;
+		if (m < end + 1) {
+			int oldm = m;
+			m = end + 1;
+			kroundup32(m);
+			idx = realloc(idx, m * sizeof(int));
+			for (j = oldm; j < m; ++j) idx[j] = -1;
+		}
+		if (beg == end) {
+			if (idx[beg] < 0) idx[beg] = i;
+		} else {
+			for (j = beg; j <= end; ++j)
+				if (idx[j] < 0) idx[j] = i;
+		}
+		*n_idx = end + 1;
+	}
+	return idx;
+}
+
+void bed_index(void *_h)
+{
+	reghash_t *h = (reghash_t*)_h;
+	khint_t k;
+	for (k = 0; k < kh_end(h); ++k) {
+		if (kh_exist(h, k)) {
+			bed_reglist_t *p = &kh_val(h, k);
+			if (p->idx) free(p->idx);
+			ks_introsort(uint64_t, p->n, p->a);
+			p->idx = bed_index_core(p->n, p->a, &p->m);
+		}
+	}
+}
+
+int bed_overlap_core(const bed_reglist_t *p, int beg, int end)
+{
+	int i, min_off;
+	if (p->n == 0) return 0;
+	min_off = (beg>>LIDX_SHIFT >= p->n)? p->idx[p->n-1] : p->idx[beg>>LIDX_SHIFT];
+	if (min_off < 0) { // TODO: this block can be improved, but speed should not matter too much here
+		int n = beg>>LIDX_SHIFT;
+		if (n > p->n) n = p->n;
+		for (i = n - 1; i >= 0; --i)
+			if (p->idx[i] >= 0) break;
+		min_off = i >= 0? p->idx[i] : 0;
+	}
+	for (i = min_off; i < p->n; ++i) {
+		if ((int)(p->a[i]>>32) >= end) break; // out of range; no need to proceed
+		if ((int32_t)p->a[i] > beg && (int32_t)(p->a[i]>>32) < end)
+			return 1; // find the overlap; return
+	}
+	return 0;
+}
+
+int bed_overlap(const void *_h, const char *chr, int beg, int end)
+{
+	const reghash_t *h = (const reghash_t*)_h;
+	khint_t k;
+	if (!h) return 0;
+	k = kh_get(reg, h, chr);
+	if (k == kh_end(h)) return 0;
+	return bed_overlap_core(&kh_val(h, k), beg, end);
+}
+
+void *bed_read(const char *fn)
+{
+	reghash_t *h = kh_init(reg);
+	gzFile fp;
+	kstream_t *ks;
+	int dret;
+	kstring_t *str;
+	// read the list
+	fp = strcmp(fn, "-")? gzopen(fn, "r") : gzdopen(fileno(stdin), "r");
+	if (fp == 0) return 0;
+	str = calloc(1, sizeof(kstring_t));
+	ks = ks_init(fp);
+	while (ks_getuntil(ks, 0, str, &dret) >= 0) { // read the chr name
+		int beg = -1, end = -1;
+		bed_reglist_t *p;
+		khint_t k = kh_get(reg, h, str->s);
+		if (k == kh_end(h)) { // absent from the hash table
+			int ret;
+			char *s = strdup(str->s);
+			k = kh_put(reg, h, s, &ret);
+			memset(&kh_val(h, k), 0, sizeof(bed_reglist_t));
+		}
+		p = &kh_val(h, k);
+		if (dret != '\n') { // if the lines has other characters
+			if (ks_getuntil(ks, 0, str, &dret) > 0 && isdigit(str->s[0])) {
+				beg = atoi(str->s); // begin
+				if (dret != '\n') {
+					if (ks_getuntil(ks, 0, str, &dret) > 0 && isdigit(str->s[0]))
+						end = atoi(str->s); // end
+				}
+			}
+		}
+		if (dret != '\n') while ((dret = ks_getc(ks)) > 0 && dret != '\n'); // skip the rest of the line
+		if (end < 0 && beg > 0) end = beg, beg = beg - 1; // if there is only one column
+		if (beg >= 0 && end > beg) {
+			if (p->n == p->m) {
+				p->m = p->m? p->m<<1 : 4;
+				p->a = realloc(p->a, p->m * 8);
+			}
+			p->a[p->n++] = (uint64_t)beg<<32 | end;
+		}
+	}
+	ks_destroy(ks);
+	gzclose(fp);
+	free(str->s); free(str);
+	bed_index(h);
+	return h;
+}
+
+void bed_destroy(void *_h)
+{
+	reghash_t *h = (reghash_t*)_h;
+	khint_t k;
+	for (k = 0; k < kh_end(h); ++k) {
+		if (kh_exist(h, k)) {
+			free(kh_val(h, k).a);
+			free(kh_val(h, k).idx);
+			free((char*)kh_key(h, k));
+		}
+	}
+	kh_destroy(reg, h);
+}
diff --git a/bgzf.c b/bgzf.c
new file mode 100644
index 0000000..216cd04
--- /dev/null
+++ b/bgzf.c
@@ -0,0 +1,714 @@
+/* The MIT License
+
+   Copyright (c) 2008 Broad Institute / Massachusetts Institute of Technology
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+/*
+  2009-06-29 by lh3: cache recent uncompressed blocks.
+  2009-06-25 by lh3: optionally use my knetfile library to access file on a FTP.
+  2009-06-12 by lh3: support a mode string like "wu" where 'u' for uncompressed output */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "bgzf.h"
+
+#include "khash.h"
+typedef struct {
+	int size;
+	uint8_t *block;
+	int64_t end_offset;
+} cache_t;
+KHASH_MAP_INIT_INT64(cache, cache_t)
+
+#if defined(_WIN32) || defined(_MSC_VER)
+#define ftello(fp) ftell(fp)
+#define fseeko(fp, offset, whence) fseek(fp, offset, whence)
+#else
+extern off_t ftello(FILE *stream);
+extern int fseeko(FILE *stream, off_t offset, int whence);
+#endif
+
+typedef int8_t bgzf_byte_t;
+
+static const int DEFAULT_BLOCK_SIZE = 64 * 1024;
+static const int MAX_BLOCK_SIZE = 64 * 1024;
+
+static const int BLOCK_HEADER_LENGTH = 18;
+static const int BLOCK_FOOTER_LENGTH = 8;
+
+static const int GZIP_ID1 = 31;
+static const int GZIP_ID2 = 139;
+static const int CM_DEFLATE = 8;
+static const int FLG_FEXTRA = 4;
+static const int OS_UNKNOWN = 255;
+static const int BGZF_ID1 = 66; // 'B'
+static const int BGZF_ID2 = 67; // 'C'
+static const int BGZF_LEN = 2;
+static const int BGZF_XLEN = 6; // BGZF_LEN+4
+
+static const int GZIP_WINDOW_BITS = -15; // no zlib header
+static const int Z_DEFAULT_MEM_LEVEL = 8;
+
+
+inline
+void
+packInt16(uint8_t* buffer, uint16_t value)
+{
+    buffer[0] = value;
+    buffer[1] = value >> 8;
+}
+
+inline
+int
+unpackInt16(const uint8_t* buffer)
+{
+    return (buffer[0] | (buffer[1] << 8));
+}
+
+inline
+void
+packInt32(uint8_t* buffer, uint32_t value)
+{
+    buffer[0] = value;
+    buffer[1] = value >> 8;
+    buffer[2] = value >> 16;
+    buffer[3] = value >> 24;
+}
+
+static inline
+int
+bgzf_min(int x, int y)
+{
+    return (x < y) ? x : y;
+}
+
+static
+void
+report_error(BGZF* fp, const char* message) {
+    fp->error = message;
+}
+
+int bgzf_check_bgzf(const char *fn)
+{
+    BGZF *fp;
+    uint8_t buf[10],magic[10]="\037\213\010\4\0\0\0\0\0\377";
+    int n;
+
+    if ((fp = bgzf_open(fn, "r")) == 0) 
+    {
+        fprintf(stderr, "[bgzf_check_bgzf] failed to open the file: %s\n",fn);
+        return -1;
+    }
+
+#ifdef _USE_KNETFILE
+    n = knet_read(fp->x.fpr, buf, 10);
+#else
+    n = fread(buf, 1, 10, fp->file);
+#endif
+    bgzf_close(fp);
+
+    if ( n!=10 ) 
+        return -1;
+
+    if ( !memcmp(magic, buf, 10) ) return 1;
+    return 0;
+}
+
+static BGZF *bgzf_read_init()
+{
+	BGZF *fp;
+	fp = calloc(1, sizeof(BGZF));
+    fp->uncompressed_block_size = MAX_BLOCK_SIZE;
+    fp->uncompressed_block = malloc(MAX_BLOCK_SIZE);
+    fp->compressed_block_size = MAX_BLOCK_SIZE;
+    fp->compressed_block = malloc(MAX_BLOCK_SIZE);
+	fp->cache_size = 0;
+	fp->cache = kh_init(cache);
+	return fp;
+}
+
+static
+BGZF*
+open_read(int fd)
+{
+#ifdef _USE_KNETFILE
+    knetFile *file = knet_dopen(fd, "r");
+#else
+    FILE* file = fdopen(fd, "r");
+#endif
+    BGZF* fp;
+	if (file == 0) return 0;
+	fp = bgzf_read_init();
+    fp->file_descriptor = fd;
+    fp->open_mode = 'r';
+#ifdef _USE_KNETFILE
+    fp->x.fpr = file;
+#else
+    fp->file = file;
+#endif
+    return fp;
+}
+
+static
+BGZF*
+open_write(int fd, int compress_level) // compress_level==-1 for the default level
+{
+    FILE* file = fdopen(fd, "w");
+    BGZF* fp;
+	if (file == 0) return 0;
+	fp = malloc(sizeof(BGZF));
+    fp->file_descriptor = fd;
+    fp->open_mode = 'w';
+    fp->owned_file = 0;
+	fp->compress_level = compress_level < 0? Z_DEFAULT_COMPRESSION : compress_level; // Z_DEFAULT_COMPRESSION==-1
+	if (fp->compress_level > 9) fp->compress_level = Z_DEFAULT_COMPRESSION;
+#ifdef _USE_KNETFILE
+    fp->x.fpw = file;
+#else
+    fp->file = file;
+#endif
+    fp->uncompressed_block_size = DEFAULT_BLOCK_SIZE;
+    fp->uncompressed_block = NULL;
+    fp->compressed_block_size = MAX_BLOCK_SIZE;
+    fp->compressed_block = malloc(MAX_BLOCK_SIZE);
+    fp->block_address = 0;
+    fp->block_offset = 0;
+    fp->block_length = 0;
+    fp->error = NULL;
+    return fp;
+}
+
+BGZF*
+bgzf_open(const char* __restrict path, const char* __restrict mode)
+{
+    BGZF* fp = NULL;
+    if (strchr(mode, 'r') || strchr(mode, 'R')) { /* The reading mode is preferred. */
+#ifdef _USE_KNETFILE
+		knetFile *file = knet_open(path, mode);
+		if (file == 0) return 0;
+		fp = bgzf_read_init();
+		fp->file_descriptor = -1;
+		fp->open_mode = 'r';
+		fp->x.fpr = file;
+#else
+		int fd, oflag = O_RDONLY;
+#ifdef _WIN32
+		oflag |= O_BINARY;
+#endif
+		fd = open(path, oflag);
+		if (fd == -1) return 0;
+        fp = open_read(fd);
+#endif
+    } else if (strchr(mode, 'w') || strchr(mode, 'W')) {
+		int fd, compress_level = -1, oflag = O_WRONLY | O_CREAT | O_TRUNC;
+#ifdef _WIN32
+		oflag |= O_BINARY;
+#endif
+		fd = open(path, oflag, 0666);
+		if (fd == -1) return 0;
+		{ // set compress_level
+			int i;
+			for (i = 0; mode[i]; ++i)
+				if (mode[i] >= '0' && mode[i] <= '9') break;
+			if (mode[i]) compress_level = (int)mode[i] - '0';
+			if (strchr(mode, 'u')) compress_level = 0;
+		}
+        fp = open_write(fd, compress_level);
+    }
+    if (fp != NULL) fp->owned_file = 1;
+    return fp;
+}
+
+BGZF*
+bgzf_fdopen(int fd, const char * __restrict mode)
+{
+	if (fd == -1) return 0;
+    if (mode[0] == 'r' || mode[0] == 'R') {
+        return open_read(fd);
+    } else if (mode[0] == 'w' || mode[0] == 'W') {
+		int i, compress_level = -1;
+		for (i = 0; mode[i]; ++i)
+			if (mode[i] >= '0' && mode[i] <= '9') break;
+		if (mode[i]) compress_level = (int)mode[i] - '0';
+		if (strchr(mode, 'u')) compress_level = 0;
+        return open_write(fd, compress_level);
+    } else {
+        return NULL;
+    }
+}
+
+static
+int
+deflate_block(BGZF* fp, int block_length)
+{
+    // Deflate the block in fp->uncompressed_block into fp->compressed_block.
+    // Also adds an extra field that stores the compressed block length.
+
+    bgzf_byte_t* buffer = fp->compressed_block;
+    int buffer_size = fp->compressed_block_size;
+
+    // Init gzip header
+    buffer[0] = GZIP_ID1;
+    buffer[1] = GZIP_ID2;
+    buffer[2] = CM_DEFLATE;
+    buffer[3] = FLG_FEXTRA;
+    buffer[4] = 0; // mtime
+    buffer[5] = 0;
+    buffer[6] = 0;
+    buffer[7] = 0;
+    buffer[8] = 0;
+    buffer[9] = OS_UNKNOWN;
+    buffer[10] = BGZF_XLEN;
+    buffer[11] = 0;
+    buffer[12] = BGZF_ID1;
+    buffer[13] = BGZF_ID2;
+    buffer[14] = BGZF_LEN;
+    buffer[15] = 0;
+    buffer[16] = 0; // placeholder for block length
+    buffer[17] = 0;
+
+    // loop to retry for blocks that do not compress enough
+    int input_length = block_length;
+    int compressed_length = 0;
+    while (1) {
+        z_stream zs;
+        zs.zalloc = NULL;
+        zs.zfree = NULL;
+        zs.next_in = fp->uncompressed_block;
+        zs.avail_in = input_length;
+        zs.next_out = (void*)&buffer[BLOCK_HEADER_LENGTH];
+        zs.avail_out = buffer_size - BLOCK_HEADER_LENGTH - BLOCK_FOOTER_LENGTH;
+
+        int status = deflateInit2(&zs, fp->compress_level, Z_DEFLATED,
+                                  GZIP_WINDOW_BITS, Z_DEFAULT_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+        if (status != Z_OK) {
+            report_error(fp, "deflate init failed");
+            return -1;
+        }
+        status = deflate(&zs, Z_FINISH);
+        if (status != Z_STREAM_END) {
+            deflateEnd(&zs);
+            if (status == Z_OK) {
+                // Not enough space in buffer.
+                // Can happen in the rare case the input doesn't compress enough.
+                // Reduce the amount of input until it fits.
+                input_length -= 1024;
+                if (input_length <= 0) {
+                    // should never happen
+                    report_error(fp, "input reduction failed");
+                    return -1;
+                }
+                continue;
+            }
+            report_error(fp, "deflate failed");
+            return -1;
+        }
+        status = deflateEnd(&zs);
+        if (status != Z_OK) {
+            report_error(fp, "deflate end failed");
+            return -1;
+        }
+        compressed_length = zs.total_out;
+        compressed_length += BLOCK_HEADER_LENGTH + BLOCK_FOOTER_LENGTH;
+        if (compressed_length > MAX_BLOCK_SIZE) {
+            // should never happen
+            report_error(fp, "deflate overflow");
+            return -1;
+        }
+        break;
+    }
+
+    packInt16((uint8_t*)&buffer[16], compressed_length-1);
+    uint32_t crc = crc32(0L, NULL, 0L);
+    crc = crc32(crc, fp->uncompressed_block, input_length);
+    packInt32((uint8_t*)&buffer[compressed_length-8], crc);
+    packInt32((uint8_t*)&buffer[compressed_length-4], input_length);
+
+    int remaining = block_length - input_length;
+    if (remaining > 0) {
+        if (remaining > input_length) {
+            // should never happen (check so we can use memcpy)
+            report_error(fp, "remainder too large");
+            return -1;
+        }
+        memcpy(fp->uncompressed_block,
+               fp->uncompressed_block + input_length,
+               remaining);
+    }
+    fp->block_offset = remaining;
+    return compressed_length;
+}
+
+static
+int
+inflate_block(BGZF* fp, int block_length)
+{
+    // Inflate the block in fp->compressed_block into fp->uncompressed_block
+
+    z_stream zs;
+	int status;
+    zs.zalloc = NULL;
+    zs.zfree = NULL;
+    zs.next_in = fp->compressed_block + 18;
+    zs.avail_in = block_length - 16;
+    zs.next_out = fp->uncompressed_block;
+    zs.avail_out = fp->uncompressed_block_size;
+
+    status = inflateInit2(&zs, GZIP_WINDOW_BITS);
+    if (status != Z_OK) {
+        report_error(fp, "inflate init failed");
+        return -1;
+    }
+    status = inflate(&zs, Z_FINISH);
+    if (status != Z_STREAM_END) {
+        inflateEnd(&zs);
+        report_error(fp, "inflate failed");
+        return -1;
+    }
+    status = inflateEnd(&zs);
+    if (status != Z_OK) {
+        report_error(fp, "inflate failed");
+        return -1;
+    }
+    return zs.total_out;
+}
+
+static
+int
+check_header(const bgzf_byte_t* header)
+{
+    return (header[0] == GZIP_ID1 &&
+            header[1] == (bgzf_byte_t) GZIP_ID2 &&
+            header[2] == Z_DEFLATED &&
+            (header[3] & FLG_FEXTRA) != 0 &&
+            unpackInt16((uint8_t*)&header[10]) == BGZF_XLEN &&
+            header[12] == BGZF_ID1 &&
+            header[13] == BGZF_ID2 &&
+            unpackInt16((uint8_t*)&header[14]) == BGZF_LEN);
+}
+
+static void free_cache(BGZF *fp)
+{
+	khint_t k;
+	khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+	if (fp->open_mode != 'r') return;
+	for (k = kh_begin(h); k < kh_end(h); ++k)
+		if (kh_exist(h, k)) free(kh_val(h, k).block);
+	kh_destroy(cache, h);
+}
+
+static int load_block_from_cache(BGZF *fp, int64_t block_address)
+{
+	khint_t k;
+	cache_t *p;
+	khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+	k = kh_get(cache, h, block_address);
+	if (k == kh_end(h)) return 0;
+	p = &kh_val(h, k);
+	if (fp->block_length != 0) fp->block_offset = 0;
+	fp->block_address = block_address;
+	fp->block_length = p->size;
+	memcpy(fp->uncompressed_block, p->block, MAX_BLOCK_SIZE);
+#ifdef _USE_KNETFILE
+	knet_seek(fp->x.fpr, p->end_offset, SEEK_SET);
+#else
+	fseeko(fp->file, p->end_offset, SEEK_SET);
+#endif
+	return p->size;
+}
+
+static void cache_block(BGZF *fp, int size)
+{
+	int ret;
+	khint_t k;
+	cache_t *p;
+	khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+	if (MAX_BLOCK_SIZE >= fp->cache_size) return;
+	if ((kh_size(h) + 1) * MAX_BLOCK_SIZE > fp->cache_size) {
+		/* A better way would be to remove the oldest block in the
+		 * cache, but here we remove a random one for simplicity. This
+		 * should not have a big impact on performance. */
+		for (k = kh_begin(h); k < kh_end(h); ++k)
+			if (kh_exist(h, k)) break;
+		if (k < kh_end(h)) {
+			free(kh_val(h, k).block);
+			kh_del(cache, h, k);
+		}
+	}
+	k = kh_put(cache, h, fp->block_address, &ret);
+	if (ret == 0) return; // if this happens, a bug!
+	p = &kh_val(h, k);
+	p->size = fp->block_length;
+	p->end_offset = fp->block_address + size;
+	p->block = malloc(MAX_BLOCK_SIZE);
+	memcpy(kh_val(h, k).block, fp->uncompressed_block, MAX_BLOCK_SIZE);
+}
+
+int
+bgzf_read_block(BGZF* fp)
+{
+    bgzf_byte_t header[BLOCK_HEADER_LENGTH];
+	int count, size = 0, block_length, remaining;
+#ifdef _USE_KNETFILE
+    int64_t block_address = knet_tell(fp->x.fpr);
+	if (load_block_from_cache(fp, block_address)) return 0;
+    count = knet_read(fp->x.fpr, header, sizeof(header));
+#else
+    int64_t block_address = ftello(fp->file);
+	if (load_block_from_cache(fp, block_address)) return 0;
+    count = fread(header, 1, sizeof(header), fp->file);
+#endif
+    if (count == 0) {
+        fp->block_length = 0;
+        return 0;
+    }
+	size = count;
+    if (count != sizeof(header)) {
+        report_error(fp, "read failed");
+        return -1;
+    }
+    if (!check_header(header)) {
+        report_error(fp, "invalid block header");
+        return -1;
+    }
+    block_length = unpackInt16((uint8_t*)&header[16]) + 1;
+    bgzf_byte_t* compressed_block = (bgzf_byte_t*) fp->compressed_block;
+    memcpy(compressed_block, header, BLOCK_HEADER_LENGTH);
+    remaining = block_length - BLOCK_HEADER_LENGTH;
+#ifdef _USE_KNETFILE
+    count = knet_read(fp->x.fpr, &compressed_block[BLOCK_HEADER_LENGTH], remaining);
+#else
+    count = fread(&compressed_block[BLOCK_HEADER_LENGTH], 1, remaining, fp->file);
+#endif
+    if (count != remaining) {
+        report_error(fp, "read failed");
+        return -1;
+    }
+	size += count;
+    count = inflate_block(fp, block_length);
+    if (count < 0) return -1;
+    if (fp->block_length != 0) {
+        // Do not reset offset if this read follows a seek.
+        fp->block_offset = 0;
+    }
+    fp->block_address = block_address;
+    fp->block_length = count;
+	cache_block(fp, size);
+    return 0;
+}
+
+int
+bgzf_read(BGZF* fp, void* data, int length)
+{
+    if (length <= 0) {
+        return 0;
+    }
+    if (fp->open_mode != 'r') {
+        report_error(fp, "file not open for reading");
+        return -1;
+    }
+
+    int bytes_read = 0;
+    bgzf_byte_t* output = data;
+    while (bytes_read < length) {
+        int copy_length, available = fp->block_length - fp->block_offset;
+		bgzf_byte_t *buffer;
+        if (available <= 0) {
+            if (bgzf_read_block(fp) != 0) {
+                return -1;
+            }
+            available = fp->block_length - fp->block_offset;
+            if (available <= 0) {
+                break;
+            }
+        }
+        copy_length = bgzf_min(length-bytes_read, available);
+        buffer = fp->uncompressed_block;
+        memcpy(output, buffer + fp->block_offset, copy_length);
+        fp->block_offset += copy_length;
+        output += copy_length;
+        bytes_read += copy_length;
+    }
+    if (fp->block_offset == fp->block_length) {
+#ifdef _USE_KNETFILE
+        fp->block_address = knet_tell(fp->x.fpr);
+#else
+        fp->block_address = ftello(fp->file);
+#endif
+        fp->block_offset = 0;
+        fp->block_length = 0;
+    }
+    return bytes_read;
+}
+
+int bgzf_flush(BGZF* fp)
+{
+    while (fp->block_offset > 0) {
+        int count, block_length;
+		block_length = deflate_block(fp, fp->block_offset);
+        if (block_length < 0) return -1;
+#ifdef _USE_KNETFILE
+        count = fwrite(fp->compressed_block, 1, block_length, fp->x.fpw);
+#else
+        count = fwrite(fp->compressed_block, 1, block_length, fp->file);
+#endif
+        if (count != block_length) {
+            report_error(fp, "write failed");
+            return -1;
+        }
+        fp->block_address += block_length;
+    }
+    return 0;
+}
+
+int bgzf_flush_try(BGZF *fp, int size)
+{
+	if (fp->block_offset + size > fp->uncompressed_block_size)
+		return bgzf_flush(fp);
+	return -1;
+}
+
+int bgzf_write(BGZF* fp, const void* data, int length)
+{
+	const bgzf_byte_t *input = data;
+	int block_length, bytes_written;
+    if (fp->open_mode != 'w') {
+        report_error(fp, "file not open for writing");
+        return -1;
+    }
+
+    if (fp->uncompressed_block == NULL)
+        fp->uncompressed_block = malloc(fp->uncompressed_block_size);
+
+    input = data;
+    block_length = fp->uncompressed_block_size;
+    bytes_written = 0;
+    while (bytes_written < length) {
+        int copy_length = bgzf_min(block_length - fp->block_offset, length - bytes_written);
+        bgzf_byte_t* buffer = fp->uncompressed_block;
+        memcpy(buffer + fp->block_offset, input, copy_length);
+        fp->block_offset += copy_length;
+        input += copy_length;
+        bytes_written += copy_length;
+        if (fp->block_offset == block_length) {
+            if (bgzf_flush(fp) != 0) {
+                break;
+            }
+        }
+    }
+    return bytes_written;
+}
+
+int bgzf_close(BGZF* fp)
+{
+    if (fp->open_mode == 'w') {
+        if (bgzf_flush(fp) != 0) return -1;
+		{ // add an empty block
+			int count, block_length = deflate_block(fp, 0);
+#ifdef _USE_KNETFILE
+			count = fwrite(fp->compressed_block, 1, block_length, fp->x.fpw);
+#else
+			count = fwrite(fp->compressed_block, 1, block_length, fp->file);
+#endif
+		}
+#ifdef _USE_KNETFILE
+        if (fflush(fp->x.fpw) != 0) {
+#else
+        if (fflush(fp->file) != 0) {
+#endif
+            report_error(fp, "flush failed");
+            return -1;
+        }
+    }
+    if (fp->owned_file) {
+#ifdef _USE_KNETFILE
+		int ret;
+		if (fp->open_mode == 'w') ret = fclose(fp->x.fpw);
+		else ret = knet_close(fp->x.fpr);
+        if (ret != 0) return -1;
+#else
+        if (fclose(fp->file) != 0) return -1;
+#endif
+    }
+    free(fp->uncompressed_block);
+    free(fp->compressed_block);
+	free_cache(fp);
+    free(fp);
+    return 0;
+}
+
+void bgzf_set_cache_size(BGZF *fp, int cache_size)
+{
+	if (fp) fp->cache_size = cache_size;
+}
+
+int bgzf_check_EOF(BGZF *fp)
+{
+	static uint8_t magic[28] = "\037\213\010\4\0\0\0\0\0\377\6\0\102\103\2\0\033\0\3\0\0\0\0\0\0\0\0\0";
+	uint8_t buf[28];
+	off_t offset;
+#ifdef _USE_KNETFILE
+	offset = knet_tell(fp->x.fpr);
+	if (knet_seek(fp->x.fpr, -28, SEEK_END) != 0) return -1;
+	knet_read(fp->x.fpr, buf, 28);
+	knet_seek(fp->x.fpr, offset, SEEK_SET);
+#else
+	offset = ftello(fp->file);
+	if (fseeko(fp->file, -28, SEEK_END) != 0) return -1;
+	fread(buf, 1, 28, fp->file);
+	fseeko(fp->file, offset, SEEK_SET);
+#endif
+	return (memcmp(magic, buf, 28) == 0)? 1 : 0;
+}
+
+int64_t bgzf_seek(BGZF* fp, int64_t pos, int where)
+{
+	int block_offset;
+	int64_t block_address;
+
+    if (fp->open_mode != 'r') {
+        report_error(fp, "file not open for read");
+        return -1;
+    }
+    if (where != SEEK_SET) {
+        report_error(fp, "unimplemented seek option");
+        return -1;
+    }
+    block_offset = pos & 0xFFFF;
+    block_address = (pos >> 16) & 0xFFFFFFFFFFFFLL;
+#ifdef _USE_KNETFILE
+    if (knet_seek(fp->x.fpr, block_address, SEEK_SET) != 0) {
+#else
+    if (fseeko(fp->file, block_address, SEEK_SET) != 0) {
+#endif
+        report_error(fp, "seek failed");
+        return -1;
+    }
+    fp->block_length = 0;  // indicates current block is not loaded
+    fp->block_address = block_address;
+    fp->block_offset = block_offset;
+    return 0;
+}
diff --git a/bgzf.h b/bgzf.h
new file mode 100644
index 0000000..7295f37
--- /dev/null
+++ b/bgzf.h
@@ -0,0 +1,157 @@
+/* The MIT License
+
+   Copyright (c) 2008 Broad Institute / Massachusetts Institute of Technology
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#ifndef __BGZF_H
+#define __BGZF_H
+
+#include <stdint.h>
+#include <stdio.h>
+#include <zlib.h>
+#ifdef _USE_KNETFILE
+#include "knetfile.h"
+#endif
+
+//typedef int8_t bool;
+
+typedef struct {
+    int file_descriptor;
+    char open_mode;  // 'r' or 'w'
+    int16_t owned_file, compress_level;
+#ifdef _USE_KNETFILE
+	union {
+		knetFile *fpr;
+		FILE *fpw;
+	} x;
+#else
+    FILE* file;
+#endif
+    int uncompressed_block_size;
+    int compressed_block_size;
+    void* uncompressed_block;
+    void* compressed_block;
+    int64_t block_address;
+    int block_length;
+    int block_offset;
+	int cache_size;
+    const char* error;
+	void *cache; // a pointer to a hash table
+} BGZF;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Open an existing file descriptor for reading or writing.
+ * Mode must be either "r" or "w".
+ * A subsequent bgzf_close will not close the file descriptor.
+ * Returns null on error.
+ */
+BGZF* bgzf_fdopen(int fd, const char* __restrict mode);
+
+/*
+ * Open the specified file for reading or writing.
+ * Mode must be either "r" or "w".
+ * Returns null on error.
+ */
+BGZF* bgzf_open(const char* path, const char* __restrict mode);
+
+/*
+ * Close the BGZ file and free all associated resources.
+ * Does not close the underlying file descriptor if created with bgzf_fdopen.
+ * Returns zero on success, -1 on error.
+ */
+int bgzf_close(BGZF* fp);
+
+/*
+ * Read up to length bytes from the file storing into data.
+ * Returns the number of bytes actually read.
+ * Returns zero on end of file.
+ * Returns -1 on error.
+ */
+int bgzf_read(BGZF* fp, void* data, int length);
+
+/*
+ * Write length bytes from data to the file.
+ * Returns the number of bytes written.
+ * Returns -1 on error.
+ */
+int bgzf_write(BGZF* fp, const void* data, int length);
+
+/*
+ * Return a virtual file pointer to the current location in the file.
+ * No interpetation of the value should be made, other than a subsequent
+ * call to bgzf_seek can be used to position the file at the same point.
+ * Return value is non-negative on success.
+ * Returns -1 on error.
+ */
+#define bgzf_tell(fp) ((fp->block_address << 16) | (fp->block_offset & 0xFFFF))
+
+/*
+ * Set the file to read from the location specified by pos, which must
+ * be a value previously returned by bgzf_tell for this file (but not
+ * necessarily one returned by this file handle).
+ * The where argument must be SEEK_SET.
+ * Seeking on a file opened for write is not supported.
+ * Returns zero on success, -1 on error.
+ */
+int64_t bgzf_seek(BGZF* fp, int64_t pos, int where);
+
+/*
+ * Set the cache size. Zero to disable. By default, caching is
+ * disabled. The recommended cache size for frequent random access is
+ * about 8M bytes.
+ */
+void bgzf_set_cache_size(BGZF *fp, int cache_size);
+
+int bgzf_check_EOF(BGZF *fp);
+int bgzf_read_block(BGZF* fp);
+int bgzf_flush(BGZF* fp);
+int bgzf_flush_try(BGZF *fp, int size);
+int bgzf_check_bgzf(const char *fn);
+
+#ifdef __cplusplus
+}
+#endif
+
+static inline int bgzf_getc(BGZF *fp)
+{
+	int c;
+	if (fp->block_offset >= fp->block_length) {
+		if (bgzf_read_block(fp) != 0) return -2; /* error */
+		if (fp->block_length == 0) return -1; /* end-of-file */
+	}
+	c = ((unsigned char*)fp->uncompressed_block)[fp->block_offset++];
+    if (fp->block_offset == fp->block_length) {
+#ifdef _USE_KNETFILE
+        fp->block_address = knet_tell(fp->x.fpr);
+#else
+        fp->block_address = ftello(fp->file);
+#endif
+        fp->block_offset = 0;
+        fp->block_length = 0;
+    }
+	return c;
+}
+
+#endif
diff --git a/bgzip.c b/bgzip.c
new file mode 100644
index 0000000..ebcafa2
--- /dev/null
+++ b/bgzip.c
@@ -0,0 +1,206 @@
+/* The MIT License
+
+   Copyright (c) 2008 Broad Institute / Massachusetts Institute of Technology
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include "bgzf.h"
+
+static const int WINDOW_SIZE = 64 * 1024;
+
+static int bgzip_main_usage()
+{
+	fprintf(stderr, "\n");
+	fprintf(stderr, "Usage:   bgzip [options] [file] ...\n\n");
+	fprintf(stderr, "Options: -c      write on standard output, keep original files unchanged\n");
+	fprintf(stderr, "         -d      decompress\n");
+	fprintf(stderr, "         -f      overwrite files without asking\n");
+	fprintf(stderr, "         -b INT  decompress at virtual file pointer INT\n");
+	fprintf(stderr, "         -s INT  decompress INT bytes in the uncompressed file\n");
+	fprintf(stderr, "         -h      give this help\n");
+	fprintf(stderr, "\n");
+	return 1;
+}
+
+static int write_open(const char *fn, int is_forced)
+{
+	int fd = -1;
+	char c;
+	if (!is_forced) {
+		if ((fd = open(fn, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0666)) < 0 && errno == EEXIST) {
+			fprintf(stderr, "[bgzip] %s already exists; do you wish to overwrite (y or n)? ", fn);
+			scanf("%c", &c);
+			if (c != 'Y' && c != 'y') {
+				fprintf(stderr, "[bgzip] not overwritten\n");
+				exit(1);
+			}
+		}
+	}
+	if (fd < 0) {
+		if ((fd = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0666)) < 0) {
+			fprintf(stderr, "[bgzip] %s: Fail to write\n", fn);
+			exit(1);
+		}
+	}
+	return fd;
+}
+
+static void fail(BGZF* fp)
+{
+    fprintf(stderr, "Error: %s\n", fp->error);
+    exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	int c, compress, pstdout, is_forced;
+	BGZF *fp;
+	void *buffer;
+	long start, end, size;
+
+	compress = 1; pstdout = 0; start = 0; size = -1; end = -1; is_forced = 0;
+	while((c  = getopt(argc, argv, "cdhfb:s:")) >= 0){
+		switch(c){
+		case 'h': return bgzip_main_usage();
+		case 'd': compress = 0; break;
+		case 'c': pstdout = 1; break;
+		case 'b': start = atol(optarg); break;
+		case 's': size = atol(optarg); break;
+		case 'f': is_forced = 1; break;
+		}
+	}
+	if (size >= 0) end = start + size;
+	if (end >= 0 && end < start) {
+		fprintf(stderr, "[bgzip] Illegal region: [%ld, %ld]\n", start, end);
+		return 1;
+	}
+	if (compress == 1) {
+		struct stat sbuf;
+		int f_src = fileno(stdin);
+		int f_dst = fileno(stdout);
+
+		if ( argc>optind )
+		{
+			if ( stat(argv[optind],&sbuf)<0 ) 
+			{ 
+				fprintf(stderr, "[bgzip] %s: %s\n", strerror(errno), argv[optind]);
+				return 1; 
+			}
+
+			if ((f_src = open(argv[optind], O_RDONLY)) < 0) {
+				fprintf(stderr, "[bgzip] %s: %s\n", strerror(errno), argv[optind]);
+				return 1;
+			}
+
+			if (pstdout)
+				f_dst = fileno(stdout);
+			else
+			{
+				char *name = malloc(strlen(argv[optind]) + 5);
+				strcpy(name, argv[optind]);
+				strcat(name, ".gz");
+				f_dst = write_open(name, is_forced);
+				if (f_dst < 0) return 1;
+				free(name);
+			}
+		}
+		else if (!pstdout && isatty(fileno((FILE *)stdout)) )
+			return bgzip_main_usage();
+
+		fp = bgzf_fdopen(f_dst, "w");
+		buffer = malloc(WINDOW_SIZE);
+		while ((c = read(f_src, buffer, WINDOW_SIZE)) > 0)
+			if (bgzf_write(fp, buffer, c) < 0) fail(fp);
+		// f_dst will be closed here
+		if (bgzf_close(fp) < 0) fail(fp);
+		if (argc > optind && !pstdout) unlink(argv[optind]);
+		free(buffer);
+		close(f_src);
+		return 0;
+	} else {
+		struct stat sbuf;
+		int f_dst;
+
+		if ( argc>optind )
+		{
+			if ( stat(argv[optind],&sbuf)<0 )
+			{
+				fprintf(stderr, "[bgzip] %s: %s\n", strerror(errno), argv[optind]);
+				return 1;
+			}
+			char *name;
+			int len = strlen(argv[optind]);
+			if ( strcmp(argv[optind]+len-3,".gz") )
+			{
+				fprintf(stderr, "[bgzip] %s: unknown suffix -- ignored\n", argv[optind]);
+				return 1;
+			}
+			fp = bgzf_open(argv[optind], "r");
+			if (fp == NULL) {
+				fprintf(stderr, "[bgzip] Could not open file: %s\n", argv[optind]);
+				return 1;
+			}
+
+			if (pstdout) {
+				f_dst = fileno(stdout);
+			}
+			else {
+				name = strdup(argv[optind]);
+				name[strlen(name) - 3] = '\0';
+				f_dst = write_open(name, is_forced);
+				free(name);
+			}
+		}
+		else if (!pstdout && isatty(fileno((FILE *)stdin)) )
+			return bgzip_main_usage();
+		else
+		{
+			f_dst = fileno(stdout);
+			fp = bgzf_fdopen(fileno(stdin), "r");
+			if (fp == NULL) {
+				fprintf(stderr, "[bgzip] Could not read from stdin: %s\n", strerror(errno));
+				return 1;
+			}
+		}
+		buffer = malloc(WINDOW_SIZE);
+		if (bgzf_seek(fp, start, SEEK_SET) < 0) fail(fp);
+		while (1) {
+			if (end < 0) c = bgzf_read(fp, buffer, WINDOW_SIZE);
+			else c = bgzf_read(fp, buffer, (end - start > WINDOW_SIZE)? WINDOW_SIZE:(end - start));
+			if (c == 0) break;
+			if (c < 0) fail(fp);
+			start += c;
+			write(f_dst, buffer, c);
+			if (end >= 0 && start >= end) break;
+		}
+		free(buffer);
+		if (bgzf_close(fp) < 0) fail(fp);
+		if (!pstdout) unlink(argv[optind]);
+		return 0;
+	}
+}
diff --git a/example.gtf.gz b/example.gtf.gz
new file mode 100644
index 0000000..693db0c
Binary files /dev/null and b/example.gtf.gz differ
diff --git a/example.gtf.gz.tbi b/example.gtf.gz.tbi
new file mode 100644
index 0000000..84a3c84
Binary files /dev/null and b/example.gtf.gz.tbi differ
diff --git a/index.c b/index.c
new file mode 100644
index 0000000..8f254e3
--- /dev/null
+++ b/index.c
@@ -0,0 +1,998 @@
+#include <ctype.h>
+#include <assert.h>
+#include <sys/stat.h>
+#include "khash.h"
+#include "ksort.h"
+#include "kstring.h"
+#include "bam_endian.h"
+#ifdef _USE_KNETFILE
+#include "knetfile.h"
+#endif
+#include "tabix.h"
+
+#define TAD_MIN_CHUNK_GAP 32768
+// 1<<14 is the size of minimum bin.
+#define TAD_LIDX_SHIFT    14
+
+typedef struct {
+	uint64_t u, v;
+} pair64_t;
+
+#define pair64_lt(a,b) ((a).u < (b).u)
+KSORT_INIT(offt, pair64_t, pair64_lt)
+
+typedef struct {
+	uint32_t m, n;
+	pair64_t *list;
+} ti_binlist_t;
+
+typedef struct {
+	int32_t n, m;
+	uint64_t *offset;
+} ti_lidx_t;
+
+KHASH_MAP_INIT_INT(i, ti_binlist_t)
+KHASH_MAP_INIT_STR(s, int)
+
+struct __ti_index_t {
+	ti_conf_t conf;
+	int32_t n, max;
+	khash_t(s) *tname;
+	khash_t(i) **index;
+	ti_lidx_t *index2;
+};
+
+struct __ti_iter_t {
+	int from_first; // read from the first record; no random access
+	int tid, beg, end, n_off, i, finished;
+	uint64_t curr_off;
+	kstring_t str;
+	const ti_index_t *idx;
+	pair64_t *off;
+};
+
+typedef struct {
+	int tid, beg, end, bin;
+} ti_intv_t;
+
+ti_conf_t ti_conf_gff = { 0, 1, 4, 5, '#', 0 };
+ti_conf_t ti_conf_bed = { TI_FLAG_UCSC, 1, 2, 3, '#', 0 };
+ti_conf_t ti_conf_psltbl = { TI_FLAG_UCSC, 15, 17, 18, '#', 0 };
+ti_conf_t ti_conf_sam = { TI_PRESET_SAM, 3, 4, 0, '@', 0 };
+ti_conf_t ti_conf_vcf = { TI_PRESET_VCF, 1, 2, 0, '#', 0 };
+
+/***************
+ * read a line *
+ ***************/
+
+/*
+int ti_readline(BGZF *fp, kstring_t *str)
+{
+	int c, l = 0;
+	str->l = 0;
+	while ((c = bgzf_getc(fp)) >= 0 && c != '\n') {
+		++l;
+		if (c != '\r') kputc(c, str);
+	}
+	if (c < 0 && l == 0) return -1; // end of file
+	return str->l;
+}
+*/
+
+/* Below is a faster implementation largely equivalent to the one
+ * commented out above. */
+int ti_readline(BGZF *fp, kstring_t *str)
+{
+	int l, state = 0;
+	unsigned char *buf = (unsigned char*)fp->uncompressed_block;
+	str->l = 0;
+	do {
+		if (fp->block_offset >= fp->block_length) {
+			if (bgzf_read_block(fp) != 0) { state = -2; break; }
+			if (fp->block_length == 0) { state = -1; break; }
+		}
+		for (l = fp->block_offset; l < fp->block_length && buf[l] != '\n'; ++l);
+		if (l < fp->block_length) state = 1;
+		l -= fp->block_offset;
+		if (str->l + l + 1 >= str->m) {
+			str->m = str->l + l + 2;
+			kroundup32(str->m);
+			str->s = (char*)realloc(str->s, str->m);
+		}
+		memcpy(str->s + str->l, buf + fp->block_offset, l);
+		str->l += l;
+		fp->block_offset += l + 1;
+		if (fp->block_offset >= fp->block_length) {
+#ifdef _USE_KNETFILE
+			fp->block_address = knet_tell(fp->x.fpr);
+#else
+			fp->block_address = ftello(fp->file);
+#endif
+			fp->block_offset = 0;
+			fp->block_length = 0;
+		} 
+	} while (state == 0);
+	if (str->l == 0 && state < 0) return state;
+	str->s[str->l] = 0;
+	return str->l;
+}
+
+/*************************************
+ * get the interval from a data line *
+ *************************************/
+
+static inline int ti_reg2bin(uint32_t beg, uint32_t end)
+{
+	--end;
+	if (beg>>14 == end>>14) return 4681 + (beg>>14);
+	if (beg>>17 == end>>17) return  585 + (beg>>17);
+	if (beg>>20 == end>>20) return   73 + (beg>>20);
+	if (beg>>23 == end>>23) return    9 + (beg>>23);
+	if (beg>>26 == end>>26) return    1 + (beg>>26);
+	return 0;
+}
+
+static int get_tid(ti_index_t *idx, const char *ss)
+{
+	khint_t k;
+	int tid;
+	k = kh_get(s, idx->tname, ss);
+	if (k == kh_end(idx->tname)) { // a new target sequence
+		int ret, size;
+		// update idx->n, ->max, ->index and ->index2
+		if (idx->n == idx->max) {
+			idx->max = idx->max? idx->max<<1 : 8;
+			idx->index = realloc(idx->index, idx->max * sizeof(void*));
+			idx->index2 = realloc(idx->index2, idx->max * sizeof(ti_lidx_t));
+		}
+		memset(&idx->index2[idx->n], 0, sizeof(ti_lidx_t));
+		idx->index[idx->n++] = kh_init(i);
+		// update ->tname
+		tid = size = kh_size(idx->tname);
+		k = kh_put(s, idx->tname, strdup(ss), &ret);
+		kh_value(idx->tname, k) = size;
+		assert(idx->n == kh_size(idx->tname));
+	} else tid = kh_value(idx->tname, k);
+	return tid;
+}
+
+int ti_get_intv(const ti_conf_t *conf, int len, char *line, ti_interval_t *intv)
+{
+	int i, b = 0, id = 1, ncols = 0;
+	char *s;
+	intv->ss = intv->se = 0; intv->beg = intv->end = -1;
+	for (i = 0; i <= len; ++i) {
+		if (line[i] == '\t' || line[i] == 0) {
+            ++ncols;
+			if (id == conf->sc) {
+				intv->ss = line + b; intv->se = line + i;
+			} else if (id == conf->bc) {
+				// here ->beg is 0-based.
+				intv->beg = intv->end = strtol(line + b, &s, 0);
+				if (!(conf->preset&TI_FLAG_UCSC)) --intv->beg;
+				else ++intv->end;
+				if (intv->beg < 0) intv->beg = 0;
+				if (intv->end < 1) intv->end = 1;
+			} else {
+				if ((conf->preset&0xffff) == TI_PRESET_GENERIC) {
+					if (id == conf->ec) intv->end = strtol(line + b, &s, 0);
+				} else if ((conf->preset&0xffff) == TI_PRESET_SAM) {
+					if (id == 6) { // CIGAR
+						int l = 0, op;
+						char *t;
+						for (s = line + b; s < line + i;) {
+							long x = strtol(s, &t, 10);
+							op = toupper(*t);
+							if (op == 'M' || op == 'D' || op == 'N') l += x;
+							s = t + 1;
+						}
+						if (l == 0) l = 1;
+						intv->end = intv->beg + l;
+					}
+				} else if ((conf->preset&0xffff) == TI_PRESET_VCF) {
+					// FIXME: the following is NOT tested and is likely to be buggy
+					if (id == 4) {
+						if (b < i) intv->end = intv->beg + (i - b);
+					} else if (id == 8) { // look for "END="
+						int c = line[i];
+						line[i] = 0;
+						s = strstr(line + b, "END=");
+						if (s == line + b) s += 4;
+						else if (s) {
+							s = strstr(line + b, ";END=");
+							if (s) s += 5;
+						}
+						if (s) intv->end = strtol(s, &s, 0);
+						line[i] = c;
+					}
+				}
+			}
+			b = i + 1;
+			++id;
+		}
+	}
+/*
+	if (ncols < conf->sc || ncols < conf->bc || ncols < conf->ec) {
+		if (ncols == 1) fprintf(stderr,"[get_intv] Is the file tab-delimited? The line has %d field only: %s\n", ncols, line);
+		else fprintf(stderr,"[get_intv] The line has %d field(s) only: %s\n", ncols, line);
+		exit(1);
+	}
+*/
+	if (intv->ss == 0 || intv->se == 0 || intv->beg < 0 || intv->end < 0) return -1;
+	return 0;
+}
+
+static int get_intv(ti_index_t *idx, kstring_t *str, ti_intv_t *intv)
+{
+	ti_interval_t x;
+	intv->tid = intv->beg = intv->end = intv->bin = -1;
+	if (ti_get_intv(&idx->conf, str->l, str->s, &x) == 0) {
+		int c = *x.se;
+		*x.se = '\0'; intv->tid = get_tid(idx, x.ss); *x.se = c;
+		intv->beg = x.beg; intv->end = x.end;
+		intv->bin = ti_reg2bin(intv->beg, intv->end);
+		return (intv->tid >= 0 && intv->beg >= 0 && intv->end >= 0)? 0 : -1;
+	} else {
+		fprintf(stderr, "[%s] the following line cannot be parsed and skipped: %s\n", __func__, str->s);
+		return -1;
+	}
+}
+
+/************
+ * indexing *
+ ************/
+
+// requirement: len <= LEN_MASK
+static inline void insert_offset(khash_t(i) *h, int bin, uint64_t beg, uint64_t end)
+{
+	khint_t k;
+	ti_binlist_t *l;
+	int ret;
+	k = kh_put(i, h, bin, &ret);
+	l = &kh_value(h, k);
+	if (ret) { // not present
+		l->m = 1; l->n = 0;
+		l->list = (pair64_t*)calloc(l->m, 16);
+	}
+	if (l->n == l->m) {
+		l->m <<= 1;
+		l->list = (pair64_t*)realloc(l->list, l->m * 16);
+	}
+	l->list[l->n].u = beg; l->list[l->n++].v = end;
+}
+
+static inline uint64_t insert_offset2(ti_lidx_t *index2, int _beg, int _end, uint64_t offset)
+{
+	int i, beg, end;
+	beg = _beg >> TAD_LIDX_SHIFT;
+	end = (_end - 1) >> TAD_LIDX_SHIFT;
+	if (index2->m < end + 1) {
+		int old_m = index2->m;
+		index2->m = end + 1;
+		kroundup32(index2->m);
+		index2->offset = (uint64_t*)realloc(index2->offset, index2->m * 8);
+		memset(index2->offset + old_m, 0, 8 * (index2->m - old_m));
+	}
+	if (beg == end) {
+		if (index2->offset[beg] == 0) index2->offset[beg] = offset;
+	} else {
+		for (i = beg; i <= end; ++i)
+			if (index2->offset[i] == 0) index2->offset[i] = offset;
+	}
+	if (index2->n < end + 1) index2->n = end + 1;
+	return (uint64_t)beg<<32 | end;
+}
+
+static void merge_chunks(ti_index_t *idx)
+{
+	khash_t(i) *index;
+	int i, l, m;
+	khint_t k;
+	for (i = 0; i < idx->n; ++i) {
+		index = idx->index[i];
+		for (k = kh_begin(index); k != kh_end(index); ++k) {
+			ti_binlist_t *p;
+			if (!kh_exist(index, k)) continue;
+			p = &kh_value(index, k);
+			m = 0;
+			for (l = 1; l < p->n; ++l) {
+				if (p->list[m].v>>16 == p->list[l].u>>16) p->list[m].v = p->list[l].v;
+				else p->list[++m] = p->list[l];
+			} // ~for(l)
+			p->n = m + 1;
+		} // ~for(k)
+	} // ~for(i)
+}
+
+static void fill_missing(ti_index_t *idx)
+{
+	int i, j;
+	for (i = 0; i < idx->n; ++i) {
+		ti_lidx_t *idx2 = &idx->index2[i];
+		for (j = 1; j < idx2->n; ++j)
+			if (idx2->offset[j] == 0)
+				idx2->offset[j] = idx2->offset[j-1];
+	}
+}
+
+ti_index_t *ti_index_core(BGZF *fp, const ti_conf_t *conf)
+{
+	int ret;
+	ti_index_t *idx;
+	uint32_t last_bin, save_bin;
+	int32_t last_coor, last_tid, save_tid;
+	uint64_t save_off, last_off, lineno = 0, offset0 = (uint64_t)-1, tmp;
+	kstring_t *str;
+
+	str = calloc(1, sizeof(kstring_t));
+
+	idx = (ti_index_t*)calloc(1, sizeof(ti_index_t));
+	idx->conf = *conf;
+	idx->n = idx->max = 0;
+	idx->tname = kh_init(s);
+	idx->index = 0;
+	idx->index2 = 0;
+
+	save_bin = save_tid = last_tid = last_bin = 0xffffffffu;
+	save_off = last_off = bgzf_tell(fp); last_coor = 0xffffffffu;
+	while ((ret = ti_readline(fp, str)) >= 0) {
+		ti_intv_t intv;
+		++lineno;
+		if (lineno <= idx->conf.line_skip || str->s[0] == idx->conf.meta_char) {
+			last_off = bgzf_tell(fp);
+			continue;
+		}
+		get_intv(idx, str, &intv);
+        if ( intv.beg<0 || intv.end<0 )
+        {
+            fprintf(stderr,"[ti_index_core] the indexes overlap or are out of bounds\n");
+            exit(1);
+        }
+		if (last_tid != intv.tid) { // change of chromosomes
+            if (last_tid>intv.tid )
+            {
+                fprintf(stderr,"[ti_index_core] the chromosome blocks not continuous at line %llu, is the file sorted? [pos %d]\n",(unsigned long long)lineno,intv.beg+1);
+                exit(1);
+            }
+			last_tid = intv.tid;
+			last_bin = 0xffffffffu;
+		} else if (last_coor > intv.beg) {
+			fprintf(stderr, "[ti_index_core] the file out of order at line %llu\n", (unsigned long long)lineno);
+			exit(1);
+		}
+		tmp = insert_offset2(&idx->index2[intv.tid], intv.beg, intv.end, last_off);
+		if (last_off == 0) offset0 = tmp;
+		if (intv.bin != last_bin) { // then possibly write the binning index
+			if (save_bin != 0xffffffffu) // save_bin==0xffffffffu only happens to the first record
+				insert_offset(idx->index[save_tid], save_bin, save_off, last_off);
+			save_off = last_off;
+			save_bin = last_bin = intv.bin;
+			save_tid = intv.tid;
+			if (save_tid < 0) break;
+		}
+		if (bgzf_tell(fp) <= last_off) {
+			fprintf(stderr, "[ti_index_core] bug in BGZF: %llx < %llx\n",
+					(unsigned long long)bgzf_tell(fp), (unsigned long long)last_off);
+			exit(1);
+		}
+		last_off = bgzf_tell(fp);
+		last_coor = intv.beg;
+	}
+	if (save_tid >= 0) insert_offset(idx->index[save_tid], save_bin, save_off, bgzf_tell(fp));
+	merge_chunks(idx);
+	fill_missing(idx);
+	if (offset0 != (uint64_t)-1 && idx->n && idx->index2[0].offset) {
+		int i, beg = offset0>>32, end = offset0&0xffffffffu;
+		for (i = beg; i <= end; ++i) idx->index2[0].offset[i] = 0;
+	}
+
+	free(str->s); free(str);
+	return idx;
+}
+
+void ti_index_destroy(ti_index_t *idx)
+{
+	khint_t k;
+	int i;
+	if (idx == 0) return;
+	// destroy the name hash table
+	for (k = kh_begin(idx->tname); k != kh_end(idx->tname); ++k) {
+		if (kh_exist(idx->tname, k))
+			free((char*)kh_key(idx->tname, k));
+	}
+	kh_destroy(s, idx->tname);
+	// destroy the binning index
+	for (i = 0; i < idx->n; ++i) {
+		khash_t(i) *index = idx->index[i];
+		ti_lidx_t *index2 = idx->index2 + i;
+		for (k = kh_begin(index); k != kh_end(index); ++k) {
+			if (kh_exist(index, k))
+				free(kh_value(index, k).list);
+		}
+		kh_destroy(i, index);
+		free(index2->offset);
+	}
+	free(idx->index);
+	// destroy the linear index
+	free(idx->index2);
+	free(idx);
+}
+
+/******************
+ * index file I/O *
+ ******************/
+
+void ti_index_save(const ti_index_t *idx, BGZF *fp)
+{
+	int32_t i, size, ti_is_be;
+	khint_t k;
+	ti_is_be = bam_is_big_endian();
+	bgzf_write(fp, "TBI\1", 4);
+	if (ti_is_be) {
+		uint32_t x = idx->n;
+		bgzf_write(fp, bam_swap_endian_4p(&x), 4);
+	} else bgzf_write(fp, &idx->n, 4);
+	assert(sizeof(ti_conf_t) == 24);
+	if (ti_is_be) { // write ti_conf_t;
+		uint32_t x[6];
+		memcpy(x, &idx->conf, 24);
+		for (i = 0; i < 6; ++i) bgzf_write(fp, bam_swap_endian_4p(&x[i]), 4);
+	} else bgzf_write(fp, &idx->conf, sizeof(ti_conf_t));
+	{ // write target names
+		char **name;
+		int32_t l = 0;
+		name = calloc(kh_size(idx->tname), sizeof(void*));
+		for (k = kh_begin(idx->tname); k != kh_end(idx->tname); ++k)
+			if (kh_exist(idx->tname, k))
+				name[kh_value(idx->tname, k)] = (char*)kh_key(idx->tname, k);
+		for (i = 0; i < kh_size(idx->tname); ++i)
+			l += strlen(name[i]) + 1;
+		if (ti_is_be) bgzf_write(fp, bam_swap_endian_4p(&l), 4);
+		else bgzf_write(fp, &l, 4);
+		for (i = 0; i < kh_size(idx->tname); ++i)
+			bgzf_write(fp, name[i], strlen(name[i]) + 1);
+		free(name);
+	}
+	for (i = 0; i < idx->n; ++i) {
+		khash_t(i) *index = idx->index[i];
+		ti_lidx_t *index2 = idx->index2 + i;
+		// write binning index
+		size = kh_size(index);
+		if (ti_is_be) { // big endian
+			uint32_t x = size;
+			bgzf_write(fp, bam_swap_endian_4p(&x), 4);
+		} else bgzf_write(fp, &size, 4);
+		for (k = kh_begin(index); k != kh_end(index); ++k) {
+			if (kh_exist(index, k)) {
+				ti_binlist_t *p = &kh_value(index, k);
+				if (ti_is_be) { // big endian
+					uint32_t x;
+					x = kh_key(index, k); bgzf_write(fp, bam_swap_endian_4p(&x), 4);
+					x = p->n; bgzf_write(fp, bam_swap_endian_4p(&x), 4);
+					for (x = 0; (int)x < p->n; ++x) {
+						bam_swap_endian_8p(&p->list[x].u);
+						bam_swap_endian_8p(&p->list[x].v);
+					}
+					bgzf_write(fp, p->list, 16 * p->n);
+					for (x = 0; (int)x < p->n; ++x) {
+						bam_swap_endian_8p(&p->list[x].u);
+						bam_swap_endian_8p(&p->list[x].v);
+					}
+				} else {
+					bgzf_write(fp, &kh_key(index, k), 4);
+					bgzf_write(fp, &p->n, 4);
+					bgzf_write(fp, p->list, 16 * p->n);
+				}
+			}
+		}
+		// write linear index (index2)
+		if (ti_is_be) {
+			int x = index2->n;
+			bgzf_write(fp, bam_swap_endian_4p(&x), 4);
+		} else bgzf_write(fp, &index2->n, 4);
+		if (ti_is_be) { // big endian
+			int x;
+			for (x = 0; (int)x < index2->n; ++x)
+				bam_swap_endian_8p(&index2->offset[x]);
+			bgzf_write(fp, index2->offset, 8 * index2->n);
+			for (x = 0; (int)x < index2->n; ++x)
+				bam_swap_endian_8p(&index2->offset[x]);
+		} else bgzf_write(fp, index2->offset, 8 * index2->n);
+	}
+}
+
+static ti_index_t *ti_index_load_core(BGZF *fp)
+{
+	int i, ti_is_be;
+	char magic[4];
+	ti_index_t *idx;
+	ti_is_be = bam_is_big_endian();
+	if (fp == 0) {
+		fprintf(stderr, "[ti_index_load_core] fail to load index.\n");
+		return 0;
+	}
+	bgzf_read(fp, magic, 4);
+	if (strncmp(magic, "TBI\1", 4)) {
+		fprintf(stderr, "[ti_index_load] wrong magic number.\n");
+		return 0;
+	}
+	idx = (ti_index_t*)calloc(1, sizeof(ti_index_t));	
+	bgzf_read(fp, &idx->n, 4);
+	if (ti_is_be) bam_swap_endian_4p(&idx->n);
+	idx->tname = kh_init(s);
+	idx->index = (khash_t(i)**)calloc(idx->n, sizeof(void*));
+	idx->index2 = (ti_lidx_t*)calloc(idx->n, sizeof(ti_lidx_t));
+	// read idx->conf
+	bgzf_read(fp, &idx->conf, sizeof(ti_conf_t));
+	if (ti_is_be) {
+		bam_swap_endian_4p(&idx->conf.preset);
+		bam_swap_endian_4p(&idx->conf.sc);
+		bam_swap_endian_4p(&idx->conf.bc);
+		bam_swap_endian_4p(&idx->conf.ec);
+		bam_swap_endian_4p(&idx->conf.meta_char);
+		bam_swap_endian_4p(&idx->conf.line_skip);
+	}
+	{ // read target names
+		int j, ret;
+		kstring_t *str;
+		int32_t l;
+		uint8_t *buf;
+		bgzf_read(fp, &l, 4);
+		if (ti_is_be) bam_swap_endian_4p(&l);
+		buf = calloc(l, 1);
+		bgzf_read(fp, buf, l);
+		str = calloc(1, sizeof(kstring_t));
+		for (i = j = 0; i < l; ++i) {
+			if (buf[i] == 0) {
+				khint_t k = kh_put(s, idx->tname, strdup(str->s), &ret);
+				kh_value(idx->tname, k) = j++;
+				str->l = 0;
+			} else kputc(buf[i], str);
+		}
+		free(str->s); free(str); free(buf);
+	}
+	for (i = 0; i < idx->n; ++i) {
+		khash_t(i) *index;
+		ti_lidx_t *index2 = idx->index2 + i;
+		uint32_t key, size;
+		khint_t k;
+		int j, ret;
+		ti_binlist_t *p;
+		index = idx->index[i] = kh_init(i);
+		// load binning index
+		bgzf_read(fp, &size, 4);
+		if (ti_is_be) bam_swap_endian_4p(&size);
+		for (j = 0; j < (int)size; ++j) {
+			bgzf_read(fp, &key, 4);
+			if (ti_is_be) bam_swap_endian_4p(&key);
+			k = kh_put(i, index, key, &ret);
+			p = &kh_value(index, k);
+			bgzf_read(fp, &p->n, 4);
+			if (ti_is_be) bam_swap_endian_4p(&p->n);
+			p->m = p->n;
+			p->list = (pair64_t*)malloc(p->m * 16);
+			bgzf_read(fp, p->list, 16 * p->n);
+			if (ti_is_be) {
+				int x;
+				for (x = 0; x < p->n; ++x) {
+					bam_swap_endian_8p(&p->list[x].u);
+					bam_swap_endian_8p(&p->list[x].v);
+				}
+			}
+		}
+		// load linear index
+		bgzf_read(fp, &index2->n, 4);
+		if (ti_is_be) bam_swap_endian_4p(&index2->n);
+		index2->m = index2->n;
+		index2->offset = (uint64_t*)calloc(index2->m, 8);
+		bgzf_read(fp, index2->offset, index2->n * 8);
+		if (ti_is_be)
+			for (j = 0; j < index2->n; ++j) bam_swap_endian_8p(&index2->offset[j]);
+	}
+	return idx;
+}
+
+ti_index_t *ti_index_load_local(const char *fnidx)
+{
+	BGZF *fp;
+	fp = bgzf_open(fnidx, "r");
+	if (fp) {
+		ti_index_t *idx = ti_index_load_core(fp);
+		bgzf_close(fp);
+		return idx;
+	} else return 0;
+}
+
+#ifdef _USE_KNETFILE
+static void download_from_remote(const char *url)
+{
+	const int buf_size = 1 * 1024 * 1024;
+	char *fn;
+	FILE *fp;
+	uint8_t *buf;
+	knetFile *fp_remote;
+	int l;
+	if (strstr(url, "ftp://") != url && strstr(url, "http://") != url) return;
+	l = strlen(url);
+	for (fn = (char*)url + l - 1; fn >= url; --fn)
+		if (*fn == '/') break;
+	++fn; // fn now points to the file name
+	fp_remote = knet_open(url, "r");
+	if (fp_remote == 0) {
+		fprintf(stderr, "[download_from_remote] fail to open remote file.\n");
+		return;
+	}
+	if ((fp = fopen(fn, "w")) == 0) {
+		fprintf(stderr, "[download_from_remote] fail to create file in the working directory.\n");
+		knet_close(fp_remote);
+		return;
+	}
+	buf = (uint8_t*)calloc(buf_size, 1);
+	while ((l = knet_read(fp_remote, buf, buf_size)) != 0)
+		fwrite(buf, 1, l, fp);
+	free(buf);
+	fclose(fp);
+	knet_close(fp_remote);
+}
+#else
+static void download_from_remote(const char *url)
+{
+	return;
+}
+#endif
+
+static char *get_local_version(const char *fn)
+{
+    struct stat sbuf;
+	char *fnidx = (char*)calloc(strlen(fn) + 5, 1);
+	strcat(strcpy(fnidx, fn), ".tbi");
+	if ((strstr(fnidx, "ftp://") == fnidx || strstr(fnidx, "http://") == fnidx)) {
+		char *p, *url;
+		int l = strlen(fnidx);
+		for (p = fnidx + l - 1; p >= fnidx; --p)
+			if (*p == '/') break;
+		url = fnidx; fnidx = strdup(p + 1);
+		if (stat(fnidx, &sbuf) == 0) {
+			free(url);
+			return fnidx;
+		}
+		fprintf(stderr, "[%s] downloading the index file...\n", __func__);
+		download_from_remote(url);
+		free(url);
+	}
+    if (stat(fnidx, &sbuf) == 0) return fnidx;
+	free(fnidx); return 0;
+}
+
+const char **ti_seqname(const ti_index_t *idx, int *n)
+{
+	const char **names;
+	khint_t k;
+	*n = idx->n;
+	names = calloc(idx->n, sizeof(void*));
+	for (k = kh_begin(idx->tname); k < kh_end(idx->tname); ++k)
+		if (kh_exist(idx->tname, k))
+			names[kh_val(idx->tname, k)] = kh_key(idx->tname, k);
+	return names;
+}
+
+ti_index_t *ti_index_load(const char *fn)
+{
+	ti_index_t *idx;
+    char *fname = get_local_version(fn);
+	if (fname == 0) return 0;
+	idx = ti_index_load_local(fname);
+	if (idx == 0) fprintf(stderr, "[ti_index_load] fail to load the index: %s\n", fname);
+    free(fname);
+	return idx;
+}
+
+int ti_index_build2(const char *fn, const ti_conf_t *conf, const char *_fnidx)
+{
+	char *fnidx;
+	BGZF *fp, *fpidx;
+	ti_index_t *idx;
+	if ((fp = bgzf_open(fn, "r")) == 0) {
+		fprintf(stderr, "[ti_index_build2] fail to open the file: %s\n", fn);
+		return -1;
+	}
+	idx = ti_index_core(fp, conf);
+	bgzf_close(fp);
+	if (_fnidx == 0) {
+		fnidx = (char*)calloc(strlen(fn) + 5, 1);
+		strcpy(fnidx, fn); strcat(fnidx, ".tbi");
+	} else fnidx = strdup(_fnidx);
+	fpidx = bgzf_open(fnidx, "w");
+	if (fpidx == 0) {
+		fprintf(stderr, "[ti_index_build2] fail to create the index file.\n");
+		free(fnidx);
+		return -1;
+	}
+	ti_index_save(idx, fpidx);
+	ti_index_destroy(idx);
+	bgzf_close(fpidx);
+	free(fnidx);
+	return 0;
+}
+
+int ti_index_build(const char *fn, const ti_conf_t *conf)
+{
+	return ti_index_build2(fn, conf, 0);
+}
+
+/********************************************
+ * parse a region in the format chr:beg-end *
+ ********************************************/
+
+int ti_get_tid(const ti_index_t *idx, const char *name)
+{
+	khiter_t iter;
+	const khash_t(s) *h = idx->tname;
+	iter = kh_get(s, h, name); /* get the tid */
+	if (iter == kh_end(h)) return -1;
+	return kh_value(h, iter);
+}
+
+int ti_parse_region(const ti_index_t *idx, const char *str, int *tid, int *begin, int *end)
+{
+	char *s, *p;
+	int i, l, k;
+	l = strlen(str);
+	p = s = (char*)malloc(l+1);
+	/* squeeze out "," */
+	for (i = k = 0; i != l; ++i)
+		if (str[i] != ',' && !isspace(str[i])) s[k++] = str[i];
+	s[k] = 0;
+	for (i = 0; i != k; ++i) if (s[i] == ':') break;
+	s[i] = 0;
+	if ((*tid = ti_get_tid(idx, s)) < 0) {
+		free(s);
+		return -1;
+	}
+	if (i == k) { /* dump the whole sequence */
+		*begin = 0; *end = 1<<29; free(s);
+		return 0;
+	}
+	for (p = s + i + 1; i != k; ++i) if (s[i] == '-') break;
+	*begin = atoi(p);
+	if (i < k) {
+		p = s + i + 1;
+		*end = atoi(p);
+	} else *end = 1<<29;
+	if (*begin > 0) --*begin;
+	free(s);
+	if (*begin > *end) return -1;
+	return 0;
+}
+
+/*******************************
+ * retrieve a specified region *
+ *******************************/
+
+#define MAX_BIN 37450 // =(8^6-1)/7+1
+
+static inline int reg2bins(uint32_t beg, uint32_t end, uint16_t list[MAX_BIN])
+{
+	int i = 0, k;
+	if (beg >= end) return 0;
+	if (end >= 1u<<29) end = 1u<<29;
+	--end;
+	list[i++] = 0;
+	for (k =    1 + (beg>>26); k <=    1 + (end>>26); ++k) list[i++] = k;
+	for (k =    9 + (beg>>23); k <=    9 + (end>>23); ++k) list[i++] = k;
+	for (k =   73 + (beg>>20); k <=   73 + (end>>20); ++k) list[i++] = k;
+	for (k =  585 + (beg>>17); k <=  585 + (end>>17); ++k) list[i++] = k;
+	for (k = 4681 + (beg>>14); k <= 4681 + (end>>14); ++k) list[i++] = k;
+	return i;
+}
+
+ti_iter_t ti_iter_first()
+{
+	ti_iter_t iter;
+	iter = calloc(1, sizeof(struct __ti_iter_t));
+	iter->from_first = 1;
+	return iter;
+}
+
+ti_iter_t ti_iter_query(const ti_index_t *idx, int tid, int beg, int end)
+{
+	uint16_t *bins;
+	int i, n_bins, n_off;
+	pair64_t *off;
+	khint_t k;
+	khash_t(i) *index;
+	uint64_t min_off;
+	ti_iter_t iter = 0;
+
+	if (beg < 0) beg = 0;
+	if (end < beg) return 0;
+	// initialize the iterator
+	iter = calloc(1, sizeof(struct __ti_iter_t));
+	iter->idx = idx; iter->tid = tid; iter->beg = beg; iter->end = end; iter->i = -1;
+	// random access
+	bins = (uint16_t*)calloc(MAX_BIN, 2);
+	n_bins = reg2bins(beg, end, bins);
+	index = idx->index[tid];
+	if (idx->index2[tid].n > 0) {
+		min_off = (beg>>TAD_LIDX_SHIFT >= idx->index2[tid].n)? idx->index2[tid].offset[idx->index2[tid].n-1]
+			: idx->index2[tid].offset[beg>>TAD_LIDX_SHIFT];
+		if (min_off == 0) { // improvement for index files built by tabix prior to 0.1.4
+			int n = beg>>TAD_LIDX_SHIFT;
+			if (n > idx->index2[tid].n) n = idx->index2[tid].n;
+			for (i = n - 1; i >= 0; --i)
+				if (idx->index2[tid].offset[i] != 0) break;
+			if (i >= 0) min_off = idx->index2[tid].offset[i];
+		}
+	} else min_off = 0; // tabix 0.1.2 may produce such index files
+	for (i = n_off = 0; i < n_bins; ++i) {
+		if ((k = kh_get(i, index, bins[i])) != kh_end(index))
+			n_off += kh_value(index, k).n;
+	}
+	if (n_off == 0) {
+		free(bins); return iter;
+	}
+	off = (pair64_t*)calloc(n_off, 16);
+	for (i = n_off = 0; i < n_bins; ++i) {
+		if ((k = kh_get(i, index, bins[i])) != kh_end(index)) {
+			int j;
+			ti_binlist_t *p = &kh_value(index, k);
+			for (j = 0; j < p->n; ++j)
+				if (p->list[j].v > min_off) off[n_off++] = p->list[j];
+		}
+	}
+	if (n_off == 0) {
+		free(bins); free(off); return iter;
+	}
+	free(bins);
+	{
+		int l;
+		ks_introsort(offt, n_off, off);
+		// resolve completely contained adjacent blocks
+		for (i = 1, l = 0; i < n_off; ++i)
+			if (off[l].v < off[i].v)
+				off[++l] = off[i];
+		n_off = l + 1;
+		// resolve overlaps between adjacent blocks; this may happen due to the merge in indexing
+		for (i = 1; i < n_off; ++i)
+			if (off[i-1].v >= off[i].u) off[i-1].v = off[i].u;
+		{ // merge adjacent blocks
+			for (i = 1, l = 0; i < n_off; ++i) {
+				if (off[l].v>>16 == off[i].u>>16) off[l].v = off[i].v;
+				else off[++l] = off[i];
+			}
+			n_off = l + 1;
+		}
+	}
+	iter->n_off = n_off; iter->off = off;
+	return iter;
+}
+
+const char *ti_iter_read(BGZF *fp, ti_iter_t iter, int *len)
+{
+	if (iter->finished) return 0;
+	if (iter->from_first) {
+		int ret;
+		if ((ret = ti_readline(fp, &iter->str)) < 0) {
+			iter->finished = 1;
+			return 0;
+		} else {
+			if (len) *len = iter->str.l;
+			return iter->str.s;
+		}
+	}
+	if (iter->n_off == 0) return 0;
+	while (1) {
+		int ret;
+		if (iter->curr_off == 0 || iter->curr_off >= iter->off[iter->i].v) { // then jump to the next chunk
+			if (iter->i == iter->n_off - 1) break; // no more chunks
+			if (iter->i >= 0) assert(iter->curr_off == iter->off[iter->i].v); // otherwise bug
+			if (iter->i < 0 || iter->off[iter->i].v != iter->off[iter->i+1].u) { // not adjacent chunks; then seek
+				bgzf_seek(fp, iter->off[iter->i+1].u, SEEK_SET);
+				iter->curr_off = bgzf_tell(fp);
+			}
+			++iter->i;
+		}
+		if ((ret = ti_readline(fp, &iter->str)) >= 0) {
+			ti_intv_t intv;
+			iter->curr_off = bgzf_tell(fp);
+			if (iter->str.s[0] == iter->idx->conf.meta_char) continue;
+			get_intv((ti_index_t*)iter->idx, &iter->str, &intv);
+			if (intv.tid != iter->tid || intv.beg >= iter->end) break; // no need to proceed
+			else if (intv.end > iter->beg && iter->end > intv.beg) {
+				if (len) *len = iter->str.l;
+				return iter->str.s;
+			}
+		} else break; // end of file
+	}
+	iter->finished = 1;
+	return 0;
+}
+
+void ti_iter_destroy(ti_iter_t iter)
+{
+	if (iter) {
+		free(iter->str.s); free(iter->off);
+		free(iter);
+	}
+}
+
+int ti_fetch(BGZF *fp, const ti_index_t *idx, int tid, int beg, int end, void *data, ti_fetch_f func)
+{
+	ti_iter_t iter;
+	const char *s;
+	int len;
+	iter = ti_iter_query(idx, tid, beg, end);
+	while ((s = ti_iter_read(fp, iter, &len)) != 0)
+		func(len, s, data);
+	ti_iter_destroy(iter);
+	return 0;
+}
+
+const ti_conf_t *ti_get_conf(ti_index_t *idx) { return idx? &idx->conf : 0; }
+
+/*******************
+ * High-level APIs *
+ *******************/
+
+tabix_t *ti_open(const char *fn, const char *fnidx)
+{
+	tabix_t *t;
+	BGZF *fp;
+	if ((fp = bgzf_open(fn, "r")) == 0) return 0;
+	t = calloc(1, sizeof(tabix_t));
+	t->fn = strdup(fn);
+	if (fnidx) t->fnidx = strdup(fnidx);
+	t->fp = fp;
+	return t;
+}
+
+void ti_close(tabix_t *t)
+{
+	if (t) {
+		bgzf_close(t->fp);
+		if (t->idx) ti_index_destroy(t->idx);
+		free(t->fn); free(t->fnidx);
+		free(t);
+	}
+}
+
+int ti_lazy_index_load(tabix_t *t)
+{
+	if (t->idx == 0) { // load index
+		if (t->fnidx) t->idx = ti_index_load_local(t->fnidx);
+		else t->idx = ti_index_load(t->fn);
+		if (t->idx == 0) return -1; // fail to load index
+	}
+	return 0;
+}
+
+ti_iter_t ti_queryi(tabix_t *t, int tid, int beg, int end)
+{
+	if (tid < 0) return ti_iter_first();
+	if (ti_lazy_index_load(t) != 0) return 0;
+	return ti_iter_query(t->idx, tid, beg, end);	
+}
+
+ti_iter_t ti_querys(tabix_t *t, const char *reg)
+{
+	int tid, beg, end;
+	if (reg == 0) return ti_iter_first();
+	if (ti_lazy_index_load(t) != 0) return 0;
+	if (ti_parse_region(t->idx, reg, &tid, &beg, &end) < 0) return 0;
+	return ti_iter_query(t->idx, tid, beg, end);
+}
+
+ti_iter_t ti_query(tabix_t *t, const char *name, int beg, int end)
+{
+	int tid;
+	if (name == 0) return ti_iter_first();
+	// then need to load the index
+	if (ti_lazy_index_load(t) != 0) return 0;
+	if ((tid = ti_get_tid(t->idx, name)) < 0) return 0;
+	return ti_iter_query(t->idx, tid, beg, end);
+}
+
+const char *ti_read(tabix_t *t, ti_iter_t iter, int *len)
+{
+	return ti_iter_read(t->fp, iter, len);
+}
diff --git a/khash.h b/khash.h
new file mode 100644
index 0000000..1d583ef
--- /dev/null
+++ b/khash.h
@@ -0,0 +1,486 @@
+/* The MIT License
+
+   Copyright (c) 2008 Genome Research Ltd (GRL).
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <lh3 at sanger.ac.uk> */
+
+/*
+  An example:
+
+#include "khash.h"
+KHASH_MAP_INIT_INT(32, char)
+int main() {
+	int ret, is_missing;
+	khiter_t k;
+	khash_t(32) *h = kh_init(32);
+	k = kh_put(32, h, 5, &ret);
+	if (!ret) kh_del(32, h, k);
+	kh_value(h, k) = 10;
+	k = kh_get(32, h, 10);
+	is_missing = (k == kh_end(h));
+	k = kh_get(32, h, 5);
+	kh_del(32, h, k);
+	for (k = kh_begin(h); k != kh_end(h); ++k)
+		if (kh_exist(h, k)) kh_value(h, k) = 1;
+	kh_destroy(32, h);
+	return 0;
+}
+*/
+
+/*
+  2008-09-19 (0.2.3):
+
+	* Corrected the example
+	* Improved interfaces
+
+  2008-09-11 (0.2.2):
+
+	* Improved speed a little in kh_put()
+
+  2008-09-10 (0.2.1):
+
+	* Added kh_clear()
+	* Fixed a compiling error
+
+  2008-09-02 (0.2.0):
+
+	* Changed to token concatenation which increases flexibility.
+
+  2008-08-31 (0.1.2):
+
+	* Fixed a bug in kh_get(), which has not been tested previously.
+
+  2008-08-31 (0.1.1):
+
+	* Added destructor
+*/
+
+
+#ifndef __AC_KHASH_H
+#define __AC_KHASH_H
+
+/*!
+  @header
+
+  Generic hash table library.
+
+  @copyright Heng Li
+ */
+
+#define AC_VERSION_KHASH_H "0.2.2"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef uint32_t khint_t;
+typedef khint_t khiter_t;
+
+#define __ac_HASH_PRIME_SIZE 32
+static const uint32_t __ac_prime_list[__ac_HASH_PRIME_SIZE] =
+{
+  0ul,          3ul,          11ul,         23ul,         53ul,
+  97ul,         193ul,        389ul,        769ul,        1543ul,
+  3079ul,       6151ul,       12289ul,      24593ul,      49157ul,
+  98317ul,      196613ul,     393241ul,     786433ul,     1572869ul,
+  3145739ul,    6291469ul,    12582917ul,   25165843ul,   50331653ul,
+  100663319ul,  201326611ul,  402653189ul,  805306457ul,  1610612741ul,
+  3221225473ul, 4294967291ul
+};
+
+#define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
+#define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
+#define __ac_iseither(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&3)
+#define __ac_set_isdel_false(flag, i) (flag[i>>4]&=~(1ul<<((i&0xfU)<<1)))
+#define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(2ul<<((i&0xfU)<<1)))
+#define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(3ul<<((i&0xfU)<<1)))
+#define __ac_set_isdel_true(flag, i) (flag[i>>4]|=1ul<<((i&0xfU)<<1))
+
+static const double __ac_HASH_UPPER = 0.77;
+
+#define KHASH_INIT(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
+	typedef struct {													\
+		khint_t n_buckets, size, n_occupied, upper_bound;				\
+		uint32_t *flags;												\
+		khkey_t *keys;													\
+		khval_t *vals;													\
+	} kh_##name##_t;													\
+	static inline kh_##name##_t *kh_init_##name() {						\
+		return (kh_##name##_t*)calloc(1, sizeof(kh_##name##_t));		\
+	}																	\
+	static inline void kh_destroy_##name(kh_##name##_t *h)				\
+	{																	\
+		if (h) {														\
+			free(h->keys); free(h->flags);								\
+			free(h->vals);												\
+			free(h);													\
+		}																\
+	}																	\
+	static inline void kh_clear_##name(kh_##name##_t *h)				\
+	{																	\
+		if (h && h->flags) {											\
+			memset(h->flags, 0xaa, ((h->n_buckets>>4) + 1) * sizeof(uint32_t)); \
+			h->size = h->n_occupied = 0;								\
+		}																\
+	}																	\
+	static inline khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key) \
+	{																	\
+		if (h->n_buckets) {												\
+			khint_t inc, k, i, last;									\
+			k = __hash_func(key); i = k % h->n_buckets;					\
+			inc = 1 + k % (h->n_buckets - 1); last = i;					\
+			while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
+				if (i + inc >= h->n_buckets) i = i + inc - h->n_buckets; \
+				else i += inc;											\
+				if (i == last) return h->n_buckets;						\
+			}															\
+			return __ac_iseither(h->flags, i)? h->n_buckets : i;		\
+		} else return 0;												\
+	}																	\
+	static inline void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
+	{																	\
+		uint32_t *new_flags = 0;										\
+		khint_t j = 1;													\
+		{																\
+			khint_t t = __ac_HASH_PRIME_SIZE - 1;						\
+			while (__ac_prime_list[t] > new_n_buckets) --t;				\
+			new_n_buckets = __ac_prime_list[t+1];						\
+			if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) j = 0;	\
+			else {														\
+				new_flags = (uint32_t*)malloc(((new_n_buckets>>4) + 1) * sizeof(uint32_t));	\
+				memset(new_flags, 0xaa, ((new_n_buckets>>4) + 1) * sizeof(uint32_t)); \
+				if (h->n_buckets < new_n_buckets) {						\
+					h->keys = (khkey_t*)realloc(h->keys, new_n_buckets * sizeof(khkey_t)); \
+					if (kh_is_map)										\
+						h->vals = (khval_t*)realloc(h->vals, new_n_buckets * sizeof(khval_t)); \
+				}														\
+			}															\
+		}																\
+		if (j) {														\
+			for (j = 0; j != h->n_buckets; ++j) {						\
+				if (__ac_iseither(h->flags, j) == 0) {					\
+					khkey_t key = h->keys[j];							\
+					khval_t val;										\
+					if (kh_is_map) val = h->vals[j];					\
+					__ac_set_isdel_true(h->flags, j);					\
+					while (1) {											\
+						khint_t inc, k, i;								\
+						k = __hash_func(key);							\
+						i = k % new_n_buckets;							\
+						inc = 1 + k % (new_n_buckets - 1);				\
+						while (!__ac_isempty(new_flags, i)) {			\
+							if (i + inc >= new_n_buckets) i = i + inc - new_n_buckets; \
+							else i += inc;								\
+						}												\
+						__ac_set_isempty_false(new_flags, i);			\
+						if (i < h->n_buckets && __ac_iseither(h->flags, i) == 0) { \
+							{ khkey_t tmp = h->keys[i]; h->keys[i] = key; key = tmp; } \
+							if (kh_is_map) { khval_t tmp = h->vals[i]; h->vals[i] = val; val = tmp; } \
+							__ac_set_isdel_true(h->flags, i);			\
+						} else {										\
+							h->keys[i] = key;							\
+							if (kh_is_map) h->vals[i] = val;			\
+							break;										\
+						}												\
+					}													\
+				}														\
+			}															\
+			if (h->n_buckets > new_n_buckets) {							\
+				h->keys = (khkey_t*)realloc(h->keys, new_n_buckets * sizeof(khkey_t)); \
+				if (kh_is_map)											\
+					h->vals = (khval_t*)realloc(h->vals, new_n_buckets * sizeof(khval_t)); \
+			}															\
+			free(h->flags);												\
+			h->flags = new_flags;										\
+			h->n_buckets = new_n_buckets;								\
+			h->n_occupied = h->size;									\
+			h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
+		}																\
+	}																	\
+	static inline khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
+	{																	\
+		khint_t x;														\
+		if (h->n_occupied >= h->upper_bound) {							\
+			if (h->n_buckets > (h->size<<1)) kh_resize_##name(h, h->n_buckets - 1); \
+			else kh_resize_##name(h, h->n_buckets + 1);					\
+		}																\
+		{																\
+			khint_t inc, k, i, site, last;								\
+			x = site = h->n_buckets; k = __hash_func(key); i = k % h->n_buckets; \
+			if (__ac_isempty(h->flags, i)) x = i;						\
+			else {														\
+				inc = 1 + k % (h->n_buckets - 1); last = i;				\
+				while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
+					if (__ac_isdel(h->flags, i)) site = i;				\
+					if (i + inc >= h->n_buckets) i = i + inc - h->n_buckets; \
+					else i += inc;										\
+					if (i == last) { x = site; break; }					\
+				}														\
+				if (x == h->n_buckets) {								\
+					if (__ac_isempty(h->flags, i) && site != h->n_buckets) x = site; \
+					else x = i;											\
+				}														\
+			}															\
+		}																\
+		if (__ac_isempty(h->flags, x)) {								\
+			h->keys[x] = key;											\
+			__ac_set_isboth_false(h->flags, x);							\
+			++h->size; ++h->n_occupied;									\
+			*ret = 1;													\
+		} else if (__ac_isdel(h->flags, x)) {							\
+			h->keys[x] = key;											\
+			__ac_set_isboth_false(h->flags, x);							\
+			++h->size;													\
+			*ret = 2;													\
+		} else *ret = 0;												\
+		return x;														\
+	}																	\
+	static inline void kh_del_##name(kh_##name##_t *h, khint_t x)		\
+	{																	\
+		if (x != h->n_buckets && !__ac_iseither(h->flags, x)) {			\
+			__ac_set_isdel_true(h->flags, x);							\
+			--h->size;													\
+		}																\
+	}
+
+/* --- BEGIN OF HASH FUNCTIONS --- */
+
+/*! @function
+  @abstract     Integer hash function
+  @param  key   The integer [uint32_t]
+  @return       The hash value [khint_t]
+ */
+#define kh_int_hash_func(key) (uint32_t)(key)
+/*! @function
+  @abstract     Integer comparison function
+ */
+#define kh_int_hash_equal(a, b) ((a) == (b))
+/*! @function
+  @abstract     64-bit integer hash function
+  @param  key   The integer [uint64_t]
+  @return       The hash value [khint_t]
+ */
+#define kh_int64_hash_func(key) (uint32_t)((key)>>33^(key)^(key)<<11)
+/*! @function
+  @abstract     64-bit integer comparison function
+ */
+#define kh_int64_hash_equal(a, b) ((a) == (b))
+/*! @function
+  @abstract     const char* hash function
+  @param  s     Pointer to a null terminated string
+  @return       The hash value
+ */
+static inline khint_t __ac_X31_hash_string(const char *s)
+{
+	khint_t h = *s;
+	if (h) for (++s ; *s; ++s) h = (h << 5) - h + *s;
+	return h;
+}
+/*! @function
+  @abstract     Another interface to const char* hash function
+  @param  key   Pointer to a null terminated string [const char*]
+  @return       The hash value [khint_t]
+ */
+#define kh_str_hash_func(key) __ac_X31_hash_string(key)
+/*! @function
+  @abstract     Const char* comparison function
+ */
+#define kh_str_hash_equal(a, b) (strcmp(a, b) == 0)
+
+/* --- END OF HASH FUNCTIONS --- */
+
+/* Other necessary macros... */
+
+/*!
+  @abstract Type of the hash table.
+  @param  name  Name of the hash table [symbol]
+ */
+#define khash_t(name) kh_##name##_t
+
+/*! @function
+  @abstract     Initiate a hash table.
+  @param  name  Name of the hash table [symbol]
+  @return       Pointer to the hash table [khash_t(name)*]
+ */
+#define kh_init(name) kh_init_##name()
+
+/*! @function
+  @abstract     Destroy a hash table.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+ */
+#define kh_destroy(name, h) kh_destroy_##name(h)
+
+/*! @function
+  @abstract     Reset a hash table without deallocating memory.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+ */
+#define kh_clear(name, h) kh_clear_##name(h)
+
+/*! @function
+  @abstract     Resize a hash table.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  s     New size [khint_t]
+ */
+#define kh_resize(name, h, s) kh_resize_##name(h, s)
+
+/*! @function
+  @abstract     Insert a key to the hash table.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  k     Key [type of keys]
+  @param  r     Extra return code: 0 if the key is present in the hash table;
+                1 if the bucket is empty (never used); 2 if the element in
+				the bucket has been deleted [int*]
+  @return       Iterator to the inserted element [khint_t]
+ */
+#define kh_put(name, h, k, r) kh_put_##name(h, k, r)
+
+/*! @function
+  @abstract     Retrieve a key from the hash table.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  k     Key [type of keys]
+  @return       Iterator to the found element, or kh_end(h) is the element is absent [khint_t]
+ */
+#define kh_get(name, h, k) kh_get_##name(h, k)
+
+/*! @function
+  @abstract     Remove a key from the hash table.
+  @param  name  Name of the hash table [symbol]
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  k     Iterator to the element to be deleted [khint_t]
+ */
+#define kh_del(name, h, k) kh_del_##name(h, k)
+
+
+/*! @function
+  @abstract     Test whether a bucket contains data.
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  x     Iterator to the bucket [khint_t]
+  @return       1 if containing data; 0 otherwise [int]
+ */
+#define kh_exist(h, x) (!__ac_iseither((h)->flags, (x)))
+
+/*! @function
+  @abstract     Get key given an iterator
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  x     Iterator to the bucket [khint_t]
+  @return       Key [type of keys]
+ */
+#define kh_key(h, x) ((h)->keys[x])
+
+/*! @function
+  @abstract     Get value given an iterator
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @param  x     Iterator to the bucket [khint_t]
+  @return       Value [type of values]
+  @discussion   For hash sets, calling this results in segfault.
+ */
+#define kh_val(h, x) ((h)->vals[x])
+
+/*! @function
+  @abstract     Alias of kh_val()
+ */
+#define kh_value(h, x) ((h)->vals[x])
+
+/*! @function
+  @abstract     Get the start iterator
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @return       The start iterator [khint_t]
+ */
+#define kh_begin(h) (khint_t)(0)
+
+/*! @function
+  @abstract     Get the end iterator
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @return       The end iterator [khint_t]
+ */
+#define kh_end(h) ((h)->n_buckets)
+
+/*! @function
+  @abstract     Get the number of elements in the hash table
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @return       Number of elements in the hash table [khint_t]
+ */
+#define kh_size(h) ((h)->size)
+
+/*! @function
+  @abstract     Get the number of buckets in the hash table
+  @param  h     Pointer to the hash table [khash_t(name)*]
+  @return       Number of buckets in the hash table [khint_t]
+ */
+#define kh_n_buckets(h) ((h)->n_buckets)
+
+/* More conenient interfaces */
+
+/*! @function
+  @abstract     Instantiate a hash set containing integer keys
+  @param  name  Name of the hash table [symbol]
+ */
+#define KHASH_SET_INIT_INT(name)										\
+	KHASH_INIT(name, uint32_t, char, 0, kh_int_hash_func, kh_int_hash_equal)
+
+/*! @function
+  @abstract     Instantiate a hash map containing integer keys
+  @param  name  Name of the hash table [symbol]
+  @param  khval_t  Type of values [type]
+ */
+#define KHASH_MAP_INIT_INT(name, khval_t)								\
+	KHASH_INIT(name, uint32_t, khval_t, 1, kh_int_hash_func, kh_int_hash_equal)
+
+/*! @function
+  @abstract     Instantiate a hash map containing 64-bit integer keys
+  @param  name  Name of the hash table [symbol]
+ */
+#define KHASH_SET_INIT_INT64(name)										\
+	KHASH_INIT(name, uint64_t, char, 0, kh_int64_hash_func, kh_int64_hash_equal)
+
+/*! @function
+  @abstract     Instantiate a hash map containing 64-bit integer keys
+  @param  name  Name of the hash table [symbol]
+  @param  khval_t  Type of values [type]
+ */
+#define KHASH_MAP_INIT_INT64(name, khval_t)								\
+	KHASH_INIT(name, uint64_t, khval_t, 1, kh_int64_hash_func, kh_int64_hash_equal)
+
+typedef const char *kh_cstr_t;
+/*! @function
+  @abstract     Instantiate a hash map containing const char* keys
+  @param  name  Name of the hash table [symbol]
+ */
+#define KHASH_SET_INIT_STR(name)										\
+	KHASH_INIT(name, kh_cstr_t, char, 0, kh_str_hash_func, kh_str_hash_equal)
+
+/*! @function
+  @abstract     Instantiate a hash map containing const char* keys
+  @param  name  Name of the hash table [symbol]
+  @param  khval_t  Type of values [type]
+ */
+#define KHASH_MAP_INIT_STR(name, khval_t)								\
+	KHASH_INIT(name, kh_cstr_t, khval_t, 1, kh_str_hash_func, kh_str_hash_equal)
+
+#endif /* __AC_KHASH_H */
diff --git a/knetfile.c b/knetfile.c
new file mode 100644
index 0000000..7c96a3e
--- /dev/null
+++ b/knetfile.c
@@ -0,0 +1,632 @@
+/* The MIT License
+
+   Copyright (c) 2008 Genome Research Ltd (GRL).
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <lh3 at sanger.ac.uk> */
+
+/* Probably I will not do socket programming in the next few years and
+   therefore I decide to heavily annotate this file, for Linux and
+   Windows as well.  -lh3 */
+
+#include <time.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#ifdef _WIN32
+#include <winsock.h>
+#else
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#endif
+
+#include "knetfile.h"
+
+/* In winsock.h, the type of a socket is SOCKET, which is: "typedef
+ * u_int SOCKET". An invalid SOCKET is: "(SOCKET)(~0)", or signed
+ * integer -1. In knetfile.c, I use "int" for socket type
+ * throughout. This should be improved to avoid confusion.
+ *
+ * In Linux/Mac, recv() and read() do almost the same thing. You can see
+ * in the header file that netread() is simply an alias of read(). In
+ * Windows, however, they are different and using recv() is mandatory.
+ */
+
+/* This function tests if the file handler is ready for reading (or
+ * writing if is_read==0). */
+static int socket_wait(int fd, int is_read)
+{
+	fd_set fds, *fdr = 0, *fdw = 0;
+	struct timeval tv;
+	int ret;
+	tv.tv_sec = 5; tv.tv_usec = 0; // 5 seconds time out
+	FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+	if (is_read) fdr = &fds;
+	else fdw = &fds;
+	ret = select(fd+1, fdr, fdw, 0, &tv);
+#ifndef _WIN32
+	if (ret == -1) perror("select");
+#else
+	if (ret == 0)
+		fprintf(stderr, "select time-out\n");
+	else if (ret == SOCKET_ERROR)
+		fprintf(stderr, "select: %d\n", WSAGetLastError());
+#endif
+	return ret;
+}
+
+#ifndef _WIN32
+/* This function does not work with Windows due to the lack of
+ * getaddrinfo() in winsock. It is addapted from an example in "Beej's
+ * Guide to Network Programming" (http://beej.us/guide/bgnet/). */
+static int socket_connect(const char *host, const char *port)
+{
+#define __err_connect(func) do { perror(func); freeaddrinfo(res); return -1; } while (0)
+
+	int on = 1, fd;
+	struct linger lng = { 0, 0 };
+	struct addrinfo hints, *res;
+	memset(&hints, 0, sizeof(struct addrinfo));
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_STREAM;
+	/* In Unix/Mac, getaddrinfo() is the most convenient way to get
+	 * server information. */
+	if (getaddrinfo(host, port, &hints, &res) != 0) __err_connect("getaddrinfo");
+	if ((fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol)) == -1) __err_connect("socket");
+	/* The following two setsockopt() are used by ftplib
+	 * (http://nbpfaus.net/~pfau/ftplib/). I am not sure if they
+	 * necessary. */
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) __err_connect("setsockopt");
+	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, &lng, sizeof(lng)) == -1) __err_connect("setsockopt");
+	if (connect(fd, res->ai_addr, res->ai_addrlen) != 0) __err_connect("connect");
+	freeaddrinfo(res);
+	return fd;
+}
+#else
+/* MinGW's printf has problem with "%lld" */
+char *int64tostr(char *buf, int64_t x)
+{
+	int cnt;
+	int i = 0;
+	do {
+		buf[i++] = '0' + x % 10;
+		x /= 10;
+	} while (x);
+	buf[i] = 0;
+	for (cnt = i, i = 0; i < cnt/2; ++i) {
+		int c = buf[i]; buf[i] = buf[cnt-i-1]; buf[cnt-i-1] = c;
+	}
+	return buf;
+}
+
+int64_t strtoint64(const char *buf)
+{
+	int64_t x;
+	for (x = 0; *buf != '\0'; ++buf)
+		x = x * 10 + ((int64_t) *buf - 48);
+	return x;
+}
+/* In windows, the first thing is to establish the TCP connection. */
+int knet_win32_init()
+{
+	WSADATA wsaData;
+	return WSAStartup(MAKEWORD(2, 2), &wsaData);
+}
+void knet_win32_destroy()
+{
+	WSACleanup();
+}
+/* A slightly modfied version of the following function also works on
+ * Mac (and presummably Linux). However, this function is not stable on
+ * my Mac. It sometimes works fine but sometimes does not. Therefore for
+ * non-Windows OS, I do not use this one. */
+static SOCKET socket_connect(const char *host, const char *port)
+{
+#define __err_connect(func)										\
+	do {														\
+		fprintf(stderr, "%s: %d\n", func, WSAGetLastError());	\
+		return -1;												\
+	} while (0)
+
+	int on = 1;
+	SOCKET fd;
+	struct linger lng = { 0, 0 };
+	struct sockaddr_in server;
+	struct hostent *hp = 0;
+	// open socket
+	if ((fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == INVALID_SOCKET) __err_connect("socket");
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char*)&on, sizeof(on)) == -1) __err_connect("setsockopt");
+	if (setsockopt(fd, SOL_SOCKET, SO_LINGER, (char*)&lng, sizeof(lng)) == -1) __err_connect("setsockopt");
+	// get host info
+	if (isalpha(host[0])) hp = gethostbyname(host);
+	else {
+		struct in_addr addr;
+		addr.s_addr = inet_addr(host);
+		hp = gethostbyaddr((char*)&addr, 4, AF_INET);
+	}
+	if (hp == 0) __err_connect("gethost");
+	// connect
+	server.sin_addr.s_addr = *((unsigned long*)hp->h_addr);
+	server.sin_family= AF_INET;
+	server.sin_port = htons(atoi(port));
+	if (connect(fd, (struct sockaddr*)&server, sizeof(server)) != 0) __err_connect("connect");
+	// freehostent(hp); // strangely in MSDN, hp is NOT freed (memory leak?!)
+	return fd;
+}
+#endif
+
+static off_t my_netread(int fd, void *buf, off_t len)
+{
+	off_t rest = len, curr, l = 0;
+	/* recv() and read() may not read the required length of data with
+	 * one call. They have to be called repeatedly. */
+	while (rest) {
+		if (socket_wait(fd, 1) <= 0) break; // socket is not ready for reading
+		curr = netread(fd, buf + l, rest);
+		/* According to the glibc manual, section 13.2, a zero returned
+		 * value indicates end-of-file (EOF), which should mean that
+		 * read() will not return zero if EOF has not been met but data
+		 * are not immediately available. */
+		if (curr == 0) break;
+		l += curr; rest -= curr;
+	}
+	return l;
+}
+
+/*************************
+ * FTP specific routines *
+ *************************/
+
+static int kftp_get_response(knetFile *ftp)
+{
+#ifndef _WIN32
+	unsigned char c;
+#else
+	char c;
+#endif
+	int n = 0;
+	char *p;
+	if (socket_wait(ftp->ctrl_fd, 1) <= 0) return 0;
+	while (netread(ftp->ctrl_fd, &c, 1)) { // FIXME: this is *VERY BAD* for unbuffered I/O
+		//fputc(c, stderr);
+		if (n >= ftp->max_response) {
+			ftp->max_response = ftp->max_response? ftp->max_response<<1 : 256;
+			ftp->response = realloc(ftp->response, ftp->max_response);
+		}
+		ftp->response[n++] = c;
+		if (c == '\n') {
+			if (n >= 4 && isdigit(ftp->response[0]) && isdigit(ftp->response[1]) && isdigit(ftp->response[2])
+				&& ftp->response[3] != '-') break;
+			n = 0;
+			continue;
+		}
+	}
+	if (n < 2) return -1;
+	ftp->response[n-2] = 0;
+	return strtol(ftp->response, &p, 0);
+}
+
+static int kftp_send_cmd(knetFile *ftp, const char *cmd, int is_get)
+{
+	if (socket_wait(ftp->ctrl_fd, 0) <= 0) return -1; // socket is not ready for writing
+	netwrite(ftp->ctrl_fd, cmd, strlen(cmd));
+	return is_get? kftp_get_response(ftp) : 0;
+}
+
+static int kftp_pasv_prep(knetFile *ftp)
+{
+	char *p;
+	int v[6];
+	kftp_send_cmd(ftp, "PASV\r\n", 1);
+	for (p = ftp->response; *p && *p != '('; ++p);
+	if (*p != '(') return -1;
+	++p;
+	sscanf(p, "%d,%d,%d,%d,%d,%d", &v[0], &v[1], &v[2], &v[3], &v[4], &v[5]);
+	memcpy(ftp->pasv_ip, v, 4 * sizeof(int));
+	ftp->pasv_port = (v[4]<<8&0xff00) + v[5];
+	return 0;
+}
+
+
+static int kftp_pasv_connect(knetFile *ftp)
+{
+	char host[80], port[10];
+	if (ftp->pasv_port == 0) {
+		fprintf(stderr, "[kftp_pasv_connect] kftp_pasv_prep() is not called before hand.\n");
+		return -1;
+	}
+	sprintf(host, "%d.%d.%d.%d", ftp->pasv_ip[0], ftp->pasv_ip[1], ftp->pasv_ip[2], ftp->pasv_ip[3]);
+	sprintf(port, "%d", ftp->pasv_port);
+	ftp->fd = socket_connect(host, port);
+	if (ftp->fd == -1) return -1;
+	return 0;
+}
+
+int kftp_connect(knetFile *ftp)
+{
+	ftp->ctrl_fd = socket_connect(ftp->host, ftp->port);
+	if (ftp->ctrl_fd == -1) return -1;
+	kftp_get_response(ftp);
+	kftp_send_cmd(ftp, "USER anonymous\r\n", 1);
+	kftp_send_cmd(ftp, "PASS kftp@\r\n", 1);
+	kftp_send_cmd(ftp, "TYPE I\r\n", 1);
+	return 0;
+}
+
+int kftp_reconnect(knetFile *ftp)
+{
+	if (ftp->ctrl_fd != -1) {
+		netclose(ftp->ctrl_fd);
+		ftp->ctrl_fd = -1;
+	}
+	netclose(ftp->fd);
+	ftp->fd = -1;
+	return kftp_connect(ftp);
+}
+
+// initialize ->type, ->host, ->retr and ->size
+knetFile *kftp_parse_url(const char *fn, const char *mode)
+{
+	knetFile *fp;
+	char *p;
+	int l;
+	if (strstr(fn, "ftp://") != fn) return 0;
+	for (p = (char*)fn + 6; *p && *p != '/'; ++p);
+	if (*p != '/') return 0;
+	l = p - fn - 6;
+	fp = calloc(1, sizeof(knetFile));
+	fp->type = KNF_TYPE_FTP;
+	fp->fd = -1;
+	/* the Linux/Mac version of socket_connect() also recognizes a port
+	 * like "ftp", but the Windows version does not. */
+	fp->port = strdup("21");
+	fp->host = calloc(l + 1, 1);
+	if (strchr(mode, 'c')) fp->no_reconnect = 1;
+	strncpy(fp->host, fn + 6, l);
+	fp->retr = calloc(strlen(p) + 8, 1);
+	sprintf(fp->retr, "RETR %s\r\n", p);
+    fp->size_cmd = calloc(strlen(p) + 8, 1);
+    sprintf(fp->size_cmd, "SIZE %s\r\n", p);
+	fp->seek_offset = 0;
+	return fp;
+}
+// place ->fd at offset off
+int kftp_connect_file(knetFile *fp)
+{
+	int ret;
+	long long file_size;
+	if (fp->fd != -1) {
+		netclose(fp->fd);
+		if (fp->no_reconnect) kftp_get_response(fp);
+	}
+	kftp_pasv_prep(fp);
+    kftp_send_cmd(fp, fp->size_cmd, 1);
+#ifndef _WIN32
+    if ( sscanf(fp->response,"%*d %lld", &file_size) != 1 )
+    {
+        fprintf(stderr,"[kftp_connect_file] %s\n", fp->response);
+        return -1;
+    }
+#else
+	const char *p = fp->response;
+	while (*p != ' ') ++p;
+	while (*p < '0' || *p > '9') ++p;
+	file_size = strtoint64(p);
+#endif
+	fp->file_size = file_size;
+	if (fp->offset>=0) {
+		char tmp[32];
+#ifndef _WIN32
+		sprintf(tmp, "REST %lld\r\n", (long long)fp->offset);
+#else
+		strcpy(tmp, "REST ");
+		int64tostr(tmp + 5, fp->offset);
+		strcat(tmp, "\r\n");
+#endif
+		kftp_send_cmd(fp, tmp, 1);
+	}
+	kftp_send_cmd(fp, fp->retr, 0);
+	kftp_pasv_connect(fp);
+	ret = kftp_get_response(fp);
+	if (ret != 150) {
+		fprintf(stderr, "[kftp_connect_file] %s\n", fp->response);
+		netclose(fp->fd);
+		fp->fd = -1;
+		return -1;
+	}
+	fp->is_ready = 1;
+	return 0;
+}
+
+
+/**************************
+ * HTTP specific routines *
+ **************************/
+
+knetFile *khttp_parse_url(const char *fn, const char *mode)
+{
+	knetFile *fp;
+	char *p, *proxy, *q;
+	int l;
+	if (strstr(fn, "http://") != fn) return 0;
+	// set ->http_host
+	for (p = (char*)fn + 7; *p && *p != '/'; ++p);
+	l = p - fn - 7;
+	fp = calloc(1, sizeof(knetFile));
+	fp->http_host = calloc(l + 1, 1);
+	strncpy(fp->http_host, fn + 7, l);
+	fp->http_host[l] = 0;
+	for (q = fp->http_host; *q && *q != ':'; ++q);
+	if (*q == ':') *q++ = 0;
+	// get http_proxy
+	proxy = getenv("http_proxy");
+	// set ->host, ->port and ->path
+	if (proxy == 0) {
+		fp->host = strdup(fp->http_host); // when there is no proxy, server name is identical to http_host name.
+		fp->port = strdup(*q? q : "80");
+		fp->path = strdup(*p? p : "/");
+	} else {
+		fp->host = (strstr(proxy, "http://") == proxy)? strdup(proxy + 7) : strdup(proxy);
+		for (q = fp->host; *q && *q != ':'; ++q);
+		if (*q == ':') *q++ = 0; 
+		fp->port = strdup(*q? q : "80");
+		fp->path = strdup(fn);
+	}
+	fp->type = KNF_TYPE_HTTP;
+	fp->ctrl_fd = fp->fd = -1;
+	fp->seek_offset = 0;
+	return fp;
+}
+
+int khttp_connect_file(knetFile *fp)
+{
+	int ret, l = 0;
+	char *buf, *p;
+	if (fp->fd != -1) netclose(fp->fd);
+	fp->fd = socket_connect(fp->host, fp->port);
+	buf = calloc(0x10000, 1); // FIXME: I am lazy... But in principle, 64KB should be large enough.
+	l += sprintf(buf + l, "GET %s HTTP/1.0\r\nHost: %s\r\n", fp->path, fp->http_host);
+    l += sprintf(buf + l, "Range: bytes=%lld-\r\n", (long long)fp->offset);
+	l += sprintf(buf + l, "\r\n");
+	netwrite(fp->fd, buf, l);
+	l = 0;
+	while (netread(fp->fd, buf + l, 1)) { // read HTTP header; FIXME: bad efficiency
+		if (buf[l] == '\n' && l >= 3)
+			if (strncmp(buf + l - 3, "\r\n\r\n", 4) == 0) break;
+		++l;
+	}
+	buf[l] = 0;
+	if (l < 14) { // prematured header
+		netclose(fp->fd);
+		fp->fd = -1;
+		return -1;
+	}
+	ret = strtol(buf + 8, &p, 0); // HTTP return code
+	if (ret == 200 && fp->offset>0) { // 200 (complete result); then skip beginning of the file
+		off_t rest = fp->offset;
+		while (rest) {
+			off_t l = rest < 0x10000? rest : 0x10000;
+			rest -= my_netread(fp->fd, buf, l);
+		}
+	} else if (ret != 206 && ret != 200) {
+		free(buf);
+		fprintf(stderr, "[khttp_connect_file] fail to open file (HTTP code: %d).\n", ret);
+		netclose(fp->fd);
+		fp->fd = -1;
+		return -1;
+	}
+	free(buf);
+	fp->is_ready = 1;
+	return 0;
+}
+
+/********************
+ * Generic routines *
+ ********************/
+
+knetFile *knet_open(const char *fn, const char *mode)
+{
+	knetFile *fp = 0;
+	if (mode[0] != 'r') {
+		fprintf(stderr, "[kftp_open] only mode \"r\" is supported.\n");
+		return 0;
+	}
+	if (strstr(fn, "ftp://") == fn) {
+		fp = kftp_parse_url(fn, mode);
+		if (fp == 0) return 0;
+		if (kftp_connect(fp) == -1) {
+			knet_close(fp);
+			return 0;
+		}
+		kftp_connect_file(fp);
+	} else if (strstr(fn, "http://") == fn) {
+		fp = khttp_parse_url(fn, mode);
+		if (fp == 0) return 0;
+		khttp_connect_file(fp);
+	} else { // local file
+#ifdef _WIN32
+		/* In windows, O_BINARY is necessary. In Linux/Mac, O_BINARY may
+		 * be undefined on some systems, although it is defined on my
+		 * Mac and the Linux I have tested on. */
+		int fd = open(fn, O_RDONLY | O_BINARY);
+#else		
+		int fd = open(fn, O_RDONLY);
+#endif
+		if (fd == -1) {
+			perror("open");
+			return 0;
+		}
+		fp = (knetFile*)calloc(1, sizeof(knetFile));
+		fp->type = KNF_TYPE_LOCAL;
+		fp->fd = fd;
+		fp->ctrl_fd = -1;
+	}
+	if (fp && fp->fd == -1) {
+		knet_close(fp);
+		return 0;
+	}
+	return fp;
+}
+
+knetFile *knet_dopen(int fd, const char *mode)
+{
+	knetFile *fp = (knetFile*)calloc(1, sizeof(knetFile));
+	fp->type = KNF_TYPE_LOCAL;
+	fp->fd = fd;
+	return fp;
+}
+
+off_t knet_read(knetFile *fp, void *buf, off_t len)
+{
+	off_t l = 0;
+	if (fp->fd == -1) return 0;
+	if (fp->type == KNF_TYPE_FTP) {
+		if (fp->is_ready == 0) {
+			if (!fp->no_reconnect) kftp_reconnect(fp);
+			kftp_connect_file(fp);
+		}
+	} else if (fp->type == KNF_TYPE_HTTP) {
+		if (fp->is_ready == 0)
+			khttp_connect_file(fp);
+	}
+	if (fp->type == KNF_TYPE_LOCAL) { // on Windows, the following block is necessary; not on UNIX
+		off_t rest = len, curr;
+		while (rest) {
+			curr = read(fp->fd, buf + l, rest);
+			if (curr == 0) break;
+			l += curr; rest -= curr;
+		}
+	} else l = my_netread(fp->fd, buf, len);
+	fp->offset += l;
+	return l;
+}
+
+off_t knet_seek(knetFile *fp, int64_t off, int whence)
+{
+	if (whence == SEEK_SET && off == fp->offset) return 0;
+	if (fp->type == KNF_TYPE_LOCAL) {
+		/* Be aware that lseek() returns the offset after seeking,
+		 * while fseek() returns zero on success. */
+		off_t offset = lseek(fp->fd, off, whence);
+		if (offset == -1) {
+            // Be silent, it is OK for knet_seek to fail when the file is streamed
+            // fprintf(stderr,"[knet_seek] %s\n", strerror(errno));
+			return -1;
+		}
+		fp->offset = offset;
+		return 0;
+	}
+    else if (fp->type == KNF_TYPE_FTP) 
+    {
+        if (whence==SEEK_CUR)
+            fp->offset += off;
+        else if (whence==SEEK_SET)
+            fp->offset = off;
+        else if ( whence==SEEK_END)
+            fp->offset = fp->file_size+off;
+		fp->is_ready = 0;
+		return 0;
+	} 
+    else if (fp->type == KNF_TYPE_HTTP) 
+    {
+		if (whence == SEEK_END) { // FIXME: can we allow SEEK_END in future?
+			fprintf(stderr, "[knet_seek] SEEK_END is not supported for HTTP. Offset is unchanged.\n");
+			errno = ESPIPE;
+			return -1;
+		}
+        if (whence==SEEK_CUR)
+            fp->offset += off;
+        else if (whence==SEEK_SET)
+            fp->offset = off;
+		fp->is_ready = 0;
+		return fp->offset;
+	}
+	errno = EINVAL;
+    fprintf(stderr,"[knet_seek] %s\n", strerror(errno));
+	return -1;
+}
+
+int knet_close(knetFile *fp)
+{
+	if (fp == 0) return 0;
+	if (fp->ctrl_fd != -1) netclose(fp->ctrl_fd); // FTP specific
+	if (fp->fd != -1) {
+		/* On Linux/Mac, netclose() is an alias of close(), but on
+		 * Windows, it is an alias of closesocket(). */
+		if (fp->type == KNF_TYPE_LOCAL) close(fp->fd);
+		else netclose(fp->fd);
+	}
+	free(fp->host); free(fp->port);
+	free(fp->response); free(fp->retr); free(fp->size_cmd); // FTP specific
+	free(fp->path); free(fp->http_host); // HTTP specific
+	free(fp);
+	return 0;
+}
+
+#ifdef KNETFILE_MAIN
+int main(void)
+{
+	char *buf;
+	knetFile *fp;
+	int type = 4, l;
+#ifdef _WIN32
+	knet_win32_init();
+#endif
+	buf = calloc(0x100000, 1);
+	if (type == 0) {
+		fp = knet_open("knetfile.c", "r");
+		knet_seek(fp, 1000, SEEK_SET);
+	} else if (type == 1) { // NCBI FTP, large file
+		fp = knet_open("ftp://ftp.ncbi.nih.gov/1000genomes/ftp/data/NA12878/alignment/NA12878.chrom6.SLX.SRP000032.2009_06.bam", "r");
+		knet_seek(fp, 2500000000ll, SEEK_SET);
+		l = knet_read(fp, buf, 255);
+	} else if (type == 2) {
+		fp = knet_open("ftp://ftp.sanger.ac.uk/pub4/treefam/tmp/index.shtml", "r");
+		knet_seek(fp, 1000, SEEK_SET);
+	} else if (type == 3) {
+		fp = knet_open("http://www.sanger.ac.uk/Users/lh3/index.shtml", "r");
+		knet_seek(fp, 1000, SEEK_SET);
+	} else if (type == 4) {
+		fp = knet_open("http://www.sanger.ac.uk/Users/lh3/ex1.bam", "r");
+		knet_read(fp, buf, 10000);
+		knet_seek(fp, 20000, SEEK_SET);
+		knet_seek(fp, 10000, SEEK_SET);
+		l = knet_read(fp, buf+10000, 10000000) + 10000;
+	}
+	if (type != 4 && type != 1) {
+		knet_read(fp, buf, 255);
+		buf[255] = 0;
+		printf("%s\n", buf);
+	} else write(fileno(stdout), buf, l);
+	knet_close(fp);
+	free(buf);
+	return 0;
+}
+#endif
diff --git a/knetfile.h b/knetfile.h
new file mode 100644
index 0000000..0a0e66f
--- /dev/null
+++ b/knetfile.h
@@ -0,0 +1,75 @@
+#ifndef KNETFILE_H
+#define KNETFILE_H
+
+#include <stdint.h>
+#include <fcntl.h>
+
+#ifndef _WIN32
+#define netread(fd, ptr, len) read(fd, ptr, len)
+#define netwrite(fd, ptr, len) write(fd, ptr, len)
+#define netclose(fd) close(fd)
+#else
+#include <winsock2.h>
+#define netread(fd, ptr, len) recv(fd, ptr, len, 0)
+#define netwrite(fd, ptr, len) send(fd, ptr, len, 0)
+#define netclose(fd) closesocket(fd)
+#endif
+
+// FIXME: currently I/O is unbuffered
+
+#define KNF_TYPE_LOCAL 1
+#define KNF_TYPE_FTP   2
+#define KNF_TYPE_HTTP  3
+
+typedef struct knetFile_s {
+	int type, fd;
+	int64_t offset;
+	char *host, *port;
+
+	// the following are for FTP only
+	int ctrl_fd, pasv_ip[4], pasv_port, max_response, no_reconnect, is_ready;
+	char *response, *retr, *size_cmd;
+	int64_t seek_offset; // for lazy seek
+    int64_t file_size;
+
+	// the following are for HTTP only
+	char *path, *http_host;
+} knetFile;
+
+#define knet_tell(fp) ((fp)->offset)
+#define knet_fileno(fp) ((fp)->fd)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef _WIN32
+	int knet_win32_init();
+	void knet_win32_destroy();
+#endif
+
+	knetFile *knet_open(const char *fn, const char *mode);
+
+	/* 
+	   This only works with local files.
+	 */
+	knetFile *knet_dopen(int fd, const char *mode);
+
+	/*
+	  If ->is_ready==0, this routine updates ->fd; otherwise, it simply
+	  reads from ->fd.
+	 */
+	off_t knet_read(knetFile *fp, void *buf, off_t len);
+
+	/*
+	  This routine only sets ->offset and ->is_ready=0. It does not
+	  communicate with the FTP server.
+	 */
+	off_t knet_seek(knetFile *fp, int64_t off, int whence);
+	int knet_close(knetFile *fp);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/kseq.h b/kseq.h
new file mode 100644
index 0000000..82face0
--- /dev/null
+++ b/kseq.h
@@ -0,0 +1,227 @@
+/* The MIT License
+
+   Copyright (c) 2008 Genome Research Ltd (GRL).
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <lh3 at sanger.ac.uk> */
+
+/*
+  2009-07-16 (lh3): in kstream_t, change "char*" to "unsigned char*"
+ */
+
+/* Last Modified: 12APR2009 */
+
+#ifndef AC_KSEQ_H
+#define AC_KSEQ_H
+
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define KS_SEP_SPACE 0 // isspace(): \t, \n, \v, \f, \r
+#define KS_SEP_TAB   1 // isspace() && !' '
+#define KS_SEP_MAX   1
+
+#define __KS_TYPE(type_t)						\
+	typedef struct __kstream_t {				\
+		unsigned char *buf;						\
+		int begin, end, is_eof;					\
+		type_t f;								\
+	} kstream_t;
+
+#define ks_eof(ks) ((ks)->is_eof && (ks)->begin >= (ks)->end)
+#define ks_rewind(ks) ((ks)->is_eof = (ks)->begin = (ks)->end = 0)
+
+#define __KS_BASIC(type_t, __bufsize)								\
+	static inline kstream_t *ks_init(type_t f)						\
+	{																\
+		kstream_t *ks = (kstream_t*)calloc(1, sizeof(kstream_t));	\
+		ks->f = f;													\
+		ks->buf = malloc(__bufsize);								\
+		return ks;													\
+	}																\
+	static inline void ks_destroy(kstream_t *ks)					\
+	{																\
+		if (ks) {													\
+			free(ks->buf);											\
+			free(ks);												\
+		}															\
+	}
+
+#define __KS_GETC(__read, __bufsize)						\
+	static inline int ks_getc(kstream_t *ks)				\
+	{														\
+		if (ks->is_eof && ks->begin >= ks->end) return -1;	\
+		if (ks->begin >= ks->end) {							\
+			ks->begin = 0;									\
+			ks->end = __read(ks->f, ks->buf, __bufsize);	\
+			if (ks->end < __bufsize) ks->is_eof = 1;		\
+			if (ks->end == 0) return -1;					\
+		}													\
+		return (int)ks->buf[ks->begin++];					\
+	}
+
+#ifndef KSTRING_T
+#define KSTRING_T kstring_t
+typedef struct __kstring_t {
+	size_t l, m;
+	char *s;
+} kstring_t;
+#endif
+
+#ifndef kroundup32
+#define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
+#endif
+
+#define __KS_GETUNTIL(__read, __bufsize)								\
+	static int ks_getuntil(kstream_t *ks, int delimiter, kstring_t *str, int *dret) \
+	{																	\
+		if (dret) *dret = 0;											\
+		str->l = 0;														\
+		if (ks->begin >= ks->end && ks->is_eof) return -1;				\
+		for (;;) {														\
+			int i;														\
+			if (ks->begin >= ks->end) {									\
+				if (!ks->is_eof) {										\
+					ks->begin = 0;										\
+					ks->end = __read(ks->f, ks->buf, __bufsize);		\
+					if (ks->end < __bufsize) ks->is_eof = 1;			\
+					if (ks->end == 0) break;							\
+				} else break;											\
+			}															\
+			if (delimiter > KS_SEP_MAX) {								\
+				for (i = ks->begin; i < ks->end; ++i)					\
+					if (ks->buf[i] == delimiter) break;					\
+			} else if (delimiter == KS_SEP_SPACE) {						\
+				for (i = ks->begin; i < ks->end; ++i)					\
+					if (isspace(ks->buf[i])) break;						\
+			} else if (delimiter == KS_SEP_TAB) {						\
+				for (i = ks->begin; i < ks->end; ++i)					\
+					if (isspace(ks->buf[i]) && ks->buf[i] != ' ') break; \
+			} else i = 0; /* never come to here! */						\
+			if (str->m - str->l < i - ks->begin + 1) {					\
+				str->m = str->l + (i - ks->begin) + 1;					\
+				kroundup32(str->m);										\
+				str->s = (char*)realloc(str->s, str->m);				\
+			}															\
+			memcpy(str->s + str->l, ks->buf + ks->begin, i - ks->begin); \
+			str->l = str->l + (i - ks->begin);							\
+			ks->begin = i + 1;											\
+			if (i < ks->end) {											\
+				if (dret) *dret = ks->buf[i];							\
+				break;													\
+			}															\
+		}																\
+		if (str->l == 0) {												\
+			str->m = 1;													\
+			str->s = (char*)calloc(1, 1);								\
+		}																\
+		str->s[str->l] = '\0';											\
+		return str->l;													\
+	}
+
+#define KSTREAM_INIT(type_t, __read, __bufsize) \
+	__KS_TYPE(type_t)							\
+	__KS_BASIC(type_t, __bufsize)				\
+	__KS_GETC(__read, __bufsize)				\
+	__KS_GETUNTIL(__read, __bufsize)
+
+#define __KSEQ_BASIC(type_t)											\
+	static inline kseq_t *kseq_init(type_t fd)							\
+	{																	\
+		kseq_t *s = (kseq_t*)calloc(1, sizeof(kseq_t));					\
+		s->f = ks_init(fd);												\
+		return s;														\
+	}																	\
+	static inline void kseq_rewind(kseq_t *ks)							\
+	{																	\
+		ks->last_char = 0;												\
+		ks->f->is_eof = ks->f->begin = ks->f->end = 0;					\
+	}																	\
+	static inline void kseq_destroy(kseq_t *ks)							\
+	{																	\
+		if (!ks) return;												\
+		free(ks->name.s); free(ks->comment.s); free(ks->seq.s);	free(ks->qual.s); \
+		ks_destroy(ks->f);												\
+		free(ks);														\
+	}
+
+/* Return value:
+   >=0  length of the sequence (normal)
+   -1   end-of-file
+   -2   truncated quality string
+ */
+#define __KSEQ_READ														\
+	static int kseq_read(kseq_t *seq)									\
+	{																	\
+		int c;															\
+		kstream_t *ks = seq->f;											\
+		if (seq->last_char == 0) { /* then jump to the next header line */ \
+			while ((c = ks_getc(ks)) != -1 && c != '>' && c != '@');	\
+			if (c == -1) return -1; /* end of file */					\
+			seq->last_char = c;											\
+		} /* the first header char has been read */						\
+		seq->comment.l = seq->seq.l = seq->qual.l = 0;					\
+		if (ks_getuntil(ks, 0, &seq->name, &c) < 0) return -1;			\
+		if (c != '\n') ks_getuntil(ks, '\n', &seq->comment, 0);			\
+		while ((c = ks_getc(ks)) != -1 && c != '>' && c != '+' && c != '@') { \
+			if (isgraph(c)) { /* printable non-space character */		\
+				if (seq->seq.l + 1 >= seq->seq.m) { /* double the memory */ \
+					seq->seq.m = seq->seq.l + 2;						\
+					kroundup32(seq->seq.m); /* rounded to next closest 2^k */ \
+					seq->seq.s = (char*)realloc(seq->seq.s, seq->seq.m); \
+				}														\
+				seq->seq.s[seq->seq.l++] = (char)c;						\
+			}															\
+		}																\
+		if (c == '>' || c == '@') seq->last_char = c; /* the first header char has been read */	\
+		seq->seq.s[seq->seq.l] = 0;	/* null terminated string */		\
+		if (c != '+') return seq->seq.l; /* FASTA */					\
+		if (seq->qual.m < seq->seq.m) {	/* allocate enough memory */	\
+			seq->qual.m = seq->seq.m;									\
+			seq->qual.s = (char*)realloc(seq->qual.s, seq->qual.m);		\
+		}																\
+		while ((c = ks_getc(ks)) != -1 && c != '\n'); /* skip the rest of '+' line */ \
+		if (c == -1) return -2; /* we should not stop here */			\
+		while ((c = ks_getc(ks)) != -1 && seq->qual.l < seq->seq.l)		\
+			if (c >= 33 && c <= 127) seq->qual.s[seq->qual.l++] = (unsigned char)c;	\
+		seq->qual.s[seq->qual.l] = 0; /* null terminated string */		\
+		seq->last_char = 0;	/* we have not come to the next header line */ \
+		if (seq->seq.l != seq->qual.l) return -2; /* qual string is shorter than seq string */ \
+		return seq->seq.l;												\
+	}
+
+#define __KSEQ_TYPE(type_t)						\
+	typedef struct {							\
+		kstring_t name, comment, seq, qual;		\
+		int last_char;							\
+		kstream_t *f;							\
+	} kseq_t;
+
+#define KSEQ_INIT(type_t, __read)				\
+	KSTREAM_INIT(type_t, __read, 4096)			\
+	__KSEQ_TYPE(type_t)							\
+	__KSEQ_BASIC(type_t)						\
+	__KSEQ_READ
+
+#endif
diff --git a/ksort.h b/ksort.h
new file mode 100644
index 0000000..16a03fd
--- /dev/null
+++ b/ksort.h
@@ -0,0 +1,271 @@
+/* The MIT License
+
+   Copyright (c) 2008 Genome Research Ltd (GRL).
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <lh3 at sanger.ac.uk> */
+
+/*
+  2008-11-16 (0.1.4):
+
+    * Fixed a bug in introsort() that happens in rare cases.
+
+  2008-11-05 (0.1.3):
+
+    * Fixed a bug in introsort() for complex comparisons.
+
+	* Fixed a bug in mergesort(). The previous version is not stable.
+
+  2008-09-15 (0.1.2):
+
+	* Accelerated introsort. On my Mac (not on another Linux machine),
+	  my implementation is as fast as std::sort on random input.
+
+	* Added combsort and in introsort, switch to combsort if the
+	  recursion is too deep.
+
+  2008-09-13 (0.1.1):
+
+	* Added k-small algorithm
+
+  2008-09-05 (0.1.0):
+
+	* Initial version
+
+*/
+
+#ifndef AC_KSORT_H
+#define AC_KSORT_H
+
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+	void *left, *right;
+	int depth;
+} ks_isort_stack_t;
+
+#define KSORT_SWAP(type_t, a, b) { register type_t t=(a); (a)=(b); (b)=t; }
+
+#define KSORT_INIT(name, type_t, __sort_lt)								\
+	void ks_mergesort_##name(size_t n, type_t array[], type_t temp[])	\
+	{																	\
+		type_t *a2[2], *a, *b;											\
+		int curr, shift;												\
+																		\
+		a2[0] = array;													\
+		a2[1] = temp? temp : (type_t*)malloc(sizeof(type_t) * n);		\
+		for (curr = 0, shift = 0; (1ul<<shift) < n; ++shift) {			\
+			a = a2[curr]; b = a2[1-curr];								\
+			if (shift == 0) {											\
+				type_t *p = b, *i, *eb = a + n;							\
+				for (i = a; i < eb; i += 2) {							\
+					if (i == eb - 1) *p++ = *i;							\
+					else {												\
+						if (__sort_lt(*(i+1), *i)) {					\
+							*p++ = *(i+1); *p++ = *i;					\
+						} else {										\
+							*p++ = *i; *p++ = *(i+1);					\
+						}												\
+					}													\
+				}														\
+			} else {													\
+				size_t i, step = 1ul<<shift;							\
+				for (i = 0; i < n; i += step<<1) {						\
+					type_t *p, *j, *k, *ea, *eb;						\
+					if (n < i + step) {									\
+						ea = a + n; eb = a;								\
+					} else {											\
+						ea = a + i + step;								\
+						eb = a + (n < i + (step<<1)? n : i + (step<<1)); \
+					}													\
+					j = a + i; k = a + i + step; p = b + i;				\
+					while (j < ea && k < eb) {							\
+						if (__sort_lt(*k, *j)) *p++ = *k++;				\
+						else *p++ = *j++;								\
+					}													\
+					while (j < ea) *p++ = *j++;							\
+					while (k < eb) *p++ = *k++;							\
+				}														\
+			}															\
+			curr = 1 - curr;											\
+		}																\
+		if (curr == 1) {												\
+			type_t *p = a2[0], *i = a2[1], *eb = array + n;				\
+			for (; p < eb; ++i) *p++ = *i;								\
+		}																\
+		if (temp == 0) free(a2[1]);										\
+	}																	\
+	void ks_heapadjust_##name(size_t i, size_t n, type_t l[])			\
+	{																	\
+		size_t k = i;													\
+		type_t tmp = l[i];												\
+		while ((k = (k << 1) + 1) < n) {								\
+			if (k != n - 1 && __sort_lt(l[k], l[k+1])) ++k;				\
+			if (__sort_lt(l[k], tmp)) break;							\
+			l[i] = l[k]; i = k;											\
+		}																\
+		l[i] = tmp;														\
+	}																	\
+	void ks_heapmake_##name(size_t lsize, type_t l[])					\
+	{																	\
+		size_t i;														\
+		for (i = (lsize >> 1) - 1; i != (size_t)(-1); --i)				\
+			ks_heapadjust_##name(i, lsize, l);							\
+	}																	\
+	void ks_heapsort_##name(size_t lsize, type_t l[])					\
+	{																	\
+		size_t i;														\
+		for (i = lsize - 1; i > 0; --i) {								\
+			type_t tmp;													\
+			tmp = *l; *l = l[i]; l[i] = tmp; ks_heapadjust_##name(0, i, l); \
+		}																\
+	}																	\
+	inline void __ks_insertsort_##name(type_t *s, type_t *t)			\
+	{																	\
+		type_t *i, *j, swap_tmp;										\
+		for (i = s + 1; i < t; ++i)										\
+			for (j = i; j > s && __sort_lt(*j, *(j-1)); --j) {			\
+				swap_tmp = *j; *j = *(j-1); *(j-1) = swap_tmp;			\
+			}															\
+	}																	\
+	void ks_combsort_##name(size_t n, type_t a[])						\
+	{																	\
+		const double shrink_factor = 1.2473309501039786540366528676643; \
+		int do_swap;													\
+		size_t gap = n;													\
+		type_t tmp, *i, *j;												\
+		do {															\
+			if (gap > 2) {												\
+				gap = (size_t)(gap / shrink_factor);					\
+				if (gap == 9 || gap == 10) gap = 11;					\
+			}															\
+			do_swap = 0;												\
+			for (i = a; i < a + n - gap; ++i) {							\
+				j = i + gap;											\
+				if (__sort_lt(*j, *i)) {								\
+					tmp = *i; *i = *j; *j = tmp;						\
+					do_swap = 1;										\
+				}														\
+			}															\
+		} while (do_swap || gap > 2);									\
+		if (gap != 1) __ks_insertsort_##name(a, a + n);					\
+	}																	\
+	void ks_introsort_##name(size_t n, type_t a[])						\
+	{																	\
+		int d;															\
+		ks_isort_stack_t *top, *stack;									\
+		type_t rp, swap_tmp;											\
+		type_t *s, *t, *i, *j, *k;										\
+																		\
+		if (n < 1) return;												\
+		else if (n == 2) {												\
+			if (__sort_lt(a[1], a[0])) { swap_tmp = a[0]; a[0] = a[1]; a[1] = swap_tmp; } \
+			return;														\
+		}																\
+		for (d = 2; 1ul<<d < n; ++d);									\
+		stack = (ks_isort_stack_t*)malloc(sizeof(ks_isort_stack_t) * ((sizeof(size_t)*d)+2)); \
+		top = stack; s = a; t = a + (n-1); d <<= 1;						\
+		while (1) {														\
+			if (s < t) {												\
+				if (--d == 0) {											\
+					ks_combsort_##name(t - s + 1, s);					\
+					t = s;												\
+					continue;											\
+				}														\
+				i = s; j = t; k = i + ((j-i)>>1) + 1;					\
+				if (__sort_lt(*k, *i)) {								\
+					if (__sort_lt(*k, *j)) k = j;						\
+				} else k = __sort_lt(*j, *i)? i : j;					\
+				rp = *k;												\
+				if (k != t) { swap_tmp = *k; *k = *t; *t = swap_tmp; }	\
+				for (;;) {												\
+					do ++i; while (__sort_lt(*i, rp));					\
+					do --j; while (i <= j && __sort_lt(rp, *j));		\
+					if (j <= i) break;									\
+					swap_tmp = *i; *i = *j; *j = swap_tmp;				\
+				}														\
+				swap_tmp = *i; *i = *t; *t = swap_tmp;					\
+				if (i-s > t-i) {										\
+					if (i-s > 16) { top->left = s; top->right = i-1; top->depth = d; ++top; } \
+					s = t-i > 16? i+1 : t;								\
+				} else {												\
+					if (t-i > 16) { top->left = i+1; top->right = t; top->depth = d; ++top; } \
+					t = i-s > 16? i-1 : s;								\
+				}														\
+			} else {													\
+				if (top == stack) {										\
+					free(stack);										\
+					__ks_insertsort_##name(a, a+n);						\
+					return;												\
+				} else { --top; s = (type_t*)top->left; t = (type_t*)top->right; d = top->depth; } \
+			}															\
+		}																\
+	}																	\
+	/* This function is adapted from: http://ndevilla.free.fr/median/ */ \
+	/* 0 <= kk < n */													\
+	type_t ks_ksmall_##name(size_t n, type_t arr[], size_t kk)			\
+	{																	\
+		type_t *low, *high, *k, *ll, *hh, *mid;							\
+		low = arr; high = arr + n - 1; k = arr + kk;					\
+		for (;;) {														\
+			if (high <= low) return *k;									\
+			if (high == low + 1) {										\
+				if (__sort_lt(*high, *low)) KSORT_SWAP(type_t, *low, *high); \
+				return *k;												\
+			}															\
+			mid = low + (high - low) / 2;								\
+			if (__sort_lt(*high, *mid)) KSORT_SWAP(type_t, *mid, *high); \
+			if (__sort_lt(*high, *low)) KSORT_SWAP(type_t, *low, *high); \
+			if (__sort_lt(*low, *mid)) KSORT_SWAP(type_t, *mid, *low);	\
+			KSORT_SWAP(type_t, *mid, *(low+1));							\
+			ll = low + 1; hh = high;									\
+			for (;;) {													\
+				do ++ll; while (__sort_lt(*ll, *low));					\
+				do --hh; while (__sort_lt(*low, *hh));					\
+				if (hh < ll) break;										\
+				KSORT_SWAP(type_t, *ll, *hh);							\
+			}															\
+			KSORT_SWAP(type_t, *low, *hh);								\
+			if (hh <= k) low = ll;										\
+			if (hh >= k) high = hh - 1;									\
+		}																\
+	}
+
+#define ks_mergesort(name, n, a, t) ks_mergesort_##name(n, a, t)
+#define ks_introsort(name, n, a) ks_introsort_##name(n, a)
+#define ks_combsort(name, n, a) ks_combsort_##name(n, a)
+#define ks_heapsort(name, n, a) ks_heapsort_##name(n, a)
+#define ks_heapmake(name, n, a) ks_heapmake_##name(n, a)
+#define ks_heapadjust(name, i, n, a) ks_heapadjust_##name(i, n, a)
+#define ks_ksmall(name, n, a, k) ks_ksmall_##name(n, a, k)
+
+#define ks_lt_generic(a, b) ((a) < (b))
+#define ks_lt_str(a, b) (strcmp((a), (b)) < 0)
+
+typedef const char *ksstr_t;
+
+#define KSORT_INIT_GENERIC(type_t) KSORT_INIT(type_t, type_t, ks_lt_generic)
+#define KSORT_INIT_STR KSORT_INIT(str, ksstr_t, ks_lt_str)
+
+#endif
diff --git a/kstring.c b/kstring.c
new file mode 100644
index 0000000..e0203fa
--- /dev/null
+++ b/kstring.c
@@ -0,0 +1,165 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdint.h>
+#include "kstring.h"
+
+int ksprintf(kstring_t *s, const char *fmt, ...)
+{
+	va_list ap;
+	int l;
+	va_start(ap, fmt);
+	l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap); // This line does not work with glibc 2.0. See `man snprintf'.
+	va_end(ap);
+	if (l + 1 > s->m - s->l) {
+		s->m = s->l + l + 2;
+		kroundup32(s->m);
+		s->s = (char*)realloc(s->s, s->m);
+		va_start(ap, fmt);
+		l = vsnprintf(s->s + s->l, s->m - s->l, fmt, ap);
+	}
+	va_end(ap);
+	s->l += l;
+	return l;
+}
+
+// s MUST BE a null terminated string; l = strlen(s)
+int ksplit_core(char *s, int delimiter, int *_max, int **_offsets)
+{
+	int i, n, max, last_char, last_start, *offsets, l;
+	n = 0; max = *_max; offsets = *_offsets;
+	l = strlen(s);
+	
+#define __ksplit_aux do {												\
+		if (_offsets) {													\
+			s[i] = 0;													\
+			if (n == max) {												\
+				max = max? max<<1 : 2;									\
+				offsets = (int*)realloc(offsets, sizeof(int) * max);	\
+			}															\
+			offsets[n++] = last_start;									\
+		} else ++n;														\
+	} while (0)
+
+	for (i = 0, last_char = last_start = 0; i <= l; ++i) {
+		if (delimiter == 0) {
+			if (isspace(s[i]) || s[i] == 0) {
+				if (isgraph(last_char)) __ksplit_aux; // the end of a field
+			} else {
+				if (isspace(last_char) || last_char == 0) last_start = i;
+			}
+		} else {
+			if (s[i] == delimiter || s[i] == 0) {
+				if (last_char != 0 && last_char != delimiter) __ksplit_aux; // the end of a field
+			} else {
+				if (last_char == delimiter || last_char == 0) last_start = i;
+			}
+		}
+		last_char = s[i];
+	}
+	*_max = max; *_offsets = offsets;
+	return n;
+}
+
+/**********************
+ * Boyer-Moore search *
+ **********************/
+
+// reference: http://www-igm.univ-mlv.fr/~lecroq/string/node14.html
+int *ksBM_prep(const uint8_t *pat, int m)
+{
+	int i, *suff, *prep, *bmGs, *bmBc;
+	prep = calloc(m + 256, 1);
+	bmGs = prep; bmBc = prep + m;
+	{ // preBmBc()
+		for (i = 0; i < 256; ++i) bmBc[i] = m;
+		for (i = 0; i < m - 1; ++i) bmBc[pat[i]] = m - i - 1;
+	}
+	suff = calloc(m, sizeof(int));
+	{ // suffixes()
+		int f = 0, g;
+		suff[m - 1] = m;
+		g = m - 1;
+		for (i = m - 2; i >= 0; --i) {
+			if (i > g && suff[i + m - 1 - f] < i - g)
+				suff[i] = suff[i + m - 1 - f];
+			else {
+				if (i < g) g = i;
+				f = i;
+				while (g >= 0 && pat[g] == pat[g + m - 1 - f]) --g;
+				suff[i] = f - g;
+			}
+		}
+	}
+	{ // preBmGs()
+		int j = 0;
+		for (i = 0; i < m; ++i) bmGs[i] = m;
+		for (i = m - 1; i >= 0; --i)
+			if (suff[i] == i + 1)
+				for (; j < m - 1 - i; ++j)
+					if (bmGs[j] == m)
+						bmGs[j] = m - 1 - i;
+		for (i = 0; i <= m - 2; ++i)
+			bmGs[m - 1 - suff[i]] = m - 1 - i;
+	}
+	free(suff);
+	return prep;
+}
+
+int *ksBM_search(const uint8_t *str, int n, const uint8_t *pat, int m, int *_prep, int *n_matches)
+{
+	int i, j, *prep, *bmGs, *bmBc;
+	int *matches = 0, mm = 0, nm = 0;
+	prep = _prep? _prep : ksBM_prep(pat, m);
+	bmGs = prep; bmBc = prep + m;
+	j = 0;
+	while (j <= n - m) {
+		for (i = m - 1; i >= 0 && pat[i] == str[i+j]; --i);
+		if (i < 0) {
+			if (nm == mm) {
+				mm = mm? mm<<1 : 1;
+				matches = realloc(matches, mm * sizeof(int));
+			}
+			matches[nm++] = j;
+			j += bmGs[0];
+		} else {
+			int max = bmBc[str[i+j]] - m + 1 + i;
+			if (max < bmGs[i]) max = bmGs[i];
+			j += max;
+		}
+	}
+	*n_matches = nm;
+	if (_prep == 0) free(prep);
+	return matches;
+}
+
+#ifdef KSTRING_MAIN
+#include <stdio.h>
+int main()
+{
+	kstring_t *s;
+	int *fields, n, i;
+	s = (kstring_t*)calloc(1, sizeof(kstring_t));
+	// test ksprintf()
+	ksprintf(s, " abcdefg:    %d ", 100);
+	printf("'%s'\n", s->s);
+	// test ksplit()
+	fields = ksplit(s, 0, &n);
+	for (i = 0; i < n; ++i)
+		printf("field[%d] = '%s'\n", i, s->s + fields[i]);
+	free(s);
+
+	{
+		static char *str = "abcdefgcdg";
+		static char *pat = "cd";
+		int n, *matches;
+		matches = ksBM_search(str, strlen(str), pat, strlen(pat), 0, &n);
+		printf("%d: \n", n);
+		for (i = 0; i < n; ++i)
+			printf("- %d\n", matches[i]);
+		free(matches);
+	}
+	return 0;
+}
+#endif
diff --git a/kstring.h b/kstring.h
new file mode 100644
index 0000000..f4e5a99
--- /dev/null
+++ b/kstring.h
@@ -0,0 +1,68 @@
+#ifndef KSTRING_H
+#define KSTRING_H
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#ifndef kroundup32
+#define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
+#endif
+
+#ifndef KSTRING_T
+#define KSTRING_T kstring_t
+typedef struct __kstring_t {
+	size_t l, m;
+	char *s;
+} kstring_t;
+#endif
+
+int ksprintf(kstring_t *s, const char *fmt, ...);
+int ksplit_core(char *s, int delimiter, int *_max, int **_offsets);
+
+// calculate the auxiliary array, allocated by calloc()
+int *ksBM_prep(const uint8_t *pat, int m);
+
+/* Search pat in str and returned the list of matches. The size of the
+ * list is returned as n_matches. _prep is the array returned by
+ * ksBM_prep(). If it is a NULL pointer, ksBM_prep() will be called. */
+int *ksBM_search(const uint8_t *str, int n, const uint8_t *pat, int m, int *_prep, int *n_matches);
+
+static inline int kputsn(const char *p, int l, kstring_t *s)
+{
+	if (s->l + l + 1 >= s->m) {
+		s->m = s->l + l + 2;
+		kroundup32(s->m);
+		s->s = (char*)realloc(s->s, s->m);
+	}
+	strncpy(s->s + s->l, p, l);
+	s->l += l;
+	s->s[s->l] = 0;
+	return l;
+}
+
+static inline int kputs(const char *p, kstring_t *s)
+{
+	return kputsn(p, strlen(p), s);
+}
+
+static inline int kputc(int c, kstring_t *s)
+{
+	if (s->l + 1 >= s->m) {
+		s->m = s->l + 2;
+		kroundup32(s->m);
+		s->s = (char*)realloc(s->s, s->m);
+	}
+	s->s[s->l++] = c;
+	s->s[s->l] = 0;
+	return c;
+}
+
+static inline int *ksplit(kstring_t *s, int delimiter, int *n)
+{
+	int max = 0, *offsets = 0;
+	*n = ksplit_core(s->s, delimiter, &max, &offsets);
+	return offsets;
+}
+
+#endif
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..364abe5
--- /dev/null
+++ b/main.c
@@ -0,0 +1,290 @@
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include "bgzf.h"
+#include "tabix.h"
+
+#define PACKAGE_VERSION "0.2.5 (r964)"
+
+#define error(...) { fprintf(stderr,__VA_ARGS__); return -1; }
+
+int reheader_file(const char *header, const char *file, int meta)
+{
+    BGZF *fp = bgzf_open(file,"r");
+    if (bgzf_read_block(fp) != 0 || !fp->block_length)
+        return -1;
+    
+    char *buffer = fp->uncompressed_block;
+    int skip_until = 0;
+
+    if ( buffer[0]==meta )
+    {
+        skip_until = 1;
+
+        // Skip the header
+        while (1)
+        {
+            if ( buffer[skip_until]=='\n' )
+            {
+                skip_until++;
+                if ( skip_until>=fp->block_length )
+                {
+                    if (bgzf_read_block(fp) != 0 || !fp->block_length)
+                        error("no body?\n");
+                    skip_until = 0;
+                }
+                // The header has finished
+                if ( buffer[skip_until]!=meta ) break;
+            }
+            skip_until++;
+            if ( skip_until>=fp->block_length )
+            {
+                if (bgzf_read_block(fp) != 0 || !fp->block_length)
+                    error("no body?\n");
+                skip_until = 0;
+            }
+        }
+    }
+
+    FILE *fh = fopen(header,"r");
+    if ( !fh )
+        error("%s: %s", header,strerror(errno));
+    int page_size = getpagesize();
+    char *buf = valloc(page_size);
+    BGZF *bgzf_out = bgzf_fdopen(fileno(stdout), "w");
+    ssize_t nread;
+    while ( (nread=fread(buf,1,page_size-1,fh))>0 )
+    {
+        if ( nread<page_size-1 && buf[nread-1]!='\n' )
+            buf[nread++] = '\n';
+        if (bgzf_write(bgzf_out, buf, nread) < 0) error("Error: %s\n",bgzf_out->error);
+    }
+    fclose(fh);
+
+    if ( fp->block_length - skip_until > 0 )
+    {
+        if (bgzf_write(bgzf_out, buffer+skip_until, fp->block_length-skip_until) < 0) 
+            error("Error: %s\n",fp->error);
+    }
+    if (bgzf_flush(bgzf_out) < 0) 
+        error("Error: %s\n",bgzf_out->error);
+
+    while (1)
+    {
+#ifdef _USE_KNETFILE
+        nread = knet_read(fp->x.fpr, buf, page_size);
+#else
+        nread = fread(buf, 1, page_size, fp->file);
+#endif
+        if ( nread<=0 ) 
+            break;
+
+#ifdef _USE_KNETFILE
+        int count = fwrite(buf, 1, nread, bgzf_out->x.fpw);
+#else
+        int count = fwrite(buf, 1, nread, bgzf_out->file);
+#endif
+        if (count != nread)
+            error("Write failed, wrote %d instead of %d bytes.\n", count,(int)nread);
+    }
+
+    if (bgzf_close(bgzf_out) < 0) 
+        error("Error: %s\n",bgzf_out->error);
+   
+    return 0;
+}
+
+
+int main(int argc, char *argv[])
+{
+	int c, skip = -1, meta = -1, list_chrms = 0, force = 0, print_header = 0, bed_reg = 0;
+	ti_conf_t conf = ti_conf_gff;
+    const char *reheader = NULL;
+	while ((c = getopt(argc, argv, "p:s:b:e:0S:c:lhfBr:")) >= 0) {
+		switch (c) {
+		case 'B': bed_reg = 1; break;
+		case '0': conf.preset |= TI_FLAG_UCSC; break;
+		case 'S': skip = atoi(optarg); break;
+		case 'c': meta = optarg[0]; break;
+		case 'p':
+			if (strcmp(optarg, "gff") == 0) conf = ti_conf_gff;
+			else if (strcmp(optarg, "bed") == 0) conf = ti_conf_bed;
+			else if (strcmp(optarg, "sam") == 0) conf = ti_conf_sam;
+			else if (strcmp(optarg, "vcf") == 0 || strcmp(optarg, "vcf4") == 0) conf = ti_conf_vcf;
+			else if (strcmp(optarg, "psltbl") == 0) conf = ti_conf_psltbl;
+			else {
+				fprintf(stderr, "[main] unrecognized preset '%s'\n", optarg);
+				return 1;
+			}
+			break;
+		case 's': conf.sc = atoi(optarg); break;
+		case 'b': conf.bc = atoi(optarg); break;
+		case 'e': conf.ec = atoi(optarg); break;
+        case 'l': list_chrms = 1; break;
+        case 'h': print_header = 1; break;
+		case 'f': force = 1; break;
+        case 'r': reheader = optarg; break;
+		}
+	}
+	if (skip >= 0) conf.line_skip = skip;
+	if (meta >= 0) conf.meta_char = meta;
+	if (optind == argc) {
+		fprintf(stderr, "\n");
+		fprintf(stderr, "Program: tabix (TAB-delimited file InderXer)\n");
+		fprintf(stderr, "Version: %s\n\n", PACKAGE_VERSION);
+		fprintf(stderr, "Usage:   tabix <in.tab.bgz> [region1 [region2 [...]]]\n\n");
+		fprintf(stderr, "Options: -p STR     preset: gff, bed, sam, vcf, psltbl [gff]\n");
+		fprintf(stderr, "         -s INT     sequence name column [1]\n");
+		fprintf(stderr, "         -b INT     start column [4]\n");
+		fprintf(stderr, "         -e INT     end column; can be identical to '-b' [5]\n");
+		fprintf(stderr, "         -S INT     skip first INT lines [0]\n");
+		fprintf(stderr, "         -c CHAR    symbol for comment/meta lines [#]\n");
+	    fprintf(stderr, "         -r FILE    replace the header with the content of FILE [null]\n");
+		fprintf(stderr, "         -B         region1 is a BED file (entire file will be read)\n");
+		fprintf(stderr, "         -0         zero-based coordinate\n");
+		fprintf(stderr, "         -h         print the header lines\n");
+		fprintf(stderr, "         -l         list chromosome names\n");
+		fprintf(stderr, "         -f         force to overwrite the index\n");
+		fprintf(stderr, "\n");
+		return 1;
+	}
+    if (list_chrms) {
+		ti_index_t *idx;
+		int i, n;
+		const char **names;
+		idx = ti_index_load(argv[optind]);
+		if (idx == 0) {
+			fprintf(stderr, "[main] fail to load the index file.\n");
+			return 1;
+		}
+		names = ti_seqname(idx, &n);
+		for (i = 0; i < n; ++i) printf("%s\n", names[i]);
+		free(names);
+		ti_index_destroy(idx);
+		return 0;
+	}
+    if (reheader)
+        return reheader_file(reheader,argv[optind],conf.meta_char);
+
+	struct stat stat_tbi,stat_vcf;
+    char *fnidx = calloc(strlen(argv[optind]) + 5, 1);
+   	strcat(strcpy(fnidx, argv[optind]), ".tbi");
+
+	if (optind + 1 == argc) {
+		if (force == 0) {
+			if (stat(fnidx, &stat_tbi) == 0) 
+            {
+                // Before complaining, check if the VCF file isn't newer. This is a common source of errors,
+                //  people tend not to notice that tabix failed
+                stat(argv[optind], &stat_vcf);
+                if ( stat_vcf.st_mtime <= stat_tbi.st_mtime )
+                {
+                    fprintf(stderr, "[tabix] the index file exists. Please use '-f' to overwrite.\n");
+                    free(fnidx);
+                    return 1;
+                }
+			}
+		}
+        if ( bgzf_check_bgzf(argv[optind])!=1 )
+        {
+            fprintf(stderr,"[tabix] was bgzip used to compress this file? %s\n", argv[optind]);
+            free(fnidx);
+            return 1;
+        }
+		return ti_index_build(argv[optind], &conf);
+	}
+	{ // retrieve
+		tabix_t *t;
+        // Common source of errors: new VCF is used with an old index
+        stat(fnidx, &stat_tbi);
+        stat(argv[optind], &stat_vcf);
+        if ( force==0 && stat_vcf.st_mtime > stat_tbi.st_mtime )
+        {
+            fprintf(stderr, "[tabix] the index file is older than the vcf file. Please use '-f' to overwrite or reindex.\n");
+            free(fnidx);
+            return 1;
+        }
+        free(fnidx);
+
+		if ((t = ti_open(argv[optind], 0)) == 0) {
+			fprintf(stderr, "[main] fail to open the data file.\n");
+			return 1;
+		}
+		if (strcmp(argv[optind+1], ".") == 0) { // retrieve all
+			ti_iter_t iter;
+			const char *s;
+			int len;
+			iter = ti_query(t, 0, 0, 0);
+			while ((s = ti_read(t, iter, &len)) != 0) {
+				fputs(s, stdout); fputc('\n', stdout);
+			}
+			ti_iter_destroy(iter);
+		} else { // retrieve from specified regions
+			int i, len;
+            ti_iter_t iter;
+            const char *s;
+			const ti_conf_t *idxconf;
+
+			if (ti_lazy_index_load(t) < 0 && bed_reg == 0) {
+                fprintf(stderr,"[tabix] failed to load the index file.\n");
+                return 1;
+            }
+			idxconf = ti_get_conf(t->idx);
+
+            if ( print_header )
+            {
+                // If requested, print the header lines here
+                iter = ti_query(t, 0, 0, 0);
+                while ((s = ti_read(t, iter, &len)) != 0) {
+                    if ((int)(*s) != idxconf->meta_char) break;
+                    fputs(s, stdout); fputc('\n', stdout);
+                }
+                ti_iter_destroy(iter);
+            }
+			if (bed_reg) {
+				extern int bed_overlap(const void *_h, const char *chr, int beg, int end);
+				extern void *bed_read(const char *fn);
+				extern void bed_destroy(void *_h);
+
+				const ti_conf_t *conf_ = idxconf? idxconf : &conf; // use the index file if available
+				void *bed = bed_read(argv[optind+1]); // load the BED file
+				ti_interval_t intv;
+
+				if (bed == 0) {
+					fprintf(stderr, "[main] fail to read the BED file.\n");
+					return 1;
+				}
+				iter = ti_query(t, 0, 0, 0);
+				while ((s = ti_read(t, iter, &len)) != 0) {
+					int c;
+					ti_get_intv(conf_, len, (char*)s, &intv);
+					c = *intv.se; *intv.se = '\0';
+					if (bed_overlap(bed, intv.ss, intv.beg, intv.end)) {
+						*intv.se = c;
+						puts(s);
+					}
+					*intv.se = c;
+				}
+                ti_iter_destroy(iter);
+				bed_destroy(bed);
+			} else {
+				for (i = optind + 1; i < argc; ++i) {
+					int tid, beg, end;
+					if (ti_parse_region(t->idx, argv[i], &tid, &beg, &end) == 0) {
+						iter = ti_queryi(t, tid, beg, end);
+							while ((s = ti_read(t, iter, &len)) != 0) {
+							fputs(s, stdout); fputc('\n', stdout);
+						}
+						ti_iter_destroy(iter);
+					} 
+            	    // else fprintf(stderr, "[main] invalid region: unknown target name or minus interval.\n");
+				}
+			}
+		}
+		ti_close(t);
+	}
+	return 0;
+}
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..592bf30
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,47 @@
+#include "tabix.hpp"
+#include <vector>
+
+using namespace std;
+
+int main(int argc, char** argv) {
+
+    if (argc < 2) {
+        cerr << argv[0] << " [file] [ [region] ... ]" << endl
+             << "Writes out regions from bgzf-compressed, tabix-indexed file." << endl
+             << "Supply 'header' to print out the header, and no regions to" << endl
+             << "print the contents of the entire file." << endl;
+        return 1;
+    }
+
+    string filename = string(argv[1]);
+    vector<string> regions;
+    for (int i = 2; i < argc; ++i) {
+        regions.push_back(string(argv[i]));
+    }
+
+    Tabix file(filename);
+
+    if (!regions.empty()) {
+        for (vector<string>::iterator r = regions.begin(); r != regions.end(); ++r) { 
+            string& region = *r;
+            if (region == "header") {
+                string header;
+                file.getHeader(header);
+                cout << header;
+            } else {
+                string line;
+                file.setRegion(region);
+                while (file.getNextLine(line)) {
+                    cout << line << endl;
+                }
+            }
+        }
+    } else {
+        string line;
+        while (file.getNextLine(line)) {
+            cout << line << endl;
+        }
+    }
+
+    return 0;
+}
diff --git a/perl/MANIFEST b/perl/MANIFEST
new file mode 100644
index 0000000..877da96
--- /dev/null
+++ b/perl/MANIFEST
@@ -0,0 +1,8 @@
+MANIFEST
+typemap
+Tabix.xs
+Tabix.pm
+TabixIterator.pm
+Makefile.PL
+t/01local.t
+t/02remote.t
\ No newline at end of file
diff --git a/perl/Makefile.PL b/perl/Makefile.PL
new file mode 100644
index 0000000..3ea6e8d
--- /dev/null
+++ b/perl/Makefile.PL
@@ -0,0 +1,8 @@
+use ExtUtils::MakeMaker;
+WriteMakefile(
+			  NAME         => 'Tabix',
+			  VERSION_FROM => 'Tabix.pm',
+			  LIBS         => ['-lz -L.. -ltabix'],
+			  DEFINE       => '-D_FILE_OFFSET_BITS=64 -D_USE_KNETFILE',
+			  INC          => '-I..',
+			 );
diff --git a/perl/Tabix.pm b/perl/Tabix.pm
new file mode 100644
index 0000000..fd7165d
--- /dev/null
+++ b/perl/Tabix.pm
@@ -0,0 +1,76 @@
+package Tabix;
+
+use strict;
+use warnings;
+use Carp qw/croak/;
+
+use TabixIterator;
+
+require Exporter;
+
+our @ISA = qw/Exporter/;
+our @EXPORT = qw/tabix_open tabix_close tabix_read tabix_query tabix_getnames tabix_iter_free/;
+
+our $VERSION = '0.2.0';
+
+require XSLoader;
+XSLoader::load('Tabix', $VERSION);
+
+sub new {
+  my $invocant = shift;
+  my %args = @_;
+  $args{-data} || croak("-data argument required");
+  my $class = ref($invocant) || $invocant;
+  my $self = {};
+  bless($self, $class);
+  $self->open($args{-data}, $args{-index});
+  return $self;
+}
+
+sub open {
+  my ($self, $fn, $fnidx) = @_;
+  $self->close;
+  $self->{_fn} = $fn;
+  $self->{_fnidx} = $fnidx;
+  $self->{_} = $fnidx? tabix_open($fn, $fnidx) : tabix_open($fn);
+}
+
+sub close {
+  my $self = shift;
+  if ($self->{_}) {
+	tabix_close($self->{_});
+	delete($self->{_}); delete($self->{_fn}); delete($self->{_fnidx});
+  }
+}
+
+sub DESTROY {
+  my $self = shift;
+  $self->close;
+}
+
+sub query {
+  my $self = shift;
+  my $iter;
+  if (@_) {
+	$iter = tabix_query($self->{_}, @_);
+  } else {
+	$iter = tabix_query($self->{_});
+  }
+  my $i = TabixIterator->new;
+  $i->set($iter);
+  return $i;
+}
+
+sub read {
+  my $self = shift;
+  my $iter = shift;
+  return tabix_read($self->{_}, $iter->get);
+}
+
+sub getnames {
+  my $self = shift;
+  return tabix_getnames($self->{_});
+}
+
+1;
+__END__
diff --git a/perl/Tabix.xs b/perl/Tabix.xs
new file mode 100644
index 0000000..50dabb1
--- /dev/null
+++ b/perl/Tabix.xs
@@ -0,0 +1,71 @@
+#include "EXTERN.h"
+#include "perl.h"
+#include "XSUB.h"
+
+#include <stdlib.h>
+#include "tabix.h"
+
+MODULE = Tabix PACKAGE = Tabix
+
+tabix_t*
+tabix_open(fn, fnidx=0)
+	char *fn
+	char *fnidx
+  CODE:
+	RETVAL = ti_open(fn, fnidx);
+  OUTPUT:
+	RETVAL
+
+void
+tabix_close(t)
+	tabix_t *t
+  CODE:
+	ti_close(t);
+
+ti_iter_t
+tabix_query(t, seq=0, beg=0, end=0x7fffffff)
+	tabix_t *t
+	const char *seq
+	int beg
+	int end
+  PREINIT:
+  CODE:
+	RETVAL = ti_query(t, seq, beg, end);
+  OUTPUT:
+	RETVAL
+
+SV*
+tabix_read(t, iter)
+	tabix_t *t
+	ti_iter_t iter
+  PREINIT:
+	const char *s;
+	int len;
+  CODE:
+	s = ti_read(t, iter, &len);
+	if (s == 0)
+	   return XSRETURN_EMPTY;
+	RETVAL = newSVpv(s, len);
+  OUTPUT:
+	RETVAL
+
+void
+tabix_getnames(t)
+	tabix_t *t
+  PREINIT:
+	const char **names;
+	int i, n;
+  PPCODE:
+	ti_lazy_index_load(t);
+	names = ti_seqname(t->idx, &n);
+	for (i = 0; i < n; ++i)
+		XPUSHs(sv_2mortal(newSVpv(names[i], 0)));
+	free(names);
+
+MODULE = Tabix PACKAGE = TabixIterator
+
+void
+tabix_iter_free(iter)
+	ti_iter_t iter
+  CODE:
+	ti_iter_destroy(iter);
diff --git a/perl/TabixIterator.pm b/perl/TabixIterator.pm
new file mode 100644
index 0000000..335194a
--- /dev/null
+++ b/perl/TabixIterator.pm
@@ -0,0 +1,41 @@
+package TabixIterator;
+
+use strict;
+use warnings;
+use Carp qw/croak/;
+
+require Exporter;
+
+our @ISA = qw/Exporter/;
+our @EXPORT = qw/tabix_iter_free/;
+
+our $VERSION = '0.2.0';
+
+require XSLoader;
+XSLoader::load('Tabix', $VERSION);
+
+sub new {
+  my $invocant = shift;
+  my $class = ref($invocant) || $invocant;
+  my $self = {};
+  bless($self, $class);
+  return $self;
+}
+
+sub set {
+  my ($self, $iter) = @_;
+  $self->{_} = $iter;
+}
+
+sub get {
+  my $self = shift;
+  return $self->{_};
+}
+
+sub DESTROY {
+  my $self = shift;
+  tabix_iter_free($self->{_}) if ($self->{_});
+}
+
+1;
+__END__
diff --git a/perl/t/01local.t b/perl/t/01local.t
new file mode 100644
index 0000000..4eb6534
--- /dev/null
+++ b/perl/t/01local.t
@@ -0,0 +1,28 @@
+#-*-Perl-*-
+use Test::More tests => 9;
+BEGIN { use_ok('Tabix') };
+
+{ # C-like low-level interface
+	my $t = tabix_open("../example.gtf.gz");
+	ok($t);
+	my $iter = tabix_query($t, "chr1", 0, 2000);
+	ok($iter);
+	$_ = 0;
+	++$_ while (tabix_read($t, $iter));
+	is($_, 6);
+	tabix_iter_free($iter);
+	@_ = tabix_getnames($t);
+	is(scalar(@_), 2);
+}
+
+{ # OOP high-level interface
+	my $t = Tabix->new(-data=>"../example.gtf.gz");
+	ok($t);
+	my $iter = $t->query("chr1", 3000, 5000);
+	ok($iter);
+	$_ = 0;
+	++$_ while ($t->read($iter));
+	is($_, 27);
+	@_ = $t->getnames;
+	is($_[1], "chr2");
+}
diff --git a/perl/t/02remote.t b/perl/t/02remote.t
new file mode 100644
index 0000000..0668e8f
--- /dev/null
+++ b/perl/t/02remote.t
@@ -0,0 +1,28 @@
+#-*-Perl-*-
+use Test::More tests => 9;
+BEGIN { use_ok('Tabix') };
+
+{ # FTP access
+	my $t = Tabix->new(-data=>"ftp://ftp.ncbi.nih.gov/1000genomes/ftp/pilot_data/release/2010_03/pilot1/CEU.SRP000031.2010_03.genotypes.vcf.gz");
+	ok($t);
+	my $iter = $t->query("1", 1000000, 1100000);
+	ok($iter);
+	$_ = 0;
+	++$_ while ($t->read($iter));
+	is($_, 306);
+	@_ = $t->getnames;
+	is(scalar(@_), 22);
+}
+
+{ # FTP access plus FTP index
+	my $t = Tabix->new(-data=>"ftp://ftp.ncbi.nih.gov/1000genomes/ftp/pilot_data/release/2010_03/pilot1/CEU.SRP000031.2010_03.genotypes.vcf.gz",
+					   -index=>"ftp://ftp.ncbi.nih.gov/1000genomes/ftp/pilot_data/release/2010_03/pilot1/CEU.SRP000031.2010_03.genotypes.vcf.gz.tbi");
+	ok($t);
+	my $iter = $t->query("19", 10000000, 10100000);
+	ok($iter);
+	$_ = 0;
+	++$_ while ($t->read($iter));
+	is($_, 268);
+	@_ = $t->getnames;
+	is(scalar(@_), 22);
+}
diff --git a/perl/typemap b/perl/typemap
new file mode 100644
index 0000000..a312f99
--- /dev/null
+++ b/perl/typemap
@@ -0,0 +1,3 @@
+TYPEMAP
+tabix_t*   T_PTROBJ
+ti_iter_t  T_PTROBJ
\ No newline at end of file
diff --git a/python/setup.py b/python/setup.py
new file mode 100644
index 0000000..2771eda
--- /dev/null
+++ b/python/setup.py
@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+#
+# The MIT License
+#
+# Copyright (c) 2011 Seoul National University.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+# Contact: Hyeshik Chang <hyeshik at snu.ac.kr>
+
+from distutils.core import setup, Extension
+
+# Change this to True when you need the knetfile support.
+USE_KNETFILE = False
+
+TABIX_SOURCE_FILES = [
+    '../bgzf.c', '../bgzip.c', '../index.c', '../knetfile.c', '../kstring.c'
+]
+
+define_options = [('_FILE_OFFSET_BITS', 64)]
+if USE_KNETFILE:
+    define_options.append(('_USE_KNETFILE', 1))
+
+ext_modules = [Extension("tabix", ["tabixmodule.c"] + TABIX_SOURCE_FILES,
+                         include_dirs=['..'],
+                         libraries=['z'],
+                         define_macros=define_options)]
+
+setup (name = 'tabix',
+       version = '1.0',
+       description = 'Python interface to tabix, a generic indexer '
+                     'for TAB-delimited genome position files',
+       author = 'Hyeshik Chang',
+       author_email = 'hyeshik at snu.ac.kr',
+       license = 'MIT',
+       ext_modules = ext_modules
+)
diff --git a/python/tabixmodule.c b/python/tabixmodule.c
new file mode 100644
index 0000000..d04d097
--- /dev/null
+++ b/python/tabixmodule.c
@@ -0,0 +1,408 @@
+/*-
+ * The MIT License
+ *
+ * Copyright (c) 2011 Seoul National University.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/*
+ * Contact: Hyeshik Chang <hyeshik at snu.ac.kr>
+ */
+
+#define PY_SSIZE_T_CLEAN
+#include "Python.h"
+#include "tabix.h"
+
+static PyObject *TabixError;
+
+typedef struct {
+    PyObject_HEAD
+    tabix_t *tb;
+    char *fn;
+} TabixObject;
+
+typedef struct {
+    PyObject_HEAD
+    TabixObject *tbobj;
+    ti_iter_t iter;
+} TabixIteratorObject;
+
+static PyTypeObject Tabix_Type, TabixIterator_Type;
+
+/* --- TabixIterator --------------------------------------------------- */
+
+static PyObject *
+tabixiter_create(TabixObject *parentidx, ti_iter_t iter)
+{
+    TabixIteratorObject *self;
+
+    self = PyObject_New(TabixIteratorObject, &TabixIterator_Type);
+    if (self == NULL)
+        return NULL;
+
+    Py_INCREF(parentidx);
+    self->tbobj = parentidx;
+    self->iter = iter;
+
+    return (PyObject *)self;
+}
+
+static void
+tabixiter_dealloc(TabixIteratorObject *self)
+{
+    ti_iter_destroy(self->iter);
+    Py_DECREF(self->tbobj);
+    PyObject_Del(self);
+}
+
+static PyObject *
+tabixiter_iter(PyObject *self)
+{
+    Py_INCREF(self);
+    return self;
+}
+
+#if PY_MAJOR_VERSION < 3
+# define PYOBJECT_FROM_STRING_AND_SIZE PyString_FromStringAndSize
+#else
+# define PYOBJECT_FROM_STRING_AND_SIZE PyUnicode_FromStringAndSize
+#endif
+
+static PyObject *
+tabixiter_iternext(TabixIteratorObject *self)
+{
+    const char *chunk;
+    int len, i;
+
+    chunk = ti_read(self->tbobj->tb, self->iter, &len);
+    if (chunk != NULL) {
+        PyObject *ret, *column;
+        Py_ssize_t colidx;
+        const char *ptr, *begin;
+
+        ret = PyList_New(0);
+        if (ret == NULL)
+            return NULL;
+
+        colidx = 0;
+        ptr = begin = chunk;
+        for (i = len; i > 0; i--, ptr++)
+            if (*ptr == '\t') {
+                column = PYOBJECT_FROM_STRING_AND_SIZE(begin,
+                                                       (Py_ssize_t)(ptr - begin));
+                if (column == NULL || PyList_Append(ret, column) == -1) {
+                    Py_DECREF(ret);
+                    return NULL;
+                }
+
+                Py_DECREF(column);
+                begin = ptr + 1;
+                colidx++;
+            }
+
+        column = PYOBJECT_FROM_STRING_AND_SIZE(begin, (Py_ssize_t)(ptr - begin));
+        if (column == NULL || PyList_Append(ret, column) == -1) {
+            Py_DECREF(ret);
+            return NULL;
+        }
+        Py_DECREF(column);
+
+        return ret;
+    }
+    else
+        return NULL;
+}
+
+static PyMethodDef tabixiter_methods[] = {
+    {NULL, NULL} /* sentinel */
+};
+
+static PyTypeObject TabixIterator_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "tabix.TabixIterator",      /*tp_name*/
+    sizeof(TabixIteratorObject), /*tp_basicsize*/
+    0,                          /*tp_itemsize*/
+    /* methods */
+    (destructor)tabixiter_dealloc,  /*tp_dealloc*/
+    0,                          /*tp_print*/
+    0,                          /*tp_getattr*/
+    0,                          /*tp_setattr*/
+    0,                          /*tp_compare*/
+    0,                          /*tp_repr*/
+    0,                          /*tp_as_number*/
+    0,                          /*tp_as_sequence*/
+    0,                          /*tp_as_mapping*/
+    0,                          /*tp_hash*/
+    0,                          /*tp_call*/
+    0,                          /*tp_str*/
+    0,                          /*tp_getattro*/
+    0,                          /*tp_setattro*/
+    0,                          /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT,         /*tp_flags*/
+    0,                          /*tp_doc*/
+    0,                          /*tp_traverse*/
+    0,                          /*tp_clear*/
+    0,                          /*tp_richcompare*/
+    0,                          /*tp_weaklistoffset*/
+    tabixiter_iter,             /*tp_iter*/
+    (iternextfunc)tabixiter_iternext, /*tp_iternext*/
+    tabixiter_methods,          /*tp_methods*/
+    0,                          /*tp_members*/
+    0,                          /*tp_getset*/
+    0,                          /*tp_base*/
+    0,                          /*tp_dict*/
+    0,                          /*tp_descr_get*/
+    0,                          /*tp_descr_set*/
+    0,                          /*tp_dictoffset*/
+    0,                          /*tp_init*/
+    0,                          /*tp_alloc*/
+    0,                          /*tp_new*/
+    0,                          /*tp_free*/
+    0,                          /*tp_is_gc*/
+};
+
+
+/* --- Tabix ----------------------------------------------------------- */
+
+static PyObject *
+tabix_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    TabixObject *self;
+    const char *fn, *fnidx=NULL;
+    static char *kwnames[]={"fn", "fnidx", NULL};
+    tabix_t *tb;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|z:Tabix",
+                                     kwnames, &fn, &fnidx))
+        return NULL;
+
+    tb = ti_open(fn, fnidx);
+    if (tb == NULL) {
+        PyErr_SetString(TabixError, "Can't open the index file.");
+        return NULL;
+    }
+
+    self = (TabixObject *)type->tp_alloc(type, 0);
+    if (self == NULL)
+        return NULL;
+
+    self->tb = tb;
+    self->fn = strdup(fn);
+
+    return (PyObject *)self;
+}
+
+static void
+tabix_dealloc(TabixObject *self)
+{
+    free(self->fn);
+    ti_close(self->tb);
+    PyObject_Del(self);
+}
+
+static PyObject *
+tabix_query(TabixObject *self, PyObject *args)
+{
+    char *name;
+    int begin, end;
+    ti_iter_t result;
+
+    if (!PyArg_ParseTuple(args, "sii:query", &name, &begin, &end))
+        return NULL;
+
+    result = ti_query(self->tb, name, begin, end);
+    if (result == NULL) {
+        PyErr_SetString(TabixError, "query failed");
+        return NULL;
+    }
+
+    return tabixiter_create(self, result);
+}
+
+static PyObject *
+tabix_queryi(TabixObject *self, PyObject *args)
+{
+    int tid, begin, end;
+    ti_iter_t result;
+
+    if (!PyArg_ParseTuple(args, "iii:queryi", &tid, &begin, &end))
+        return NULL;
+
+    result = ti_queryi(self->tb, tid, begin, end);
+    if (result == NULL) {
+        PyErr_SetString(TabixError, "query failed");
+        return NULL;
+    }
+
+    return tabixiter_create(self, result);
+}
+
+static PyObject *
+tabix_querys(TabixObject *self, PyObject *args)
+{
+    const char *reg;
+    ti_iter_t result;
+
+    if (!PyArg_ParseTuple(args, "s:querys", &reg))
+        return NULL;
+
+    result = ti_querys(self->tb, reg);
+    if (result == NULL) {
+        PyErr_SetString(TabixError, "query failed");
+        return NULL;
+    }
+
+    return tabixiter_create(self, result);
+}
+
+static PyObject *
+tabix_repr(TabixObject *self)
+{
+#if PY_MAJOR_VERSION < 3
+    return PyString_FromFormat("<Tabix fn=\"%s\">", self->fn);
+#else
+    return PyUnicode_FromFormat("<Tabix fn=\"%s\">", self->fn);
+#endif
+}
+
+static PyMethodDef tabix_methods[] = {
+    {"query",           (PyCFunction)tabix_query, METH_VARARGS,
+        PyDoc_STR("T.query(name, begin, end) -> iterator")},
+    {"queryi",          (PyCFunction)tabix_queryi, METH_VARARGS,
+        PyDoc_STR("T.queryi(tid, begin, id) -> iterator")},
+    {"querys",          (PyCFunction)tabix_querys, METH_VARARGS,
+        PyDoc_STR("T.querys(region) -> iterator")},
+    {NULL,              NULL}           /* sentinel */
+};
+
+static PyTypeObject Tabix_Type = {
+    /* The ob_type field must be initialized in the module init function
+     * to be portable to Windows without using C++. */
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "tabix.Tabix",              /*tp_name*/
+    sizeof(TabixObject),        /*tp_basicsize*/
+    0,                          /*tp_itemsize*/
+    /* methods */
+    (destructor)tabix_dealloc,  /*tp_dealloc*/
+    0,                          /*tp_print*/
+    0,                          /*tp_getattr*/
+    0,                          /*tp_setattr*/
+    0,                          /*tp_compare*/
+    (reprfunc)tabix_repr,       /*tp_repr*/
+    0,                          /*tp_as_number*/
+    0,                          /*tp_as_sequence*/
+    0,                          /*tp_as_mapping*/
+    0,                          /*tp_hash*/
+    0,                          /*tp_call*/
+    0,                          /*tp_str*/
+    0,                          /*tp_getattro*/
+    0,                          /*tp_setattro*/
+    0,                          /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT,         /*tp_flags*/
+    0,                          /*tp_doc*/
+    0,                          /*tp_traverse*/
+    0,                          /*tp_clear*/
+    0,                          /*tp_richcompare*/
+    0,                          /*tp_weaklistoffset*/
+    0,                          /*tp_iter*/
+    0,                          /*tp_iternext*/
+    tabix_methods,              /*tp_methods*/
+    0,                          /*tp_members*/
+    0,                          /*tp_getset*/
+    0,                          /*tp_base*/
+    0,                          /*tp_dict*/
+    0,                          /*tp_descr_get*/
+    0,                          /*tp_descr_set*/
+    0,                          /*tp_dictoffset*/
+    0,                          /*tp_init*/
+    0,                          /*tp_alloc*/
+    (newfunc)tabix_new,         /*tp_new*/
+    0,                          /*tp_free*/
+    0,                          /*tp_is_gc*/
+};
+/* --------------------------------------------------------------------- */
+
+static PyMethodDef tabix_functions[] = {
+    {NULL, NULL} /* sentinel */
+};
+
+PyDoc_STRVAR(module_doc,
+"Python interface to tabix, Heng Li's generic indexer for TAB-delimited "
+"genome position filesThis is a template module just for instruction.");
+
+#if PY_MAJOR_VERSION >= 3
+static struct PyModuleDef tabixmodule = { 
+    PyModuleDef_HEAD_INIT,
+    "tabix",
+    module_doc,
+    -1, 
+    tabix_functions,
+    NULL,
+    NULL,
+    NULL,
+    NULL
+};
+#endif
+
+#if PY_MAJOR_VERSION < 3
+PyMODINIT_FUNC inittabix(void)
+#else
+PyMODINIT_FUNC PyInit_tabix(void)
+#endif
+{
+    PyObject *m;
+
+    if (PyType_Ready(&Tabix_Type) < 0)
+        goto fail;
+    if (PyType_Ready(&TabixIterator_Type) < 0)
+        goto fail;
+
+#if PY_MAJOR_VERSION < 3
+    m = Py_InitModule3("tabix", tabix_functions, module_doc);
+#else
+    m = PyModule_Create(&tabixmodule);
+#endif
+    if (m == NULL)
+        goto fail;
+
+    if (TabixError == NULL) {
+        TabixError = PyErr_NewException("tabix.error", NULL, NULL);
+        if (TabixError == NULL)
+            goto fail;
+    }
+    Py_INCREF(TabixError);
+    PyModule_AddObject(m, "error", TabixError);
+
+    PyModule_AddObject(m, "Tabix", (PyObject *)&Tabix_Type);
+    PyModule_AddObject(m, "TabixIterator", (PyObject *)&TabixIterator_Type);
+
+#if PY_MAJOR_VERSION >= 3
+    return m;
+#endif
+
+ fail:
+#if PY_MAJOR_VERSION < 3
+    return;
+#else
+    return NULL;
+#endif
+}
diff --git a/python/test.py b/python/test.py
new file mode 100755
index 0000000..804a565
--- /dev/null
+++ b/python/test.py
@@ -0,0 +1,91 @@
+#
+# The MIT License
+#
+# Copyright (c) 2011 Seoul National University.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
+# Contact: Hyeshik Chang <hyeshik at snu.ac.kr>
+
+import unittest
+import random
+import gzip
+import tabix
+
+EXAMPLEFILE = '../example.gtf.gz'
+
+def load_example_regions(path):
+    alldata = []
+    for line in gzip.GzipFile(EXAMPLEFILE):
+        fields = line.decode('ascii')[:-1].split('\t')
+        seqid = fields[0]
+        begin = int(fields[3])
+        end = int(fields[4])
+        alldata.append((seqid, begin, end, fields[:7]))
+
+    return alldata
+
+def does_overlap(A, B, C, D):
+    return (A <= D <= B) or (C <= B <= D)
+
+def sample_test_dataset(regions, ntests):
+    seqids = [seqid for seqid, _, _, _ in regions]
+    lowerbound = max(0, min(begin for _, begin, _, _ in regions) - 1000)
+    upperbound = max(end for _, _, end, _ in regions) + 1000
+
+    tests = []
+    for i in range(ntests):
+        seqid = random.choice(seqids)
+        low = random.randrange(lowerbound, upperbound)
+        high = random.randrange(low, upperbound)
+
+        # for 1-based both-end inclusive intervals
+        matches = [info for seq, begin, end, info in regions
+                   if seqid == seq and does_overlap(begin, end, low, high)]
+
+        tests.append((seqid, low, high, matches))
+
+    return tests
+
+def tbresult2excerpt(tbmatches):
+    return [fields[:7] for fields in tbmatches]
+
+class TabixTest(unittest.TestCase):
+    regions = load_example_regions(EXAMPLEFILE)
+    testset = sample_test_dataset(regions, 500)
+
+    def setUp(self):
+        self.tb = tabix.Tabix(EXAMPLEFILE)
+
+    def testQuery(self):
+        for seqid, low, high, matches in self.testset:
+            tbresult = tbresult2excerpt(self.tb.query(seqid, low, high))
+            self.assertEqual(tbresult, matches)
+
+    def testQueryS(self):
+        for seqid, low, high, matches in self.testset:
+            tbresult = tbresult2excerpt(self.tb.querys('%s:%d-%d' %
+                                                       (seqid, low, high)))
+            self.assertEqual(tbresult, matches)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/tabix.1 b/tabix.1
new file mode 100644
index 0000000..1bd9533
--- /dev/null
+++ b/tabix.1
@@ -0,0 +1,132 @@
+.TH tabix 1 "11 May 2010" "tabix-0.2.0" "Bioinformatics tools"
+.SH NAME
+.PP
+bgzip - Block compression/decompression utility
+.PP
+tabix - Generic indexer for TAB-delimited genome position files
+.SH SYNOPSIS
+.PP
+.B bgzip
+.RB [ \-cdhB ]
+.RB [ \-b
+.IR virtualOffset ]
+.RB [ \-s
+.IR size ]
+.RI [ file ]
+.PP
+.B tabix
+.RB [ \-0lf ]
+.RB [ \-p
+.R gff|bed|sam|vcf]
+.RB [ \-s
+.IR seqCol ]
+.RB [ \-b
+.IR begCol ]
+.RB [ \-e
+.IR endCol ]
+.RB [ \-S
+.IR lineSkip ]
+.RB [ \-c
+.IR metaChar ]
+.I in.tab.bgz
+.RI [ "region1 " [ "region2 " [ ... "]]]"
+
+.SH DESCRIPTION
+.PP
+Tabix indexes a TAB-delimited genome position file
+.I in.tab.bgz
+and creates an index file
+.I in.tab.bgz.tbi
+when
+.I region
+is absent from the command-line. The input data file must be position
+sorted and compressed by
+.B bgzip
+which has a
+.BR gzip (1)
+like interface. After indexing, tabix is able to quickly retrieve data
+lines overlapping
+.I regions
+specified in the format "chr:beginPos-endPos". Fast data retrieval also
+works over network if URI is given as a file name and in this case the
+index file will be downloaded if it is not present locally.
+
+.SH OPTIONS OF TABIX
+.TP 10
+.BI "-p " STR
+Input format for indexing. Valid values are: gff, bed, sam, vcf and
+psltab. This option should not be applied together with any of
+.BR \-s ", " \-b ", " \-e ", " \-c " and " \-0 ;
+it is not used for data retrieval because this setting is stored in
+the index file. [gff]
+.TP
+.BI "-s " INT
+Column of sequence name. Option
+.BR \-s ", " \-b ", " \-e ", " \-S ", " \-c " and " \-0
+are all stored in the index file and thus not used in data retrieval. [1]
+.TP
+.BI "-b " INT
+Column of start chromosomal position. [4]
+.TP
+.BI "-e " INT
+Column of end chromosomal position. The end column can be the same as the
+start column. [5]
+.TP
+.BI "-S " INT
+Skip first INT lines in the data file. [0]
+.TP
+.BI "-c " CHAR
+Skip lines started with character CHAR. [#]
+.TP
+.B -0
+Specify that the position in the data file is 0-based (e.g. UCSC files)
+rather than 1-based.
+.TP
+.B -h
+Print the header/meta lines.
+.TP
+.B -B
+The second argument is a BED file. When this option is in use, the input
+file may not be sorted or indexed. The entire input will be read sequentially. Nonetheless,
+with this option, the format of the input must be specificed correctly on the command line.
+.TP
+.B -f
+Force to overwrite the index file if it is present.
+.TP
+.B -l
+List the sequence names stored in the index file.
+.RE
+
+.SH EXAMPLE
+(grep ^"#" in.gff; grep -v ^"#" in.gff | sort -k1,1 -k4,4n) | bgzip > sorted.gff.gz;
+
+tabix -p gff sorted.gff.gz;
+
+tabix sorted.gff.gz chr1:10,000,000-20,000,000;
+
+.SH NOTES
+It is straightforward to achieve overlap queries using the standard
+B-tree index (with or without binning) implemented in all SQL databases,
+or the R-tree index in PostgreSQL and Oracle. But there are still many
+reasons to use tabix. Firstly, tabix directly works with a lot of widely
+used TAB-delimited formats such as GFF/GTF and BED. We do not need to
+design database schema or specialized binary formats. Data do not need
+to be duplicated in different formats, either. Secondly, tabix works on
+compressed data files while most SQL databases do not. The GenCode
+annotation GTF can be compressed down to 4%.  Thirdly, tabix is
+fast. The same indexing algorithm is known to work efficiently for an
+alignment with a few billion short reads. SQL databases probably cannot
+easily handle data at this scale. Last but not the least, tabix supports
+remote data retrieval. One can put the data file and the index at an FTP
+or HTTP server, and other users or even web services will be able to get
+a slice without downloading the entire file.
+
+.SH AUTHOR
+.PP
+Tabix was written by Heng Li. The BGZF library was originally
+implemented by Bob Handsaker and modified by Heng Li for remote file
+access and in-memory caching.
+
+.SH SEE ALSO
+.PP
+.BR samtools (1)
diff --git a/tabix.cpp b/tabix.cpp
new file mode 100644
index 0000000..1d75996
--- /dev/null
+++ b/tabix.cpp
@@ -0,0 +1,89 @@
+#include "tabix.hpp"
+
+Tabix::Tabix(void) { }
+
+Tabix::Tabix(string& file) {
+    filename = file;
+    const char* cfilename = file.c_str();
+    struct stat stat_tbi,stat_vcf;
+    char *fnidx = (char*) calloc(strlen(cfilename) + 5, 1);
+    strcat(strcpy(fnidx, cfilename), ".tbi");
+    if ( bgzf_check_bgzf(cfilename)!=1 )
+    {
+        cerr << "[tabix++] was bgzip used to compress this file? " << file << endl;
+        free(fnidx);
+        exit(1);
+    }
+    // Common source of errors: new VCF is used with an old index
+    stat(fnidx, &stat_tbi);
+    stat(cfilename, &stat_vcf);
+    if ( stat_vcf.st_mtime > stat_tbi.st_mtime )
+    {
+        cerr << "[tabix++] the index file is older than the vcf file. Please use '-f' to overwrite or reindex." << endl;
+        free(fnidx);
+        exit(1);
+    }
+    free(fnidx);
+
+    if ((t = ti_open(cfilename, 0)) == 0) {
+        cerr << "[tabix++] fail to open the data file." << endl;
+        exit(1);
+    }
+
+    if (ti_lazy_index_load(t) < 0) {
+        cerr << "[tabix++] failed to load the index file." << endl;
+        exit(1);
+    }
+
+    idxconf = ti_get_conf(t->idx);
+
+    // set up the iterator, defaults to the beginning
+    iter = ti_query(t, 0, 0, 0);
+
+}
+
+Tabix::~Tabix(void) {
+    ti_iter_destroy(iter);
+    ti_close(t);
+}
+
+
+void Tabix::getHeader(string& header) {
+    header.clear();
+    ti_iter_destroy(iter);
+    iter = ti_query(t, 0, 0, 0);
+    const char* s;
+    int len;
+    while ((s = ti_read(t, iter, &len)) != 0) {
+        if ((int)(*s) != idxconf->meta_char) {
+            firstline = string(s); // stash this line
+            break;
+        } else {
+            header += string(s);
+            header += "\n";
+        }
+    }
+}
+
+bool Tabix::setRegion(string& region) {
+    if (ti_parse_region(t->idx, region.c_str(), &tid, &beg, &end) == 0) {
+        firstline.clear();
+        ti_iter_destroy(iter);
+        iter = ti_queryi(t, tid, beg, end);
+        return true;
+    } else return false;
+}
+
+bool Tabix::getNextLine(string& line) {
+    const char* s;
+    int len;
+    if (!firstline.empty()) {
+        line = firstline; // recovers line read if header is parsed
+        firstline.clear();
+        return true;
+    }
+    if ((s = ti_read(t, iter, &len)) != 0) {
+        line = string(s);
+        return true;
+    } else return false;
+}
diff --git a/tabix.h b/tabix.h
new file mode 100644
index 0000000..7b4497a
--- /dev/null
+++ b/tabix.h
@@ -0,0 +1,145 @@
+/* The MIT License
+
+   Copyright (c) 2009 Genome Research Ltd (GRL), 2010 Broad Institute
+
+   Permission is hereby granted, free of charge, to any person obtaining
+   a copy of this software and associated documentation files (the
+   "Software"), to deal in the Software without restriction, including
+   without limitation the rights to use, copy, modify, merge, publish,
+   distribute, sublicense, and/or sell copies of the Software, and to
+   permit persons to whom the Software is furnished to do so, subject to
+   the following conditions:
+
+   The above copyright notice and this permission notice shall be
+   included in all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+*/
+
+/* Contact: Heng Li <lh3 at live.co.uk> */
+
+#ifndef __TABIDX_H
+#define __TABIDX_H
+
+#include <stdint.h>
+#include "kstring.h"
+#include "bgzf.h"
+
+#define TI_PRESET_GENERIC 0
+#define TI_PRESET_SAM     1
+#define TI_PRESET_VCF     2
+
+#define TI_FLAG_UCSC      0x10000
+
+typedef int (*ti_fetch_f)(int l, const char *s, void *data);
+
+struct __ti_index_t;
+typedef struct __ti_index_t ti_index_t;
+
+struct __ti_iter_t;
+typedef struct __ti_iter_t *ti_iter_t;
+
+typedef struct {
+	BGZF *fp;
+	ti_index_t *idx;
+	char *fn, *fnidx;
+} tabix_t;
+
+typedef struct {
+	int32_t preset;
+	int32_t sc, bc, ec; // seq col., beg col. and end col.
+	int32_t meta_char, line_skip;
+} ti_conf_t;
+
+typedef struct {
+	int beg, end;
+	char *ss, *se;
+} ti_interval_t;
+
+extern ti_conf_t ti_conf_gff, ti_conf_bed, ti_conf_psltbl, ti_conf_vcf, ti_conf_sam; // preset
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+	/*******************
+	 * High-level APIs *
+	 *******************/
+
+	tabix_t *ti_open(const char *fn, const char *fnidx);
+	int ti_lazy_index_load(tabix_t *t);
+	void ti_close(tabix_t *t);
+	ti_iter_t ti_query(tabix_t *t, const char *name, int beg, int end);
+	ti_iter_t ti_queryi(tabix_t *t, int tid, int beg, int end);
+	ti_iter_t ti_querys(tabix_t *t, const char *reg);
+	const char *ti_read(tabix_t *t, ti_iter_t iter, int *len);
+
+	/* Destroy the iterator */
+	void ti_iter_destroy(ti_iter_t iter);
+
+	/* Get the list of sequence names. Each "char*" pointer points to a
+	 * internal member of the index, so DO NOT modify the returned
+	 * pointer; otherwise the index will be corrupted. The returned
+	 * pointer should be freed by a single free() call by the routine
+	 * calling this function. The number of sequences is returned at *n. */
+	const char **ti_seqname(const ti_index_t *idx, int *n);
+
+	/******************
+	 * Low-level APIs *
+	 ******************/
+
+	/* Build the index for file <fn>. File <fn>.tbi will be generated
+	 * and overwrite the file of the same name. Return -1 on failure. */
+	int ti_index_build(const char *fn, const ti_conf_t *conf);
+
+	/* Load the index from file <fn>.tbi. If <fn> is a URL and the index
+	 * file is not in the working directory, <fn>.tbi will be
+	 * downloaded. Return NULL on failure. */
+	ti_index_t *ti_index_load(const char *fn);
+
+	ti_index_t *ti_index_load_local(const char *fnidx);
+
+	/* Destroy the index */
+	void ti_index_destroy(ti_index_t *idx);
+
+	/* Parse a region like: chr2, chr2:100, chr2:100-200. Return -1 on failure. */
+	int ti_parse_region(const ti_index_t *idx, const char *str, int *tid, int *begin, int *end);
+
+	int ti_get_tid(const ti_index_t *idx, const char *name);
+
+	/* Get the iterator pointing to the first record at the current file
+	 * position. If the file is just openned, the iterator points to the
+	 * first record in the file. */
+	ti_iter_t ti_iter_first(void);
+
+	/* Get the iterator pointing to the first record in region tid:beg-end */
+	ti_iter_t ti_iter_query(const ti_index_t *idx, int tid, int beg, int end);
+
+	/* Get the data line pointed by the iterator and iterate to the next record. */
+	const char *ti_iter_read(BGZF *fp, ti_iter_t iter, int *len);
+
+	const ti_conf_t *ti_get_conf(ti_index_t *idx);
+	int ti_get_intv(const ti_conf_t *conf, int len, char *line, ti_interval_t *intv);
+
+	/*******************
+	 * Deprecated APIs *
+	 *******************/
+
+	/* The callback version for random access */
+	int ti_fetch(BGZF *fp, const ti_index_t *idx, int tid, int beg, int end, void *data, ti_fetch_f func);
+
+	/* Read one line. */
+	int ti_readline(BGZF *fp, kstring_t *str);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/tabix.hpp b/tabix.hpp
new file mode 100644
index 0000000..7b67a6f
--- /dev/null
+++ b/tabix.hpp
@@ -0,0 +1,31 @@
+#include <string>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include "bgzf.h"
+#include "tabix.h"
+#include <iostream>
+
+
+using namespace std;
+
+class Tabix {
+
+    tabix_t *t;
+    ti_iter_t iter;
+    const ti_conf_t *idxconf;
+    int tid, beg, end;
+    string firstline;
+
+public:
+
+    string filename;
+
+    Tabix(void);
+    Tabix(string& file);
+    ~Tabix(void);
+
+    void getHeader(string& header);
+    bool setRegion(string& region);
+    bool getNextLine(string& line);
+
+};
diff --git a/tabix.py b/tabix.py
new file mode 100755
index 0000000..8b5c7c8
--- /dev/null
+++ b/tabix.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+
+# Author: Heng Li and Aaron Quinlan
+# License: MIT/X11
+
+import sys
+from ctypes import *
+from ctypes.util import find_library
+import glob, platform
+
+def load_shared_library(lib, _path='.', ver='*'):
+    """Search for and load the tabix library. The
+    expectation is that the library is located in
+    the current directory (ie. "./")
+    """
+    # find from the system path
+    path = find_library(lib)
+    if (path == None): # if fail, search in the custom directory
+        s = platform.system()
+        if (s == 'Darwin'): suf = ver+'.dylib'
+        elif (s == 'Linux'): suf = '.so'+ver
+        candidates = glob.glob(_path+'/lib'+lib+suf);
+        if (len(candidates) == 1): path = candidates[0]
+        else: return None
+    cdll.LoadLibrary(path)
+    return CDLL(path)
+
+def tabix_init():
+    """Initialize and return a tabix reader object
+    for subsequent tabix_get() calls.  
+    """
+    tabix = load_shared_library('tabix')
+    if (tabix == None): return None
+    tabix.ti_read.restype = c_char_p
+    # on Mac OS X 10.6, the following declarations are required.
+    tabix.ti_open.restype = c_void_p
+    tabix.ti_querys.argtypes = [c_void_p, c_char_p]
+    tabix.ti_querys.restype = c_void_p
+    tabix.ti_query.argtypes = [c_void_p, c_char_p, c_int, c_int]
+    tabix.ti_query.restype = c_void_p
+    tabix.ti_read.argtypes = [c_void_p, c_void_p, c_void_p]
+    tabix.ti_iter_destroy.argtypes = [c_void_p]
+    tabix.ti_close.argtypes = [c_void_p]
+    # FIXME: explicit declarations for APIs not used in this script
+    return tabix
+
+# OOP interface
+class Tabix:
+    def __init__(self, fn, fnidx=0):
+        self.tabix = tabix_init();
+        if (self.tabix == None):
+            sys.stderr.write("[Tabix] Please make sure the shared library is compiled and available.\n")
+            return
+        self.fp = self.tabix.ti_open(fn, fnidx);
+
+    def __del__(self):
+        if (self.tabix): self.tabix.ti_close(self.fp)
+
+    def fetch(self, chr, start=-1, end=-1):
+        """Generator function that will yield each interval
+        within the requested range from the requested file.
+        """
+        if (self.tabix == None): return
+        if (start < 0): iter = self.tabix.ti_querys(self.fp, chr) # chr looks like: "chr2:1,000-2,000" or "chr2"
+        else: iter = self.tabix.ti_query(self.fp, chr, start, end) # chr must be a sequence name
+        if (iter == None):        
+            sys.stderr.write("[Tabix] Malformatted query or wrong sequence name.\n")
+            return
+        while (1): # iterate
+            s = self.tabix.ti_read(self.fp, iter, 0)
+            if (s == None): break
+            yield s   
+        self.tabix.ti_iter_destroy(iter)
+
+# command-line interface
+def main():
+    if (len(sys.argv) < 3):
+        sys.stderr.write("Usage: tabix.py <in.gz> <reg>\n")
+        sys.exit(1)
+    
+    # report the features in the requested interval
+    tabix = Tabix(sys.argv[1])
+    for line in tabix.fetch(sys.argv[2]):
+        print line
+
+if __name__ == '__main__':
+    main()
diff --git a/tabix.tex b/tabix.tex
new file mode 100644
index 0000000..669d673
--- /dev/null
+++ b/tabix.tex
@@ -0,0 +1,121 @@
+\documentclass[10pt]{article}
+\usepackage{color}
+\definecolor{gray}{rgb}{0.7,0.7,0.7}
+
+\setlength{\topmargin}{0.0cm}
+\setlength{\textheight}{21.5cm}
+\setlength{\oddsidemargin}{0cm} 
+\setlength{\textwidth}{16.5cm}
+\setlength{\columnsep}{0.6cm}
+
+\begin{document}
+
+\title{The Tabix index file format}
+\author{Heng Li}
+\date{}
+
+\maketitle
+
+\begin{center}
+\begin{tabular}{|l|l|l|l|l|l|l|}
+\hline
+\multicolumn{4}{|c|}{\bf Field} & \multicolumn{1}{c|}{\bf Descrption} & \multicolumn{1}{c|}{\bf Type} & \multicolumn{1}{c|}{\bf Value} \\
+\hline\hline
+\multicolumn{4}{|l|}{\tt magic} & Magic string & {\tt char[4]} & TBI$\backslash$1 \\
+\hline
+\multicolumn{4}{|l|}{\tt n\_ref} & \# sequences & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt format} & Format (0: generic; 1: SAM; 2: VCF) & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt col\_seq} & Column for the sequence name & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt col\_beg} & Column for the start of a region & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt col\_end} & Column for the end of a region & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt meta} & Leading character for comment lines & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt skip} & \# lines to skip at the beginning & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt l\_nm} & Length of concatenated sequence names & {\tt int32\_t} & \\
+\hline
+\multicolumn{4}{|l|}{\tt names} & Concatenated names, each zero terminated & {\tt char[l\_nm]} & \\
+\hline
+\multicolumn{7}{|c|}{\textcolor{gray}{\it List of indices (n=n\_ref)}}\\
+\cline{2-7}
+\hspace{0.1cm} & \multicolumn{3}{l|}{\tt n\_bin} & \# distinct bins (for the binning index) & {\tt int32\_t} & \\
+\cline{2-7}
+ & \multicolumn{6}{c|}{\textcolor{gray}{\it List of distinct bins (n=n\_bin)}} \\
+\cline{3-7}
+ & \hspace{0.1cm} & \multicolumn{2}{l|}{\tt bin} & Distinct bin number & {\tt uint32\_t} & \\
+\cline{3-7}
+ & & \multicolumn{2}{l|}{\tt n\_chunk} & \# chunks & {\tt int32\_t} & \\
+\cline{3-7}
+ & & \multicolumn{5}{c|}{\textcolor{gray}{\it List of chunks (n=n\_chunk)}} \\
+\cline{4-7}
+ & & \hspace{0.1cm} & {\tt cnk\_beg} & Virtual file offset of the start of the chunk & {\tt uint64\_t} & \\
+\cline{4-7}
+ & & & {\tt cnk\_end} & Virtual file offset of the end of the chunk & {\tt uint64\_t} & \\
+\cline{2-7}
+ & \multicolumn{3}{l|}{\tt n\_intv} & \# 16kb intervals (for the linear index) & {\tt int32\_t} & \\
+\cline{2-7}
+ & \multicolumn{6}{c|}{\textcolor{gray}{\it List of distinct intervals (n=n\_intv)}} \\
+\cline{3-7}
+ & & \multicolumn{2}{l|}{\tt ioff} & File offset of the first record in the interval & {\tt uint64\_t} & \\
+\hline
+\end{tabular}
+\end{center}
+
+{\bf Notes:}
+
+\begin{itemize}
+\item The index file is BGZF compressed.
+\item All integers are little-endian.
+\item When {\tt (format\&0x10000)} is true, the coordinate follows the
+  {\tt BED} rule (i.e. half-closed-half-open and zero based); otherwise,
+  the coordinate follows the {\tt GFF} rule (closed and one based).
+\item For the SAM format, the end of a region equals {\tt POS} plus the
+  reference length in the alignment, inferred from {\tt CIGAR}. For the
+  VCF format, the end of a region equals {\tt POS} plus the size of the
+  deletion.
+\item Field {\tt col\_beg} may equal {\tt col\_end}, and in this case,
+  the end of a region is {\tt end}={\tt beg+1}.
+\item Example. For {\tt GFF}, {\tt format}=0, {\tt col\_seq}=1, {\tt
+    col\_beg}=4, {\tt col\_end}=5, {\tt meta}=`{\tt \#}' and {\tt
+    skip}=0. For {\tt BED}, {\tt format}=0x10000, {\tt col\_seq}=1, {\tt
+    col\_beg}=2, {\tt col\_end}=3, {\tt meta}=`{\tt \#}' and {\tt
+    skip}=0.
+\item Given a zero-based, half-closed and half-open region {\tt
+    [beg,end)}, the {\tt bin} number is calculated with the following C
+  function:
+\begin{verbatim}
+int reg2bin(int beg, int end) {
+  --end;
+  if (beg>>14 == end>>14) return ((1<<15)-1)/7 + (beg>>14);
+  if (beg>>17 == end>>17) return ((1<<12)-1)/7 + (beg>>17);
+  if (beg>>20 == end>>20) return  ((1<<9)-1)/7 + (beg>>20);
+  if (beg>>23 == end>>23) return  ((1<<6)-1)/7 + (beg>>23);
+  if (beg>>26 == end>>26) return  ((1<<3)-1)/7 + (beg>>26);
+  return 0;
+}
+\end{verbatim}
+\item The list of bins that may overlap a region {\tt [beg,end)} can be
+  obtained with the following C function.
+\begin{verbatim}
+#define MAX_BIN (((1<<18)-1)/7)
+int reg2bins(int rbeg, int rend, uint16_t list[MAX_BIN])
+{
+  int i = 0, k;
+  --rend;
+  list[i++] = 0;
+  for (k =    1 + (rbeg>>26); k <=    1 + (rend>>26); ++k) list[i++] = k;
+  for (k =    9 + (rbeg>>23); k <=    9 + (rend>>23); ++k) list[i++] = k;
+  for (k =   73 + (rbeg>>20); k <=   73 + (rend>>20); ++k) list[i++] = k;
+  for (k =  585 + (rbeg>>17); k <=  585 + (rend>>17); ++k) list[i++] = k;
+  for (k = 4681 + (rbeg>>14); k <= 4681 + (rend>>14); ++k) list[i++] = k;
+  return i; // #elements in list[]
+}
+\end{verbatim}
+\end{itemize}
+
+\end{document}
\ No newline at end of file

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