This is the README for bzip2/libzip2.
This version is fully compatible with the previous public releases.

------------------------------------------------------------------
This file is part of bzip2/libbzip2, a program and library for
lossless, block-sorting data compression.

bzip2/libbzip2 version 1.0.8 of 13 July 2019
Copyright (C) 1996-2019 Julian Seward <jseward@acm.org>

Please read the WARNING, DISCLAIMER and PATENTS sections in this file.

This program is released under the terms of the license contained
in the file LICENSE.
------------------------------------------------------------------

Complete documentation is available in Postscript form (manual.ps),
PDF (manual.pdf) or html (manual.html).  A plain-text version of the
manual page is available as bzip2.txt.


HOW TO BUILD -- UNIX

Type 'make'.  This builds the library libbz2.a and then the programs
bzip2 and bzip2recover.  Six self-tests are run.  If the self-tests
complete ok, carry on to installation:

To install in /usr/local/bin, /usr/local/lib, /usr/local/man and
/usr/local/include, type

   make install

To install somewhere else, eg, /xxx/yyy/{bin,lib,man,include}, type

   make install PREFIX=/xxx/yyy

If you are (justifiably) paranoid and want to see what 'make install'
is going to do, you can first do

   make -n install                      or
   make -n install PREFIX=/xxx/yyy      respectively.

The -n instructs make to show the commands it would execute, but not
actually execute them.


HOW TO BUILD -- UNIX, shared library libbz2.so.

Do 'make -f Makefile-libbz2_so'.  This Makefile seems to work for
Linux-ELF (RedHat 7.2 on an x86 box), with gcc.  I make no claims
that it works for any other platform, though I suspect it probably
will work for most platforms employing both ELF and gcc.

bzip2-shared, a client of the shared library, is also built, but not
self-tested.  So I suggest you also build using the normal Makefile,
since that conducts a self-test.  A second reason to prefer the
version statically linked to the library is that, on x86 platforms,
building shared objects makes a valuable register (%ebx) unavailable
to gcc, resulting in a slowdown of 10%-20%, at least for bzip2.

Important note for people upgrading .so's from 0.9.0/0.9.5 to version
1.0.X.  All the functions in the library have been renamed, from (eg)
bzCompress to BZ2_bzCompress, to avoid namespace pollution.
Unfortunately this means that the libbz2.so created by
Makefile-libbz2_so will not work with any program which used an older
version of the library.  I do encourage library clients to make the
effort to upgrade to use version 1.0, since it is both faster and more
robust than previous versions.


HOW TO BUILD -- Windows 95, NT, DOS, Mac, etc.

It's difficult for me to support compilation on all these platforms.
My approach is to collect binaries for these platforms, and put them
on the master web site (https://sourceware.org/bzip2/).  Look there.  However
(FWIW), bzip2-1.0.X is very standard ANSI C and should compile
unmodified with MS Visual C.  If you have difficulties building, you
might want to read README.COMPILATION.PROBLEMS.

At least using MS Visual C++ 6, you can build from the unmodified
sources by issuing, in a command shell:

   nmake -f makefile.msc

(you may need to first run the MSVC-provided script VCVARS32.BAT
 so as to set up paths to the MSVC tools correctly).


VALIDATION

Correct operation, in the sense that a compressed file can always be
decompressed to reproduce the original, is obviously of paramount
importance.  To validate bzip2, I used a modified version of Mark
Nelson's churn program.  Churn is an automated test driver which
recursively traverses a directory structure, using bzip2 to compress
and then decompress each file it encounters, and checking that the
decompressed data is the same as the original.



Please read and be aware of the following:

WARNING:

   This program and library (attempts to) compress data by
   performing several non-trivial transformations on it.
   Unless you are 100% familiar with *all* the algorithms
   contained herein, and with the consequences of modifying them,
   you should NOT meddle with the compression or decompression
   machinery.  Incorrect changes can and very likely *will*
   lead to disastrous loss of data.


DISCLAIMER:

   I TAKE NO RESPONSIBILITY FOR ANY LOSS OF DATA ARISING FROM THE
   USE OF THIS PROGRAM/LIBRARY, HOWSOEVER CAUSED.

   Every compression of a file implies an assumption that the
   compressed file can be decompressed to reproduce the original.
   Great efforts in design, coding and testing have been made to
   ensure that this program works correctly.  However, the complexity
   of the algorithms, and, in particular, the presence of various
   special cases in the code which occur with very low but non-zero
   probability make it impossible to rule out the possibility of bugs
   remaining in the program.  DO NOT COMPRESS ANY DATA WITH THIS
   PROGRAM UNLESS YOU ARE PREPARED TO ACCEPT THE POSSIBILITY, HOWEVER
   SMALL, THAT THE DATA WILL NOT BE RECOVERABLE.

   That is not to say this program is inherently unreliable.
   Indeed, I very much hope the opposite is true.  bzip2/libbzip2
   has been carefully constructed and extensively tested.


PATENTS:

   To the best of my knowledge, bzip2/libbzip2 does not use any
   patented algorithms.  However, I do not have the resources
   to carry out a patent search.  Therefore I cannot give any
   guarantee of the above statement.



WHAT'S NEW IN 0.9.0 (as compared to 0.1pl2) ?

   * Approx 10% faster compression, 30% faster decompression
   * -t (test mode) is a lot quicker
   * Can decompress concatenated compressed files
   * Programming interface, so programs can directly read/write .bz2 files
   * Less restrictive (BSD-style) licensing
   * Flag handling more compatible with GNU gzip
   * Much more documentation, i.e., a proper user manual
   * Hopefully, improved portability (at least of the library)

WHAT'S NEW IN 0.9.5 ?

   * Compression speed is much less sensitive to the input
     data than in previous versions.  Specifically, the very
     slow performance caused by repetitive data is fixed.
   * Many small improvements in file and flag handling.
   * A Y2K statement.

WHAT'S NEW IN 1.0.x ?

   See the CHANGES file.

I hope you find bzip2 useful.  Feel free to contact the developers at
   bzip2-devel@sourceware.org
if you have any suggestions or queries.  Many people mailed me with
comments, suggestions and patches after the releases of bzip-0.15,
bzip-0.21, and bzip2 versions 0.1pl2, 0.9.0, 0.9.5, 1.0.0, 1.0.1,
1.0.2 and 1.0.3, and the changes in bzip2 are largely a result of this
feedback.  I thank you for your comments.

bzip2's "home" is https://sourceware.org/bzip2/

Julian Seward
jseward@acm.org
Cambridge, UK.

18     July 1996 (version 0.15)
25   August 1996 (version 0.21)
 7   August 1997 (bzip2, version 0.1)
29   August 1997 (bzip2, version 0.1pl2)
23   August 1998 (bzip2, version 0.9.0)
 8     June 1999 (bzip2, version 0.9.5)
 4     Sept 1999 (bzip2, version 0.9.5d)
 5      May 2000 (bzip2, version 1.0pre8)
30 December 2001 (bzip2, version 1.0.2pre1)
15 February 2005 (bzip2, version 1.0.3)
20 December 2006 (bzip2, version 1.0.4)
10 December 2007 (bzip2, version 1.0.5)
 6     Sept 2010 (bzip2, version 1.0.6)
27     June 2019 (bzip2, version 1.0.7)
13     July 2019 (bzip2, version 1.0.8)

------------------------------------------------------------------
This file is part of bzip2/libbzip2, a program and library for
lossless, block-sorting data compression.

bzip2/libbzip2 version 1.0.8 of 13 July 2019
Copyright (C) 1996-2019 Julian Seward <jseward@acm.org>

Please read the WARNING, DISCLAIMER and PATENTS sections in the
README file.

This program is released under the terms of the license contained
in the file LICENSE.
------------------------------------------------------------------

bzip2 should compile without problems on the vast majority of
platforms.  Using the supplied Makefile, I've built and tested it
myself for x86-linux and amd64-linux.  With makefile.msc, Visual C++
6.0 and nmake, you can build a native Win32 version too.  Large file
support seems to work correctly on at least on amd64-linux.

When I say "large file" I mean a file of size 2,147,483,648 (2^31)
bytes or above.  Many older OSs can't handle files above this size,
but many newer ones can.  Large files are pretty huge -- most files
you'll encounter are not Large Files.

Early versions of bzip2 (0.1, 0.9.0, 0.9.5) compiled on a wide variety
of platforms without difficulty, and I hope this version will continue
in that tradition.  However, in order to support large files, I've had
to include the define -D_FILE_OFFSET_BITS=64 in the Makefile.  This
can cause problems.

The technique of adding -D_FILE_OFFSET_BITS=64 to get large file
support is, as far as I know, the Recommended Way to get correct large
file support.  For more details, see the Large File Support
Specification, published by the Large File Summit, at

   http://ftp.sas.com/standards/large.file

As a general comment, if you get compilation errors which you think
are related to large file support, try removing the above define from
the Makefile, ie, delete the line

   BIGFILES=-D_FILE_OFFSET_BITS=64

from the Makefile, and do 'make clean ; make'.  This will give you a
version of bzip2 without large file support, which, for most
applications, is probably not a problem.

Alternatively, try some of the platform-specific hints listed below.

You can use the spewG.c program to generate huge files to test bzip2's
large file support, if you are feeling paranoid.  Be aware though that
any compilation problems which affect bzip2 will also affect spewG.c,
alas.

AIX: I have reports that for large file support, you need to specify
-D_LARGE_FILES rather than -D_FILE_OFFSET_BITS=64.  I have not tested
this myself.

[
  {
    "Name": "Bzip2",
    "License": "Bzip2 License",
    "License File": "LICENSE",
    "Version Number": "1.0.8",
    "Owner": "shaolexi@huawei.com",
    "Upstream URL": "https://www.sourceware.org/bzip2/",
    "Description": "bzip2 is a freely available, patent free (see below), high-quality data compressor. It typically compresses files to within 10% to 15% of the best available techniques (the PPM family of statistical compressors), whilst being around twice as fast at compression and six times faster at decompression."
  }
]

  ----------------------------------------------------------------
  This file is part of bzip2/libbzip2, a program and library for
  lossless, block-sorting data compression.

  bzip2/libbzip2 version 1.0.8 of 13 July 2019
  Copyright (C) 1996-2019 Julian Seward <jseward@acm.org>

  Please read the WARNING, DISCLAIMER and PATENTS sections in the
  README file.

  This program is released under the terms of the license contained
  in the file LICENSE.
  ----------------------------------------------------------------

The script xmlproc.sh takes an xml file as input,
and processes it to create .pdf, .html or .ps output.
It uses format.pl, a perl script to format <pre> blocks nicely,
 and add CDATA tags so writers do not have to use eg. &lt;

The file "entities.xml" must be edited to reflect current
version, year, etc.


Usage:

  ./xmlproc.sh -v manual.xml
  Validates an xml file to ensure no dtd-compliance errors

  ./xmlproc.sh -html manual.xml
  Output: manual.html

  ./xmlproc.sh -pdf manual.xml
  Output: manual.pdf

  ./xmlproc.sh -ps manual.xml
  Output: manual.ps


Notum bene:
- pdfxmltex barfs if given a filename with an underscore in it

- xmltex won't work yet - there's a bug in passivetex
    which we are all waiting for Sebastian to fix.
  So we are going the xml -> pdf -> ps route for the time being,
    using pdfxmltex.