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 forlossless, block-sorting data compression.bzip2/libbzip2 version 1.0.8 of 13 July 2019Copyright (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 containedin the file LICENSE.------------------------------------------------------------------Complete documentation is available in Postscript form (manual.ps),PDF (manual.pdf) or html (manual.html).  A plain-text version of themanual page is available as bzip2.txt.HOW TO BUILD -- UNIXType 'make'.  This builds the library libbz2.a and then the programsbzip2 and bzip2recover.  Six self-tests are run.  If the self-testscomplete ok, carry on to installation:To install in /usr/local/bin, /usr/local/lib, /usr/local/man and/usr/local/include, type   make installTo install somewhere else, eg, /xxx/yyy/{bin,lib,man,include}, type   make install PREFIX=/xxx/yyyIf 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 notactually execute them.HOW TO BUILD -- UNIX, shared library libbz2.so.Do 'make -f Makefile-libbz2_so'.  This Makefile seems to work forLinux-ELF (RedHat 7.2 on an x86 box), with gcc.  I make no claimsthat it works for any other platform, though I suspect it probablywill work for most platforms employing both ELF and gcc.bzip2-shared, a client of the shared library, is also built, but notself-tested.  So I suggest you also build using the normal Makefile,since that conducts a self-test.  A second reason to prefer theversion statically linked to the library is that, on x86 platforms,building shared objects makes a valuable register (%ebx) unavailableto 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 version1.0.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 byMakefile-libbz2_so will not work with any program which used an olderversion of the library.  I do encourage library clients to make theeffort to upgrade to use version 1.0, since it is both faster and morerobust 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 themon the master web site (https://sourceware.org/bzip2/).  Look there.  However(FWIW), bzip2-1.0.X is very standard ANSI C and should compileunmodified with MS Visual C.  If you have difficulties building, youmight want to read README.COMPILATION.PROBLEMS.At least using MS Visual C++ 6, you can build from the unmodifiedsources 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).VALIDATIONCorrect operation, in the sense that a compressed file can always bedecompressed to reproduce the original, is obviously of paramountimportance.  To validate bzip2, I used a modified version of MarkNelson's churn program.  Churn is an automated test driver whichrecursively traverses a directory structure, using bzip2 to compressand then decompress each file it encounters, and checking that thedecompressed 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.orgif you have any suggestions or queries.  Many people mailed me withcomments, 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 thisfeedback.  I thank you for your comments.bzip2's "home" ishttps://sourceware.org/bzip2/Julian Sewardjseward@acm.orgCambridge, 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)