| 1 |
|
|---|
| 2 | This is the README for bzip2/libzip2.
|
|---|
| 3 | This version is fully compatible with the previous public releases.
|
|---|
| 4 |
|
|---|
| 5 | ------------------------------------------------------------------
|
|---|
| 6 | This file is part of bzip2/libbzip2, a program and library for
|
|---|
| 7 | lossless, block-sorting data compression.
|
|---|
| 8 |
|
|---|
| 9 | bzip2/libbzip2 version 1.0.4 of 20 December 2006
|
|---|
| 10 | Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org>
|
|---|
| 11 |
|
|---|
| 12 | Please read the WARNING, DISCLAIMER and PATENTS sections in this file.
|
|---|
| 13 |
|
|---|
| 14 | This program is released under the terms of the license contained
|
|---|
| 15 | in the file LICENSE.
|
|---|
| 16 | ------------------------------------------------------------------
|
|---|
| 17 |
|
|---|
| 18 | Complete documentation is available in Postscript form (manual.ps),
|
|---|
| 19 | PDF (manual.pdf) or html (manual.html). A plain-text version of the
|
|---|
| 20 | manual page is available as bzip2.txt.
|
|---|
| 21 |
|
|---|
| 22 |
|
|---|
| 23 | HOW TO BUILD -- UNIX
|
|---|
| 24 |
|
|---|
| 25 | Type 'make'. This builds the library libbz2.a and then the programs
|
|---|
| 26 | bzip2 and bzip2recover. Six self-tests are run. If the self-tests
|
|---|
| 27 | complete ok, carry on to installation:
|
|---|
| 28 |
|
|---|
| 29 | To install in /usr/local/bin, /usr/local/lib, /usr/local/man and
|
|---|
| 30 | /usr/local/include, type
|
|---|
| 31 |
|
|---|
| 32 | make install
|
|---|
| 33 |
|
|---|
| 34 | To install somewhere else, eg, /xxx/yyy/{bin,lib,man,include}, type
|
|---|
| 35 |
|
|---|
| 36 | make install PREFIX=/xxx/yyy
|
|---|
| 37 |
|
|---|
| 38 | If you are (justifiably) paranoid and want to see what 'make install'
|
|---|
| 39 | is going to do, you can first do
|
|---|
| 40 |
|
|---|
| 41 | make -n install or
|
|---|
| 42 | make -n install PREFIX=/xxx/yyy respectively.
|
|---|
| 43 |
|
|---|
| 44 | The -n instructs make to show the commands it would execute, but not
|
|---|
| 45 | actually execute them.
|
|---|
| 46 |
|
|---|
| 47 |
|
|---|
| 48 | HOW TO BUILD -- UNIX, shared library libbz2.so.
|
|---|
| 49 |
|
|---|
| 50 | Do 'make -f Makefile-libbz2_so'. This Makefile seems to work for
|
|---|
| 51 | Linux-ELF (RedHat 7.2 on an x86 box), with gcc. I make no claims
|
|---|
| 52 | that it works for any other platform, though I suspect it probably
|
|---|
| 53 | will work for most platforms employing both ELF and gcc.
|
|---|
| 54 |
|
|---|
| 55 | bzip2-shared, a client of the shared library, is also built, but not
|
|---|
| 56 | self-tested. So I suggest you also build using the normal Makefile,
|
|---|
| 57 | since that conducts a self-test. A second reason to prefer the
|
|---|
| 58 | version statically linked to the library is that, on x86 platforms,
|
|---|
| 59 | building shared objects makes a valuable register (%ebx) unavailable
|
|---|
| 60 | to gcc, resulting in a slowdown of 10%-20%, at least for bzip2.
|
|---|
| 61 |
|
|---|
| 62 | Important note for people upgrading .so's from 0.9.0/0.9.5 to version
|
|---|
| 63 | 1.0.X. All the functions in the library have been renamed, from (eg)
|
|---|
| 64 | bzCompress to BZ2_bzCompress, to avoid namespace pollution.
|
|---|
| 65 | Unfortunately this means that the libbz2.so created by
|
|---|
| 66 | Makefile-libbz2_so will not work with any program which used an older
|
|---|
| 67 | version of the library. I do encourage library clients to make the
|
|---|
| 68 | effort to upgrade to use version 1.0, since it is both faster and more
|
|---|
| 69 | robust than previous versions.
|
|---|
| 70 |
|
|---|
| 71 |
|
|---|
| 72 | HOW TO BUILD -- Windows 95, NT, DOS, Mac, etc.
|
|---|
| 73 |
|
|---|
| 74 | It's difficult for me to support compilation on all these platforms.
|
|---|
| 75 | My approach is to collect binaries for these platforms, and put them
|
|---|
| 76 | on the master web site (http://www.bzip.org). Look there. However
|
|---|
| 77 | (FWIW), bzip2-1.0.X is very standard ANSI C and should compile
|
|---|
| 78 | unmodified with MS Visual C. If you have difficulties building, you
|
|---|
| 79 | might want to read README.COMPILATION.PROBLEMS.
|
|---|
| 80 |
|
|---|
| 81 | At least using MS Visual C++ 6, you can build from the unmodified
|
|---|
| 82 | sources by issuing, in a command shell:
|
|---|
| 83 |
|
|---|
| 84 | nmake -f makefile.msc
|
|---|
| 85 |
|
|---|
| 86 | (you may need to first run the MSVC-provided script VCVARS32.BAT
|
|---|
| 87 | so as to set up paths to the MSVC tools correctly).
|
|---|
| 88 |
|
|---|
| 89 |
|
|---|
| 90 | VALIDATION
|
|---|
| 91 |
|
|---|
| 92 | Correct operation, in the sense that a compressed file can always be
|
|---|
| 93 | decompressed to reproduce the original, is obviously of paramount
|
|---|
| 94 | importance. To validate bzip2, I used a modified version of Mark
|
|---|
| 95 | Nelson's churn program. Churn is an automated test driver which
|
|---|
| 96 | recursively traverses a directory structure, using bzip2 to compress
|
|---|
| 97 | and then decompress each file it encounters, and checking that the
|
|---|
| 98 | decompressed data is the same as the original.
|
|---|
| 99 |
|
|---|
| 100 |
|
|---|
| 101 |
|
|---|
| 102 | Please read and be aware of the following:
|
|---|
| 103 |
|
|---|
| 104 | WARNING:
|
|---|
| 105 |
|
|---|
| 106 | This program and library (attempts to) compress data by
|
|---|
| 107 | performing several non-trivial transformations on it.
|
|---|
| 108 | Unless you are 100% familiar with *all* the algorithms
|
|---|
| 109 | contained herein, and with the consequences of modifying them,
|
|---|
| 110 | you should NOT meddle with the compression or decompression
|
|---|
| 111 | machinery. Incorrect changes can and very likely *will*
|
|---|
| 112 | lead to disastrous loss of data.
|
|---|
| 113 |
|
|---|
| 114 |
|
|---|
| 115 | DISCLAIMER:
|
|---|
| 116 |
|
|---|
| 117 | I TAKE NO RESPONSIBILITY FOR ANY LOSS OF DATA ARISING FROM THE
|
|---|
| 118 | USE OF THIS PROGRAM/LIBRARY, HOWSOEVER CAUSED.
|
|---|
| 119 |
|
|---|
| 120 | Every compression of a file implies an assumption that the
|
|---|
| 121 | compressed file can be decompressed to reproduce the original.
|
|---|
| 122 | Great efforts in design, coding and testing have been made to
|
|---|
| 123 | ensure that this program works correctly. However, the complexity
|
|---|
| 124 | of the algorithms, and, in particular, the presence of various
|
|---|
| 125 | special cases in the code which occur with very low but non-zero
|
|---|
| 126 | probability make it impossible to rule out the possibility of bugs
|
|---|
| 127 | remaining in the program. DO NOT COMPRESS ANY DATA WITH THIS
|
|---|
| 128 | PROGRAM UNLESS YOU ARE PREPARED TO ACCEPT THE POSSIBILITY, HOWEVER
|
|---|
| 129 | SMALL, THAT THE DATA WILL NOT BE RECOVERABLE.
|
|---|
| 130 |
|
|---|
| 131 | That is not to say this program is inherently unreliable.
|
|---|
| 132 | Indeed, I very much hope the opposite is true. bzip2/libbzip2
|
|---|
| 133 | has been carefully constructed and extensively tested.
|
|---|
| 134 |
|
|---|
| 135 |
|
|---|
| 136 | PATENTS:
|
|---|
| 137 |
|
|---|
| 138 | To the best of my knowledge, bzip2/libbzip2 does not use any
|
|---|
| 139 | patented algorithms. However, I do not have the resources
|
|---|
| 140 | to carry out a patent search. Therefore I cannot give any
|
|---|
| 141 | guarantee of the above statement.
|
|---|
| 142 |
|
|---|
| 143 |
|
|---|
| 144 |
|
|---|
| 145 | WHAT'S NEW IN 0.9.0 (as compared to 0.1pl2) ?
|
|---|
| 146 |
|
|---|
| 147 | * Approx 10% faster compression, 30% faster decompression
|
|---|
| 148 | * -t (test mode) is a lot quicker
|
|---|
| 149 | * Can decompress concatenated compressed files
|
|---|
| 150 | * Programming interface, so programs can directly read/write .bz2 files
|
|---|
| 151 | * Less restrictive (BSD-style) licensing
|
|---|
| 152 | * Flag handling more compatible with GNU gzip
|
|---|
| 153 | * Much more documentation, i.e., a proper user manual
|
|---|
| 154 | * Hopefully, improved portability (at least of the library)
|
|---|
| 155 |
|
|---|
| 156 | WHAT'S NEW IN 0.9.5 ?
|
|---|
| 157 |
|
|---|
| 158 | * Compression speed is much less sensitive to the input
|
|---|
| 159 | data than in previous versions. Specifically, the very
|
|---|
| 160 | slow performance caused by repetitive data is fixed.
|
|---|
| 161 | * Many small improvements in file and flag handling.
|
|---|
| 162 | * A Y2K statement.
|
|---|
| 163 |
|
|---|
| 164 | WHAT'S NEW IN 1.0.0 ?
|
|---|
| 165 |
|
|---|
| 166 | See the CHANGES file.
|
|---|
| 167 |
|
|---|
| 168 | WHAT'S NEW IN 1.0.2 ?
|
|---|
| 169 |
|
|---|
| 170 | See the CHANGES file.
|
|---|
| 171 |
|
|---|
| 172 | WHAT'S NEW IN 1.0.3 ?
|
|---|
| 173 |
|
|---|
| 174 | See the CHANGES file.
|
|---|
| 175 |
|
|---|
| 176 | WHAT'S NEW IN 1.0.4 ?
|
|---|
| 177 |
|
|---|
| 178 | See the CHANGES file.
|
|---|
| 179 |
|
|---|
| 180 |
|
|---|
| 181 | I hope you find bzip2 useful. Feel free to contact me at
|
|---|
| 182 | jseward@bzip.org
|
|---|
| 183 | if you have any suggestions or queries. Many people mailed me with
|
|---|
| 184 | comments, suggestions and patches after the releases of bzip-0.15,
|
|---|
| 185 | bzip-0.21, and bzip2 versions 0.1pl2, 0.9.0, 0.9.5, 1.0.0, 1.0.1,
|
|---|
| 186 | 1.0.2 and 1.0.3, and the changes in bzip2 are largely a result of this
|
|---|
| 187 | feedback. I thank you for your comments.
|
|---|
| 188 |
|
|---|
| 189 | bzip2's "home" is http://www.bzip.org/
|
|---|
| 190 |
|
|---|
| 191 | Julian Seward
|
|---|
| 192 | jseward@bzip.org
|
|---|
| 193 | Cambridge, UK.
|
|---|
| 194 |
|
|---|
| 195 | 18 July 1996 (version 0.15)
|
|---|
| 196 | 25 August 1996 (version 0.21)
|
|---|
| 197 | 7 August 1997 (bzip2, version 0.1)
|
|---|
| 198 | 29 August 1997 (bzip2, version 0.1pl2)
|
|---|
| 199 | 23 August 1998 (bzip2, version 0.9.0)
|
|---|
| 200 | 8 June 1999 (bzip2, version 0.9.5)
|
|---|
| 201 | 4 Sept 1999 (bzip2, version 0.9.5d)
|
|---|
| 202 | 5 May 2000 (bzip2, version 1.0pre8)
|
|---|
| 203 | 30 December 2001 (bzip2, version 1.0.2pre1)
|
|---|
| 204 | 15 February 2005 (bzip2, version 1.0.3)
|
|---|
| 205 | 20 December 2006 (bzip2, version 1.0.4)
|
|---|
