2
This is the README for bzip2/libzip2.
3
This version is fully compatible with the previous public releases.
5
------------------------------------------------------------------
6
This file is part of bzip2/libbzip2, a program and library for
7
lossless, block-sorting data compression.
9
bzip2/libbzip2 version 1.0.5 of 10 December 2007
10
Copyright (C) 1996-2007 Julian Seward <jseward@bzip.org>
12
Please read the WARNING, DISCLAIMER and PATENTS sections in this file.
14
This program is released under the terms of the license contained
16
------------------------------------------------------------------
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.
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:
29
To install in /usr/local/bin, /usr/local/lib, /usr/local/man and
30
/usr/local/include, type
34
To install somewhere else, eg, /xxx/yyy/{bin,lib,man,include}, type
36
make install PREFIX=/xxx/yyy
38
If you are (justifiably) paranoid and want to see what 'make install'
39
is going to do, you can first do
42
make -n install PREFIX=/xxx/yyy respectively.
44
The -n instructs make to show the commands it would execute, but not
45
actually execute them.
48
HOW TO BUILD -- UNIX, shared library libbz2.so.
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.
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.
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.
72
HOW TO BUILD -- Windows 95, NT, DOS, Mac, etc.
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.
81
At least using MS Visual C++ 6, you can build from the unmodified
82
sources by issuing, in a command shell:
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).
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.
102
Please read and be aware of the following:
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.
117
I TAKE NO RESPONSIBILITY FOR ANY LOSS OF DATA ARISING FROM THE
118
USE OF THIS PROGRAM/LIBRARY, HOWSOEVER CAUSED.
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.
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.
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.
145
WHAT'S NEW IN 0.9.0 (as compared to 0.1pl2) ?
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)
156
WHAT'S NEW IN 0.9.5 ?
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.
164
WHAT'S NEW IN 1.0.0 ?
166
See the CHANGES file.
168
WHAT'S NEW IN 1.0.2 ?
170
See the CHANGES file.
172
WHAT'S NEW IN 1.0.3 ?
174
See the CHANGES file.
176
WHAT'S NEW IN 1.0.4 ?
178
See the CHANGES file.
180
WHAT'S NEW IN 1.0.5 ?
182
See the CHANGES file.
185
I hope you find bzip2 useful. Feel free to contact me at
187
if you have any suggestions or queries. Many people mailed me with
188
comments, suggestions and patches after the releases of bzip-0.15,
189
bzip-0.21, and bzip2 versions 0.1pl2, 0.9.0, 0.9.5, 1.0.0, 1.0.1,
190
1.0.2 and 1.0.3, and the changes in bzip2 are largely a result of this
191
feedback. I thank you for your comments.
193
bzip2's "home" is http://www.bzip.org/
199
18 July 1996 (version 0.15)
200
25 August 1996 (version 0.21)
201
7 August 1997 (bzip2, version 0.1)
202
29 August 1997 (bzip2, version 0.1pl2)
203
23 August 1998 (bzip2, version 0.9.0)
204
8 June 1999 (bzip2, version 0.9.5)
205
4 Sept 1999 (bzip2, version 0.9.5d)
206
5 May 2000 (bzip2, version 1.0pre8)
207
30 December 2001 (bzip2, version 1.0.2pre1)
208
15 February 2005 (bzip2, version 1.0.3)
209
20 December 2006 (bzip2, version 1.0.4)
210
10 December 2007 (bzip2, version 1.0.5)
added
removed
win32/3rdparty/bzip2/README
