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Revision: 1.58
Committed: Sun Aug 25 17:53:39 2013 UTC (10 years, 8 months ago) by root
Branch: MAIN
Changes since 1.57: +2 -0 lines
Log Message:
*** empty log message ***

File Contents

# Content
1
2 TODO: try unaligned copy again in decompressor
3 TODO: allow size-optimised binaries by avoiding unrolling
4 TODO: implement lzf_c_best in lzf.
5 TODO: fix lzf_c_best.
6
7 3.7 (unreleased)
8 - add lzf_c_best.c, a slower but better compressor.
9 - switch to a multiplicative hash (developed with Steinar Gunderson),
10 which is faster on modern cpus and compresses a bit better. The old
11 hash function which uses only shifts is still available.
12 - allow user configurable hash table slots, which makes it possible
13 to use e.g. 16 bit offsets for a smaller hashtable (if your data is
14 always < 64kb).
15 - use _WIN32, not WIN32, when testing for windows (fails with bcc),
16 patch by Tamas Tevesz.
17 - try to port to win64+gcc, which is non-posix but doesn't have _int64
18 (reported by Maciej Adamczyk).
19
20 3.6 Mon Feb 7 17:37:31 CET 2011
21 - fixed hash calculation in C♯ version (Tiago Freitas Leal).
22 - unroll copy for small sizes, use memcpy for larger sizes,
23 greatly speeding up decompression in most cases.
24 - finally disable rep movsb - it's a big loss on modern intel cpus,
25 and only a small win on amd cpus.
26 - improve C++ compatibility of the code.
27 - slightly improve compressor speed.
28 - halved memory requirements for compressor on 64 bit architectures,
29 which can improve the speed quite a bit on older cpus.
30
31 3.5 Fri May 1 02:28:42 CEST 2009
32 - lzf_compress did sometimes write one octet past the given output
33 buffer (analyzed and nice testcase by Salvatore Sanfilippo).
34
35 3.4 Tue Sep 2 06:45:00 CEST 2008
36 - the fix from 3.3 introduced a compression bug, which is fixed in
37 this release (which explains the mysterious prerelease...). Thanks
38 once more to Clément Calmels.
39
40 3.3 Mon Aug 25 03:17:42 CEST 2008
41 - lzf_compress could access memory after the given input buffer
42 when outputting back references. reported with nice testcase
43 by Clément Calmels.
44
45 3.2 Fri May 9 18:52:23 CEST 2008
46 - include a workaround for failing POSIX and real-world compliance
47 on 64 bit windows (microsoft claims to support POSIX, but is far
48 from it). (bug found and analysed nicely by John Lilley).
49
50 3.1 Fri Nov 30 11:33:04 CET 2007
51 - IMPORTANT BUGFIX: a too long final literal run would corrupt data
52 in the encoder (this was introduced in 3.0 only, earlier versions
53 are safe).
54
55 3.0 Tue Nov 13 22:13:09 CET 2007
56 - switched to 2-clause bsd with "GPL v2 or any later version" option.
57 - speed up compression by ~10-15% in common cases
58 by some manual unrolling.
59 - import some compiler tricks from JSON::XS, for further speed-ups.
60 - tune hash functions depending on ULTRA_FAST or VERY_FAST settings.
61 - for typical binary data (e.g. /bin/bash, memory dumps,
62 canterbury corpus etc.), speed is now comparable to fastlz, but
63 with better compression ratio. with ULTRA_FAST, it's typically
64 3-15% faster than fastlz while still maintaining a similar ratio.
65 (amd64 and core 2 duo, ymmv). thanks a lot for the competition :)
66 - undo inline assembly in compressor, it is no longer helpful.
67 - no changes to the decompressor.
68 - use a HLOG of 16 by default now (formerly 15).
69
70 2.1 Fri Nov 2 13:34:42 CET 2007
71 - switched to a 2-clause bsd license with GPL exception.
72 - get rid of memcpy.
73 - tentatively use rep movsb on x86 and x86_64 (gcc only) for a
74 moderate speed improvement.
75 - applied patch by Kein-Hong Man to maske lzf.c compile under
76 the crippled mingw32 environment.
77
78 2.0 Fri Feb 16 23:11:18 CET 2007
79 - replaced lzf demo by industrial-strength lzf utility with behaviour
80 similar other compression utilities. Thanks for Stefan Traby for
81 rewriting it!
82 - fix state arg prototype.
83
84 1.7 Wed Sep 27 17:29:15 CEST 2006
85 - remove bogus "unlzf" patch.
86 note to self: never accept well-meant patches.
87 - make lzf more robust in presence of padding bytes or sudden eof.
88
89 1.6 Fri Jul 7 17:31:26 CEST 2006
90 - the lzf example utility will now uncompress if invoked
91 as "unlzf" (patch by Scott Feeney).
92 - add CHECK_INPUT option that adds more checks for input
93 data validity.
94 - help applications that do not pass in the correct length
95 (such as php) by returning either EINVAL or E2BIG.
96 - default HLOG size is now 15 (cpu caches have increased).
97 - documentation fixes.
98
99 1.51 Thu Apr 14 22:15:46 CEST 2005
100 - incorporated C♯ implementation of both the en- and decoder,
101 written by "Oren J. Maurice".
102 You can find it in the cs/ subdirectory.
103 - make FRST, NEXT IDX overridable if lzf_c.c is directly included
104 in the code.
105
106 1.5 Tue Mar 8 20:23:23 CET 2005
107 - incorporated improvements by Adam D. Moss,
108 which includes a new VERY_FAST mode which is
109 a bit slower than ULTRA_FAST but much better,
110 and enabled it as default.
111
112 1.401 Thu Mar 3 18:00:52 CET 2005
113 - use cstring in c++, not string.h.
114 - change of contact address.
115
116 1.4 Wed Dec 15 08:08:49 CET 2004
117 - very very slight tuning of the hashing function.
118
119 1.3 Thu Mar 25 15:41:17 CET 2004
120 - changed license of lzf core code to explicitly allow
121 relicensing under the GPLv2.
122 - added VPATH support as suggested by Björn Eriksson.
123
124 1.2 Mon Dec 29 13:47:28 CET 2003
125 - avoid spurious memory accesses after the to-be-compressed
126 memory region. originally reported by Michal Zalewski.
127 - flip LZF_STACK_ARG meaning (to be correct).
128
129 1.1 Tue Dec 23 05:48:32 CET 2003
130 - removed #warn directive, it's not worth the hassle.
131 - add LZF_STACK_ARG and AVOID_ERRNO configurations
132 for embedded systems.
133 - make it compile cleanly as c++.
134 - some small documentation and code fixes.
135
136 1.0 Sun Nov 17 12:37:37 CET 2002
137 - slightly better compression ratio, almost unmeasurably
138 slower.
139 - some documentation fixes.
140
141 0.4 Thu Jun 13 14:11:10 CEST 2002
142 - typoe fix.
143 - lzf demo program now properly decompresses small files.
144 - fix another 64 bit issue, found by Laurent Deniel.
145
146 0.3 Tue Jan 16 13:21:14 CET 2001
147 - fix silly beginners 32/64 bit mistake.
148
149 0.2 Thu Jan 4 05:56:42 CET 2001
150 - now totally independent of autoconfig, for
151 easy inclusion into other programs.
152 - much better fine-tuning, faster and better than 0.1.
153
154 0.1 2000
155 - initial release.