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Diffstat (limited to 'DOC/lzma.txt')
| -rwxr-xr-x | DOC/lzma.txt | 42 |
1 files changed, 16 insertions, 26 deletions
diff --git a/DOC/lzma.txt b/DOC/lzma.txt index 47021022..cddc0723 100755 --- a/DOC/lzma.txt +++ b/DOC/lzma.txt @@ -1,7 +1,7 @@ -LZMA SDK 4.32 +LZMA SDK 4.33 ------------- -LZMA SDK 4.32 Copyright (C) 1999-2005 Igor Pavlov +LZMA SDK 4.33 Copyright (C) 1999-2006 Igor Pavlov LZMA SDK provides the documentation, samples, header files, libraries, and tools you need to develop applications that use LZMA compression. @@ -185,10 +185,10 @@ other directories of SDK for compiling. http://sourceforge.net/projects/sevenzip/ -LZMA Decompression features ---------------------------- - - Variable dictionary size (up to 256 MB) - - Estimated compressing speed: about 500 KB/s on 1 GHz CPU +LZMA features +------------- + - Variable dictionary size (up to 1 GB) + - Estimated compressing speed: about 1 MB/s on 1 GHz CPU - Estimated decompressing speed: - 8-12 MB/s on 1 GHz Intel Pentium 3 or AMD Athlon - 500-1000 KB/s on 100 MHz ARM, MIPS, PowerPC or other simple RISC @@ -224,7 +224,7 @@ Usage: LZMA <e|d> inputFile outputFile [<switches>...] b: Benchmark. There are two tests: compressing and decompressing with LZMA method. Benchmark shows rating in MIPS (million instructions per second). Rating value is calculated from - measured speed and it is normalized with AMD Athlon XP CPU + measured speed and it is normalized with AMD Athlon 64 X2 CPU results. Also Benchmark checks possible hardware errors (RAM errors in most cases). Benchmark uses these settings: (-a1, -d21, -fb32, -mfbt4). You can change only -d. Also you @@ -235,11 +235,11 @@ Usage: LZMA <e|d> inputFile outputFile [<switches>...] <Switches> - -a{N}: set compression mode 0 = fast, 1 = normal, 2 = max - default: 2 (max) + -a{N}: set compression mode 0 = fast, 1 = normal + default: 1 (normal) - d{N}: Sets Dictionary size - [0, 28], default: 23 (8MB) - The maximum value for dictionary size is 256 MB = 2^28 bytes. + d{N}: Sets Dictionary size - [0, 30], default: 23 (8MB) + The maximum value for dictionary size is 1 GB = 2^30 bytes. Dictionary size is calculated as DictionarySize = 2^N bytes. For decompressing file compressed by LZMA method with dictionary size D = 2^N you need about D bytes of memory (RAM). @@ -262,29 +262,19 @@ Usage: LZMA <e|d> inputFile outputFile [<switches>...] when period is equal 2^N. -mf{MF_ID}: set Match Finder. Default: bt4. - Compression ratio for all bt* and pat* almost the same. Algorithms from hc* group doesn't provide good compression ratio, but they often works pretty fast in combination with - fast mode (-a0). Methods from bt* group require less memory - than methods from pat* group. Usually bt4 works faster than - any pat*, but for some types of files pat* can work faster. + fast mode (-a0). Memory requirements depend from dictionary size (parameter "d" in table below). MF_ID Memory Description - bt2 d*9.5 + 1MB Binary Tree with 2 bytes hashing. - bt3 d*9.5 + 65MB Binary Tree with 2-3(full) bytes hashing. - bt4 d*9.5 + 6MB Binary Tree with 2-3-4 bytes hashing. - bt4b d*9.5 + 34MB Binary Tree with 2-3-4(big) bytes hashing. - pat2r d*26 + 1MB Patricia Tree with 2-bits nodes, removing. - pat2 d*38 + 1MB Patricia Tree with 2-bits nodes. - pat2h d*38 + 77MB Patricia Tree with 2-bits nodes, 2-3 bytes hashing. - pat3h d*62 + 85MB Patricia Tree with 3-bits nodes, 2-3 bytes hashing. - pat4h d*110 +101MB Patricia Tree with 4-bits nodes, 2-3 bytes hashing. - hc3 d*5.5 + 1MB Hash Chain with 2-3 bytes hashing. - hc4 d*5.5 + 6MB Hash Chain with 2-3-4 bytes hashing. + bt2 d * 9.5 + 4MB Binary Tree with 2 bytes hashing. + bt3 d * 11.5 + 4MB Binary Tree with 3 bytes hashing. + bt4 d * 11.5 + 4MB Binary Tree with 4 bytes hashing. + hc4 d * 7.5 + 4MB Hash Chain with 4 bytes hashing. -eos: write End Of Stream marker. By default LZMA doesn't write eos marker, since LZMA decoder knows uncompressed size |