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| -rw-r--r-- | README | 26 |
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@@ -5,13 +5,23 @@ small size makes it well suited for embedded devices or software installers that need to decompress files but do not need compression capabilities. Lunzip is fully compatible with lzip-1.4 or newer. +If the size of the output buffer is specified with the "--buffer-size" +option, lunzip uses the decompressed file as dictionary for distances +beyond the buffer size and is able to decompress any file using as +little memory as 50 kB, irrespective of the dictionary size used to +compress the file. Of course, the smaller the output buffer size used in +relation to the dictionary size, the more accesses to disk are needed +and the slower the decompression is. This "low memory" mode only works +when decompressing to a regular file. + The lzip file format is designed for long-term data archiving. It is clean, provides very safe 4 factor integrity checking, and is backed by the recovery capabilities of lziprecover. Lunzip uses the same well-defined exit status values used by lzip and -bzip2, which makes it safer when used in pipes or scripts than -decompressors returning ambiguous warning values, like gunzip. +bzip2, which makes it safer than decompressors returning ambiguous +warning values (like gunzip) when it is used as a back end for tar or +zutils. Lunzip replaces every file given in the command line with a decompressed version of itself. Each decompressed file has the same modification @@ -35,9 +45,15 @@ two or more compressed files. The result is the concatenation of the corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported. -The amount of memory required by lunzip to decompress a file is only a -few tens of KiB larger than the dictionary size used to compress that -file. +The amount of memory required by lunzip to decompress a file is about +46 kB larger than the dictionary size used to compress that file, unless +the "--buffer-size" option is specified. + +The ideas embodied in lunzip are due to (at least) the following people: +Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrey Markov (for +the definition of Markov chains), G.N.N. Martin (for the definition of +range encoding), Igor Pavlov (for putting all the above together in +LZMA), and Julian Seward (for bzip2's CLI). Copyright (C) 2010, 2011, 2012, 2013 Antonio Diaz Diaz. |