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Diffstat (limited to 'README')
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@@ -1,17 +1,32 @@ Description -Lzip is a lossless data compressor based on the LZMA algorithm, with -very safe integrity checking and a user interface similar to the one of -gzip or bzip2. Lzip decompresses almost as fast as gzip and compresses -better than bzip2, which makes it well suited for software distribution -and data archiving. +Lzip is a lossless data compressor with a user interface similar to the +one of gzip or bzip2. Lzip decompresses almost as fast as gzip and +compresses more than bzip2, which makes it well suited for software +distribution and data archiving. Lzip is a clean implementation of the +LZMA algorithm. Lzip uses the same well-defined exit status values used by bzip2, which makes it safer when used in pipes or scripts than compressors returning ambiguous warning values, like gzip. +The lzip file format is designed for long-term data archiving and +provides very safe integrity checking. The member trailer stores the +32-bit CRC of the original data, the size of the original data and the +size of the member. These values, together with the value remaining in +the range decoder and the end-of-stream marker, provide a 4 factor +integrity checking which guarantees that the decompressed version of the +data is identical to the original. This guards against corruption of the +compressed data, and against undetected bugs in lzip (hopefully very +unlikely). The chances of data corruption going undetected are +microscopic. Be aware, though, that the check occurs upon decompression, +so it can only tell you that something is wrong. It can't help you +recover the original uncompressed data. + If you ever need to recover data from a damaged lzip file, try the -lziprecover program. +lziprecover program. Lziprecover makes lzip files resistant to bit-flip +(one of the most common forms of data corruption), and provides data +recovery capabilities, including error-checked merging of damaged files. Lzip replaces every file given in the command line with a compressed version of itself, with the name "original_name.lz". Each compressed @@ -45,18 +60,6 @@ without exceeding the given limit. Keep in mind that the decompression memory requirement is affected at compression time by the choice of dictionary size limit. -As a self-check for your protection, lzip stores in the member trailer -the 32-bit CRC of the original data, the size of the original data and -the size of the member. These values, together with the value remaining -in the range decoder and the end-of-stream marker, provide a very safe 4 -factor integrity checking which guarantees that the decompressed version -of the data is identical to the original. This guards against corruption -of the compressed data, and against undetected bugs in lzip (hopefully -very unlikely). The chances of data corruption going undetected are -microscopic. Be aware, though, that the check occurs upon decompression, -so it can only tell you that something is wrong. It can't help you -recover the original uncompressed data. - Lzip implements a simplified version of the LZMA (Lempel-Ziv-Markov chain-Algorithm) algorithm. The high compression of LZMA comes from combining two basic, well-proven compression ideas: sliding dictionaries |