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diff --git a/doc/clzip.texinfo b/doc/clzip.texinfo index e372d60..49d0761 100644 --- a/doc/clzip.texinfo +++ b/doc/clzip.texinfo @@ -6,19 +6,19 @@ @finalout @c %**end of header -@set UPDATED 13 May 2013 -@set VERSION 1.5-pre1 +@set UPDATED 17 July 2013 +@set VERSION 1.5-pre2 @dircategory Data Compression @direntry -* Clzip: (clzip). Data compressor based on the LZMA algorithm +* Clzip: (clzip). LZMA lossless data compressor @end direntry @ifnothtml @titlepage @title Clzip -@subtitle Data compressor based on the LZMA algorithm +@subtitle LZMA lossless data compressor @subtitle for Clzip version @value{VERSION}, @value{UPDATED} @author by Antonio Diaz Diaz @@ -35,13 +35,13 @@ This manual is for Clzip (version @value{VERSION}, @value{UPDATED}). @menu -* Introduction:: Purpose and features of clzip -* Algorithm:: How clzip compresses the data -* Invoking Clzip:: Command line interface -* File Format:: Detailed format of the compressed file -* Examples:: A small tutorial with examples -* Problems:: Reporting bugs -* Concept Index:: Index of concepts +* Introduction:: Purpose and features of clzip +* Algorithm:: How clzip compresses the data +* Invoking clzip:: Command line interface +* File format:: Detailed format of the compressed file +* Examples:: A small tutorial with examples +* Problems:: Reporting bugs +* Concept index:: Index of concepts @end menu @sp 1 @@ -55,23 +55,39 @@ to copy, distribute and modify it. @chapter Introduction @cindex introduction -Clzip 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. Clzip decompresses almost as fast as gzip and compresses -better than bzip2, which makes it well suited for software distribution -and data archiving. +Clzip is a lossless data compressor with a user interface similar to the +one of gzip or bzip2. Clzip decompresses almost as fast as gzip and +compresses more than bzip2, which makes it well suited for software +distribution and data archiving. Clzip is a clean implementation of the +LZMA algorithm. -Clzip 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. +Clzip uses the same well-defined exit status values used by lzip and +bzip2, which makes it safer when used in pipes or scripts than +compressors returning ambiguous warning values, like gzip. Clzip uses the lzip file format; the files produced by clzip are fully -compatible with lzip-1.4 or newer. Clzip is in fact a C language version -of lzip, intended for embedded devices or systems lacking a C++ -compiler. +compatible with lzip-1.4 or newer, and can be rescued with lziprecover. +Clzip is in fact a C language version of lzip, intended for embedded +devices or systems lacking a C++ compiler. + +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 clzip (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 copies +of a file. Clzip replaces every file given in the command line with a compressed version of itself, with the name "original_name.lz". Each compressed @@ -120,18 +136,6 @@ file from that of the compressed file as follows: @item anyothername @tab becomes @tab anyothername.out @end multitable -As a self-check for your protection, clzip 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 clzip (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. - @node Algorithm @chapter Algorithm @@ -194,8 +198,8 @@ range encoding), Igor Pavlov (for putting all the above together in LZMA), and Julian Seward (for bzip2's CLI and the idea of unzcrash). -@node Invoking Clzip -@chapter Invoking Clzip +@node Invoking clzip +@chapter Invoking clzip @cindex invoking @cindex options @cindex usage @@ -296,9 +300,10 @@ Use it together with @samp{-v} to see information about the file. @item -v @itemx --verbose Verbose mode.@* -When compressing, show the compression ratio for each file processed.@* +When compressing, show the compression ratio for each file processed. A +second -v shows the progress of compression.@* When decompressing or testing, further -v's (up to 4) increase the -verbosity level, showing status, dictionary size, compression ratio, +verbosity level, showing status, compression ratio, dictionary size, and trailer contents (CRC, data size, member size). @item -1 .. -9 @@ -356,8 +361,8 @@ invalid input file, 3 for an internal consistency error (eg, bug) which caused clzip to panic. -@node File Format -@chapter File Format +@node File format +@chapter File format @cindex file format Perfection is reached, not when there is no longer anything to add, but @@ -415,7 +420,7 @@ Valid values for dictionary size range from 4KiB to 512MiB. @item Lzma stream The lzma stream, finished by an end of stream marker. Uses default values -for encoder properties. +for encoder properties. See the lzip manual for a full description. @item CRC32 (4 bytes) CRC of the uncompressed original data. @@ -549,8 +554,8 @@ If you find a bug in clzip, please send electronic mail to find by running @w{@samp{clzip --version}}. -@node Concept Index -@unnumbered Concept Index +@node Concept index +@unnumbered Concept index @printindex cp |