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authorDaniel Baumann <mail@daniel-baumann.ch>2015-11-06 12:53:18 +0000
committerDaniel Baumann <mail@daniel-baumann.ch>2015-11-06 12:53:18 +0000
commit99b720cb7d83e01ca75f8089225167866f5aa63d (patch)
tree3ded428ddce1b6aeb0e1d0a3302cb2304cbe4dac /doc/clzip.texi
parentAdding upstream version 1.7~rc1. (diff)
downloadclzip-99b720cb7d83e01ca75f8089225167866f5aa63d.tar.xz
clzip-99b720cb7d83e01ca75f8089225167866f5aa63d.zip
Adding upstream version 1.7.upstream/1.7
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to '')
-rw-r--r--doc/clzip.texi162
1 files changed, 83 insertions, 79 deletions
diff --git a/doc/clzip.texi b/doc/clzip.texi
index a74ec6f..e2ca889 100644
--- a/doc/clzip.texi
+++ b/doc/clzip.texi
@@ -6,8 +6,8 @@
@finalout
@c %**end of header
-@set UPDATED 23 May 2015
-@set VERSION 1.7-rc1
+@set UPDATED 7 July 2015
+@set VERSION 1.7
@dircategory Data Compression
@direntry
@@ -36,9 +36,9 @@ 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
+* Algorithm:: How clzip compresses the data
* Examples:: A small tutorial with examples
* Problems:: Reporting bugs
* Concept index:: Index of concepts
@@ -72,10 +72,14 @@ availability:
@itemize @bullet
@item
The lzip format provides very safe integrity checking and some data
-recovery means. The lziprecover program can repair bit-flip errors (one
-of the most common forms of data corruption) in lzip files, and provides
-data recovery capabilities, including error-checked merging of damaged
-copies of a file.
+recovery means. The
+@uref{http://www.nongnu.org/lzip/manual/lziprecover_manual.html#Data-safety,,lziprecover}
+program can repair bit-flip errors (one of the most common forms of data
+corruption) in lzip files, and provides data recovery capabilities,
+including error-checked merging of damaged copies of a file.
+@ifnothtml
+@ref{Data safety,,,lziprecover}.
+@end ifnothtml
@item
The lzip format is as simple as possible (but not simpler). The lzip
@@ -111,6 +115,11 @@ bzip2, which makes it safer than compressors returning ambiguous warning
values (like gzip) when it is used as a back end for other programs like
tar or zutils.
+Clzip will automatically use the smallest possible dictionary size for
+each file 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.
+
The amount of memory required for compression is about 1 or 2 times the
dictionary size limit (1 if input file size is less than dictionary size
limit, else 2) plus 9 times the dictionary size really used. The option
@@ -118,11 +127,6 @@ limit, else 2) plus 9 times the dictionary size really used. The option
of memory required for decompression is about 46 kB larger than the
dictionary size really used.
-Clzip will automatically use the smallest possible dictionary size for
-each file 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.
-
When compressing, clzip replaces every file given in the command line
with a compressed version of itself, with the name "original_name.lz".
When decompressing, clzip attempts to guess the name for the decompressed
@@ -164,72 +168,6 @@ automatically creating multi-member output. The members so created are
large, about 2 PiB each.
-@node Algorithm
-@chapter Algorithm
-@cindex algorithm
-
-In spite of its name (Lempel-Ziv-Markov chain-Algorithm), LZMA is not a
-concrete algorithm; it is more like "any algorithm using the LZMA coding
-scheme". For example, the option '-0' of lzip uses the scheme in almost
-the simplest way possible; issuing the longest match it can find, or a
-literal byte if it can't find a match. Inversely, a much more elaborated
-way of finding coding sequences of minimum size than the one currently
-used by lzip could be developed, and the resulting sequence could also
-be coded using the LZMA coding scheme.
-
-Clzip currently implements two variants of the LZMA algorithm; fast
-(used by option -0) and normal (used by all other compression levels).
-
-The high compression of LZMA comes from combining two basic, well-proven
-compression ideas: sliding dictionaries (LZ77/78) and markov models (the
-thing used by every compression algorithm that uses a range encoder or
-similar order-0 entropy coder as its last stage) with segregation of
-contexts according to what the bits are used for.
-
-Clzip is a two stage compressor. The first stage is a Lempel-Ziv coder,
-which reduces redundancy by translating chunks of data to their
-corresponding distance-length pairs. The second stage is a range encoder
-that uses a different probability model for each type of data;
-distances, lengths, literal bytes, etc.
-
-Here is how it works, step by step:
-
-1) The member header is written to the output stream.
-
-2) The first byte is coded literally, because there are no previous
-bytes to which the match finder can refer to.
-
-3) The main encoder advances to the next byte in the input data and
-calls the match finder.
-
-4) The match finder fills an array with the minimum distances before the
-current byte where a match of a given length can be found.
-
-5) Go back to step 3 until a sequence (formed of pairs, repeated
-distances and literal bytes) of minimum price has been formed. Where the
-price represents the number of output bits produced.
-
-6) The range encoder encodes the sequence produced by the main encoder
-and sends the produced bytes to the output stream.
-
-7) Go back to step 3 until the input data are finished or until the
-member or volume size limits are reached.
-
-8) The range encoder is flushed.
-
-9) The member trailer is written to the output stream.
-
-10) If there are more data to compress, go back to step 1.
-
-@sp 1
-@noindent
-The ideas embodied in clzip 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).
-
-
@node Invoking clzip
@chapter Invoking clzip
@cindex invoking
@@ -276,7 +214,7 @@ Force overwrite of output files.
@item -F
@itemx --recompress
-Force recompression of files whose name already has the @samp{.lz} or
+Force re-compression of files whose name already has the @samp{.lz} or
@samp{.tlz} suffix.
@item -k
@@ -476,6 +414,72 @@ facilitates safe recovery of undamaged members from multi-member files.
@end table
+@node Algorithm
+@chapter Algorithm
+@cindex algorithm
+
+In spite of its name (Lempel-Ziv-Markov chain-Algorithm), LZMA is not a
+concrete algorithm; it is more like "any algorithm using the LZMA coding
+scheme". For example, the option @samp{-0} of lzip uses the scheme in almost
+the simplest way possible; issuing the longest match it can find, or a
+literal byte if it can't find a match. Inversely, a much more elaborated
+way of finding coding sequences of minimum size than the one currently
+used by lzip could be developed, and the resulting sequence could also
+be coded using the LZMA coding scheme.
+
+Clzip currently implements two variants of the LZMA algorithm; fast
+(used by option @samp{-0}) and normal (used by all other compression levels).
+
+The high compression of LZMA comes from combining two basic, well-proven
+compression ideas: sliding dictionaries (LZ77/78) and markov models (the
+thing used by every compression algorithm that uses a range encoder or
+similar order-0 entropy coder as its last stage) with segregation of
+contexts according to what the bits are used for.
+
+Clzip is a two stage compressor. The first stage is a Lempel-Ziv coder,
+which reduces redundancy by translating chunks of data to their
+corresponding distance-length pairs. The second stage is a range encoder
+that uses a different probability model for each type of data;
+distances, lengths, literal bytes, etc.
+
+Here is how it works, step by step:
+
+1) The member header is written to the output stream.
+
+2) The first byte is coded literally, because there are no previous
+bytes to which the match finder can refer to.
+
+3) The main encoder advances to the next byte in the input data and
+calls the match finder.
+
+4) The match finder fills an array with the minimum distances before the
+current byte where a match of a given length can be found.
+
+5) Go back to step 3 until a sequence (formed of pairs, repeated
+distances and literal bytes) of minimum price has been formed. Where the
+price represents the number of output bits produced.
+
+6) The range encoder encodes the sequence produced by the main encoder
+and sends the produced bytes to the output stream.
+
+7) Go back to step 3 until the input data are finished or until the
+member or volume size limits are reached.
+
+8) The range encoder is flushed.
+
+9) The member trailer is written to the output stream.
+
+10) If there are more data to compress, go back to step 1.
+
+@sp 1
+@noindent
+The ideas embodied in clzip 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).
+
+
@node Examples
@chapter A small tutorial with examples
@cindex examples