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Diffstat (limited to 'doc/lzlib.texinfo')
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1 files changed, 51 insertions, 36 deletions
diff --git a/doc/lzlib.texinfo b/doc/lzlib.texinfo index c08303e..2830694 100644 --- a/doc/lzlib.texinfo +++ b/doc/lzlib.texinfo @@ -6,19 +6,19 @@ @finalout @c %**end of header -@set UPDATED 28 May 2013 -@set VERSION 1.4 +@set UPDATED 28 July 2013 +@set VERSION 1.5-rc1 @dircategory Data Compression @direntry -* Lzlib: (lzlib). A compression library for lzip files +* Lzlib: (lzlib). Compression library for lzip files @end direntry @ifnothtml @titlepage @title Lzlib -@subtitle A compression library for lzip files +@subtitle Compression library for lzip files @subtitle for Lzlib version @value{VERSION}, @value{UPDATED} @author by Antonio Diaz Diaz @@ -36,17 +36,17 @@ This manual is for Lzlib (version @value{VERSION}, @value{UPDATED}). @menu * Introduction:: Purpose and features of Lzlib -* Library Version:: Checking library version +* Library version:: Checking library version * Buffering:: Sizes of Lzlib's buffers -* Parameter Limits:: Min / max values for some parameters -* Compression Functions:: Descriptions of the compression functions -* Decompression Functions:: Descriptions of the decompression functions -* Error Codes:: Meaning of codes returned by functions -* Error Messages:: Error messages corresponding to error codes -* Data Format:: Detailed format of the compressed data +* Parameter limits:: Min / max values for some parameters +* Compression functions:: Descriptions of the compression functions +* Decompression functions:: Descriptions of the decompression functions +* Error codes:: Meaning of codes returned by functions +* Error messages:: Error messages corresponding to error codes +* Data format:: Detailed format of the compressed data * Examples:: A small tutorial with examples * Problems:: Reporting bugs -* Concept Index:: Index of concepts +* Concept index:: Index of concepts @end menu @sp 1 @@ -65,6 +65,10 @@ and decompression functions, including integrity checking of the decompressed data. The compressed data format used by the library is the lzip format. Lzlib is written in C. +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. + The functions and variables forming the interface of the compression library are declared in the file @samp{lzlib.h}. Usage examples of the library are given in the files @samp{main.c} and @samp{bbexample.c} from @@ -91,13 +95,22 @@ any signal handler. The decoder checks the consistency of the compressed data, so the library should never crash even in case of corrupted input. Lzlib implements a simplified version of the LZMA (Lempel-Ziv-Markov -chain-Algorithm) algorithm. The original LZMA algorithm was designed by -Igor Pavlov. For a description of the LZMA algorithm, see the Lzip -manual. - - -@node Library Version -@chapter Library Version +chain-Algorithm) algorithm. 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. + +The ideas embodied in lzlib 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 Library version +@chapter Library version @cindex library version @deftypefun {const char *} LZ_version ( void ) @@ -150,8 +163,8 @@ whichever is larger. @end itemize -@node Parameter Limits -@chapter Parameter Limits +@node Parameter limits +@chapter Parameter limits @cindex parameter limits These functions provide minimum and maximum values for some parameters. @@ -182,8 +195,8 @@ Returns the largest valid match length limit [273]. @end deftypefun -@node Compression Functions -@chapter Compression Functions +@node Compression functions +@chapter Compression functions @cindex compression functions These are the functions used to compress data. In case of error, all of @@ -288,7 +301,7 @@ accept a @var{size} up to the returned number of bytes. @deftypefun {enum LZ_Errno} LZ_compress_errno ( struct LZ_Encoder * const @var{encoder} ) -Returns the current error code for @var{encoder} (@pxref{Error Codes}). +Returns the current error code for @var{encoder} (@pxref{Error codes}). @end deftypefun @@ -328,8 +341,8 @@ perhaps not yet read. @end deftypefun -@node Decompression Functions -@chapter Decompression Functions +@node Decompression functions +@chapter Decompression functions @cindex decompression functions These are the functions used to decompress data. In case of error, all @@ -421,7 +434,7 @@ will accept a @var{size} up to the returned number of bytes. @deftypefun {enum LZ_Errno} LZ_decompress_errno ( struct LZ_Decoder * const @var{decoder} ) -Returns the current error code for @var{decoder} (@pxref{Error Codes}). +Returns the current error code for @var{decoder} (@pxref{Error codes}). @end deftypefun @@ -480,8 +493,8 @@ perhaps not yet read. @end deftypefun -@node Error Codes -@chapter Error Codes +@node Error codes +@chapter Error codes @cindex error codes Most library functions return -1 to indicate that they have failed. But @@ -538,8 +551,8 @@ A bug was detected in the library. Please, report it (@pxref{Problems}). @end deftypevr -@node Error Messages -@chapter Error Messages +@node Error messages +@chapter Error messages @cindex error messages @deftypefun {const char *} LZ_strerror ( const enum LZ_Errno @var{lz_errno} ) @@ -553,8 +566,8 @@ The value of @var{lz_errno} normally comes from a call to @end deftypefun -@node Data Format -@chapter Data Format +@node Data format +@chapter Data format @cindex data format Perfection is reached, not when there is no longer anything to add, but @@ -612,7 +625,9 @@ 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. See the lzip manual for a full description. +for encoder properties. See the lzip manual for a full description.@* +Lzip only uses the LZMA marker @samp{2} ("End Of Stream" marker). Lzlib +also uses the LZMA marker @samp{3} ("Sync Flush" marker). @item CRC32 (4 bytes) CRC of the uncompressed original data. @@ -793,8 +808,8 @@ find by running @w{@samp{minilzip --version}} or in @samp{LZ_version_string} from @samp{lzlib.h}. -@node Concept Index -@unnumbered Concept Index +@node Concept index +@unnumbered Concept index @printindex cp |