diff options
Diffstat (limited to '')
| -rw-r--r-- | doc/lzlib.info | 243 | ||||
| -rw-r--r-- | doc/lzlib.texi | 244 | ||||
| -rw-r--r-- | doc/minilzip.1 | 35 |
3 files changed, 270 insertions, 252 deletions
diff --git a/doc/lzlib.info b/doc/lzlib.info index bef1859..d81bc88 100644 --- a/doc/lzlib.info +++ b/doc/lzlib.info @@ -1,6 +1,6 @@ This is lzlib.info, produced by makeinfo version 4.13+ from lzlib.texi. -INFO-DIR-SECTION Data Compression +INFO-DIR-SECTION Compression START-INFO-DIR-ENTRY * Lzlib: (lzlib). Compression library for the lzip format END-INFO-DIR-ENTRY @@ -11,7 +11,7 @@ File: lzlib.info, Node: Top, Next: Introduction, Up: (dir) Lzlib Manual ************ -This manual is for Lzlib (version 1.12, 2 January 2021). +This manual is for Lzlib (version 1.13, 23 January 2022). * Menu: @@ -30,7 +30,7 @@ This manual is for Lzlib (version 1.12, 2 January 2021). * Concept index:: Index of concepts - Copyright (C) 2009-2021 Antonio Diaz Diaz. + Copyright (C) 2009-2022 Antonio Diaz Diaz. This manual is free documentation: you have unlimited permission to copy, distribute, and modify it. @@ -73,8 +73,12 @@ byte near the beginning is a thing of the past. The functions and variables forming the interface of the compression library are declared in the file 'lzlib.h'. Usage examples of the library -are given in the files 'bbexample.c', 'ffexample.c', and 'main.c' from the -source distribution. +are given in the files 'bbexample.c', 'ffexample.c', and 'minilzip.c' from +the source distribution. + + All the library functions are thread safe. The library does not install +any signal handler. The decoder checks the consistency of the compressed +data, so the library should never crash even in case of corrupted input. Compression/decompression is done by repeatedly calling a couple of read/write functions until all the data have been processed by the library. @@ -102,20 +106,16 @@ concatenated compressed data streams is also supported. automatically creating multimember output. The members so created are large, about 2 PiB each. - All the library functions are thread safe. The library does not install -any signal handler. The decoder checks the consistency of the compressed -data, so the library should never crash even in case of corrupted input. - 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. +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. - Lzlib currently implements two variants of the LZMA algorithm; fast + Lzlib currently implements two variants of the LZMA algorithm: fast (used by option '-0' of minilzip) and normal (used by all other compression levels). @@ -145,7 +145,8 @@ One goal of lzlib is to keep perfect backward compatibility with older versions of itself down to 1.0. Any application working with an older lzlib should work with a newer lzlib. Installing a newer lzlib should not break anything. This chapter describes the constants and functions that the -application can use to discover the version of the library being used. +application can use to discover the version of the library being used. All +of them are declared in 'lzlib.h'. -- Constant: LZ_API_VERSION This constant is defined in 'lzlib.h' and works as a version test @@ -325,13 +326,13 @@ except 'LZ_compress_open' whose return value must be verified by calling 'LZ_compress_sync_flush'. Then call 'LZ_compress_read' until it returns 0. - This function writes a LZMA marker '3' ("Sync Flush" marker) to the - compressed output. Note that the sync flush marker is not allowed in - lzip files; it is a device for interactive communication between - applications using lzlib, but is useless and wasteful in a file, and - is excluded from the media type 'application/lzip'. The LZMA marker - '2' ("End Of Stream" marker) is the only marker allowed in lzip files. - *Note Data format::. + This function writes at least one LZMA marker '3' ("Sync Flush" marker) + to the compressed output. Note that the sync flush marker is not + allowed in lzip files; it is a device for interactive communication + between applications using lzlib, but is useless and wasteful in a + file, and is excluded from the media type 'application/lzip'. The LZMA + marker '2' ("End Of Stream" marker) is the only marker allowed in lzip + files. *Note Data format::. Repeated use of 'LZ_compress_sync_flush' may degrade compression ratio, so use it only when needed. If the interval between calls to @@ -347,34 +348,30 @@ except 'LZ_compress_open' whose return value must be verified by calling -- Function: int LZ_compress_read ( struct LZ_Encoder * const ENCODER, uint8_t * const BUFFER, const int SIZE ) - The function 'LZ_compress_read' reads up to SIZE bytes from the stream - pointed to by ENCODER, storing the results in BUFFER. If - LZ_API_VERSION >= 1012, BUFFER may be a null pointer, in which case - the bytes read are discarded. - - The return value is the number of bytes actually read. This might be - less than SIZE; for example, if there aren't that many bytes left in - the stream or if more bytes have to be yet written with the function + Reads up to SIZE bytes from the stream pointed to by ENCODER, storing + the results in BUFFER. If LZ_API_VERSION >= 1012, BUFFER may be a null + pointer, in which case the bytes read are discarded. + + Returns the number of bytes actually read. This might be less than + SIZE; for example, if there aren't that many bytes left in the stream + or if more bytes have to be yet written with the function 'LZ_compress_write'. Note that reading less than SIZE bytes is not an error. -- Function: int LZ_compress_write ( struct LZ_Encoder * const ENCODER, uint8_t * const BUFFER, const int SIZE ) - The function 'LZ_compress_write' writes up to SIZE bytes from BUFFER - to the stream pointed to by ENCODER. - - The return value is the number of bytes actually written. This might be + Writes up to SIZE bytes from BUFFER to the stream pointed to by + ENCODER. Returns the number of bytes actually written. This might be less than SIZE. Note that writing less than SIZE bytes is not an error. -- Function: int LZ_compress_write_size ( struct LZ_Encoder * const ENCODER ) - The function 'LZ_compress_write_size' returns the maximum number of - bytes that can be immediately written through 'LZ_compress_write'. For - efficiency reasons, once the input buffer is full and - 'LZ_compress_write_size' returns 0, almost all the buffer must be - compressed before a size greater than 0 is returned again. (This is - done to minimize the amount of data that must be copied to the - beginning of the buffer before new data can be accepted). + Returns the maximum number of bytes that can be immediately written + through 'LZ_compress_write'. For efficiency reasons, once the input + buffer is full and 'LZ_compress_write_size' returns 0, almost all the + buffer must be compressed before a size greater than 0 is returned + again. (This is done to minimize the amount of data that must be + copied to the beginning of the buffer before new data can be accepted). It is guaranteed that an immediate call to 'LZ_compress_write' will accept a SIZE up to the returned number of bytes. @@ -472,14 +469,13 @@ except 'LZ_decompress_open' whose return value must be verified by calling -- Function: int LZ_decompress_read ( struct LZ_Decoder * const DECODER, uint8_t * const BUFFER, const int SIZE ) - The function 'LZ_decompress_read' reads up to SIZE bytes from the - stream pointed to by DECODER, storing the results in BUFFER. If - LZ_API_VERSION >= 1012, BUFFER may be a null pointer, in which case - the bytes read are discarded. - - The return value is the number of bytes actually read. This might be - less than SIZE; for example, if there aren't that many bytes left in - the stream or if more bytes have to be yet written with the function + Reads up to SIZE bytes from the stream pointed to by DECODER, storing + the results in BUFFER. If LZ_API_VERSION >= 1012, BUFFER may be a null + pointer, in which case the bytes read are discarded. + + Returns the number of bytes actually read. This might be less than + SIZE; for example, if there aren't that many bytes left in the stream + or if more bytes have to be yet written with the function 'LZ_decompress_write'. Note that reading less than SIZE bytes is not an error. @@ -499,18 +495,16 @@ except 'LZ_decompress_open' whose return value must be verified by calling -- Function: int LZ_decompress_write ( struct LZ_Decoder * const DECODER, uint8_t * const BUFFER, const int SIZE ) - The function 'LZ_decompress_write' writes up to SIZE bytes from BUFFER - to the stream pointed to by DECODER. - - The return value is the number of bytes actually written. This might be + Writes up to SIZE bytes from BUFFER to the stream pointed to by + DECODER. Returns the number of bytes actually written. This might be less than SIZE. Note that writing less than SIZE bytes is not an error. -- Function: int LZ_decompress_write_size ( struct LZ_Decoder * const DECODER ) - The function 'LZ_decompress_write_size' returns the maximum number of - bytes that can be immediately written through 'LZ_decompress_write'. - This number varies smoothly; each compressed byte consumed may be - overwritten immediately, increasing by 1 the value returned. + Returns the maximum number of bytes that can be immediately written + through 'LZ_decompress_write'. This number varies smoothly; each + compressed byte consumed may be overwritten immediately, increasing by + 1 the value returned. It is guaranteed that an immediate call to 'LZ_decompress_write' will accept a SIZE up to the returned number of bytes. @@ -530,24 +524,24 @@ except 'LZ_decompress_open' whose return value must be verified by calling -- Function: int LZ_decompress_member_finished ( struct LZ_Decoder * const DECODER ) Returns 1 if the previous call to 'LZ_decompress_read' finished reading - the current member, indicating that final values for member are + the current member, indicating that final values for the member are available through 'LZ_decompress_data_crc', 'LZ_decompress_data_position', and 'LZ_decompress_member_position'. Otherwise it returns 0. -- Function: int LZ_decompress_member_version ( struct LZ_Decoder * const DECODER ) - Returns the version of current member from member header. + Returns the version of the current member, read from the member header. -- Function: int LZ_decompress_dictionary_size ( struct LZ_Decoder * const DECODER ) - Returns the dictionary size of the current member, read from the member - header. + Returns the dictionary size of the current member, read from the + member header. -- Function: unsigned LZ_decompress_data_crc ( struct LZ_Decoder * const DECODER ) Returns the 32 bit Cyclic Redundancy Check of the data decompressed - from the current member. The returned value is valid only when + from the current member. The value returned is valid only when 'LZ_decompress_member_finished' returns 1. -- Function: unsigned long long LZ_decompress_data_position ( struct @@ -650,13 +644,14 @@ compatible with lzip 1.4 or newer. Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov -chain-Algorithm' (LZMA) stream format, chosen to maximize safety and -interoperability. Lzip can compress about as fast as gzip (lzip -0) or -compress most files more than bzip2 (lzip -9). Decompression speed is -intermediate between gzip and bzip2. Lzip is better than gzip and bzip2 -from a data recovery perspective. Lzip has been designed, written, and -tested with great care to replace gzip and bzip2 as the standard -general-purpose compressed format for unix-like systems. +chain-Algorithm' (LZMA) stream format and provides a 3 factor integrity +checking to maximize interoperability and optimize safety. Lzip can compress +about as fast as gzip (lzip -0) or compress most files more than bzip2 +(lzip -9). Decompression speed is intermediate between gzip and bzip2. Lzip +is better than gzip and bzip2 from a data recovery perspective. Lzip has +been designed, written, and tested with great care to replace gzip and +bzip2 as the standard general-purpose compressed format for unix-like +systems. The format for running minilzip is: @@ -705,10 +700,13 @@ once, the first time it appears in the command line. '-d' '--decompress' - Decompress the files specified. If a file does not exist or can't be - opened, minilzip continues decompressing the rest of the files. If a - file fails to decompress, or is a terminal, minilzip exits immediately - without decompressing the rest of the files. + Decompress the files specified. If a file does not exist, can't be + opened, or the destination file already exists and '--force' has not + been specified, minilzip continues decompressing the rest of the files + and exits with error status 1. If a file fails to decompress, or is a + terminal, minilzip exits immediately with error status 2 without + decompressing the rest of the files. A terminal is considered an + uncompressed file, and therefore invalid. '-f' '--force' @@ -831,12 +829,14 @@ once, the first time it appears in the command line. '--check-lib' Compare the version of lzlib used to compile minilzip with the version - actually being used and exit. Report any differences found. Exit with - error status 1 if differences are found. A mismatch may indicate that - lzlib is not correctly installed or that a different version of lzlib - has been installed after compiling the shared version of minilzip. - 'minilzip -v --check-lib' shows the version of lzlib being used and - the value of 'LZ_API_VERSION' (if defined). *Note Library version::. + actually being used at run time and exit. Report any differences + found. Exit with error status 1 if differences are found. A mismatch + may indicate that lzlib is not correctly installed or that a different + version of lzlib has been installed after compiling the shared version + of minilzip. Exit with error status 2 if LZ_API_VERSION and + LZ_version_string don't match. 'minilzip -v --check-lib' shows the + version of lzlib being used and the value of LZ_API_VERSION (if + defined). *Note Library version::. Numbers given as arguments to options may be followed by a multiplier @@ -857,7 +857,7 @@ Y yottabyte (10^24) | Yi yobibyte (2^80) Exit status: 0 for a normal exit, 1 for environmental problems (file not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or invalid -input file, 3 for an internal consistency error (eg, bug) which caused +input file, 3 for an internal consistency error (e.g., bug) which caused minilzip to panic. @@ -886,9 +886,11 @@ when there is no longer anything to take away. represents a variable number of bytes. - A lzip data stream consists of a series of "members" (compressed data + Lzip data consist of a series of independent "members" (compressed data sets). The members simply appear one after another in the data stream, with -no additional information before, between, or after them. +no additional information before, between, or after them. Each member can +encode in compressed form up to 16 EiB - 1 byte of uncompressed data. The +size of a multimember data stream is unlimited. Each member has the following structure: @@ -916,7 +918,7 @@ no additional information before, between, or after them. Valid values for dictionary size range from 4 KiB to 512 MiB. 'LZMA stream' - The LZMA stream, finished by an end of stream marker. Uses default + The LZMA stream, finished by an "End Of Stream" marker. Uses default values for encoder properties. *Note Stream format: (lzip)Stream format, for a complete description. Lzip only uses the LZMA marker '2' ("End Of Stream" marker). Lzlib @@ -924,16 +926,17 @@ no additional information before, between, or after them. sync_flush::. 'CRC32 (4 bytes)' - Cyclic Redundancy Check (CRC) of the uncompressed original data. + Cyclic Redundancy Check (CRC) of the original uncompressed data. 'Data size (8 bytes)' - Size of the uncompressed original data. + Size of the original uncompressed data. 'Member size (8 bytes)' Total size of the member, including header and trailer. This field acts as a distributed index, allows the verification of stream integrity, - and facilitates safe recovery of undamaged members from multimember - files. + and facilitates the safe recovery of undamaged members from + multimember files. Member size should be limited to 2 PiB to prevent + the data size field from overflowing. @@ -967,10 +970,10 @@ File: lzlib.info, Node: Buffer compression, Next: Buffer decompression, Up: E Buffer-to-buffer single-member compression (MEMBER_SIZE > total output). -/* Compresses 'insize' bytes from 'inbuf' to 'outbuf'. - Returns the size of the compressed data in '*outlenp'. - In case of error, or if 'outsize' is too small, returns false and does - not modify '*outlenp'. +/* Compress 'insize' bytes from 'inbuf' to 'outbuf'. + Return the size of the compressed data in '*outlenp'. + In case of error, or if 'outsize' is too small, return false and do not + modify '*outlenp'. */ bool bbcompress( const uint8_t * const inbuf, const int insize, const int dictionary_size, const int match_len_limit, @@ -1011,10 +1014,10 @@ File: lzlib.info, Node: Buffer decompression, Next: File compression, Prev: B Buffer-to-buffer decompression. -/* Decompresses 'insize' bytes from 'inbuf' to 'outbuf'. - Returns the size of the decompressed data in '*outlenp'. - In case of error, or if 'outsize' is too small, returns false and does - not modify '*outlenp'. +/* Decompress 'insize' bytes from 'inbuf' to 'outbuf'. + Return the size of the decompressed data in '*outlenp'. + In case of error, or if 'outsize' is too small, return false and do not + modify '*outlenp'. */ bool bbdecompress( const uint8_t * const inbuf, const int insize, uint8_t * const outbuf, const int outsize, @@ -1159,9 +1162,9 @@ int ffmmcompress( FILE * const infile, FILE * const outfile ) Example 2: Multimember compression (user-restarted members). (Call LZ_compress_open with MEMBER_SIZE > largest member). -/* Compresses 'infile' to 'outfile' as a multimember stream with one member +/* Compress 'infile' to 'outfile' as a multimember stream with one member for each line of text terminated by a newline character or by EOF. - Returns 0 if success, 1 if error. + Return 0 if success, 1 if error. */ int fflfcompress( struct LZ_Encoder * const encoder, FILE * const infile, FILE * const outfile ) @@ -1205,7 +1208,7 @@ File: lzlib.info, Node: Skipping data errors, Prev: File compression mm, Up: 11.6 Skipping data errors ========================= -/* Decompresses 'infile' to 'outfile' with automatic resynchronization to +/* Decompress 'infile' to 'outfile' with automatic resynchronization to next member in case of data error, including the automatic removal of leading garbage. */ @@ -1253,7 +1256,7 @@ eternity, if not longer. If you find a bug in lzlib, please send electronic mail to <lzip-bug@nongnu.org>. Include the version number, which you can find by -running 'minilzip --version' or in 'LZ_version_string' from 'lzlib.h'. +running 'minilzip --version' and 'minilzip -v --check-lib'. File: lzlib.info, Node: Concept index, Prev: Problems, Up: Top @@ -1288,29 +1291,29 @@ Concept index Tag Table: -Node: Top220 -Node: Introduction1342 +Node: Top215 +Node: Introduction1338 Node: Library version6413 -Node: Buffering8918 -Node: Parameter limits10143 -Node: Compression functions11097 -Ref: member_size12907 -Ref: sync_flush14673 -Node: Decompression functions19493 -Node: Error codes27187 -Node: Error messages29478 -Node: Invoking minilzip30057 -Node: Data format39651 -Ref: coded-dict-size40957 -Node: Examples42267 -Node: Buffer compression43228 -Node: Buffer decompression44754 -Node: File compression46174 -Node: File decompression47157 -Node: File compression mm48161 -Node: Skipping data errors51193 -Node: Problems52505 -Node: Concept index53077 +Node: Buffering8957 +Node: Parameter limits10182 +Node: Compression functions11136 +Ref: member_size12946 +Ref: sync_flush14712 +Node: Decompression functions19400 +Node: Error codes26968 +Node: Error messages29259 +Node: Invoking minilzip29838 +Node: Data format39786 +Ref: coded-dict-size41232 +Node: Examples42641 +Node: Buffer compression43602 +Node: Buffer decompression45122 +Node: File compression46536 +Node: File decompression47519 +Node: File compression mm48523 +Node: Skipping data errors51552 +Node: Problems52862 +Node: Concept index53423 End Tag Table diff --git a/doc/lzlib.texi b/doc/lzlib.texi index 644a3d7..3caf9dd 100644 --- a/doc/lzlib.texi +++ b/doc/lzlib.texi @@ -6,10 +6,10 @@ @finalout @c %**end of header -@set UPDATED 2 January 2021 -@set VERSION 1.12 +@set UPDATED 23 January 2022 +@set VERSION 1.13 -@dircategory Data Compression +@dircategory Compression @direntry * Lzlib: (lzlib). Compression library for the lzip format @end direntry @@ -52,7 +52,7 @@ This manual is for Lzlib (version @value{VERSION}, @value{UPDATED}). @end menu @sp 1 -Copyright @copyright{} 2009-2021 Antonio Diaz Diaz. +Copyright @copyright{} 2009-2022 Antonio Diaz Diaz. This manual is free documentation: you have unlimited permission to copy, distribute, and modify it. @@ -77,9 +77,9 @@ taking into account both data integrity and decoder availability: The lzip format provides very safe integrity checking and some data recovery means. The program @uref{http://www.nongnu.org/lzip/manual/lziprecover_manual.html#Data-safety,,lziprecover} -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. +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 @xref{Data safety,,,lziprecover}. @end ifnothtml @@ -89,8 +89,8 @@ The lzip format is as simple as possible (but not simpler). The lzip manual provides the source code of a simple decompressor along with a detailed explanation of how it works, so that with the only help of the lzip manual it would be possible for a digital archaeologist to extract -the data from a lzip file long after quantum computers eventually render -LZMA obsolete. +the data from a lzip file long after quantum computers eventually +render LZMA obsolete. @item Additionally the lzip reference implementation is copylefted, which @@ -104,8 +104,12 @@ the beginning is a thing of the past. 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{bbexample.c}, @samp{ffexample.c}, and @samp{main.c} -from the source distribution. +given in the files @samp{bbexample.c}, @samp{ffexample.c}, and +@samp{minilzip.c} from the source distribution. + +All the library functions are thread safe. The library does not install any +signal handler. The decoder checks the consistency of the compressed data, +so the library should never crash even in case of corrupted input. Compression/decompression is done by repeatedly calling a couple of read/write functions until all the data have been processed by the library. @@ -134,22 +138,17 @@ Lzlib is able to compress and decompress streams of unlimited size by automatically creating multimember output. The members so created are large, about @w{2 PiB} each. -All the library functions are thread safe. The library does not install -any signal handler. The decoder checks the consistency of the compressed -data, so the library should never crash even in case of corrupted input. - 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. +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. -Lzlib currently implements two variants of the LZMA algorithm; fast (used by -option @samp{-0} of minilzip) and normal (used by all other compression -levels). +Lzlib currently implements two variants of the LZMA algorithm: fast (used by +option @samp{-0} of minilzip) 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 @@ -176,7 +175,8 @@ One goal of lzlib is to keep perfect backward compatibility with older versions of itself down to 1.0. Any application working with an older lzlib should work with a newer lzlib. Installing a newer lzlib should not break anything. This chapter describes the constants and functions that the -application can use to discover the version of the library being used. +application can use to discover the version of the library being used. All +of them are declared in @samp{lzlib.h}. @defvr Constant LZ_API_VERSION This constant is defined in @samp{lzlib.h} and works as a version test @@ -372,12 +372,13 @@ already written with the function @samp{LZ_compress_write}. First call @samp{LZ_compress_sync_flush}. Then call @samp{LZ_compress_read} until it returns 0. -This function writes a LZMA marker @samp{3} ("Sync Flush" marker) to the -compressed output. Note that the sync flush marker is not allowed in lzip -files; it is a device for interactive communication between applications -using lzlib, but is useless and wasteful in a file, and is excluded from the -media type @samp{application/lzip}. The LZMA marker @samp{2} ("End Of -Stream" marker) is the only marker allowed in lzip files. @xref{Data format}. +This function writes at least one LZMA marker @samp{3} ("Sync Flush" marker) +to the compressed output. Note that the sync flush marker is not allowed in +lzip files; it is a device for interactive communication between +applications using lzlib, but is useless and wasteful in a file, and is +excluded from the media type @samp{application/lzip}. The LZMA marker +@samp{2} ("End Of Stream" marker) is the only marker allowed in lzip files. +@xref{Data format}. Repeated use of @samp{LZ_compress_sync_flush} may degrade compression ratio, so use it only when needed. If the interval between calls to @@ -394,36 +395,33 @@ are more bytes available than those needed to complete @var{member_size}, @deftypefun int LZ_compress_read ( struct LZ_Encoder * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} ) -The function @samp{LZ_compress_read} reads up to @var{size} bytes from the -stream pointed to by @var{encoder}, storing the results in @var{buffer}. -If @w{LZ_API_VERSION >= 1012}, @var{buffer} may be a null pointer, in which -case the bytes read are discarded. - -The return value is the number of bytes actually read. This might be less -than @var{size}; for example, if there aren't that many bytes left in the -stream or if more bytes have to be yet written with the function +Reads up to @var{size} bytes from the stream pointed to by @var{encoder}, +storing the results in @var{buffer}. If @w{LZ_API_VERSION >= 1012}, +@var{buffer} may be a null pointer, in which case the bytes read are +discarded. + +Returns the number of bytes actually read. This might be less than +@var{size}; for example, if there aren't that many bytes left in the stream +or if more bytes have to be yet written with the function @samp{LZ_compress_write}. Note that reading less than @var{size} bytes is not an error. @end deftypefun @deftypefun int LZ_compress_write ( struct LZ_Encoder * const @var{encoder}, uint8_t * const @var{buffer}, const int @var{size} ) -The function @samp{LZ_compress_write} writes up to @var{size} bytes from -@var{buffer} to the stream pointed to by @var{encoder}. - -The return value is the number of bytes actually written. This might be -less than @var{size}. Note that writing less than @var{size} bytes is -not an error. +Writes up to @var{size} bytes from @var{buffer} to the stream pointed to by +@var{encoder}. Returns the number of bytes actually written. This might be +less than @var{size}. Note that writing less than @var{size} bytes is not an +error. @end deftypefun @deftypefun int LZ_compress_write_size ( struct LZ_Encoder * const @var{encoder} ) -The function @samp{LZ_compress_write_size} returns the maximum number of -bytes that can be immediately written through @samp{LZ_compress_write}. -For efficiency reasons, once the input buffer is full and -@samp{LZ_compress_write_size} returns 0, almost all the buffer must be -compressed before a size greater than 0 is returned again. (This is done to -minimize the amount of data that must be copied to the beginning of the +Returns the maximum number of bytes that can be immediately written through +@samp{LZ_compress_write}. For efficiency reasons, once the input buffer is +full and @samp{LZ_compress_write_size} returns 0, almost all the buffer must +be compressed before a size greater than 0 is returned again. (This is done +to minimize the amount of data that must be copied to the beginning of the buffer before new data can be accepted). It is guaranteed that an immediate call to @samp{LZ_compress_write} will @@ -478,10 +476,10 @@ perhaps not yet read. @chapter Decompression functions @cindex decompression functions -These are the functions used to decompress data. In case of error, all -of them return -1 or 0, for signed and unsigned return values -respectively, except @samp{LZ_decompress_open} whose return value must -be verified by calling @samp{LZ_decompress_errno} before using it. +These are the functions used to decompress data. In case of error, all of +them return -1 or 0, for signed and unsigned return values respectively, +except @samp{LZ_decompress_open} whose return value must be verified by +calling @samp{LZ_decompress_errno} before using it. @deftypefun {struct LZ_Decoder *} LZ_decompress_open ( void ) @@ -539,14 +537,14 @@ function does nothing. @deftypefun int LZ_decompress_read ( struct LZ_Decoder * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} ) -The function @samp{LZ_decompress_read} reads up to @var{size} bytes from the -stream pointed to by @var{decoder}, storing the results in @var{buffer}. -If @w{LZ_API_VERSION >= 1012}, @var{buffer} may be a null pointer, in which -case the bytes read are discarded. - -The return value is the number of bytes actually read. This might be less -than @var{size}; for example, if there aren't that many bytes left in the -stream or if more bytes have to be yet written with the function +Reads up to @var{size} bytes from the stream pointed to by @var{decoder}, +storing the results in @var{buffer}. If @w{LZ_API_VERSION >= 1012}, +@var{buffer} may be a null pointer, in which case the bytes read are +discarded. + +Returns the number of bytes actually read. This might be less than +@var{size}; for example, if there aren't that many bytes left in the stream +or if more bytes have to be yet written with the function @samp{LZ_decompress_write}. Note that reading less than @var{size} bytes is not an error. @@ -571,20 +569,18 @@ recover as much data as possible from each damaged member. @deftypefun int LZ_decompress_write ( struct LZ_Decoder * const @var{decoder}, uint8_t * const @var{buffer}, const int @var{size} ) -The function @samp{LZ_decompress_write} writes up to @var{size} bytes from -@var{buffer} to the stream pointed to by @var{decoder}. - -The return value is the number of bytes actually written. This might be -less than @var{size}. Note that writing less than @var{size} bytes is -not an error. +Writes up to @var{size} bytes from @var{buffer} to the stream pointed to by +@var{decoder}. Returns the number of bytes actually written. This might be +less than @var{size}. Note that writing less than @var{size} bytes is not an +error. @end deftypefun @deftypefun int LZ_decompress_write_size ( struct LZ_Decoder * const @var{decoder} ) -The function @samp{LZ_decompress_write_size} returns the maximum number of -bytes that can be immediately written through @samp{LZ_decompress_write}. -This number varies smoothly; each compressed byte consumed may be -overwritten immediately, increasing by 1 the value returned. +Returns the maximum number of bytes that can be immediately written through +@samp{LZ_decompress_write}. This number varies smoothly; each compressed +byte consumed may be overwritten immediately, increasing by 1 the value +returned. It is guaranteed that an immediate call to @samp{LZ_decompress_write} will accept a @var{size} up to the returned number of bytes. @@ -607,26 +603,25 @@ does not imply @samp{LZ_decompress_member_finished}. @deftypefun int LZ_decompress_member_finished ( struct LZ_Decoder * const @var{decoder} ) Returns 1 if the previous call to @samp{LZ_decompress_read} finished reading -the current member, indicating that final values for member are available +the current member, indicating that final values for the member are available through @samp{LZ_decompress_data_crc}, @samp{LZ_decompress_data_position}, and @samp{LZ_decompress_member_position}. Otherwise it returns 0. @end deftypefun @deftypefun int LZ_decompress_member_version ( struct LZ_Decoder * const @var{decoder} ) -Returns the version of current member from member header. +Returns the version of the current member, read from the member header. @end deftypefun @deftypefun int LZ_decompress_dictionary_size ( struct LZ_Decoder * const @var{decoder} ) -Returns the dictionary size of the current member, read from the member -header. +Returns the dictionary size of the current member, read from the member header. @end deftypefun @deftypefun {unsigned} LZ_decompress_data_crc ( struct LZ_Decoder * const @var{decoder} ) Returns the 32 bit Cyclic Redundancy Check of the data decompressed from -the current member. The returned value is valid only when +the current member. The value returned is valid only when @samp{LZ_decompress_member_finished} returns 1. @end deftypefun @@ -672,8 +667,7 @@ examine @samp{LZ_(de)compress_errno}. The error codes are defined in the header file @samp{lzlib.h}. @deftypevr Constant {enum LZ_Errno} LZ_ok -The value of this constant is 0 and is used to indicate that there is no -error. +The value of this constant is 0 and is used to indicate that there is no error. @end deftypevr @deftypevr Constant {enum LZ_Errno} LZ_bad_argument @@ -737,16 +731,17 @@ The value of @var{lz_errno} normally comes from a call to Minilzip is a test program for the compression library lzlib, fully compatible with lzip 1.4 or newer. -@uref{http://www.nongnu.org/lzip/lzip.html,,Lzip} is a lossless data -compressor with a user interface similar to the one of gzip or bzip2. Lzip -uses a simplified form of the 'Lempel-Ziv-Markov chain-Algorithm' (LZMA) -stream format, chosen to maximize safety and interoperability. Lzip can -compress about as fast as gzip @w{(lzip -0)} or compress most files more -than bzip2 @w{(lzip -9)}. Decompression speed is intermediate between gzip -and bzip2. Lzip is better than gzip and bzip2 from a data recovery -perspective. Lzip has been designed, written, and tested with great care to -replace gzip and bzip2 as the standard general-purpose compressed format for -unix-like systems. +@uref{http://www.nongnu.org/lzip/lzip.html,,Lzip} +is a lossless data compressor with a user interface similar to the one +of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov +chain-Algorithm' (LZMA) stream format and provides a 3 factor integrity +checking to maximize interoperability and optimize safety. Lzip can compress +about as fast as gzip @w{(lzip -0)} or compress most files more than bzip2 +@w{(lzip -9)}. Decompression speed is intermediate between gzip and bzip2. +Lzip is better than gzip and bzip2 from a data recovery perspective. Lzip +has been designed, written, and tested with great care to replace gzip and +bzip2 as the standard general-purpose compressed format for unix-like +systems. @noindent The format for running minilzip is: @@ -803,10 +798,12 @@ and @samp{-S}. @samp{-c} has no effect when testing or listing. @item -d @itemx --decompress -Decompress the files specified. If a file does not exist or can't be -opened, minilzip continues decompressing the rest of the files. If a file -fails to decompress, or is a terminal, minilzip exits immediately without -decompressing the rest of the files. +Decompress the files specified. If a file does not exist, can't be opened, +or the destination file already exists and @samp{--force} has not been +specified, minilzip continues decompressing the rest of the files and exits with +error status 1. If a file fails to decompress, or is a terminal, minilzip exits +immediately with error status 2 without decompressing the rest of the files. +A terminal is considered an uncompressed file, and therefore invalid. @item -f @itemx --force @@ -932,12 +929,13 @@ header" error and the cause is not indeed a corrupt header. @item --check-lib Compare the @uref{#Library-version,,version of lzlib} used to compile -minilzip with the version actually being used and exit. Report any -differences found. Exit with error status 1 if differences are found. A +minilzip with the version actually being used at run time and exit. Report +any differences found. Exit with error status 1 if differences are found. A mismatch may indicate that lzlib is not correctly installed or that a different version of lzlib has been installed after compiling the shared -version of minilzip. @w{@samp{minilzip -v --check-lib}} shows the version of -lzlib being used and the value of @samp{LZ_API_VERSION} (if defined). +version of minilzip. Exit with error status 2 if LZ_API_VERSION and +LZ_version_string don't match. @w{@samp{minilzip -v --check-lib}} shows the +version of lzlib being used and the value of LZ_API_VERSION (if defined). @ifnothtml @xref{Library version}. @end ifnothtml @@ -963,9 +961,9 @@ Table of SI and binary prefixes (unit multipliers): @sp 1 Exit status: 0 for a normal exit, 1 for environmental problems (file not -found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or -invalid input file, 3 for an internal consistency error (eg, bug) which -caused minilzip to panic. +found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or invalid +input file, 3 for an internal consistency error (e.g., bug) which caused +minilzip to panic. @node Data format @@ -996,9 +994,11 @@ represents one byte; a box like this: represents a variable number of bytes. @sp 1 -A lzip data stream consists of a series of "members" (compressed data sets). -The members simply appear one after another in the data stream, with no -additional information before, between, or after them. +Lzip data consist of a series of independent "members" (compressed data +sets). The members simply appear one after another in the data stream, with +no additional information before, between, or after them. Each member can +encode in compressed form up to @w{16 EiB - 1 byte} of uncompressed data. +The size of a multimember data stream is unlimited. Each member has the following structure: @@ -1029,7 +1029,7 @@ Example: 0xD3 = 2^19 - 6 * 2^15 = 512 KiB - 6 * 32 KiB = 320 KiB@* Valid values for dictionary size range from 4 KiB to 512 MiB. @item LZMA stream -The LZMA stream, finished by an end of stream marker. Uses default values +The LZMA stream, finished by an "End Of Stream" marker. Uses default values for encoder properties. @ifnothtml @xref{Stream format,,,lzip}, @@ -1043,15 +1043,17 @@ Lzip only uses the LZMA marker @samp{2} ("End Of Stream" marker). Lzlib also uses the LZMA marker @samp{3} ("Sync Flush" marker). @xref{sync_flush}. @item CRC32 (4 bytes) -Cyclic Redundancy Check (CRC) of the uncompressed original data. +Cyclic Redundancy Check (CRC) of the original uncompressed data. @item Data size (8 bytes) -Size of the uncompressed original data. +Size of the original uncompressed data. @item Member size (8 bytes) Total size of the member, including header and trailer. This field acts as a distributed index, allows the verification of stream integrity, and -facilitates safe recovery of undamaged members from multimember files. +facilitates the safe recovery of undamaged members from multimember files. +Member size should be limited to @w{2 PiB} to prevent the data size field +from overflowing. @end table @@ -1086,10 +1088,10 @@ Buffer-to-buffer single-member compression @w{(@var{member_size} > total output)}. @verbatim -/* Compresses 'insize' bytes from 'inbuf' to 'outbuf'. - Returns the size of the compressed data in '*outlenp'. - In case of error, or if 'outsize' is too small, returns false and does - not modify '*outlenp'. +/* Compress 'insize' bytes from 'inbuf' to 'outbuf'. + Return the size of the compressed data in '*outlenp'. + In case of error, or if 'outsize' is too small, return false and do not + modify '*outlenp'. */ bool bbcompress( const uint8_t * const inbuf, const int insize, const int dictionary_size, const int match_len_limit, @@ -1131,10 +1133,10 @@ bool bbcompress( const uint8_t * const inbuf, const int insize, Buffer-to-buffer decompression. @verbatim -/* Decompresses 'insize' bytes from 'inbuf' to 'outbuf'. - Returns the size of the decompressed data in '*outlenp'. - In case of error, or if 'outsize' is too small, returns false and does - not modify '*outlenp'. +/* Decompress 'insize' bytes from 'inbuf' to 'outbuf'. + Return the size of the decompressed data in '*outlenp'. + In case of error, or if 'outsize' is too small, return false and do not + modify '*outlenp'. */ bool bbdecompress( const uint8_t * const inbuf, const int insize, uint8_t * const outbuf, const int outsize, @@ -1285,9 +1287,9 @@ Example 2: Multimember compression (user-restarted members). (Call LZ_compress_open with @var{member_size} > largest member). @verbatim -/* Compresses 'infile' to 'outfile' as a multimember stream with one member +/* Compress 'infile' to 'outfile' as a multimember stream with one member for each line of text terminated by a newline character or by EOF. - Returns 0 if success, 1 if error. + Return 0 if success, 1 if error. */ int fflfcompress( struct LZ_Encoder * const encoder, FILE * const infile, FILE * const outfile ) @@ -1332,7 +1334,7 @@ int fflfcompress( struct LZ_Encoder * const encoder, @cindex skipping data errors @verbatim -/* Decompresses 'infile' to 'outfile' with automatic resynchronization to +/* Decompress 'infile' to 'outfile' with automatic resynchronization to next member in case of data error, including the automatic removal of leading garbage. */ @@ -1381,8 +1383,8 @@ for all eternity, if not longer. If you find a bug in lzlib, please send electronic mail to @email{lzip-bug@@nongnu.org}. Include the version number, which you can -find by running @w{@samp{minilzip --version}} or in -@samp{LZ_version_string} from @samp{lzlib.h}. +find by running @w{@samp{minilzip --version}} and +@w{@samp{minilzip -v --check-lib}}. @node Concept index diff --git a/doc/minilzip.1 b/doc/minilzip.1 index 13a2d6d..0c4c06d 100644 --- a/doc/minilzip.1 +++ b/doc/minilzip.1 @@ -1,5 +1,5 @@ .\" DO NOT MODIFY THIS FILE! It was generated by help2man 1.47.16. -.TH MINILZIP "1" "January 2021" "minilzip 1.12" "User Commands" +.TH MINILZIP "1" "January 2022" "minilzip 1.13" "User Commands" .SH NAME minilzip \- reduces the size of files .SH SYNOPSIS @@ -11,13 +11,14 @@ compatible with lzip 1.4 or newer. .PP Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip uses a simplified form of the 'Lempel\-Ziv\-Markov -chain\-Algorithm' (LZMA) stream format, chosen to maximize safety and -interoperability. Lzip can compress about as fast as gzip (lzip \fB\-0\fR) or -compress most files more than bzip2 (lzip \fB\-9\fR). Decompression speed is -intermediate between gzip and bzip2. Lzip is better than gzip and bzip2 from -a data recovery perspective. Lzip has been designed, written, and tested -with great care to replace gzip and bzip2 as the standard general\-purpose -compressed format for unix\-like systems. +chain\-Algorithm' (LZMA) stream format and provides a 3 factor integrity +checking to maximize interoperability and optimize safety. Lzip can compress +about as fast as gzip (lzip \fB\-0\fR) or compress most files more than bzip2 +(lzip \fB\-9\fR). Decompression speed is intermediate between gzip and bzip2. +Lzip is better than gzip and bzip2 from a data recovery perspective. Lzip +has been designed, written, and tested with great care to replace gzip and +bzip2 as the standard general\-purpose compressed format for unix\-like +systems. .SH OPTIONS .TP \fB\-h\fR, \fB\-\-help\fR @@ -100,7 +101,7 @@ To extract all the files from archive 'foo.tar.lz', use the commands .PP Exit status: 0 for a normal exit, 1 for environmental problems (file not found, invalid flags, I/O errors, etc), 2 to indicate a corrupt or -invalid input file, 3 for an internal consistency error (eg, bug) which +invalid input file, 3 for an internal consistency error (e.g., bug) which caused minilzip to panic. .PP The ideas embodied in lzlib are due to (at least) the following people: @@ -113,9 +114,21 @@ Report bugs to lzip\-bug@nongnu.org .br Lzlib home page: http://www.nongnu.org/lzip/lzlib.html .SH COPYRIGHT -Copyright \(co 2021 Antonio Diaz Diaz. -Using lzlib 1.12 +Copyright \(co 2022 Antonio Diaz Diaz. +Using lzlib 1.13 License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html> .br This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. +.SH "SEE ALSO" +The full documentation for +.B minilzip +is maintained as a Texinfo manual. If the +.B info +and +.B minilzip +programs are properly installed at your site, the command +.IP +.B info lzlib +.PP +should give you access to the complete manual. |