lzip/lzlib
1
0
Fork 0
Code Issues Activity

Merging upstream version 1.11.

Browse source 
Signed-off-by: Daniel Baumann <daniel@debian.org>
This commit is contained in:
Daniel Baumann 2025-02-20 21:28:08 +01:00
parent 37996bac79
commit bb8f341eba
Signed by: daniel
GPG key ID: FBB4F0E80A80222F
27 changed files with 614 additions and 442 deletions
Download patch file Download diff file Expand all files Collapse all files

162
doc/lzlib.info
View file

@ -11,7 +11,7 @@ File: lzlib.info, Node: Top, Next: Introduction, Up: (dir)
Lzlib Manual
************
This manual is for Lzlib (version 1.10, 7 February 2018).
This manual is for Lzlib (version 1.11, 2 January 2019).
* Menu:
@ -30,7 +30,7 @@ This manual is for Lzlib (version 1.10, 7 February 2018).
* Concept index:: Index of concepts
Copyright (C) 2009-2018 Antonio Diaz Diaz.
Copyright (C) 2009-2019 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission to
copy, distribute and modify it.
@ -41,10 +41,10 @@ File: lzlib.info, Node: Introduction, Next: Library version, Prev: Top, Up:
1 Introduction
**************
Lzlib is a data compression library providing in-memory LZMA compression
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.
Lzlib is a data compression library providing in-memory LZMA
compression 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 data sharing and long-term
archiving, taking into account both data integrity and decoder
@ -90,15 +90,20 @@ with a SIZE equal to 0.
If all the data to be compressed are written in advance, lzlib will
automatically adjust the header of the compressed data to use the
smallest possible dictionary size. This feature reduces the amount of
memory needed for decompression and allows minilzip to produce identical
compressed output as lzip.
largest dictionary size that does not exceed neither the data size nor
the limit given to 'LZ_compress_open'. This feature reduces the amount
of memory needed for decompression and allows minilzip to produce
identical compressed output as lzip.
Lzlib will correctly decompress a data stream which is the
concatenation of two or more compressed data streams. The result is the
concatenation of the corresponding decompressed data streams. Integrity
testing of concatenated compressed data streams is also supported.
Lzlib is able to compress and decompress streams of unlimited size by
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
@ -253,11 +258,13 @@ calling 'LZ_compress_errno' before using it.
output as 'lzip -0'. (The dictionary size used will be rounded
upwards to 64 KiB).
MEMBER_SIZE sets the member size limit in bytes. Minimum member
size limit is 100 kB. Small member size may degrade compression
ratio, so use it only when needed. To produce a single-member data
stream, give MEMBER_SIZE a value larger than the amount of data to
be produced, for example INT64_MAX.
MEMBER_SIZE sets the member size limit in bytes. Valid values
range from 100 kB to 2 PiB. Small member size may degrade
compression ratio, so use it only when needed. To produce a
single-member data stream, give MEMBER_SIZE a value larger than
the amount of data to be produced. Values larger than 2 PiB will be
reduced to 2 PiB to prevent the uncompressed size of the member
from overflowing.
-- Function: int LZ_compress_close ( struct LZ_Encoder * const ENCODER
)
@ -270,6 +277,7 @@ calling 'LZ_compress_errno' before using it.
ENCODER )
Use this function to tell 'lzlib' that all the data for this member
have already been written (with the 'LZ_compress_write' function).
It is safe to call 'LZ_compress_finish' as many times as needed.
After all the produced compressed data have been read with
'LZ_compress_read' and 'LZ_compress_member_finished' returns 1, a
new member can be started with 'LZ_compress_restart_member'.
@ -322,7 +330,7 @@ calling 'LZ_compress_errno' before using it.
-- Function: enum LZ_Errno LZ_compress_errno ( struct LZ_Encoder *
const ENCODER )
Returns the current error code for ENCODER (*note Error codes::).
Returns the current error code for ENCODER. *Note Error codes::.
-- Function: int LZ_compress_finished ( struct LZ_Encoder * const
ENCODER )
@ -388,7 +396,8 @@ verified by calling 'LZ_decompress_errno' before using it.
DECODER )
Use this function to tell 'lzlib' that all the data for this stream
have already been written (with the 'LZ_decompress_write'
function).
function). It is safe to call 'LZ_decompress_finish' as many
times as needed.
-- Function: int LZ_decompress_reset ( struct LZ_Decoder * const
DECODER )
@ -420,6 +429,12 @@ verified by calling 'LZ_decompress_errno' before using it.
'LZ_decompress_write' function. Note that reading less than SIZE
bytes is not an error.
In case of decompression error caused by corrupt or truncated data,
'LZ_decompress_read' does not signal the error immediately to the
application, but waits until all decoded bytes have been read. This
allows tools like tarlz to recover as much data as possible from
each damaged member. *Note tarlz manual: (tarlz)Top.
-- Function: int LZ_decompress_write ( struct LZ_Decoder * const
DECODER, uint8_t * const BUFFER, const int SIZE )
The 'LZ_decompress_write' function writes up to SIZE bytes from
@ -440,7 +455,7 @@ verified by calling 'LZ_decompress_errno' before using it.
-- Function: enum LZ_Errno LZ_decompress_errno ( struct LZ_Decoder *
const DECODER )
Returns the current error code for DECODER (*note Error codes::).
Returns the current error code for DECODER. *Note Error codes::.
-- Function: int LZ_decompress_finished ( struct LZ_Decoder * const
DECODER )
@ -543,8 +558,8 @@ whether a call failed. If the call failed, then you can examine
file.
-- Constant: enum LZ_Errno LZ_library_error
A bug was detected in the library. Please, report it (*note
Problems::).
A bug was detected in the library. Please, report it. *Note
Problems::.

File: lzlib.info, Node: Error messages, Next: Invoking minilzip, Prev: Error codes, Up: Top
@ -568,6 +583,9 @@ File: lzlib.info, Node: Invoking minilzip, Next: Data format, Prev: Error mes
9 Invoking minilzip
*******************
Minilzip is a test program for the lzlib compression library, fully
compatible with lzip 1.4 or newer.
The format for running minilzip is:
minilzip [OPTIONS] [FILES]
@ -585,7 +603,7 @@ command line.
'-V'
'--version'
Print the version number of minilzip on the standard output and
exit.
exit. This version number should be included in all bug reports.
'-a'
'--trailing-error'
@ -654,12 +672,14 @@ command line.
'-s BYTES'
'--dictionary-size=BYTES'
When compressing, set the dictionary size limit in bytes. Minilzip
will use the smallest possible dictionary size for each file
without exceeding this limit. Valid values range from 4 KiB to
512 MiB. Values 12 to 29 are interpreted as powers of two, meaning
2^12 to 2^29 bytes. Note that dictionary sizes are quantized. If
the specified size does not match one of the valid sizes, it will
be rounded upwards by adding up to (BYTES / 8) to it.
will use for each file the largest dictionary size that does not
exceed neither the file size nor this limit. Valid values range
from 4 KiB to 512 MiB. Values 12 to 29 are interpreted as powers
of two, meaning 2^12 to 2^29 bytes. Dictionary sizes are quantized
so that they can be coded in just one byte (*note
coded-dict-size::). If the specified size does not match one of
the valid sizes, it will be rounded upwards by adding up to
(BYTES / 8) to it.
For maximum compression you should use a dictionary size limit as
large as possible, but keep in mind that the decompression memory
@ -695,27 +715,32 @@ command line.
size, and trailer contents (CRC, data size, member size).
'-0 .. -9'
Set the compression parameters (dictionary size and match length
limit) as shown in the table below. The default compression level
is '-6'. Note that '-9' can be much slower than '-0'. These
options have no effect when decompressing or testing.
Compression level. Set the compression parameters (dictionary size
and match length limit) as shown in the table below. The default
compression level is '-6', equivalent to '-s8MiB -m36'. Note that
'-9' can be much slower than '-0'. These options have no effect
when decompressing or testing.
The bidimensional parameter space of LZMA can't be mapped to a
linear scale optimal for all files. If your files are large, very
repetitive, etc, you may need to use the '--dictionary-size' and
'--match-length' options directly to achieve optimal performance.
Level Dictionary size Match length limit
-0 64 KiB 16 bytes
-1 1 MiB 5 bytes
-2 1.5 MiB 6 bytes
-3 2 MiB 8 bytes
-4 3 MiB 12 bytes
-5 4 MiB 20 bytes
-6 8 MiB 36 bytes
-7 16 MiB 68 bytes
-8 24 MiB 132 bytes
-9 32 MiB 273 bytes
If several compression levels or '-s' or '-m' options are given,
the last setting is used. For example '-9 -s64MiB' is equivalent
to '-s64MiB -m273'
Level Dictionary size (-s) Match length limit (-m)
-0 64 KiB 16 bytes
-1 1 MiB 5 bytes
-2 1.5 MiB 6 bytes
-3 2 MiB 8 bytes
-4 3 MiB 12 bytes
-5 4 MiB 20 bytes
-6 8 MiB 36 bytes
-7 16 MiB 68 bytes
-8 24 MiB 132 bytes
-9 32 MiB 273 bytes
'--fast'
'--best'
@ -795,11 +820,11 @@ stream, with no additional information before, between, or after them.
'DS (coded dictionary size, 1 byte)'
The dictionary size is calculated by taking a power of 2 (the base
size) and substracting from it a fraction between 0/16 and 7/16 of
size) and subtracting from it a fraction between 0/16 and 7/16 of
the base size.
Bits 4-0 contain the base 2 logarithm of the base size (12 to 29).
Bits 7-5 contain the numerator of the fraction (0 to 7) to
substract from the base size to obtain the dictionary size.
Bits 7-5 contain the numerator of the fraction (0 to 7) to subtract
from the base size to obtain the dictionary size.
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.
@ -845,12 +870,10 @@ Example 1: Normal compression (MEMBER_SIZE > total output).
1) LZ_compress_open
2) LZ_compress_write
3) LZ_compress_read
4) go back to step 2 until all input data have been written
5) LZ_compress_finish
6) LZ_compress_read
7) go back to step 6 until LZ_compress_finished returns 1
8) LZ_compress_close
3) if no more data to write, call LZ_compress_finish
4) LZ_compress_read
5) go back to step 2 until LZ_compress_finished returns 1
6) LZ_compress_close
Example 2: Normal compression using LZ_compress_write_size.
@ -868,12 +891,10 @@ Example 3: Decompression.
1) LZ_decompress_open
2) LZ_decompress_write
3) LZ_decompress_read
4) go back to step 2 until all input data have been written
5) LZ_decompress_finish
6) LZ_decompress_read
7) go back to step 6 until LZ_decompress_finished returns 1
8) LZ_decompress_close
3) if no more data to write, call LZ_decompress_finish
4) LZ_decompress_read
5) go back to step 2 until LZ_decompress_finished returns 1
6) LZ_decompress_close
Example 4: Decompression using LZ_decompress_write_size.
@ -988,20 +1009,21 @@ Concept index

Tag Table:
Node: Top220
Node: Introduction1342
Node: Library version6154
Node: Buffering6799
Node: Parameter limits8024
Node: Compression functions8983
Node: Decompression functions15592
Node: Error codes21762
Node: Error messages24064
Node: Invoking minilzip24649
Ref: --trailing-error25243
Node: Data format31883
Node: Examples34454
Node: Problems38570
Node: Concept index39142
Node: Introduction1341
Node: Library version6397
Node: Buffering7042
Node: Parameter limits8267
Node: Compression functions9226
Node: Decompression functions16010
Node: Error codes22599
Node: Error messages24900
Node: Invoking minilzip25485
Ref: --trailing-error26243
Node: Data format33248
Ref: coded-dict-size34557
Node: Examples35817
Node: Problems39813
Node: Concept index40385

End Tag Table