lzip/lzlib
1
0
Fork 0
Code Issues Activity

Merging upstream version 0.4.

Browse source 
Signed-off-by: Daniel Baumann <daniel@debian.org>
This commit is contained in:
Daniel Baumann 2025-02-20 16:01:38 +01:00
parent 3de47bdbc0
commit a40555eef7
Signed by: daniel
GPG key ID: FBB4F0E80A80222F
16 changed files with 536 additions and 317 deletions
Download patch file Download diff file Expand all files Collapse all files

79
doc/lzlib.texinfo
View file

@ -5,8 +5,8 @@
@finalout
@c %**end of header
@set UPDATED 3 May 2009
@set VERSION 0.3
@set UPDATED 3 June 2009
@set VERSION 0.4
@dircategory Data Compression
@direntry
@ -34,6 +34,7 @@ This manual is for Lzlib (version @value{VERSION}, @value{UPDATED}).
@menu
* Introduction:: Purpose and features of Lzlib
* Library Version:: Checking library version
* Buffering:: Sizes of Lzlib's buffers
* Compression Functions:: Descriptions of the compression functions
* Decompression Functions:: Descriptions of the decompression functions
* Error Codes:: Meaning of codes returned by functions
@ -54,8 +55,8 @@ to copy, distribute and modify it.
@chapter Introduction
@cindex introduction
The lzlib compression library provides in-memory LZMA compression and
decompression functions, including integrity checking of the
Lzlib is a data compression library providing in-memory LZMA compression
and decompression functions, including integrity checking of the
uncompressed data. The compressed data format used by the library is the
lzip format.
@ -106,6 +107,37 @@ if( LZ_version()[0] != LZ_version_string[0] )
@end example
@node Buffering
@chapter Buffering
@cindex buffering
Lzlib internal functions need access to a memory chunk at least as large
as the dictionary size (sliding window). For efficiency reasons, the
input buffer for compression is twice as large as the dictionary size.
Finally, for security reasons, lzlib uses two more internal buffers.
These are the four buffers used by lzlib, and their guaranteed minimum
sizes:
@itemize @bullet
@item Input compression buffer. Written to by the
@samp{LZ_compress_write} function. Its size is two times the dictionary
size set with the @samp{LZ_compress_open} function or 128KiB, whichever
is larger.
@item Output compression buffer. Read from by the
@samp{LZ_compress_read} function. Its size is 64KiB.
@item Input decompression buffer. Written to by the
@samp{LZ_decompress_write} function. Its size is 64KiB.
@item Output decompression buffer. Read from by the
@samp{LZ_decompress_read} function. Its size is the dictionary size set
with the @samp{LZ_decompress_open} function or 64KiB, whichever is
larger.
@end itemize
@node Compression Functions
@chapter Compression Functions
@cindex compression functions
@ -142,6 +174,14 @@ for example LLONG_MAX.
@end deftypefun
@deftypefun int LZ_compress_restart_member ( void * const @var{encoder}, const long long @var{member_size} )
Use this function to start a new member, in a multimember data stream.
Call this function only after @samp{LZ_compress_member_finished}
indicates that the current member has been fully read (with the
@samp{LZ_compress_read} function).
@end deftypefun
@deftypefun int LZ_compress_close ( void * const @var{encoder} )
Frees all dynamically allocated data structures for this stream. This
function discards any unprocessed input and does not flush any pending
@ -156,18 +196,11 @@ has already been written (with the @samp{LZ_compress_write} function).
@end deftypefun
@deftypefun int LZ_compress_finish_member ( void * const @var{encoder} )
Use this function to tell @samp{lzlib} that all the data for the current
member, in a multimember data stream, has already been written (with the
@samp{LZ_compress_write} function).
@end deftypefun
@deftypefun int LZ_compress_restart_member ( void * const @var{encoder}, const long long @var{member_size} )
Use this function to start a new member, in a multimember data stream.
Call this function only after @samp{LZ_compress_member_finished}
indicates that the current member has been fully read (with the
@samp{LZ_compress_read} function).
@deftypefun int LZ_compress_sync_flush ( void * const @var{encoder} )
Use this function to make available to @samp{LZ_compress_read} all the
data already written with the @samp{LZ_compress_write} function.
Repeated use of @samp{LZ_compress_sync_flush} may degrade compression
ratio, so use it only when needed.
@end deftypefun
@ -194,6 +227,16 @@ not an error.
@end deftypefun
@deftypefun int LZ_compress_write_size ( void * const @var{encoder} )
The @samp{LZ_compress_write_size} function returns the maximum number of
bytes that can be inmediately written through the @samp{LZ_compress_write}
function.
It is guaranteed that an inmediate call to @samp{LZ_compress_write} will
accept a @var{size} up to the returned number of bytes.
@end deftypefun
@deftypefun {enum LZ_errno} LZ_compress_errno ( void * const @var{encoder} )
Returns the current error code for @var{encoder} (@pxref{Error Codes})
@end deftypefun
@ -340,8 +383,8 @@ what kind of error it was, you need to verify the error code by calling
Library functions do not change the value returned by
@samp{LZ_(de)compress_errno} when they succeed; thus, the value returned
by @samp{LZ_(de)compress_errno} after a successful call is not
necessarily zero, and you should not use @samp{LZ_(de)compress_errno} to
determine whether a call failed. If the call failed, then you can
necessarily LZ_ok, and you should not use @samp{LZ_(de)compress_errno}
to determine whether a call failed. If the call failed, then you can
examine @samp{LZ_(de)compress_errno}.
The error codes are defined in the header file @samp{lzlib.h}.