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[PATCH] zlib_inflate: Upgrade library code to a recent version

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Upgrade the zlib_inflate implementation in the kernel from a patched
version 1.1.3/4 to a patched 1.2.3.

The code in the kernel is about seven years old and I noticed that the
external zlib library's inflate performance was significantly faster (~50%)
than the code in the kernel on ARM (and faster again on x86_32).

For comparison the newer deflate code is 20% slower on ARM and 50% slower
on x86_32 but gives an approx 1% compression ratio improvement.  I don't
consider this to be an improvement for kernel use so have no plans to
change the zlib_deflate code.

Various changes have been made to the zlib code in the kernel, the most
significant being the extra functions/flush option used by ppp_deflate.
This update reimplements the features PPP needs to ensure it continues to
work.

This code has been tested on ARM under both JFFS2 (with zlib compression
enabled) and ppp_deflate and on x86_32.  JFFS2 sees an approx.  10% real
world file read speed improvement.

This patch also removes ZLIB_VERSION as it no longer has a correct value.
We don't need version checks anyway as the kernel's module handling will
take care of that for us.  This removal is also more in keeping with the
zlib author's wishes (http://www.zlib.net/zlib_faq.html#faq24) and I've
added something to the zlib.h header to note its a modified version.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Joern Engel <joern@wh.fh-wedel.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Richard Purdie 2006-06-22 14:47:34 -07:00 • committed by Linus Torvalds
parent 4f1bcaf094
commit 4f3865fb57
24 changed files with 1861 additions and 1990 deletions
Download patch file Download diff file Expand all files Collapse all files

207
include/linux/zlib.h
View file

@ -1,7 +1,6 @@
/* zlib.h -- interface of the 'zlib' general purpose compression library
version 1.1.3, July 9th, 1998
Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
@ -24,7 +23,7 @@
The data format used by the zlib library is described by RFCs (Request for
Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
*/
@ -33,7 +32,22 @@
#include <linux/zconf.h>
#define ZLIB_VERSION "1.1.3"
/* zlib deflate based on ZLIB_VERSION "1.1.3" */
/* zlib inflate based on ZLIB_VERSION "1.2.3" */
/*
This is a modified version of zlib for use inside the Linux kernel.
The main changes are to perform all memory allocation in advance.
Inflation Changes:
* Z_PACKET_FLUSH is added and used by ppp_deflate. Before returning
this checks there is no more input data available and the next data
is a STORED block. It also resets the mode to be read for the next
data, all as per PPP requirements.
* Addition of zlib_inflateIncomp which copies incompressible data into
the history window and adjusts the accoutning without calling
zlib_inflate itself to inflate the data.
*/
/*
The 'zlib' compression library provides in-memory compression and
@ -48,9 +62,18 @@
application must provide more input and/or consume the output
(providing more output space) before each call.
The compressed data format used by default by the in-memory functions is
the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
around a deflate stream, which is itself documented in RFC 1951.
The library also supports reading and writing files in gzip (.gz) format
with an interface similar to that of stdio.
The zlib format was designed to be compact and fast for use in memory
and on communications channels. The gzip format was designed for single-
file compression on file systems, has a larger header than zlib to maintain
directory information, and uses a different, slower check method than zlib.
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.
@ -119,7 +142,8 @@ typedef z_stream *z_streamp;
#define Z_SYNC_FLUSH 3
#define Z_FULL_FLUSH 4
#define Z_FINISH 5
/* Allowed flush values; see deflate() below for details */
#define Z_BLOCK 6 /* Only for inflate at present */
/* Allowed flush values; see deflate() and inflate() below for details */
#define Z_OK 0
#define Z_STREAM_END 1
@ -155,13 +179,6 @@ typedef z_stream *z_streamp;
/* basic functions */
extern const char * zlib_zlibVersion (void);
/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
If the first character differs, the library code actually used is
not compatible with the zlib.h header file used by the application.
This check is automatically made by deflateInit and inflateInit.
*/
extern int zlib_deflate_workspacesize (void);
/*
Returns the number of bytes that needs to be allocated for a per-
@ -315,9 +332,9 @@ extern int zlib_inflateInit (z_streamp strm);
extern int zlib_inflate (z_streamp strm, int flush);
/*
inflate decompresses as much data as possible, and stops when the input
buffer becomes empty or the output buffer becomes full. It may some
introduce some output latency (reading input without producing any output)
except when forced to flush.
buffer becomes empty or the output buffer becomes full. It may introduce
some output latency (reading input without producing any output) except when
forced to flush.
The detailed semantics are as follows. inflate performs one or both of the
following actions:
@ -341,11 +358,26 @@ extern int zlib_inflate (z_streamp strm, int flush);
must be called again after making room in the output buffer because there
might be more output pending.
If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
output as possible to the output buffer. The flushing behavior of inflate is
not specified for values of the flush parameter other than Z_SYNC_FLUSH
and Z_FINISH, but the current implementation actually flushes as much output
as possible anyway.
The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
output as possible to the output buffer. Z_BLOCK requests that inflate() stop
if and when it gets to the next deflate block boundary. When decoding the
zlib or gzip format, this will cause inflate() to return immediately after
the header and before the first block. When doing a raw inflate, inflate()
will go ahead and process the first block, and will return when it gets to
the end of that block, or when it runs out of data.
The Z_BLOCK option assists in appending to or combining deflate streams.
Also to assist in this, on return inflate() will set strm->data_type to the
number of unused bits in the last byte taken from strm->next_in, plus 64
if inflate() is currently decoding the last block in the deflate stream,
plus 128 if inflate() returned immediately after decoding an end-of-block
code or decoding the complete header up to just before the first byte of the
deflate stream. The end-of-block will not be indicated until all of the
uncompressed data from that block has been written to strm->next_out. The
number of unused bits may in general be greater than seven, except when
bit 7 of data_type is set, in which case the number of unused bits will be
less than eight.
inflate() should normally be called until it returns Z_STREAM_END or an
error. However if all decompression is to be performed in a single step
@ -355,29 +387,44 @@ extern int zlib_inflate (z_streamp strm, int flush);
uncompressed data. (The size of the uncompressed data may have been saved
by the compressor for this purpose.) The next operation on this stream must
be inflateEnd to deallocate the decompression state. The use of Z_FINISH
is never required, but can be used to inform inflate that a faster routine
is never required, but can be used to inform inflate that a faster approach
may be used for the single inflate() call.
If a preset dictionary is needed at this point (see inflateSetDictionary
below), inflate sets strm-adler to the adler32 checksum of the
dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
it sets strm->adler to the adler32 checksum of all output produced
so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
an error code as described below. At the end of the stream, inflate()
checks that its computed adler32 checksum is equal to that saved by the
compressor and returns Z_STREAM_END only if the checksum is correct.
In this implementation, inflate() always flushes as much output as
possible to the output buffer, and always uses the faster approach on the
first call. So the only effect of the flush parameter in this implementation
is on the return value of inflate(), as noted below, or when it returns early
because Z_BLOCK is used.
If a preset dictionary is needed after this call (see inflateSetDictionary
below), inflate sets strm->adler to the adler32 checksum of the dictionary
chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
strm->adler to the adler32 checksum of all output produced so far (that is,
total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
below. At the end of the stream, inflate() checks that its computed adler32
checksum is equal to that saved by the compressor and returns Z_STREAM_END
only if the checksum is correct.
inflate() will decompress and check either zlib-wrapped or gzip-wrapped
deflate data. The header type is detected automatically. Any information
contained in the gzip header is not retained, so applications that need that
information should instead use raw inflate, see inflateInit2() below, or
inflateBack() and perform their own processing of the gzip header and
trailer.
inflate() returns Z_OK if some progress has been made (more input processed
or more output produced), Z_STREAM_END if the end of the compressed data has
been reached and all uncompressed output has been produced, Z_NEED_DICT if a
preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
corrupted (input stream not conforming to the zlib format or incorrect
adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
(for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR if no progress is possible or if there was not
enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
case, the application may then call inflateSync to look for a good
compression block.
corrupted (input stream not conforming to the zlib format or incorrect check
value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
Z_BUF_ERROR if no progress is possible or if there was not enough room in the
output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
inflate() can be called again with more input and more output space to
continue decompressing. If Z_DATA_ERROR is returned, the application may then
call inflateSync() to look for a good compression block if a partial recovery
of the data is desired.
*/
@ -547,16 +594,36 @@ extern int inflateInit2 (z_streamp strm, int windowBits);
The windowBits parameter is the base two logarithm of the maximum window
size (the size of the history buffer). It should be in the range 8..15 for
this version of the library. The default value is 15 if inflateInit is used
instead. If a compressed stream with a larger window size is given as
input, inflate() will return with the error code Z_DATA_ERROR instead of
trying to allocate a larger window.
instead. windowBits must be greater than or equal to the windowBits value
provided to deflateInit2() while compressing, or it must be equal to 15 if
deflateInit2() was not used. If a compressed stream with a larger window
size is given as input, inflate() will return with the error code
Z_DATA_ERROR instead of trying to allocate a larger window.
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
memLevel). msg is set to null if there is no error message. inflateInit2
does not perform any decompression apart from reading the zlib header if
present: this will be done by inflate(). (So next_in and avail_in may be
modified, but next_out and avail_out are unchanged.)
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
determines the window size. inflate() will then process raw deflate data,
not looking for a zlib or gzip header, not generating a check value, and not
looking for any check values for comparison at the end of the stream. This
is for use with other formats that use the deflate compressed data format
such as zip. Those formats provide their own check values. If a custom
format is developed using the raw deflate format for compressed data, it is
recommended that a check value such as an adler32 or a crc32 be applied to
the uncompressed data as is done in the zlib, gzip, and zip formats. For
most applications, the zlib format should be used as is. Note that comments
above on the use in deflateInit2() applies to the magnitude of windowBits.
windowBits can also be greater than 15 for optional gzip decoding. Add
32 to windowBits to enable zlib and gzip decoding with automatic header
detection, or add 16 to decode only the gzip format (the zlib format will
return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
a crc32 instead of an adler32.
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
is set to null if there is no error message. inflateInit2 does not perform
any decompression apart from reading the zlib header if present: this will
be done by inflate(). (So next_in and avail_in may be modified, but next_out
and avail_out are unchanged.)
*/
extern int zlib_inflateSetDictionary (z_streamp strm,
@ -564,16 +631,19 @@ extern int zlib_inflateSetDictionary (z_streamp strm,
uInt dictLength);
/*
Initializes the decompression dictionary from the given uncompressed byte
sequence. This function must be called immediately after a call of inflate
if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
can be determined from the Adler32 value returned by this call of
inflate. The compressor and decompressor must use exactly the same
dictionary (see deflateSetDictionary).
sequence. This function must be called immediately after a call of inflate,
if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
can be determined from the adler32 value returned by that call of inflate.
The compressor and decompressor must use exactly the same dictionary (see
deflateSetDictionary). For raw inflate, this function can be called
immediately after inflateInit2() or inflateReset() and before any call of
inflate() to set the dictionary. The application must insure that the
dictionary that was used for compression is provided.
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
parameter is invalid (such as NULL dictionary) or the stream state is
inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
expected one (incorrect Adler32 value). inflateSetDictionary does not
expected one (incorrect adler32 value). inflateSetDictionary does not
perform any decompression: this will be done by subsequent calls of
inflate().
*/
@ -614,40 +684,19 @@ extern int zlib_inflateIncomp (z_stream *strm);
containing the data at next_in (except that the data is not output).
*/
/* various hacks, don't look :) */
/* deflateInit and inflateInit are macros to allow checking the zlib version
* and the compiler's view of z_stream:
*/
extern int zlib_deflateInit_ (z_streamp strm, int level,
const char *version, int stream_size);
extern int zlib_inflateInit_ (z_streamp strm,
const char *version, int stream_size);
extern int zlib_deflateInit2_ (z_streamp strm, int level, int method,
int windowBits, int memLevel,
int strategy, const char *version,
int stream_size);
extern int zlib_inflateInit2_ (z_streamp strm, int windowBits,
const char *version, int stream_size);
#define zlib_deflateInit(strm, level) \
zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
zlib_deflateInit2((strm), (level), Z_DEFLATED, MAX_WBITS, \
DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY)
#define zlib_inflateInit(strm) \
zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
#define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
(strategy), ZLIB_VERSION, sizeof(z_stream))
#define zlib_inflateInit2(strm, windowBits) \
zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
zlib_inflateInit2((strm), DEF_WBITS)
extern int zlib_deflateInit2(z_streamp strm, int level, int method,
int windowBits, int memLevel,
int strategy);
extern int zlib_inflateInit2(z_streamp strm, int windowBits);
#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
struct internal_state {int dummy;}; /* hack for buggy compilers */
#endif
extern const char * zlib_zError (int err);
#if 0
extern int zlib_inflateSyncPoint (z_streamp z);
#endif
extern const uLong * zlib_get_crc_table (void);
#endif /* _ZLIB_H */