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4f3865fb57
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>
56 lines
2.3 KiB
C
56 lines
2.3 KiB
C
/* inftrees.h -- header to use inftrees.c
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* Copyright (C) 1995-2005 Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/* WARNING: this file should *not* be used by applications. It is
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part of the implementation of the compression library and is
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subject to change. Applications should only use zlib.h.
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*/
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/* Structure for decoding tables. Each entry provides either the
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information needed to do the operation requested by the code that
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indexed that table entry, or it provides a pointer to another
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table that indexes more bits of the code. op indicates whether
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the entry is a pointer to another table, a literal, a length or
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distance, an end-of-block, or an invalid code. For a table
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pointer, the low four bits of op is the number of index bits of
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that table. For a length or distance, the low four bits of op
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is the number of extra bits to get after the code. bits is
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the number of bits in this code or part of the code to drop off
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of the bit buffer. val is the actual byte to output in the case
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of a literal, the base length or distance, or the offset from
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the current table to the next table. Each entry is four bytes. */
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typedef struct {
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unsigned char op; /* operation, extra bits, table bits */
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unsigned char bits; /* bits in this part of the code */
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unsigned short val; /* offset in table or code value */
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} code;
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/* op values as set by inflate_table():
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00000000 - literal
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0000tttt - table link, tttt != 0 is the number of table index bits
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0001eeee - length or distance, eeee is the number of extra bits
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01100000 - end of block
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01000000 - invalid code
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*/
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/* Maximum size of dynamic tree. The maximum found in a long but non-
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exhaustive search was 1444 code structures (852 for length/literals
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and 592 for distances, the latter actually the result of an
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exhaustive search). The true maximum is not known, but the value
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below is more than safe. */
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#define ENOUGH 2048
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#define MAXD 592
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/* Type of code to build for inftable() */
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typedef enum {
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CODES,
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LENS,
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DISTS
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} codetype;
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extern int zlib_inflate_table (codetype type, unsigned short *lens,
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unsigned codes, code **table,
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unsigned *bits, unsigned short *work);
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