c72ac7a1a9
This patchset is for supporting LZ4 compression and the crypto API using
it.
As shown below, the size of data is a little bit bigger but compressing
speed is faster under the enabled unaligned memory access. We can use
lz4 de/compression through crypto API as well. Also, It will be useful
for another potential user of lz4 compression.
lz4 Compression Benchmark:
Compiler: ARM gcc 4.6.4
ARMv7, 1 GHz based board
Kernel: linux 3.4
Uncompressed data Size: 101 MB
Compressed Size compression Speed
LZO 72.1MB 32.1MB/s, 33.0MB/s(UA)
LZ4 75.1MB 30.4MB/s, 35.9MB/s(UA)
LZ4HC 59.8MB 2.4MB/s, 2.5MB/s(UA)
- UA: Unaligned memory Access support
- Latest patch set for LZO applied
This patch:
Add support for LZ4 compression in the Linux Kernel. LZ4 Compression APIs
for kernel are based on LZ4 implementation by Yann Collet and were changed
for kernel coding style.
LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/
svn revision : r90
Two APIs are added:
lz4_compress() support basic lz4 compression whereas lz4hc_compress()
support high compression or CPU performance get lower but compression
ratio get higher. Also, we require the pre-allocated working memory with
the defined size and destination buffer must be allocated with the size of
lz4_compressbound.
[akpm@linux-foundation.org: make lz4_compresshcctx() static]
Signed-off-by: Chanho Min <chanho.min@lge.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
444 lines
10 KiB
C
444 lines
10 KiB
C
/*
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* LZ4 - Fast LZ compression algorithm
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* Copyright (C) 2011-2012, Yann Collet.
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* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* You can contact the author at :
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* - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
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* - LZ4 source repository : http://code.google.com/p/lz4/
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*
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* Changed for kernel use by:
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* Chanho Min <chanho.min@lge.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/lz4.h>
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#include <asm/unaligned.h>
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#include "lz4defs.h"
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/*
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* LZ4_compressCtx :
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* -----------------
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* Compress 'isize' bytes from 'source' into an output buffer 'dest' of
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* maximum size 'maxOutputSize'. * If it cannot achieve it, compression
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* will stop, and result of the function will be zero.
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* return : the number of bytes written in buffer 'dest', or 0 if the
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* compression fails
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*/
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static inline int lz4_compressctx(void *ctx,
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const char *source,
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char *dest,
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int isize,
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int maxoutputsize)
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{
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HTYPE *hashtable = (HTYPE *)ctx;
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const u8 *ip = (u8 *)source;
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#if LZ4_ARCH64
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const BYTE * const base = ip;
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#else
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const int base = 0;
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#endif
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const u8 *anchor = ip;
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const u8 *const iend = ip + isize;
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const u8 *const mflimit = iend - MFLIMIT;
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#define MATCHLIMIT (iend - LASTLITERALS)
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u8 *op = (u8 *) dest;
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u8 *const oend = op + maxoutputsize;
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int length;
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const int skipstrength = SKIPSTRENGTH;
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u32 forwardh;
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int lastrun;
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/* Init */
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if (isize < MINLENGTH)
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goto _last_literals;
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memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
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/* First Byte */
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hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
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ip++;
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forwardh = LZ4_HASH_VALUE(ip);
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/* Main Loop */
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for (;;) {
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int findmatchattempts = (1U << skipstrength) + 3;
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const u8 *forwardip = ip;
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const u8 *ref;
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u8 *token;
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/* Find a match */
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do {
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u32 h = forwardh;
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int step = findmatchattempts++ >> skipstrength;
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ip = forwardip;
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forwardip = ip + step;
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if (unlikely(forwardip > mflimit))
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goto _last_literals;
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forwardh = LZ4_HASH_VALUE(forwardip);
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ref = base + hashtable[h];
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hashtable[h] = ip - base;
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} while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
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/* Catch up */
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while ((ip > anchor) && (ref > (u8 *)source) &&
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unlikely(ip[-1] == ref[-1])) {
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ip--;
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ref--;
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}
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/* Encode Literal length */
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length = (int)(ip - anchor);
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token = op++;
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/* check output limit */
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if (unlikely(op + length + (2 + 1 + LASTLITERALS) +
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(length >> 8) > oend))
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return 0;
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if (length >= (int)RUN_MASK) {
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int len;
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*token = (RUN_MASK << ML_BITS);
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len = length - RUN_MASK;
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for (; len > 254 ; len -= 255)
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*op++ = 255;
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*op++ = (u8)len;
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} else
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*token = (length << ML_BITS);
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/* Copy Literals */
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LZ4_BLINDCOPY(anchor, op, length);
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_next_match:
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/* Encode Offset */
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LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
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/* Start Counting */
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ip += MINMATCH;
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/* MinMatch verified */
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ref += MINMATCH;
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anchor = ip;
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while (likely(ip < MATCHLIMIT - (STEPSIZE - 1))) {
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#if LZ4_ARCH64
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u64 diff = A64(ref) ^ A64(ip);
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#else
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u32 diff = A32(ref) ^ A32(ip);
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#endif
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if (!diff) {
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ip += STEPSIZE;
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ref += STEPSIZE;
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continue;
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}
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ip += LZ4_NBCOMMONBYTES(diff);
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goto _endcount;
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}
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#if LZ4_ARCH64
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if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
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ip += 4;
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ref += 4;
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}
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#endif
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if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
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ip += 2;
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ref += 2;
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}
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if ((ip < MATCHLIMIT) && (*ref == *ip))
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ip++;
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_endcount:
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/* Encode MatchLength */
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length = (int)(ip - anchor);
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/* Check output limit */
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if (unlikely(op + (1 + LASTLITERALS) + (length >> 8) > oend))
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return 0;
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if (length >= (int)ML_MASK) {
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*token += ML_MASK;
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length -= ML_MASK;
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for (; length > 509 ; length -= 510) {
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*op++ = 255;
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*op++ = 255;
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}
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if (length > 254) {
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length -= 255;
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*op++ = 255;
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}
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*op++ = (u8)length;
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} else
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*token += length;
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/* Test end of chunk */
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if (ip > mflimit) {
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anchor = ip;
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break;
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}
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/* Fill table */
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hashtable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;
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/* Test next position */
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ref = base + hashtable[LZ4_HASH_VALUE(ip)];
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hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
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if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) {
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token = op++;
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*token = 0;
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goto _next_match;
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}
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/* Prepare next loop */
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anchor = ip++;
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forwardh = LZ4_HASH_VALUE(ip);
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}
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_last_literals:
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/* Encode Last Literals */
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lastrun = (int)(iend - anchor);
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if (((char *)op - dest) + lastrun + 1
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+ ((lastrun + 255 - RUN_MASK) / 255) > (u32)maxoutputsize)
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return 0;
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if (lastrun >= (int)RUN_MASK) {
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*op++ = (RUN_MASK << ML_BITS);
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lastrun -= RUN_MASK;
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for (; lastrun > 254 ; lastrun -= 255)
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*op++ = 255;
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*op++ = (u8)lastrun;
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} else
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*op++ = (lastrun << ML_BITS);
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memcpy(op, anchor, iend - anchor);
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op += iend - anchor;
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/* End */
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return (int)(((char *)op) - dest);
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}
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static inline int lz4_compress64kctx(void *ctx,
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const char *source,
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char *dest,
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int isize,
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int maxoutputsize)
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{
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u16 *hashtable = (u16 *)ctx;
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const u8 *ip = (u8 *) source;
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const u8 *anchor = ip;
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const u8 *const base = ip;
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const u8 *const iend = ip + isize;
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const u8 *const mflimit = iend - MFLIMIT;
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#define MATCHLIMIT (iend - LASTLITERALS)
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u8 *op = (u8 *) dest;
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u8 *const oend = op + maxoutputsize;
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int len, length;
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const int skipstrength = SKIPSTRENGTH;
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u32 forwardh;
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int lastrun;
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/* Init */
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if (isize < MINLENGTH)
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goto _last_literals;
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memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
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/* First Byte */
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ip++;
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forwardh = LZ4_HASH64K_VALUE(ip);
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/* Main Loop */
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for (;;) {
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int findmatchattempts = (1U << skipstrength) + 3;
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const u8 *forwardip = ip;
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const u8 *ref;
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u8 *token;
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/* Find a match */
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do {
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u32 h = forwardh;
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int step = findmatchattempts++ >> skipstrength;
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ip = forwardip;
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forwardip = ip + step;
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if (forwardip > mflimit)
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goto _last_literals;
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forwardh = LZ4_HASH64K_VALUE(forwardip);
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ref = base + hashtable[h];
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hashtable[h] = (u16)(ip - base);
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} while (A32(ref) != A32(ip));
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/* Catch up */
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while ((ip > anchor) && (ref > (u8 *)source)
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&& (ip[-1] == ref[-1])) {
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ip--;
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ref--;
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}
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/* Encode Literal length */
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length = (int)(ip - anchor);
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token = op++;
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/* Check output limit */
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if (unlikely(op + length + (2 + 1 + LASTLITERALS)
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+ (length >> 8) > oend))
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return 0;
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if (length >= (int)RUN_MASK) {
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*token = (RUN_MASK << ML_BITS);
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len = length - RUN_MASK;
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for (; len > 254 ; len -= 255)
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*op++ = 255;
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*op++ = (u8)len;
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} else
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*token = (length << ML_BITS);
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/* Copy Literals */
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LZ4_BLINDCOPY(anchor, op, length);
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_next_match:
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/* Encode Offset */
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LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
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/* Start Counting */
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ip += MINMATCH;
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/* MinMatch verified */
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ref += MINMATCH;
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anchor = ip;
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while (ip < MATCHLIMIT - (STEPSIZE - 1)) {
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#if LZ4_ARCH64
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u64 diff = A64(ref) ^ A64(ip);
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#else
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u32 diff = A32(ref) ^ A32(ip);
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#endif
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if (!diff) {
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ip += STEPSIZE;
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ref += STEPSIZE;
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continue;
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}
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ip += LZ4_NBCOMMONBYTES(diff);
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goto _endcount;
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}
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#if LZ4_ARCH64
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if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
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ip += 4;
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ref += 4;
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}
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#endif
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if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
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ip += 2;
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ref += 2;
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}
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if ((ip < MATCHLIMIT) && (*ref == *ip))
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ip++;
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_endcount:
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/* Encode MatchLength */
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len = (int)(ip - anchor);
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/* Check output limit */
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if (unlikely(op + (1 + LASTLITERALS) + (len >> 8) > oend))
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return 0;
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if (len >= (int)ML_MASK) {
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*token += ML_MASK;
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len -= ML_MASK;
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for (; len > 509 ; len -= 510) {
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*op++ = 255;
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*op++ = 255;
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}
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if (len > 254) {
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len -= 255;
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*op++ = 255;
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}
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*op++ = (u8)len;
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} else
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*token += len;
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/* Test end of chunk */
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if (ip > mflimit) {
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anchor = ip;
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break;
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}
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/* Fill table */
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hashtable[LZ4_HASH64K_VALUE(ip-2)] = (u16)(ip - 2 - base);
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/* Test next position */
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ref = base + hashtable[LZ4_HASH64K_VALUE(ip)];
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hashtable[LZ4_HASH64K_VALUE(ip)] = (u16)(ip - base);
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if (A32(ref) == A32(ip)) {
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token = op++;
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*token = 0;
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goto _next_match;
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}
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/* Prepare next loop */
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anchor = ip++;
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forwardh = LZ4_HASH64K_VALUE(ip);
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}
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_last_literals:
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/* Encode Last Literals */
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lastrun = (int)(iend - anchor);
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if (op + lastrun + 1 + (lastrun - RUN_MASK + 255) / 255 > oend)
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return 0;
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if (lastrun >= (int)RUN_MASK) {
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*op++ = (RUN_MASK << ML_BITS);
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lastrun -= RUN_MASK;
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for (; lastrun > 254 ; lastrun -= 255)
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*op++ = 255;
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*op++ = (u8)lastrun;
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} else
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*op++ = (lastrun << ML_BITS);
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memcpy(op, anchor, iend - anchor);
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op += iend - anchor;
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/* End */
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return (int)(((char *)op) - dest);
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}
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int lz4_compress(const unsigned char *src, size_t src_len,
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unsigned char *dst, size_t *dst_len, void *wrkmem)
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{
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int ret = -1;
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int out_len = 0;
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if (src_len < LZ4_64KLIMIT)
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out_len = lz4_compress64kctx(wrkmem, src, dst, src_len,
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lz4_compressbound(src_len));
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else
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out_len = lz4_compressctx(wrkmem, src, dst, src_len,
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lz4_compressbound(src_len));
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if (out_len < 0)
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goto exit;
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*dst_len = out_len;
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return 0;
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exit:
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return ret;
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}
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EXPORT_SYMBOL_GPL(lz4_compress);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("LZ4 compressor");
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