248 строки
6.7 KiB
C
248 строки
6.7 KiB
C
#ifndef __LZ4DEFS_H__
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#define __LZ4DEFS_H__
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/*
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* lz4defs.h -- common and architecture specific defines for the kernel usage
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* LZ4 - Fast LZ compression algorithm
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* Copyright (C) 2011-2016, 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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* * 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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* 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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* You can contact the author at :
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* - LZ4 homepage : http://www.lz4.org
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* - LZ4 source repository : https://github.com/lz4/lz4
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*
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* Changed for kernel usage by:
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* Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
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*/
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#include <asm/unaligned.h>
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#include <linux/bitops.h>
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#include <linux/string.h> /* memset, memcpy */
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#define FORCE_INLINE __always_inline
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/*-************************************
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* Basic Types
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**************************************/
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#include <linux/types.h>
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typedef uint8_t BYTE;
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typedef uint16_t U16;
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typedef uint32_t U32;
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typedef int32_t S32;
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typedef uint64_t U64;
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typedef uintptr_t uptrval;
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/*-************************************
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* Architecture specifics
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**************************************/
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#if defined(CONFIG_64BIT)
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#define LZ4_ARCH64 1
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#else
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#define LZ4_ARCH64 0
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#endif
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#if defined(__LITTLE_ENDIAN)
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#define LZ4_LITTLE_ENDIAN 1
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#else
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#define LZ4_LITTLE_ENDIAN 0
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#endif
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/*-************************************
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* Constants
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**************************************/
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#define MINMATCH 4
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#define WILDCOPYLENGTH 8
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#define LASTLITERALS 5
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#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
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/*
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* ensure it's possible to write 2 x wildcopyLength
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* without overflowing output buffer
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*/
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#define MATCH_SAFEGUARD_DISTANCE ((2 * WILDCOPYLENGTH) - MINMATCH)
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/* Increase this value ==> compression run slower on incompressible data */
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#define LZ4_SKIPTRIGGER 6
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#define HASH_UNIT sizeof(size_t)
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#define KB (1 << 10)
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#define MB (1 << 20)
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#define GB (1U << 30)
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#define MAXD_LOG 16
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#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
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#define STEPSIZE sizeof(size_t)
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#define ML_BITS 4
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#define ML_MASK ((1U << ML_BITS) - 1)
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#define RUN_BITS (8 - ML_BITS)
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#define RUN_MASK ((1U << RUN_BITS) - 1)
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/*-************************************
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* Reading and writing into memory
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**************************************/
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static FORCE_INLINE U16 LZ4_read16(const void *ptr)
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{
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return get_unaligned((const U16 *)ptr);
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}
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static FORCE_INLINE U32 LZ4_read32(const void *ptr)
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{
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return get_unaligned((const U32 *)ptr);
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}
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static FORCE_INLINE size_t LZ4_read_ARCH(const void *ptr)
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{
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return get_unaligned((const size_t *)ptr);
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}
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static FORCE_INLINE void LZ4_write16(void *memPtr, U16 value)
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{
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put_unaligned(value, (U16 *)memPtr);
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}
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static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
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{
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put_unaligned(value, (U32 *)memPtr);
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}
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static FORCE_INLINE U16 LZ4_readLE16(const void *memPtr)
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{
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return get_unaligned_le16(memPtr);
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}
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static FORCE_INLINE void LZ4_writeLE16(void *memPtr, U16 value)
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{
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return put_unaligned_le16(value, memPtr);
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}
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/*
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* LZ4 relies on memcpy with a constant size being inlined. In freestanding
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* environments, the compiler can't assume the implementation of memcpy() is
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* standard compliant, so apply its specialized memcpy() inlining logic. When
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* possible, use __builtin_memcpy() to tell the compiler to analyze memcpy()
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* as-if it were standard compliant, so it can inline it in freestanding
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* environments. This is needed when decompressing the Linux Kernel, for example.
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*/
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#define LZ4_memcpy(dst, src, size) __builtin_memcpy(dst, src, size)
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#define LZ4_memmove(dst, src, size) __builtin_memmove(dst, src, size)
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static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
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{
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#if LZ4_ARCH64
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U64 a = get_unaligned((const U64 *)src);
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put_unaligned(a, (U64 *)dst);
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#else
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U32 a = get_unaligned((const U32 *)src);
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U32 b = get_unaligned((const U32 *)src + 1);
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put_unaligned(a, (U32 *)dst);
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put_unaligned(b, (U32 *)dst + 1);
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#endif
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}
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/*
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* customized variant of memcpy,
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* which can overwrite up to 7 bytes beyond dstEnd
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*/
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static FORCE_INLINE void LZ4_wildCopy(void *dstPtr,
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const void *srcPtr, void *dstEnd)
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{
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BYTE *d = (BYTE *)dstPtr;
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const BYTE *s = (const BYTE *)srcPtr;
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BYTE *const e = (BYTE *)dstEnd;
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do {
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LZ4_copy8(d, s);
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d += 8;
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s += 8;
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} while (d < e);
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}
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static FORCE_INLINE unsigned int LZ4_NbCommonBytes(register size_t val)
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{
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#if LZ4_LITTLE_ENDIAN
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return __ffs(val) >> 3;
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#else
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return (BITS_PER_LONG - 1 - __fls(val)) >> 3;
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#endif
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}
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static FORCE_INLINE unsigned int LZ4_count(
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const BYTE *pIn,
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const BYTE *pMatch,
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const BYTE *pInLimit)
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{
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const BYTE *const pStart = pIn;
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while (likely(pIn < pInLimit - (STEPSIZE - 1))) {
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size_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
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if (!diff) {
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pIn += STEPSIZE;
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pMatch += STEPSIZE;
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continue;
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}
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pIn += LZ4_NbCommonBytes(diff);
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return (unsigned int)(pIn - pStart);
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}
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#if LZ4_ARCH64
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if ((pIn < (pInLimit - 3))
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&& (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
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pIn += 4;
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pMatch += 4;
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}
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#endif
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if ((pIn < (pInLimit - 1))
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&& (LZ4_read16(pMatch) == LZ4_read16(pIn))) {
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pIn += 2;
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pMatch += 2;
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}
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if ((pIn < pInLimit) && (*pMatch == *pIn))
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pIn++;
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return (unsigned int)(pIn - pStart);
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}
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typedef enum { noLimit = 0, limitedOutput = 1 } limitedOutput_directive;
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typedef enum { byPtr, byU32, byU16 } tableType_t;
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typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
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typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
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typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
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typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
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#define LZ4_STATIC_ASSERT(c) BUILD_BUG_ON(!(c))
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#endif
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