861 lines
26 KiB
C
861 lines
26 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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* 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://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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//**************************************
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// Tuning parameters
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//**************************************
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// MEMORY_USAGE :
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// Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
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// Increasing memory usage improves compression ratio
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// Reduced memory usage can improve speed, due to cache effect
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// Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
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#define MEMORY_USAGE 14
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// NOTCOMPRESSIBLE_DETECTIONLEVEL :
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// Decreasing this value will make the algorithm skip faster data segments considered "incompressible"
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// This may decrease compression ratio dramatically, but will be faster on incompressible data
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// Increasing this value will make the algorithm search more before declaring a segment "incompressible"
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// This could improve compression a bit, but will be slower on incompressible data
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// The default value (6) is recommended
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#define NOTCOMPRESSIBLE_DETECTIONLEVEL 6
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// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :
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// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU.
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// You can set this option to 1 in situations where data will remain within closed environment
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// This option is useless on Little_Endian CPU (such as x86)
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//#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1
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//**************************************
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// CPU Feature Detection
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//**************************************
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// 32 or 64 bits ?
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#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode
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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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// Little Endian or Big Endian ?
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// Note : overwrite the below #define if you know your architecture endianess
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#if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )
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# define LZ4_BIG_ENDIAN 1
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#else
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// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.
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#endif
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// Unaligned memory access is automatically enabled for "common" CPU, such as x86.
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// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected
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// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance
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#if defined(__ARM_FEATURE_UNALIGNED)
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# define LZ4_FORCE_UNALIGNED_ACCESS 1
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#endif
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// Define this parameter if your target system or compiler does not support hardware bit count
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#if defined(_MSC_VER) && defined(_WIN32_WCE) // Visual Studio for Windows CE does not support Hardware bit count
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# define LZ4_FORCE_SW_BITCOUNT
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#endif
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//**************************************
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// Compiler Options
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//**************************************
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#if __STDC_VERSION__ >= 199901L // C99
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/* "restrict" is a known keyword */
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#else
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# define restrict // Disable restrict
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#endif
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#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
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#ifdef _MSC_VER // Visual Studio
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# define inline __forceinline // Visual is not C99, but supports some kind of inline
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# if LZ4_ARCH64 // 64-bit
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# pragma intrinsic(_BitScanForward64) // For Visual 2005
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# pragma intrinsic(_BitScanReverse64) // For Visual 2005
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# else
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# pragma intrinsic(_BitScanForward) // For Visual 2005
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# pragma intrinsic(_BitScanReverse) // For Visual 2005
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# endif
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#endif
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#ifdef _MSC_VER
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# define lz4_bswap16(x) _byteswap_ushort(x)
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#else
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# define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
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#endif
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#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
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# define expect(expr,value) (__builtin_expect ((expr),(value)) )
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#else
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# define expect(expr,value) (expr)
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#endif
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#define likely(expr) expect((expr) != 0, 1)
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#define unlikely(expr) expect((expr) != 0, 0)
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//**************************************
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// Includes
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//**************************************
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#include <stdlib.h> // for malloc
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#include <string.h> // for memset
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#include "lz4.h"
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//**************************************
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// Basic Types
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//**************************************
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#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively
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# define BYTE unsigned __int8
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# define U16 unsigned __int16
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# define U32 unsigned __int32
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# define S32 __int32
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# define U64 unsigned __int64
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#else
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# include <stdint.h>
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# define BYTE uint8_t
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# define U16 uint16_t
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# define U32 uint32_t
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# define S32 int32_t
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# define U64 uint64_t
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#endif
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#ifndef LZ4_FORCE_UNALIGNED_ACCESS
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# pragma pack(push, 1)
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#endif
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typedef struct _U16_S { U16 v; } U16_S;
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typedef struct _U32_S { U32 v; } U32_S;
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typedef struct _U64_S { U64 v; } U64_S;
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#ifndef LZ4_FORCE_UNALIGNED_ACCESS
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# pragma pack(pop)
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#endif
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#define A64(x) (((U64_S *)(x))->v)
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#define A32(x) (((U32_S *)(x))->v)
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#define A16(x) (((U16_S *)(x))->v)
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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 HASH_LOG (MEMORY_USAGE-2)
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#define HASHTABLESIZE (1 << HASH_LOG)
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#define HASH_MASK (HASHTABLESIZE - 1)
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#define SKIPSTRENGTH (NOTCOMPRESSIBLE_DETECTIONLEVEL>2?NOTCOMPRESSIBLE_DETECTIONLEVEL:2)
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#define STACKLIMIT 13
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#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).
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#define COPYLENGTH 8
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#define LASTLITERALS 5
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#define MFLIMIT (COPYLENGTH+MINMATCH)
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#define MINLENGTH (MFLIMIT+1)
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#define MAXD_LOG 16
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#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
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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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// Architecture-specific macros
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//**************************************
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#if LZ4_ARCH64 // 64-bit
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# define STEPSIZE 8
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# define UARCH U64
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# define AARCH A64
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# define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8;
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# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d)
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# define LZ4_SECURECOPY(s,d,e) if (d<e) LZ4_WILDCOPY(s,d,e)
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# define HTYPE U32
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# define INITBASE(base) const BYTE* const base = ip
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#else // 32-bit
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# define STEPSIZE 4
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# define UARCH U32
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# define AARCH A32
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# define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4;
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# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);
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# define LZ4_SECURECOPY LZ4_WILDCOPY
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# define HTYPE const BYTE*
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# define INITBASE(base) const int base = 0
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#endif
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#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
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# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
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# define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }
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#else // Little Endian
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# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
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# define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }
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#endif
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//**************************************
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// Local structures
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//**************************************
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struct refTables
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{
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HTYPE hashTable[HASHTABLESIZE];
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};
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//**************************************
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// Macros
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//**************************************
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#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
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#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))
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#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
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#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; }
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//****************************
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// Private functions
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//****************************
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#if LZ4_ARCH64
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inline int LZ4_NbCommonBytes (register U64 val)
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{
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#if defined(LZ4_BIG_ENDIAN)
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#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanReverse64( &r, val );
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return (int)(r>>3);
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#elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clzll(val) >> 3);
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#else
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int r;
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if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
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if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
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r += (!val);
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return r;
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#endif
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#else
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#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanForward64( &r, val );
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return (int)(r>>3);
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#elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctzll(val) >> 3);
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#else
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static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
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return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
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#endif
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#endif
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}
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#else
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inline int LZ4_NbCommonBytes (register U32 val)
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{
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#if defined(LZ4_BIG_ENDIAN)
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#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanReverse( &r, val );
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return (int)(r>>3);
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#elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clz(val) >> 3);
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#else
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int r;
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if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
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r += (!val);
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return r;
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#endif
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#else
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#if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanForward( &r, val );
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return (int)(r>>3);
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#elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctz(val) >> 3);
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#else
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static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
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return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
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#endif
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#endif
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}
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#endif
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//******************************
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// Compression functions
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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 maximum size 'maxOutputSize'.
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// If it cannot achieve it, compression 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 compression fails
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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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#if HEAPMODE
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struct refTables *srt = (struct refTables *) (*ctx);
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HTYPE* HashTable;
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#else
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HTYPE HashTable[HASHTABLESIZE] = {0};
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#endif
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const BYTE* ip = (BYTE*) source;
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INITBASE(base);
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const BYTE* anchor = ip;
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const BYTE* const iend = ip + isize;
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const BYTE* const mflimit = iend - MFLIMIT;
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#define matchlimit (iend - LASTLITERALS)
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BYTE* op = (BYTE*) dest;
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BYTE* 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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// Init
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if (isize<MINLENGTH) goto _last_literals;
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#if HEAPMODE
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if (*ctx == NULL)
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{
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srt = (struct refTables *) malloc ( sizeof(struct refTables) );
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*ctx = (void*) srt;
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}
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HashTable = (HTYPE*)(srt->hashTable);
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memset((void*)HashTable, 0, sizeof(srt->hashTable));
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#else
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(void) ctx;
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#endif
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// First Byte
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HashTable[LZ4_HASH_VALUE(ip)] = ip - base;
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ip++; forwardH = LZ4_HASH_VALUE(ip);
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// Main Loop
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for ( ; ; )
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{
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int findMatchAttempts = (1U << skipStrength) + 3;
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const BYTE* forwardIp = ip;
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const BYTE* ref;
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BYTE* 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) { 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>(BYTE*)source) && unlikely(ip[-1]==ref[-1])) { ip--; ref--; }
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// Encode Literal length
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length = ip - anchor;
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token = op++;
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if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) >= oend) return 0; // Check output limit
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#ifdef _MSC_VER
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if (length>=(int)RUN_MASK)
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{
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int len = length-RUN_MASK;
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*token=(RUN_MASK<<ML_BITS);
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if (len>254)
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{
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do { *op++ = 255; len -= 255; } while (len>254);
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*op++ = (BYTE)len;
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memcpy(op, anchor, length);
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op += length;
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goto _next_match;
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}
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else
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*op++ = (BYTE)len;
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}
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else *token = (length<<ML_BITS);
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#else
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if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }
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else *token = (length<<ML_BITS);
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#endif
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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,ip-ref);
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// Start Counting
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ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
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anchor = ip;
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while likely(ip<matchlimit-(STEPSIZE-1))
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{
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UARCH diff = AARCH(ref) ^ AARCH(ip);
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if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }
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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) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }
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if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
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if ((ip<matchlimit) && (*ref == *ip)) ip++;
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_endCount:
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// Encode MatchLength
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len = (ip - anchor);
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|
if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }
|
|
else *token += len;
|
|
|
|
// Test end of chunk
|
|
if (ip > mflimit) { anchor = ip; break; }
|
|
|
|
// Fill table
|
|
HashTable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;
|
|
|
|
// Test next position
|
|
ref = base + HashTable[LZ4_HASH_VALUE(ip)];
|
|
HashTable[LZ4_HASH_VALUE(ip)] = ip - base;
|
|
if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }
|
|
|
|
// Prepare next loop
|
|
anchor = ip++;
|
|
forwardH = LZ4_HASH_VALUE(ip);
|
|
}
|
|
|
|
_last_literals:
|
|
// Encode Last Literals
|
|
{
|
|
int lastRun = iend - anchor;
|
|
if (((char*)op - dest) + lastRun + 1 + ((lastRun-15)/255) >= maxOutputSize) return 0;
|
|
if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
|
|
else *op++ = (lastRun<<ML_BITS);
|
|
memcpy(op, anchor, iend - anchor);
|
|
op += iend-anchor;
|
|
}
|
|
|
|
// End
|
|
return (int) (((char*)op)-dest);
|
|
}
|
|
|
|
|
|
|
|
// Note : this function is valid only if isize < LZ4_64KLIMIT
|
|
#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1))
|
|
#define HASHLOG64K (HASH_LOG+1)
|
|
#define HASH64KTABLESIZE (1U<<HASHLOG64K)
|
|
#define LZ4_HASH64K_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG64K))
|
|
#define LZ4_HASH64K_VALUE(p) LZ4_HASH64K_FUNCTION(A32(p))
|
|
inline int LZ4_compress64kCtx(void** ctx,
|
|
const char* source,
|
|
char* dest,
|
|
int isize,
|
|
int maxOutputSize)
|
|
{
|
|
#if HEAPMODE
|
|
struct refTables *srt = (struct refTables *) (*ctx);
|
|
U16* HashTable;
|
|
#else
|
|
U16 HashTable[HASH64KTABLESIZE] = {0};
|
|
#endif
|
|
|
|
const BYTE* ip = (BYTE*) source;
|
|
const BYTE* anchor = ip;
|
|
const BYTE* const base = ip;
|
|
const BYTE* const iend = ip + isize;
|
|
const BYTE* const mflimit = iend - MFLIMIT;
|
|
#define matchlimit (iend - LASTLITERALS)
|
|
|
|
BYTE* op = (BYTE*) dest;
|
|
BYTE* const oend = op + maxOutputSize;
|
|
|
|
int len, length;
|
|
const int skipStrength = SKIPSTRENGTH;
|
|
U32 forwardH;
|
|
|
|
|
|
// Init
|
|
if (isize<MINLENGTH) goto _last_literals;
|
|
#if HEAPMODE
|
|
if (*ctx == NULL)
|
|
{
|
|
srt = (struct refTables *) malloc ( sizeof(struct refTables) );
|
|
*ctx = (void*) srt;
|
|
}
|
|
HashTable = (U16*)(srt->hashTable);
|
|
memset((void*)HashTable, 0, sizeof(srt->hashTable));
|
|
#else
|
|
(void) ctx;
|
|
#endif
|
|
|
|
|
|
// First Byte
|
|
ip++; forwardH = LZ4_HASH64K_VALUE(ip);
|
|
|
|
// Main Loop
|
|
for ( ; ; )
|
|
{
|
|
int findMatchAttempts = (1U << skipStrength) + 3;
|
|
const BYTE* forwardIp = ip;
|
|
const BYTE* ref;
|
|
BYTE* token;
|
|
|
|
// Find a match
|
|
do {
|
|
U32 h = forwardH;
|
|
int step = findMatchAttempts++ >> skipStrength;
|
|
ip = forwardIp;
|
|
forwardIp = ip + step;
|
|
|
|
if (forwardIp > mflimit) { goto _last_literals; }
|
|
|
|
forwardH = LZ4_HASH64K_VALUE(forwardIp);
|
|
ref = base + HashTable[h];
|
|
HashTable[h] = ip - base;
|
|
|
|
} while (A32(ref) != A32(ip));
|
|
|
|
// Catch up
|
|
while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }
|
|
|
|
// Encode Literal length
|
|
length = ip - anchor;
|
|
token = op++;
|
|
if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) >= oend) return 0; // Check output limit
|
|
#ifdef _MSC_VER
|
|
if (length>=(int)RUN_MASK)
|
|
{
|
|
int len = length-RUN_MASK;
|
|
*token=(RUN_MASK<<ML_BITS);
|
|
if (len>254)
|
|
{
|
|
do { *op++ = 255; len -= 255; } while (len>254);
|
|
*op++ = (BYTE)len;
|
|
memcpy(op, anchor, length);
|
|
op += length;
|
|
goto _next_match;
|
|
}
|
|
else
|
|
*op++ = (BYTE)len;
|
|
}
|
|
else *token = (length<<ML_BITS);
|
|
#else
|
|
if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }
|
|
else *token = (length<<ML_BITS);
|
|
#endif
|
|
|
|
// Copy Literals
|
|
LZ4_BLINDCOPY(anchor, op, length);
|
|
|
|
_next_match:
|
|
// Encode Offset
|
|
LZ4_WRITE_LITTLEENDIAN_16(op,ip-ref);
|
|
|
|
// Start Counting
|
|
ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
|
|
anchor = ip;
|
|
while (ip<matchlimit-(STEPSIZE-1))
|
|
{
|
|
UARCH diff = AARCH(ref) ^ AARCH(ip);
|
|
if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }
|
|
ip += LZ4_NbCommonBytes(diff);
|
|
goto _endCount;
|
|
}
|
|
if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }
|
|
if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
|
|
if ((ip<matchlimit) && (*ref == *ip)) ip++;
|
|
_endCount:
|
|
|
|
// Encode MatchLength
|
|
len = (ip - anchor);
|
|
if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }
|
|
else *token += len;
|
|
|
|
// Test end of chunk
|
|
if (ip > mflimit) { anchor = ip; break; }
|
|
|
|
// Fill table
|
|
HashTable[LZ4_HASH64K_VALUE(ip-2)] = ip - 2 - base;
|
|
|
|
// Test next position
|
|
ref = base + HashTable[LZ4_HASH64K_VALUE(ip)];
|
|
HashTable[LZ4_HASH64K_VALUE(ip)] = ip - base;
|
|
if (A32(ref) == A32(ip)) { token = op++; *token=0; goto _next_match; }
|
|
|
|
// Prepare next loop
|
|
anchor = ip++;
|
|
forwardH = LZ4_HASH64K_VALUE(ip);
|
|
}
|
|
|
|
_last_literals:
|
|
// Encode Last Literals
|
|
{
|
|
int lastRun = iend - anchor;
|
|
if (((char*)op - dest) + lastRun + 1 + ((lastRun)>>8) >= maxOutputSize) return 0;
|
|
if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
|
|
else *op++ = (lastRun<<ML_BITS);
|
|
memcpy(op, anchor, iend - anchor);
|
|
op += iend-anchor;
|
|
}
|
|
|
|
// End
|
|
return (int) (((char*)op)-dest);
|
|
}
|
|
|
|
|
|
int LZ4_compress_limitedOutput(const char* source,
|
|
char* dest,
|
|
int isize,
|
|
int maxOutputSize)
|
|
{
|
|
#if HEAPMODE
|
|
void* ctx = malloc(sizeof(struct refTables));
|
|
int result;
|
|
if (isize < LZ4_64KLIMIT)
|
|
result = LZ4_compress64kCtx(&ctx, source, dest, isize, maxOutputSize);
|
|
else result = LZ4_compressCtx(&ctx, source, dest, isize, maxOutputSize);
|
|
free(ctx);
|
|
return result;
|
|
#else
|
|
if (isize < (int)LZ4_64KLIMIT) return LZ4_compress64kCtx(NULL, source, dest, isize, maxOutputSize);
|
|
return LZ4_compressCtx(NULL, source, dest, isize, maxOutputSize);
|
|
#endif
|
|
}
|
|
|
|
|
|
int LZ4_compress(const char* source,
|
|
char* dest,
|
|
int isize)
|
|
{
|
|
return LZ4_compress_limitedOutput(source, dest, isize, LZ4_compressBound(isize));
|
|
}
|
|
|
|
|
|
|
|
|
|
//****************************
|
|
// Decompression functions
|
|
//****************************
|
|
|
|
// Note : The decoding functions LZ4_uncompress() and LZ4_uncompress_unknownOutputSize()
|
|
// are safe against "buffer overflow" attack type.
|
|
// They will never write nor read outside of the provided output buffers.
|
|
// LZ4_uncompress_unknownOutputSize() also insures that it will never read outside of the input buffer.
|
|
// A corrupted input will produce an error result, a negative int, indicating the position of the error within input stream.
|
|
|
|
int LZ4_uncompress(const char* source,
|
|
char* dest,
|
|
int osize)
|
|
{
|
|
// Local Variables
|
|
const BYTE* restrict ip = (const BYTE*) source;
|
|
const BYTE* restrict ref;
|
|
|
|
BYTE* restrict op = (BYTE*) dest;
|
|
BYTE* const oend = op + osize;
|
|
BYTE* cpy;
|
|
|
|
BYTE token;
|
|
|
|
int len, length;
|
|
size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};
|
|
|
|
|
|
// Main Loop
|
|
while (1)
|
|
{
|
|
// get runlength
|
|
token = *ip++;
|
|
if ((length=(token>>ML_BITS)) == RUN_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }
|
|
|
|
// copy literals
|
|
cpy = op+length;
|
|
if unlikely(cpy>oend-COPYLENGTH)
|
|
{
|
|
if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer
|
|
memcpy(op, ip, length);
|
|
ip += length;
|
|
break; // Necessarily EOF
|
|
}
|
|
LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
|
|
|
|
// get offset
|
|
LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
|
|
if (ref < (BYTE* const)dest) goto _output_error; // Error : offset create reference outside destination buffer
|
|
|
|
// get matchlength
|
|
if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }
|
|
|
|
// copy repeated sequence
|
|
if unlikely(op-ref<STEPSIZE)
|
|
{
|
|
#if LZ4_ARCH64
|
|
size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};
|
|
size_t dec2 = dec2table[op-ref];
|
|
#else
|
|
const int dec2 = 0;
|
|
#endif
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
ref -= dec[op-ref];
|
|
A32(op)=A32(ref); op += STEPSIZE-4;
|
|
ref -= dec2;
|
|
} else { LZ4_COPYSTEP(ref,op); }
|
|
cpy = op + length - (STEPSIZE-4);
|
|
if (cpy>oend-COPYLENGTH)
|
|
{
|
|
if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer
|
|
LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
|
|
while(op<cpy) *op++=*ref++;
|
|
op=cpy;
|
|
if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
|
|
continue;
|
|
}
|
|
LZ4_SECURECOPY(ref, op, cpy);
|
|
op=cpy; // correction
|
|
}
|
|
|
|
// end of decoding
|
|
return (int) (((char*)ip)-source);
|
|
|
|
// write overflow error detected
|
|
_output_error:
|
|
return (int) (-(((char*)ip)-source));
|
|
}
|
|
|
|
|
|
int LZ4_uncompress_unknownOutputSize(
|
|
const char* source,
|
|
char* dest,
|
|
int isize,
|
|
int maxOutputSize)
|
|
{
|
|
// Local Variables
|
|
const BYTE* restrict ip = (const BYTE*) source;
|
|
const BYTE* const iend = ip + isize;
|
|
const BYTE* restrict ref;
|
|
|
|
BYTE* restrict op = (BYTE*) dest;
|
|
BYTE* const oend = op + maxOutputSize;
|
|
BYTE* cpy;
|
|
|
|
size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};
|
|
|
|
|
|
// Main Loop
|
|
while (ip<iend)
|
|
{
|
|
BYTE token;
|
|
int length;
|
|
|
|
// get runlength
|
|
token = *ip++;
|
|
if ((length=(token>>ML_BITS)) == RUN_MASK) { int s=255; while ((ip<iend) && (s==255)) { s=*ip++; length += s; } }
|
|
|
|
// copy literals
|
|
cpy = op+length;
|
|
if ((cpy>oend-COPYLENGTH) || (ip+length>iend-COPYLENGTH))
|
|
{
|
|
if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer
|
|
if (ip+length > iend) goto _output_error; // Error : request to read beyond source buffer
|
|
memcpy(op, ip, length);
|
|
op += length;
|
|
ip += length;
|
|
if (ip<iend) goto _output_error; // Error : LZ4 format violation
|
|
break; // Necessarily EOF, due to parsing restrictions
|
|
}
|
|
LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
|
|
|
|
// get offset
|
|
LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
|
|
if (ref < (BYTE* const)dest) goto _output_error; // Error : offset creates reference outside of destination buffer
|
|
|
|
// get matchlength
|
|
if ((length=(token&ML_MASK)) == ML_MASK) { while (ip<iend) { int s = *ip++; length +=s; if (s==255) continue; break; } }
|
|
|
|
// copy repeated sequence
|
|
if unlikely(op-ref<STEPSIZE)
|
|
{
|
|
#if LZ4_ARCH64
|
|
size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};
|
|
size_t dec2 = dec2table[op-ref];
|
|
#else
|
|
const int dec2 = 0;
|
|
#endif
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
*op++ = *ref++;
|
|
ref -= dec[op-ref];
|
|
A32(op)=A32(ref); op += STEPSIZE-4;
|
|
ref -= dec2;
|
|
} else { LZ4_COPYSTEP(ref,op); }
|
|
cpy = op + length - (STEPSIZE-4);
|
|
if (cpy>oend-COPYLENGTH)
|
|
{
|
|
if (cpy > oend) goto _output_error; // Error : request to write outside of destination buffer
|
|
LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
|
|
while(op<cpy) *op++=*ref++;
|
|
op=cpy;
|
|
if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
|
|
continue;
|
|
}
|
|
LZ4_SECURECOPY(ref, op, cpy);
|
|
op=cpy; // correction
|
|
}
|
|
|
|
// end of decoding
|
|
return (int) (((char*)op)-dest);
|
|
|
|
// write overflow error detected
|
|
_output_error:
|
|
return (int) (-(((char*)ip)-source));
|
|
}
|
|
|