/*
LZ4 - Fast LZ compression algorithm
Copyright ( C ) 2011 - 2023 , Yann Collet .
BSD 2 - Clause License ( http : //www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms , with or without
modification , are permitted provided that the following conditions are
met :
* Redistributions of source code must retain the above copyright
notice , this list of conditions and the following disclaimer .
* Redistributions in binary form must reproduce the above
copyright notice , this list of conditions and the following disclaimer
in the documentation and / or other materials provided with the
distribution .
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
" AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED . IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT , INDIRECT , INCIDENTAL ,
SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT
LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE ,
DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT
( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE , EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE .
You can contact the author at :
- LZ4 homepage : http : //www.lz4.org
- LZ4 source repository : https : //github.com/lz4/lz4
*/
/*-************************************
* Tuning parameters
**************************************/
/*
* LZ4_HEAPMODE :
* Select how stateless compression functions like ` LZ4_compress_default ( ) `
* allocate memory for their hash table ,
* in memory stack ( 0 : default , fastest ) , or in memory heap ( 1 : requires malloc ( ) ) .
*/
#ifndef LZ4_HEAPMODE
# define LZ4_HEAPMODE
0
#endif
/*
* LZ4_ACCELERATION_DEFAULT :
* Select " acceleration " for LZ4_compress_fast ( ) when parameter value < = 0
*/
#define LZ4_ACCELERATION_DEFAULT
1
/*
* LZ4_ACCELERATION_MAX :
* Any " acceleration " value higher than this threshold
* get treated as LZ4_ACCELERATION_MAX instead ( fix # 876 )
*/
#define LZ4_ACCELERATION_MAX
65537
/*-************************************
* CPU Feature Detection
**************************************/
/* LZ4_FORCE_MEMORY_ACCESS
* By default , access to unaligned memory is controlled by ` memcpy ( ) ` , which is safe and portable .
* Unfortunately , on some target / compiler combinations , the generated assembly is sub - optimal .
* The below switch allow to select different access method for improved performance .
* Method 0 ( default ) : use ` memcpy ( ) ` . Safe and portable .
* Method 1 : ` _ _ packed ` statement . It depends on compiler extension ( ie , not portable ) .
* This method is safe if your compiler supports it , and * generally * as fast or faster than ` memcpy ` .
* Method 2 : direct access . This method is portable but violate C standard .
* It can generate buggy code on targets which assembly generation depends on alignment .
* But in some circumstances , it ' s the only known way to get the most performance ( ie GCC + ARMv6 )
* See https : //fastcompression.blogspot.fr/2015/08/accessing-unaligned-memory.html for details.
* Prefer these methods in priority order ( 0 > 1 > 2 )
*/
#ifndef LZ4_FORCE_MEMORY_ACCESS
/* can be defined externally */
# if defined (__GNUC__) && \
(
defined (__ARM_ARCH_6__) ||
defined (__ARM_ARCH_6J__) ||
defined (__ARM_ARCH_6K__) \
||
defined (__ARM_ARCH_6Z__) ||
defined (__ARM_ARCH_6ZK__) ||
defined (__ARM_ARCH_6T2__)
)
# define LZ4_FORCE_MEMORY_ACCESS 2
# elif (defined (__INTEL_COMPILER) && !defined (_WIN32)) || defined (__GNUC__) || defined (_MSC_VER)
# define LZ4_FORCE_MEMORY_ACCESS 1
# endif
#endif
/*
* LZ4_FORCE_SW_BITCOUNT
* Define this parameter if your target system or compiler does not support hardware bit count
*/
#if defined (_MSC_VER) && defined (_WIN32_WCE) /* Visual Studio for WinCE doesn't support Hardware bit count */
# undef LZ4_FORCE_SW_BITCOUNT /* avoid double def */
# define LZ4_FORCE_SW_BITCOUNT
#endif
/*-************************************
* Dependency
**************************************/
/*
* LZ4_SRC_INCLUDED :
* Amalgamation flag , whether lz4 . c is included
*/
#ifndef LZ4_SRC_INCLUDED
# define LZ4_SRC_INCLUDED 1
#endif
#ifndef LZ4_DISABLE_DEPRECATE_WARNINGS
# define LZ4_DISABLE_DEPRECATE_WARNINGS /* due to LZ4_decompress_safe_withPrefix64k */
#endif
#ifndef LZ4_STATIC_LINKING_ONLY
# define LZ4_STATIC_LINKING_ONLY
#endif
#include "lz4.h"
/* see also "memory routines" below */
/*-************************************
* Compiler Options
**************************************/
#if defined (_MSC_VER) && (_MSC_VER >= 1400 ) /* Visual Studio 2005+ */
# include <intrin.h> /* only present in VS2005+ */
# pragma warning(disable : 4127 ) /* disable: C4127: conditional expression is constant */
# pragma warning(disable : 6237 ) /* disable: C6237: conditional expression is always 0 */
# pragma warning(disable : 6239 ) /* disable: C6239: (<non-zero constant> && <expression>) always evaluates to the result of <expression> */
# pragma warning(disable : 6240 ) /* disable: C6240: (<expression> && <non-zero constant>) always evaluates to the result of <expression> */
# pragma warning(disable : 6326 ) /* disable: C6326: Potential comparison of a constant with another constant */
#endif /* _MSC_VER */
#ifndef LZ4_FORCE_INLINE
# if defined (_MSC_VER) && !defined (__clang__) /* MSVC */
# define LZ4_FORCE_INLINE static __forceinline
# else
# if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901 L /* C99 */
# if defined (__GNUC__) || defined (__clang__)
# define LZ4_FORCE_INLINE static inline __attribute__((always_inline))
# else
# define LZ4_FORCE_INLINE static inline
# endif
# else
# define LZ4_FORCE_INLINE static
# endif /* __STDC_VERSION__ */
# endif /* _MSC_VER */
#endif /* LZ4_FORCE_INLINE */
/* LZ4_FORCE_O2 and LZ4_FORCE_INLINE
* gcc on ppc64le generates an unrolled SIMDized loop for LZ4_wildCopy8 ,
* together with a simple 8 - byte copy loop as a fall - back path .
* However , this optimization hurts the decompression speed by > 30 % ,
* because the execution does not go to the optimized loop
* for typical compressible data , and all of the preamble checks
* before going to the fall - back path become useless overhead .
* This optimization happens only with the - O3 flag , and - O2 generates
* a simple 8 - byte copy loop .
* With gcc on ppc64le , all of the LZ4_decompress_ * and LZ4_wildCopy8
* functions are annotated with _ _ attribute__ ( ( optimize ( " O2 " ) ) ) ,
* and also LZ4_wildCopy8 is forcibly inlined , so that the O2 attribute
* of LZ4_wildCopy8 does not affect the compression speed .
*/
#if defined (__PPC64__) && defined (__LITTLE_ENDIAN__) && defined (__GNUC__) && !defined (__clang__)
# define LZ4_FORCE_O2 __attribute__((optimize("O2" )))
# undef LZ4_FORCE_INLINE
# define LZ4_FORCE_INLINE static __inline __attribute__((optimize("O2" ),always_inline))
#else
# define LZ4_FORCE_O2
#endif
#if (defined (__GNUC__) && (__GNUC__ >= 3 )) || (defined (__INTEL_COMPILER) && (__INTEL_COMPILER >= 800 )) || defined (__clang__)
# define expect(expr,value) (__builtin_expect ((expr),(value)) )
#else
# define expect(expr,value) (expr)
#endif
#ifndef likely
#define likely(expr) expect((expr) != 0 , 1 )
#endif
#ifndef unlikely
#define unlikely(expr) expect((expr) != 0 , 0 )
#endif
/* Should the alignment test prove unreliable, for some reason,
* it can be disabled by setting LZ4_ALIGN_TEST to 0 */
#ifndef LZ4_ALIGN_TEST /* can be externally provided */
# define LZ4_ALIGN_TEST 1
#endif
/*-************************************
* Memory routines
**************************************/
/*! LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION :
* Disable relatively high - level LZ4 / HC functions that use dynamic memory
* allocation functions ( malloc ( ) , calloc ( ) , free ( ) ) .
*
* Note that this is a compile - time switch . And since it disables
* public / stable LZ4 v1 API functions , we don ' t recommend using this
* symbol to generate a library for distribution .
*
* The following public functions are removed when this symbol is defined .
* - lz4 : LZ4_createStream , LZ4_freeStream ,
* LZ4_createStreamDecode , LZ4_freeStreamDecode , LZ4_create ( deprecated )
* - lz4hc : LZ4_createStreamHC , LZ4_freeStreamHC ,
* LZ4_createHC ( deprecated ) , LZ4_freeHC ( deprecated )
* - lz4frame , lz4file : All LZ4F_ * functions
*/
#if defined (LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
# define ALLOC(s) lz4_error_memory_allocation_is_disabled
# define ALLOC_AND_ZERO(s) lz4_error_memory_allocation_is_disabled
# define FREEMEM(p) lz4_error_memory_allocation_is_disabled
#elif defined (LZ4_USER_MEMORY_FUNCTIONS)
/* memory management functions can be customized by user project.
* Below functions must exist somewhere in the Project
* and be available at link time */
void * LZ4_malloc(size_t s);
void * LZ4_calloc(size_t n, size_t s);
void LZ4_free(void * p);
# define ALLOC(s) LZ4_malloc(s)
# define ALLOC_AND_ZERO(s) LZ4_calloc(1 ,s)
# define FREEMEM(p) LZ4_free(p)
#else
# include <stdlib.h> /* malloc, calloc, free */
# define ALLOC(s) malloc(s)
# define ALLOC_AND_ZERO(s) calloc(1 ,s)
# define FREEMEM(p) free(p)
#endif
#if ! LZ4_FREESTANDING
# include <string.h> /* memset, memcpy */
#endif
#if !defined (LZ4_memset)
# define LZ4_memset(p,v,s) memset((p),(v),(s))
#endif
#define MEM_INIT(p,v,s) LZ4_memset((p),(v),(s))
/*-************************************
* Common Constants
**************************************/
#define MINMATCH 4
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MFLIMIT 12 /* see ../doc/lz4_Block_format.md#parsing-restrictions */
#define MATCH_SAFEGUARD_DISTANCE ((2 *WILDCOPYLENGTH) - MINMATCH) /* ensure it's possible to write 2 x wildcopyLength without overflowing output buffer */
#define FASTLOOP_SAFE_DISTANCE 64
static const int LZ4_minLength = (MFLIMIT+1 );
#define KB *(1 <<10 )
#define MB *(1 <<20 )
#define GB *(1 U<<30 )
#define LZ4_DISTANCE_ABSOLUTE_MAX 65535
#if (LZ4_DISTANCE_MAX > LZ4_DISTANCE_ABSOLUTE_MAX) /* max supported by LZ4 format */
# error "LZ4_DISTANCE_MAX is too big : must be <= 65535"
#endif
#define ML_BITS 4
#define ML_MASK ((1 U<<ML_BITS)-1 )
#define RUN_BITS (8 -ML_BITS)
#define RUN_MASK ((1 U<<RUN_BITS)-1 )
/*-************************************
* Error detection
**************************************/
#if defined (LZ4_DEBUG) && (LZ4_DEBUG>=1 )
# include <assert.h>
#else
# ifndef assert
# define assert(condition) ((void )0 )
# endif
#endif
#define LZ4_STATIC_ASSERT(c) { enum { LZ4_static_assert = 1 /(int )(!!(c)) }; } /* use after variable declarations */
#if defined (LZ4_DEBUG) && (LZ4_DEBUG>=2 )
# include <stdio.h>
static int g_debuglog_enable = 1 ;
# define DEBUGLOG(l, ...) { \
if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \
fprintf(stderr, __FILE__ " %i: " , __LINE__); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, " \n" ); \
} }
#else
# define DEBUGLOG(l, ...) {} /* disabled */
#endif
static int LZ4_isAligned(const void * ptr, size_t alignment)
{
return ((size_t)ptr & (alignment -1 )) == 0 ;
}
/*-************************************
* Types
**************************************/
#include <limits.h>
#if defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901 L) /* C99 */)
# include <stdint.h>
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef int32_t S32;
typedef uint64_t U64;
typedef uintptr_t uptrval;
#else
# if UINT_MAX != 4294967295 UL
# error "LZ4 code (when not C++ or C99) assumes that sizeof(int) == 4"
# endif
typedef unsigned char BYTE;
typedef unsigned short U16;
typedef unsigned int U32;
typedef signed int S32;
typedef unsigned long long U64;
typedef size_t uptrval; /* generally true, except OpenVMS-64 */
#endif
#if defined (__x86_64__)
typedef U64 reg_t; /* 64-bits in x32 mode */
#else
typedef size_t reg_t; /* 32-bits in x32 mode */
#endif
typedef enum {
notLimited = 0 ,
limitedOutput = 1 ,
fillOutput = 2
} limitedOutput_directive;
/*-************************************
* Reading and writing into memory
**************************************/
/**
* LZ4 relies on memcpy with a constant size being inlined . In freestanding
* environments , the compiler can ' t assume the implementation of memcpy ( ) is
* standard compliant , so it can ' t apply its specialized memcpy ( ) inlining
* logic . When possible , use _ _ builtin_memcpy ( ) to tell the compiler to analyze
* memcpy ( ) as if it were standard compliant , so it can inline it in freestanding
* environments . This is needed when decompressing the Linux Kernel , for example .
*/
#if !defined (LZ4_memcpy)
# if defined (__GNUC__) && (__GNUC__ >= 4 )
# define LZ4_memcpy(dst, src, size) __builtin_memcpy(dst, src, size)
# else
# define LZ4_memcpy(dst, src, size) memcpy(dst, src, size)
# endif
#endif
#if !defined (LZ4_memmove)
# if defined (__GNUC__) && (__GNUC__ >= 4 )
# define LZ4_memmove __builtin_memmove
# else
# define LZ4_memmove memmove
# endif
#endif
static unsigned LZ4_isLittleEndian(void )
{
const union { U32 u; BYTE c[4 ]; } one = { 1 }; /* don't use static : performance detrimental */
return one.c[0 ];
}
#if defined (__GNUC__) || defined (__INTEL_COMPILER)
#define LZ4_PACK( __Declaration__ ) __Declaration__ __attribute__((__packed__))
#elif defined (_MSC_VER)
#define LZ4_PACK( __Declaration__ ) __pragma( pack (push, 1 ) ) __Declaration__ __pragma( pack (pop))
#endif
#if defined (LZ4_FORCE_MEMORY_ACCESS) && (LZ4_FORCE_MEMORY_ACCESS==2 )
/* lie to the compiler about data alignment; use with caution */
static U16 LZ4_read16(const void * memPtr) { return *(const U16*) memPtr; }
static U32 LZ4_read32(const void * memPtr) { return *(const U32*) memPtr; }
static reg_t LZ4_read_ARCH(const void * memPtr) { return *(const reg_t*) memPtr; }
static void LZ4_write16(void * memPtr, U16 value) { *(U16*)memPtr = value; }
static void LZ4_write32(void * memPtr, U32 value) { *(U32*)memPtr = value; }
#elif defined (LZ4_FORCE_MEMORY_ACCESS) && (LZ4_FORCE_MEMORY_ACCESS==1 )
/* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
/* currently only defined for gcc and icc */
LZ4_PACK(typedef struct { U16 u16; }) LZ4_unalign16;
LZ4_PACK(typedef struct { U32 u32; }) LZ4_unalign32;
LZ4_PACK(typedef struct { reg_t uArch; }) LZ4_unalignST;
static U16 LZ4_read16(const void * ptr) { return ((const LZ4_unalign16*)ptr)->u16; }
static U32 LZ4_read32(const void * ptr) { return ((const LZ4_unalign32*)ptr)->u32; }
static reg_t LZ4_read_ARCH(const void * ptr) { return ((const LZ4_unalignST*)ptr)->uArch; }
static void LZ4_write16(void * memPtr, U16 value) { ((LZ4_unalign16*)memPtr)->u16 = value; }
static void LZ4_write32(void * memPtr, U32 value) { ((LZ4_unalign32*)memPtr)->u32 = value; }
#else /* safe and portable access using memcpy() */
static U16 LZ4_read16(const void * memPtr)
{
U16 val; LZ4_memcpy(&val, memPtr, sizeof (val)); return val;
}
static U32 LZ4_read32(const void * memPtr)
{
U32 val; LZ4_memcpy(&val, memPtr, sizeof (val)); return val;
}
static reg_t LZ4_read_ARCH(const void * memPtr)
{
reg_t val; LZ4_memcpy(&val, memPtr, sizeof (val)); return val;
}
static void LZ4_write16(void * memPtr, U16 value)
{
LZ4_memcpy(memPtr, &value, sizeof (value));
}
static void LZ4_write32(void * memPtr, U32 value)
{
LZ4_memcpy(memPtr, &value, sizeof (value));
}
#endif /* LZ4_FORCE_MEMORY_ACCESS */
static U16 LZ4_readLE16(const void * memPtr)
{
if (LZ4_isLittleEndian()) {
return LZ4_read16(memPtr);
} else {
const BYTE* p = (const BYTE*)memPtr;
return (U16)((U16)p[0 ] | (p[1 ]<<8 ));
}
}
#ifdef LZ4_STATIC_LINKING_ONLY_ENDIANNESS_INDEPENDENT_OUTPUT
static U32 LZ4_readLE32(const void * memPtr)
{
if (LZ4_isLittleEndian()) {
return LZ4_read32(memPtr);
} else {
const BYTE* p = (const BYTE*)memPtr;
return (U32)p[0 ] | (p[1 ]<<8 ) | (p[2 ]<<16 ) | (p[3 ]<<24 );
}
}
#endif
static void LZ4_writeLE16(void * memPtr, U16 value)
{
if (LZ4_isLittleEndian()) {
LZ4_write16(memPtr, value);
} else {
BYTE* p = (BYTE*)memPtr;
p[0 ] = (BYTE) value;
p[1 ] = (BYTE)(value>>8 );
}
}
/* customized variant of memcpy, which can overwrite up to 8 bytes beyond dstEnd */
LZ4_FORCE_INLINE
void LZ4_wildCopy8(void * dstPtr, const void * srcPtr, void * dstEnd)
{
BYTE* d = (BYTE*)dstPtr;
const BYTE* s = (const BYTE*)srcPtr;
BYTE* const e = (BYTE*)dstEnd;
do { LZ4_memcpy(d,s,8 ); d+=8 ; s+=8 ; } while (d<e);
}
static const unsigned inc32table[8 ] = {0 , 1 , 2 , 1 , 0 , 4 , 4 , 4 };
static const int dec64table[8 ] = {0 , 0 , 0 , -1 , -4 , 1 , 2 , 3 };
#ifndef LZ4_FAST_DEC_LOOP
# if defined __i386__ || defined _M_IX86 || defined __x86_64__ || defined _M_X64
# define LZ4_FAST_DEC_LOOP 1
# elif defined (__aarch64__) && defined (__APPLE__)
# define LZ4_FAST_DEC_LOOP 1
# elif defined (__aarch64__) && !defined (__clang__)
/* On non-Apple aarch64, we disable this optimization for clang because
* on certain mobile chipsets , performance is reduced with clang . For
* more information refer to https://github.com/lz4/lz4/pull/707 */
# define LZ4_FAST_DEC_LOOP 1
# else
# define LZ4_FAST_DEC_LOOP 0
# endif
#endif
#if LZ4_FAST_DEC_LOOP
LZ4_FORCE_INLINE void
LZ4_memcpy_using_offset_base(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const size_t offset)
{
assert(srcPtr + offset == dstPtr);
if (offset < 8 ) {
LZ4_write32(dstPtr, 0 ); /* silence an msan warning when offset==0 */
dstPtr[0 ] = srcPtr[0 ];
dstPtr[1 ] = srcPtr[1 ];
dstPtr[2 ] = srcPtr[2 ];
dstPtr[3 ] = srcPtr[3 ];
srcPtr += inc32table[offset];
LZ4_memcpy(dstPtr+4 , srcPtr, 4 );
srcPtr -= dec64table[offset];
dstPtr += 8 ;
} else {
LZ4_memcpy(dstPtr, srcPtr, 8 );
dstPtr += 8 ;
srcPtr += 8 ;
}
LZ4_wildCopy8(dstPtr, srcPtr, dstEnd);
}
/* customized variant of memcpy, which can overwrite up to 32 bytes beyond dstEnd
* this version copies two times 16 bytes ( instead of one time 32 bytes )
* because it must be compatible with offsets >= 16. */
LZ4_FORCE_INLINE void
LZ4_wildCopy32(void * dstPtr, const void * srcPtr, void * dstEnd)
{
BYTE* d = (BYTE*)dstPtr;
const BYTE* s = (const BYTE*)srcPtr;
BYTE* const e = (BYTE*)dstEnd;
do { LZ4_memcpy(d,s,16 ); LZ4_memcpy(d+16 ,s+16 ,16 ); d+=32 ; s+=32 ; } while (d<e);
}
/* LZ4_memcpy_using_offset() presumes :
* - dstEnd > = dstPtr + MINMATCH
* - there is at least 12 bytes available to write after dstEnd */
LZ4_FORCE_INLINE void
LZ4_memcpy_using_offset(BYTE* dstPtr, const BYTE* srcPtr, BYTE* dstEnd, const size_t offset)
{
BYTE v[8 ];
assert(dstEnd >= dstPtr + MINMATCH);
switch (offset) {
case 1 :
MEM_INIT(v, *srcPtr, 8 );
break ;
case 2 :
LZ4_memcpy(v, srcPtr, 2 );
LZ4_memcpy(&v[2 ], srcPtr, 2 );
#if defined (_MSC_VER) && (_MSC_VER <= 1937 ) /* MSVC 2022 ver 17.7 or earlier */
# pragma warning(push)
# pragma warning(disable : 6385 ) /* warning C6385: Reading invalid data from 'v'. */
#endif
LZ4_memcpy(&v[4 ], v, 4 );
#if defined (_MSC_VER) && (_MSC_VER <= 1937 ) /* MSVC 2022 ver 17.7 or earlier */
# pragma warning(pop)
#endif
break ;
case 4 :
LZ4_memcpy(v, srcPtr, 4 );
LZ4_memcpy(&v[4 ], srcPtr, 4 );
break ;
default :
LZ4_memcpy_using_offset_base(dstPtr, srcPtr, dstEnd, offset);
return ;
}
LZ4_memcpy(dstPtr, v, 8 );
dstPtr += 8 ;
while (dstPtr < dstEnd) {
LZ4_memcpy(dstPtr, v, 8 );
dstPtr += 8 ;
}
}
#endif
/*-************************************
* Common functions
**************************************/
static unsigned LZ4_NbCommonBytes (reg_t val)
{
assert(val != 0 );
if (LZ4_isLittleEndian()) {
if (sizeof (val) == 8 ) {
# if defined (_MSC_VER) && (_MSC_VER >= 1800 ) && (defined (_M_AMD64) && !defined (_M_ARM64EC)) && !defined (LZ4_FORCE_SW_BITCOUNT)
/*-*************************************************************************************************
* ARM64EC is a Microsoft - designed ARM64 ABI compatible with AMD64 applications on ARM64 Windows 11 .
* The ARM64EC ABI does not support AVX / AVX2 / AVX512 instructions , nor their relevant intrinsics
* including _ tzcnt_u64 . Therefore , we need to neuter the _ tzcnt_u64 code path for ARM64EC .
****************************************************************************************************/
# if defined (__clang__) && (__clang_major__ < 10 )
/* Avoid undefined clang-cl intrinsics issue.
* See https://github.com/lz4/lz4/pull/1017 for details. */
return (unsigned )__builtin_ia32_tzcnt_u64(val) >> 3 ;
# else
/* x64 CPUS without BMI support interpret `TZCNT` as `REP BSF` */
return (unsigned )_tzcnt_u64(val) >> 3 ;
# endif
# elif defined (_MSC_VER) && defined (_WIN64) && !defined (LZ4_FORCE_SW_BITCOUNT)
unsigned long r = 0 ;
_BitScanForward64(&r, (U64)val);
return (unsigned )r >> 3 ;
# elif (defined (__clang__) || (defined (__GNUC__) && ((__GNUC__ > 3 ) || \
((__GNUC__ == 3 ) && (__GNUC_MINOR__ >= 4 ))))) && \
!defined (LZ4_FORCE_SW_BITCOUNT)
return (unsigned )__builtin_ctzll((U64)val) >> 3 ;
# else
const U64 m = 0 x0101010101010101ULL;
val ^= val - 1 ;
return (unsigned )(((U64)((val & (m - 1 )) * m)) >> 56 );
# endif
} else /* 32 bits */ {
# if defined (_MSC_VER) && (_MSC_VER >= 1400 ) && !defined (LZ4_FORCE_SW_BITCOUNT)
unsigned long r;
_BitScanForward(&r, (U32)val);
return (unsigned )r >> 3 ;
# elif (defined (__clang__) || (defined (__GNUC__) && ((__GNUC__ > 3 ) || \
((__GNUC__ == 3 ) && (__GNUC_MINOR__ >= 4 ))))) && \
!defined (__TINYC__) && !defined (LZ4_FORCE_SW_BITCOUNT)
return (unsigned )__builtin_ctz((U32)val) >> 3 ;
# else
const U32 m = 0 x01010101;
return (unsigned )((((val - 1 ) ^ val) & (m - 1 )) * m) >> 24 ;
# endif
}
} else /* Big Endian CPU */ {
if (sizeof (val)==8 ) {
# if (defined (__clang__) || (defined (__GNUC__) && ((__GNUC__ > 3 ) || \
((__GNUC__ == 3 ) && (__GNUC_MINOR__ >= 4 ))))) && \
!defined (__TINYC__) && !defined (LZ4_FORCE_SW_BITCOUNT)
return (unsigned )__builtin_clzll((U64)val) >> 3 ;
# else
#if 1
/* this method is probably faster,
* but adds a 128 bytes lookup table */
static const unsigned char ctz7_tab[128 ] = {
7 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
4 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
5 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
4 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
6 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
4 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
5 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
4 , 0 , 1 , 0 , 2 , 0 , 1 , 0 , 3 , 0 , 1 , 0 , 2 , 0 , 1 , 0 ,
};
U64 const mask = 0 x0101010101010101ULL;
U64 const t = (((val >> 8 ) - mask) | val) & mask;
return ctz7_tab[(t * 0 x0080402010080402ULL) >> 57 ];
#else
/* this method doesn't consume memory space like the previous one,
* but it contains several branches ,
* that may end up slowing execution */
static const U32 by32 = sizeof (val)*4 ; /* 32 on 64 bits (goal), 16 on 32 bits.
Just to avoid some static analyzer complaining about shift by 32 on 32 - bits target .
Note that this code path is never triggered in 32-bits mode. */
unsigned r;
if (!(val>>by32)) { r=4 ; } else { r=0 ; val>>=by32; }
if (!(val>>16 )) { r+=2 ; val>>=8 ; } else { val>>=24 ; }
r += (!val);
return r;
#endif
# endif
} else /* 32 bits */ {
# if (defined (__clang__) || (defined (__GNUC__) && ((__GNUC__ > 3 ) || \
((__GNUC__ == 3 ) && (__GNUC_MINOR__ >= 4 ))))) && \
!defined (LZ4_FORCE_SW_BITCOUNT)
return (unsigned )__builtin_clz((U32)val) >> 3 ;
# else
val >>= 8 ;
val = ((((val + 0 x00FFFF00) | 0 x00FFFFFF) + val) |
(val + 0 x00FF0000)) >> 24 ;
return (unsigned )val ^ 3 ;
# endif
}
}
}
#define STEPSIZE sizeof (reg_t)
LZ4_FORCE_INLINE
unsigned LZ4_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* pInLimit)
{
const BYTE* const pStart = pIn;
if (likely(pIn < pInLimit-(STEPSIZE-1 ))) {
reg_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
if (!diff) {
pIn+=STEPSIZE; pMatch+=STEPSIZE;
} else {
return LZ4_NbCommonBytes(diff);
} }
while (likely(pIn < pInLimit-(STEPSIZE-1 ))) {
reg_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
if (!diff) { pIn+=STEPSIZE; pMatch+=STEPSIZE; continue ; }
pIn += LZ4_NbCommonBytes(diff);
return (unsigned )(pIn - pStart);
}
if ((STEPSIZE==8 ) && (pIn<(pInLimit-3 )) && (LZ4_read32(pMatch) == LZ4_read32(pIn))) { pIn+=4 ; pMatch+=4 ; }
if ((pIn<(pInLimit-1 )) && (LZ4_read16(pMatch) == LZ4_read16(pIn))) { pIn+=2 ; pMatch+=2 ; }
if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++;
return (unsigned )(pIn - pStart);
}
#ifndef LZ4_COMMONDEFS_ONLY
/*-************************************
* Local Constants
**************************************/
static const int LZ4_64Klimit = ((64 KB) + (MFLIMIT-1 ));
static const U32 LZ4_skipTrigger = 6 ; /* Increase this value ==> compression run slower on incompressible data */
/*-************************************
* Local Structures and types
**************************************/
typedef enum { clearedTable = 0 , byPtr, byU32, byU16 } tableType_t;
/**
* This enum distinguishes several different modes of accessing previous
* content in the stream .
*
* - noDict : There is no preceding content .
* - withPrefix64k : Table entries up to ctx - > dictSize before the current blob
* blob being compressed are valid and refer to the preceding
* content ( of length ctx - > dictSize ) , which is available
* contiguously preceding in memory the content currently
* being compressed .
* - usingExtDict : Like withPrefix64k , but the preceding content is somewhere
* else in memory , starting at ctx - > dictionary with length
* ctx - > dictSize .
* - usingDictCtx : Everything concerning the preceding content is
* in a separate context , pointed to by ctx - > dictCtx .
* ctx - > dictionary , ctx - > dictSize , and table entries
* in the current context that refer to positions
* preceding the beginning of the current compression are
* ignored . Instead , ctx - > dictCtx - > dictionary and ctx - > dictCtx
* - > dictSize describe the location and size of the preceding
* content , and matches are found by looking in the ctx
* - > dictCtx - > hashTable .
*/
typedef enum { noDict = 0 , withPrefix64k, usingExtDict, usingDictCtx } dict_directive;
typedef enum { noDictIssue = 0 , dictSmall } dictIssue_directive;
/*-************************************
* Local Utils
**************************************/
int LZ4_versionNumber (void ) { return LZ4_VERSION_NUMBER; }
const char * LZ4_versionString(void ) { return LZ4_VERSION_STRING; }
int LZ4_compressBound(int isize) { return LZ4_COMPRESSBOUND(isize); }
int LZ4_sizeofState(void ) { return sizeof (LZ4_stream_t); }
/*-****************************************
* Internal Definitions , used only in Tests
*******************************************/
#if defined (__cplusplus)
extern "C" {
#endif
int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char * source, char * dest, int srcSize);
int LZ4_decompress_safe_forceExtDict(const char * source, char * dest,
int compressedSize, int maxOutputSize,
const void * dictStart, size_t dictSize);
int LZ4_decompress_safe_partial_forceExtDict(const char * source, char * dest,
int compressedSize, int targetOutputSize, int dstCapacity,
const void * dictStart, size_t dictSize);
#if defined (__cplusplus)
}
#endif
/*-******************************
* Compression functions
********************************/
LZ4_FORCE_INLINE U32 LZ4_hash4(U32 sequence, tableType_t const tableType)
{
if (tableType == byU16)
return ((sequence * 2654435761 U) >> ((MINMATCH*8 )-(LZ4_HASHLOG+1 )));
else
return ((sequence * 2654435761 U) >> ((MINMATCH*8 )-LZ4_HASHLOG));
}
LZ4_FORCE_INLINE U32 LZ4_hash5(U64 sequence, tableType_t const tableType)
{
const U32 hashLog = (tableType == byU16) ? LZ4_HASHLOG+1 : LZ4_HASHLOG;
if (LZ4_isLittleEndian()) {
const U64 prime5bytes = 889523592379 ULL;
return (U32)(((sequence << 24 ) * prime5bytes) >> (64 - hashLog));
} else {
const U64 prime8bytes = 11400714785074694791 ULL;
return (U32)(((sequence >> 24 ) * prime8bytes) >> (64 - hashLog));
}
}
LZ4_FORCE_INLINE U32 LZ4_hashPosition(const void * const p, tableType_t const tableType)
{
if ((sizeof (reg_t)==8 ) && (tableType != byU16)) return LZ4_hash5(LZ4_read_ARCH(p), tableType);
#ifdef LZ4_STATIC_LINKING_ONLY_ENDIANNESS_INDEPENDENT_OUTPUT
return LZ4_hash4(LZ4_readLE32(p), tableType);
#else
return LZ4_hash4(LZ4_read32(p), tableType);
#endif
}
LZ4_FORCE_INLINE void LZ4_clearHash(U32 h, void * tableBase, tableType_t const tableType)
{
switch (tableType)
{
default : /* fallthrough */
case clearedTable: { /* illegal! */ assert(0); return; }
case byPtr: { const BYTE** hashTable = (const BYTE**)tableBase; hashTable[h] = NULL; return ; }
case byU32: { U32* hashTable = (U32*) tableBase; hashTable[h] = 0 ; return ; }
case byU16: { U16* hashTable = (U16*) tableBase; hashTable[h] = 0 ; return ; }
}
}
LZ4_FORCE_INLINE void LZ4_putIndexOnHash(U32 idx, U32 h, void * tableBase, tableType_t const tableType)
{
switch (tableType)
{
default : /* fallthrough */
case clearedTable: /* fallthrough */
case byPtr: { /* illegal! */ assert(0); return; }
case byU32: { U32* hashTable = (U32*) tableBase; hashTable[h] = idx; return ; }
case byU16: { U16* hashTable = (U16*) tableBase; assert(idx < 65536 ); hashTable[h] = (U16)idx; return ; }
}
}
/* LZ4_putPosition*() : only used in byPtr mode */
LZ4_FORCE_INLINE void LZ4_putPositionOnHash(const BYTE* p, U32 h,
void * tableBase, tableType_t const tableType)
{
const BYTE** const hashTable = (const BYTE**)tableBase;
assert(tableType == byPtr); (void )tableType;
hashTable[h] = p;
}
LZ4_FORCE_INLINE void LZ4_putPosition(const BYTE* p, void * tableBase, tableType_t tableType)
{
U32 const h = LZ4_hashPosition(p, tableType);
LZ4_putPositionOnHash(p, h, tableBase, tableType);
}
/* LZ4_getIndexOnHash() :
* Index of match position registered in hash table .
* hash position must be calculated by using base + index , or dictBase + index .
* Assumption 1 : only valid if tableType = = byU32 or byU16 .
* Assumption 2 : h is presumed valid ( within limits of hash table )
*/
LZ4_FORCE_INLINE U32 LZ4_getIndexOnHash(U32 h, const void * tableBase, tableType_t tableType)
{
LZ4_STATIC_ASSERT(LZ4_MEMORY_USAGE > 2 );
if (tableType == byU32) {
const U32* const hashTable = (const U32*) tableBase;
assert(h < (1 U << (LZ4_MEMORY_USAGE-2 )));
return hashTable[h];
}
if (tableType == byU16) {
const U16* const hashTable = (const U16*) tableBase;
assert(h < (1 U << (LZ4_MEMORY_USAGE-1 )));
return hashTable[h];
}
assert(0 ); return 0 ; /* forbidden case */
}
static const BYTE* LZ4_getPositionOnHash(U32 h, const void * tableBase, tableType_t tableType)
{
assert(tableType == byPtr); (void )tableType;
{ const BYTE* const * hashTable = (const BYTE* const *) tableBase; return hashTable[h]; }
}
LZ4_FORCE_INLINE const BYTE*
LZ4_getPosition(const BYTE* p,
const void * tableBase, tableType_t tableType)
{
U32 const h = LZ4_hashPosition(p, tableType);
return LZ4_getPositionOnHash(h, tableBase, tableType);
}
LZ4_FORCE_INLINE void
LZ4_prepareTable(LZ4_stream_t_internal* const cctx,
const int inputSize,
const tableType_t tableType) {
/* If the table hasn't been used, it's guaranteed to be zeroed out, and is
* therefore safe to use no matter what mode we ' re in . Otherwise , we figure
* out if it ' s safe to leave as is or whether it needs to be reset .
*/
if ((tableType_t)cctx->tableType != clearedTable) {
assert(inputSize >= 0 );
if ((tableType_t)cctx->tableType != tableType
|| ((tableType == byU16) && cctx->currentOffset + (unsigned )inputSize >= 0 xFFFFU)
|| ((tableType == byU32) && cctx->currentOffset > 1 GB)
|| tableType == byPtr
|| inputSize >= 4 KB)
{
DEBUGLOG(4 , "LZ4_prepareTable: Resetting table in %p" , cctx);
MEM_INIT(cctx->hashTable, 0 , LZ4_HASHTABLESIZE);
cctx->currentOffset = 0 ;
cctx->tableType = (U32)clearedTable;
} else {
DEBUGLOG(4 , "LZ4_prepareTable: Re-use hash table (no reset)" );
}
}
/* Adding a gap, so all previous entries are > LZ4_DISTANCE_MAX back,
* is faster than compressing without a gap .
* However , compressing with currentOffset = = 0 is faster still ,
* so we preserve that case .
*/
if (cctx->currentOffset != 0 && tableType == byU32) {
DEBUGLOG(5 , "LZ4_prepareTable: adding 64KB to currentOffset" );
cctx->currentOffset += 64 KB;
}
/* Finally, clear history */
cctx->dictCtx = NULL;
cctx->dictionary = NULL;
cctx->dictSize = 0 ;
}
/** LZ4_compress_generic_validated() :
* inlined , to ensure branches are decided at compilation time .
* The following conditions are presumed already validated :
* - source ! = NULL
* - inputSize > 0
*/
LZ4_FORCE_INLINE int LZ4_compress_generic_validated(
LZ4_stream_t_internal* const cctx,
const char * const source,
char * const dest,
const int inputSize,
int * inputConsumed, /* only written when outputDirective == fillOutput */
const int maxOutputSize,
const limitedOutput_directive outputDirective,
const tableType_t tableType,
const dict_directive dictDirective,
const dictIssue_directive dictIssue,
const int acceleration)
{
int result;
const BYTE* ip = (const BYTE*)source;
U32 const startIndex = cctx->currentOffset;
const BYTE* base = (const BYTE*)source - startIndex;
const BYTE* lowLimit;
const LZ4_stream_t_internal* dictCtx = (const LZ4_stream_t_internal*) cctx->dictCtx;
const BYTE* const dictionary =
dictDirective == usingDictCtx ? dictCtx->dictionary : cctx->dictionary;
const U32 dictSize =
dictDirective == usingDictCtx ? dictCtx->dictSize : cctx->dictSize;
const U32 dictDelta =
(dictDirective == usingDictCtx) ? startIndex - dictCtx->currentOffset : 0 ; /* make indexes in dictCtx comparable with indexes in current context */
int const maybe_extMem = (dictDirective == usingExtDict) || (dictDirective == usingDictCtx);
U32 const prefixIdxLimit = startIndex - dictSize; /* used when dictDirective == dictSmall */
const BYTE* const dictEnd = dictionary ? dictionary + dictSize : dictionary;
const BYTE* anchor = (const BYTE*) source;
const BYTE* const iend = ip + inputSize;
const BYTE* const mflimitPlusOne = iend - MFLIMIT + 1 ;
const BYTE* const matchlimit = iend - LASTLITERALS;
/* the dictCtx currentOffset is indexed on the start of the dictionary,
* while a dictionary in the current context precedes the currentOffset */
const BYTE* dictBase = (dictionary == NULL) ? NULL :
(dictDirective == usingDictCtx) ?
dictionary + dictSize - dictCtx->currentOffset :
dictionary + dictSize - startIndex;
BYTE* op = (BYTE*) dest;
BYTE* const olimit = op + maxOutputSize;
U32 offset = 0 ;
U32 forwardH;
DEBUGLOG(5 , "LZ4_compress_generic_validated: srcSize=%i, tableType=%u" , inputSize, tableType);
assert(ip != NULL);
if (tableType == byU16) assert(inputSize<LZ4_64Klimit); /* Size too large (not within 64K limit) */
if (tableType == byPtr) assert(dictDirective==noDict); /* only supported use case with byPtr */
/* If init conditions are not met, we don't have to mark stream
* as having dirty context, since no action was taken yet */
if (outputDirective == fillOutput && maxOutputSize < 1 ) { return 0 ; } /* Impossible to store anything */
assert(acceleration >= 1 );
lowLimit = (const BYTE*)source - (dictDirective == withPrefix64k ? dictSize : 0 );
/* Update context state */
if (dictDirective == usingDictCtx) {
/* Subsequent linked blocks can't use the dictionary. */
/* Instead, they use the block we just compressed. */
cctx->dictCtx = NULL;
cctx->dictSize = (U32)inputSize;
} else {
cctx->dictSize += (U32)inputSize;
}
cctx->currentOffset += (U32)inputSize;
cctx->tableType = (U32)tableType;
if (inputSize<LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */
/* First Byte */
{ U32 const h = LZ4_hashPosition(ip, tableType);
if (tableType == byPtr) {
LZ4_putPositionOnHash(ip, h, cctx->hashTable, byPtr);
} else {
LZ4_putIndexOnHash(startIndex, h, cctx->hashTable, tableType);
} }
ip++; forwardH = LZ4_hashPosition(ip, tableType);
/* Main Loop */
for ( ; ; ) {
const BYTE* match;
BYTE* token;
const BYTE* filledIp;
/* Find a match */
if (tableType == byPtr) {
const BYTE* forwardIp = ip;
int step = 1 ;
int searchMatchNb = acceleration << LZ4_skipTrigger;
do {
U32 const h = forwardH;
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >> LZ4_skipTrigger);
if (unlikely(forwardIp > mflimitPlusOne)) goto _last_literals;
assert(ip < mflimitPlusOne);
match = LZ4_getPositionOnHash(h, cctx->hashTable, tableType);
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putPositionOnHash(ip, h, cctx->hashTable, tableType);
} while ( (match+LZ4_DISTANCE_MAX < ip)
|| (LZ4_read32(match) != LZ4_read32(ip)) );
} else { /* byU32, byU16 */
const BYTE* forwardIp = ip;
int step = 1 ;
int searchMatchNb = acceleration << LZ4_skipTrigger;
do {
U32 const h = forwardH;
U32 const current = (U32)(forwardIp - base);
U32 matchIndex = LZ4_getIndexOnHash(h, cctx->hashTable, tableType);
assert(matchIndex <= current);
assert(forwardIp - base < (ptrdiff_t)(2 GB - 1 ));
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >> LZ4_skipTrigger);
if (unlikely(forwardIp > mflimitPlusOne)) goto _last_literals;
assert(ip < mflimitPlusOne);
if (dictDirective == usingDictCtx) {
if (matchIndex < startIndex) {
/* there was no match, try the dictionary */
assert(tableType == byU32);
matchIndex = LZ4_getIndexOnHash(h, dictCtx->hashTable, byU32);
match = dictBase + matchIndex;
matchIndex += dictDelta; /* make dictCtx index comparable with current context */
lowLimit = dictionary;
} else {
match = base + matchIndex;
lowLimit = (const BYTE*)source;
}
} else if (dictDirective == usingExtDict) {
if (matchIndex < startIndex) {
DEBUGLOG(7 , "extDict candidate: matchIndex=%5u < startIndex=%5u" , matchIndex, startIndex);
assert(startIndex - matchIndex >= MINMATCH);
assert(dictBase);
match = dictBase + matchIndex;
lowLimit = dictionary;
} else {
match = base + matchIndex;
lowLimit = (const BYTE*)source;
}
} else { /* single continuous memory segment */
match = base + matchIndex;
}
forwardH = LZ4_hashPosition(forwardIp, tableType);
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
DEBUGLOG(7 , "candidate at pos=%u (offset=%u \n" , matchIndex, current - matchIndex);
if ((dictIssue == dictSmall) && (matchIndex < prefixIdxLimit)) { continue ; } /* match outside of valid area */
assert(matchIndex < current);
if ( ((tableType != byU16) || (LZ4_DISTANCE_MAX < LZ4_DISTANCE_ABSOLUTE_MAX))
&& (matchIndex+LZ4_DISTANCE_MAX < current)) {
continue ;
} /* too far */
assert((current - matchIndex) <= LZ4_DISTANCE_MAX); /* match now expected within distance */
if (LZ4_read32(match) == LZ4_read32(ip)) {
if (maybe_extMem) offset = current - matchIndex;
break ; /* match found */
}
} while (1 );
}
/* Catch up */
filledIp = ip;
assert(ip > anchor); /* this is always true as ip has been advanced before entering the main loop */
if ((match > lowLimit) && unlikely(ip[-1 ] == match[-1 ])) {
do { ip--; match--; } while (((ip > anchor) & (match > lowLimit)) && (unlikely(ip[-1 ] == match[-1 ])));
}
/* Encode Literals */
{ unsigned const litLength = (unsigned )(ip - anchor);
token = op++;
if ((outputDirective == limitedOutput) && /* Check output buffer overflow */
(unlikely(op + litLength + (2 + 1 + LASTLITERALS) + (litLength/255 ) > olimit)) ) {
return 0 ; /* cannot compress within `dst` budget. Stored indexes in hash table are nonetheless fine */
}
if ((outputDirective == fillOutput) &&
(unlikely(op + (litLength+240 )/255 /* litlen */ + litLength /* literals */ + 2 /* offset */ + 1 /* token */ + MFLIMIT - MINMATCH /* min last literals so last match is <= end - MFLIMIT */ > olimit))) {
op--;
goto _last_literals;
}
if (litLength >= RUN_MASK) {
unsigned len = litLength - RUN_MASK;
*token = (RUN_MASK<<ML_BITS);
for (; len >= 255 ; len-=255 ) *op++ = 255 ;
*op++ = (BYTE)len;
}
else *token = (BYTE)(litLength<<ML_BITS);
/* Copy Literals */
LZ4_wildCopy8(op, anchor, op+litLength);
op+=litLength;
DEBUGLOG(6 , "seq.start:%i, literals=%u, match.start:%i" ,
(int )(anchor-(const BYTE*)source), litLength, (int )(ip-(const BYTE*)source));
}
_next_match:
/* at this stage, the following variables must be correctly set :
* - ip : at start of LZ operation
* - match : at start of previous pattern occurrence ; can be within current prefix , or within extDict
* - offset : if maybe_ext_memSegment = = 1 ( constant )
* - lowLimit : must be = = dictionary to mean " match is within extDict " ; must be = = source otherwise
* - token and * token : position to write 4 - bits for match length ; higher 4 - bits for literal length supposed already written
*/
if ((outputDirective == fillOutput) &&
(op + 2 /* offset */ + 1 /* token */ + MFLIMIT - MINMATCH /* min last literals so last match is <= end - MFLIMIT */ > olimit)) {
/* the match was too close to the end, rewind and go to last literals */
op = token;
goto _last_literals;
}
/* Encode Offset */
if (maybe_extMem) { /* static test */
DEBUGLOG(6 , " with offset=%u (ext if > %i)" , offset, (int )(ip - (const BYTE*)source));
assert(offset <= LZ4_DISTANCE_MAX && offset > 0 );
LZ4_writeLE16(op, (U16)offset); op+=2 ;
} else {
DEBUGLOG(6 , " with offset=%u (same segment)" , (U32)(ip - match));
assert(ip-match <= LZ4_DISTANCE_MAX);
LZ4_writeLE16(op, (U16)(ip - match)); op+=2 ;
}
/* Encode MatchLength */
{ unsigned matchCode;
if ( (dictDirective==usingExtDict || dictDirective==usingDictCtx)
&& (lowLimit==dictionary) /* match within extDict */ ) {
const BYTE* limit = ip + (dictEnd-match);
assert(dictEnd > match);
if (limit > matchlimit) limit = matchlimit;
matchCode = LZ4_count(ip+MINMATCH, match+MINMATCH, limit);
ip += (size_t)matchCode + MINMATCH;
if (ip==limit) {
unsigned const more = LZ4_count(limit, (const BYTE*)source, matchlimit);
matchCode += more;
ip += more;
}
DEBUGLOG(6 , " with matchLength=%u starting in extDict" , matchCode+MINMATCH);
} else {
matchCode = LZ4_count(ip+MINMATCH, match+MINMATCH, matchlimit);
ip += (size_t)matchCode + MINMATCH;
DEBUGLOG(6 , " with matchLength=%u" , matchCode+MINMATCH);
}
if ((outputDirective) && /* Check output buffer overflow */
(unlikely(op + (1 + LASTLITERALS) + (matchCode+240 )/255 > olimit)) ) {
if (outputDirective == fillOutput) {
/* Match description too long : reduce it */
U32 newMatchCode = 15 /* in token */ - 1 /* to avoid needing a zero byte */ + ((U32)(olimit - op) - 1 - LASTLITERALS) * 255;
ip -= matchCode - newMatchCode;
assert(newMatchCode < matchCode);
matchCode = newMatchCode;
if (unlikely(ip <= filledIp)) {
/* We have already filled up to filledIp so if ip ends up less than filledIp
* we have positions in the hash table beyond the current position . This is
* a problem if we reuse the hash table . So we have to remove these positions
* from the hash table .
*/
const BYTE* ptr;
DEBUGLOG(5 , "Clearing %u positions" , (U32)(filledIp - ip));
for (ptr = ip; ptr <= filledIp; ++ptr) {
U32 const h = LZ4_hashPosition(ptr, tableType);
LZ4_clearHash(h, cctx->hashTable, tableType);
}
}
} else {
assert(outputDirective == limitedOutput);
return 0 ; /* cannot compress within `dst` budget. Stored indexes in hash table are nonetheless fine */
}
}
if (matchCode >= ML_MASK) {
*token += ML_MASK;
matchCode -= ML_MASK;
LZ4_write32(op, 0 xFFFFFFFF);
while (matchCode >= 4 *255 ) {
op+=4 ;
LZ4_write32(op, 0 xFFFFFFFF);
matchCode -= 4 *255 ;
}
op += matchCode / 255 ;
*op++ = (BYTE)(matchCode % 255 );
} else
*token += (BYTE)(matchCode);
}
/* Ensure we have enough space for the last literals. */
assert(!(outputDirective == fillOutput && op + 1 + LASTLITERALS > olimit));
anchor = ip;
/* Test end of chunk */
if (ip >= mflimitPlusOne) break ;
/* Fill table */
{ U32 const h = LZ4_hashPosition(ip-2 , tableType);
if (tableType == byPtr) {
LZ4_putPositionOnHash(ip-2 , h, cctx->hashTable, byPtr);
} else {
U32 const idx = (U32)((ip-2 ) - base);
LZ4_putIndexOnHash(idx, h, cctx->hashTable, tableType);
} }
/* Test next position */
if (tableType == byPtr) {
match = LZ4_getPosition(ip, cctx->hashTable, tableType);
LZ4_putPosition(ip, cctx->hashTable, tableType);
if ( (match+LZ4_DISTANCE_MAX >= ip)
&& (LZ4_read32(match) == LZ4_read32(ip)) )
{ token=op++; *token=0 ; goto _next_match; }
} else { /* byU32, byU16 */
U32 const h = LZ4_hashPosition(ip, tableType);
U32 const current = (U32)(ip-base);
U32 matchIndex = LZ4_getIndexOnHash(h, cctx->hashTable, tableType);
assert(matchIndex < current);
if (dictDirective == usingDictCtx) {
if (matchIndex < startIndex) {
/* there was no match, try the dictionary */
assert(tableType == byU32);
matchIndex = LZ4_getIndexOnHash(h, dictCtx->hashTable, byU32);
match = dictBase + matchIndex;
lowLimit = dictionary; /* required for match length counter */
matchIndex += dictDelta;
} else {
match = base + matchIndex;
lowLimit = (const BYTE*)source; /* required for match length counter */
}
} else if (dictDirective==usingExtDict) {
if (matchIndex < startIndex) {
assert(dictBase);
match = dictBase + matchIndex;
lowLimit = dictionary; /* required for match length counter */
} else {
match = base + matchIndex;
lowLimit = (const BYTE*)source; /* required for match length counter */
}
} else { /* single memory segment */
match = base + matchIndex;
}
LZ4_putIndexOnHash(current, h, cctx->hashTable, tableType);
assert(matchIndex < current);
if ( ((dictIssue==dictSmall) ? (matchIndex >= prefixIdxLimit) : 1 )
&& (((tableType==byU16) && (LZ4_DISTANCE_MAX == LZ4_DISTANCE_ABSOLUTE_MAX)) ? 1 : (matchIndex+LZ4_DISTANCE_MAX >= current))
&& (LZ4_read32(match) == LZ4_read32(ip)) ) {
token=op++;
*token=0 ;
if (maybe_extMem) offset = current - matchIndex;
DEBUGLOG(6 , "seq.start:%i, literals=%u, match.start:%i" ,
(int )(anchor-(const BYTE*)source), 0 , (int )(ip-(const BYTE*)source));
goto _next_match;
}
}
/* Prepare next loop */
forwardH = LZ4_hashPosition(++ip, tableType);
}
_last_literals:
/* Encode Last Literals */
{ size_t lastRun = (size_t)(iend - anchor);
if ( (outputDirective) && /* Check output buffer overflow */
(op + lastRun + 1 + ((lastRun+255 -RUN_MASK)/255 ) > olimit)) {
if (outputDirective == fillOutput) {
/* adapt lastRun to fill 'dst' */
assert(olimit >= op);
lastRun = (size_t)(olimit-op) - 1 /*token*/;
lastRun -= (lastRun + 256 - RUN_MASK) / 256 ; /*additional length tokens*/
} else {
assert(outputDirective == limitedOutput);
return 0 ; /* cannot compress within `dst` budget. Stored indexes in hash table are nonetheless fine */
}
}
DEBUGLOG(6 , "Final literal run : %i literals" , (int )lastRun);
if (lastRun >= RUN_MASK) {
size_t accumulator = lastRun - RUN_MASK;
*op++ = RUN_MASK << ML_BITS;
for (; accumulator >= 255 ; accumulator-=255 ) *op++ = 255 ;
*op++ = (BYTE) accumulator;
} else {
*op++ = (BYTE)(lastRun<<ML_BITS);
}
LZ4_memcpy(op, anchor, lastRun);
ip = anchor + lastRun;
op += lastRun;
}
if (outputDirective == fillOutput) {
*inputConsumed = (int ) (((const char *)ip)-source);
}
result = (int )(((char *)op) - dest);
assert(result > 0 );
DEBUGLOG(5 , "LZ4_compress_generic: compressed %i bytes into %i bytes" , inputSize, result);
return result;
}
/** LZ4_compress_generic() :
* inlined , to ensure branches are decided at compilation time ;
* takes care of src = = ( NULL , 0 )
* and forward the rest to LZ4_compress_generic_validated */
LZ4_FORCE_INLINE int LZ4_compress_generic(
LZ4_stream_t_internal* const cctx,
const char * const src,
char * const dst,
const int srcSize,
int *inputConsumed, /* only written when outputDirective == fillOutput */
const int dstCapacity,
const limitedOutput_directive outputDirective,
const tableType_t tableType,
const dict_directive dictDirective,
const dictIssue_directive dictIssue,
const int acceleration)
{
DEBUGLOG(5 , "LZ4_compress_generic: srcSize=%i, dstCapacity=%i" ,
srcSize, dstCapacity);
if ((U32)srcSize > (U32)LZ4_MAX_INPUT_SIZE) { return 0 ; } /* Unsupported srcSize, too large (or negative) */
if (srcSize == 0 ) { /* src == NULL supported if srcSize == 0 */
if (outputDirective != notLimited && dstCapacity <= 0 ) return 0 ; /* no output, can't write anything */
DEBUGLOG(5 , "Generating an empty block" );
assert(outputDirective == notLimited || dstCapacity >= 1 );
assert(dst != NULL);
dst[0 ] = 0 ;
if (outputDirective == fillOutput) {
assert (inputConsumed != NULL);
*inputConsumed = 0 ;
}
return 1 ;
}
assert(src != NULL);
return LZ4_compress_generic_validated(cctx, src, dst, srcSize,
inputConsumed, /* only written into if outputDirective == fillOutput */
dstCapacity, outputDirective,
tableType, dictDirective, dictIssue, acceleration);
}
int LZ4_compress_fast_extState(void * state, const char * source, char * dest, int inputSize, int maxOutputSize, int acceleration)
{
LZ4_stream_t_internal* const ctx = & LZ4_initStream(state, sizeof (LZ4_stream_t)) -> internal_donotuse;
assert(ctx != NULL);
if (acceleration < 1 ) acceleration = LZ4_ACCELERATION_DEFAULT;
if (acceleration > LZ4_ACCELERATION_MAX) acceleration = LZ4_ACCELERATION_MAX;
if (maxOutputSize >= LZ4_compressBound(inputSize)) {
if (inputSize < LZ4_64Klimit) {
return LZ4_compress_generic(ctx, source, dest, inputSize, NULL, 0 , notLimited, byU16, noDict, noDictIssue, acceleration);
} else {
const tableType_t tableType = ((sizeof (void *)==4 ) && ((uptrval)source > LZ4_DISTANCE_MAX)) ? byPtr : byU32;
return LZ4_compress_generic(ctx, source, dest, inputSize, NULL, 0 , notLimited, tableType, noDict, noDictIssue, acceleration);
}
} else {
if (inputSize < LZ4_64Klimit) {
return LZ4_compress_generic(ctx, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, byU16, noDict, noDictIssue, acceleration);
} else {
const tableType_t tableType = ((sizeof (void *)==4 ) && ((uptrval)source > LZ4_DISTANCE_MAX)) ? byPtr : byU32;
return LZ4_compress_generic(ctx, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, noDict, noDictIssue, acceleration);
}
}
}
/**
* LZ4_compress_fast_extState_fastReset ( ) :
* A variant of LZ4_compress_fast_extState ( ) .
*
* Using this variant avoids an expensive initialization step . It is only safe
* to call if the state buffer is known to be correctly initialized already
* ( see comment in lz4 . h on LZ4_resetStream_fast ( ) for a definition of
* " correctly initialized " ) .
*/
int LZ4_compress_fast_extState_fastReset(void * state, const char * src, char * dst, int srcSize, int dstCapacity, int acceleration)
{
LZ4_stream_t_internal* const ctx = &((LZ4_stream_t*)state)->internal_donotuse;
if (acceleration < 1 ) acceleration = LZ4_ACCELERATION_DEFAULT;
if (acceleration > LZ4_ACCELERATION_MAX) acceleration = LZ4_ACCELERATION_MAX;
assert(ctx != NULL);
if (dstCapacity >= LZ4_compressBound(srcSize)) {
if (srcSize < LZ4_64Klimit) {
const tableType_t tableType = byU16;
LZ4_prepareTable(ctx, srcSize, tableType);
if (ctx->currentOffset) {
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, 0 , notLimited, tableType, noDict, dictSmall, acceleration);
} else {
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, 0 , notLimited, tableType, noDict, noDictIssue, acceleration);
}
} else {
const tableType_t tableType = ((sizeof (void *)==4 ) && ((uptrval)src > LZ4_DISTANCE_MAX)) ? byPtr : byU32;
LZ4_prepareTable(ctx, srcSize, tableType);
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, 0 , notLimited, tableType, noDict, noDictIssue, acceleration);
}
} else {
if (srcSize < LZ4_64Klimit) {
const tableType_t tableType = byU16;
LZ4_prepareTable(ctx, srcSize, tableType);
if (ctx->currentOffset) {
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, dstCapacity, limitedOutput, tableType, noDict, dictSmall, acceleration);
} else {
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, dstCapacity, limitedOutput, tableType, noDict, noDictIssue, acceleration);
}
} else {
const tableType_t tableType = ((sizeof (void *)==4 ) && ((uptrval)src > LZ4_DISTANCE_MAX)) ? byPtr : byU32;
LZ4_prepareTable(ctx, srcSize, tableType);
return LZ4_compress_generic(ctx, src, dst, srcSize, NULL, dstCapacity, limitedOutput, tableType, noDict, noDictIssue, acceleration);
}
}
}
int LZ4_compress_fast(const char * src, char * dest, int srcSize, int dstCapacity, int acceleration)
{
int result;
#if (LZ4_HEAPMODE)
LZ4_stream_t* const ctxPtr = (LZ4_stream_t*)ALLOC(sizeof (LZ4_stream_t)); /* malloc-calloc always properly aligned */
if (ctxPtr == NULL) return 0 ;
#else
LZ4_stream_t ctx;
LZ4_stream_t* const ctxPtr = &ctx;
#endif
result = LZ4_compress_fast_extState(ctxPtr, src, dest, srcSize, dstCapacity, acceleration);
#if (LZ4_HEAPMODE)
FREEMEM(ctxPtr);
#endif
return result;
}
int LZ4_compress_default(const char * src, char * dst, int srcSize, int dstCapacity)
{
return LZ4_compress_fast(src, dst, srcSize, dstCapacity, 1 );
}
/* Note!: This function leaves the stream in an unclean/broken state!
* It is not safe to subsequently use the same state with a _ fastReset ( ) or
* _continue() call without resetting it. */
static int LZ4_compress_destSize_extState_internal(LZ4_stream_t* state, const char * src, char * dst, int * srcSizePtr, int targetDstSize, int acceleration)
{
void * const s = LZ4_initStream(state, sizeof (*state));
assert(s != NULL); (void )s;
if (targetDstSize >= LZ4_compressBound(*srcSizePtr)) { /* compression success is guaranteed */
return LZ4_compress_fast_extState(state, src, dst, *srcSizePtr, targetDstSize, acceleration);
} else {
if (*srcSizePtr < LZ4_64Klimit) {
return LZ4_compress_generic(&state->internal_donotuse, src, dst, *srcSizePtr, srcSizePtr, targetDstSize, fillOutput, byU16, noDict, noDictIssue, acceleration);
} else {
tableType_t const addrMode = ((sizeof (void *)==4 ) && ((uptrval)src > LZ4_DISTANCE_MAX)) ? byPtr : byU32;
return LZ4_compress_generic(&state->internal_donotuse, src, dst, *srcSizePtr, srcSizePtr, targetDstSize, fillOutput, addrMode, noDict, noDictIssue, acceleration);
} }
}
int LZ4_compress_destSize_extState(void * state, const char * src, char * dst, int * srcSizePtr, int targetDstSize, int acceleration)
{
int const r = LZ4_compress_destSize_extState_internal((LZ4_stream_t*)state, src, dst, srcSizePtr, targetDstSize, acceleration);
/* clean the state on exit */
LZ4_initStream(state, sizeof (LZ4_stream_t));
return r;
}
int LZ4_compress_destSize(const char * src, char * dst, int * srcSizePtr, int targetDstSize)
{
#if (LZ4_HEAPMODE)
LZ4_stream_t* const ctx = (LZ4_stream_t*)ALLOC(sizeof (LZ4_stream_t)); /* malloc-calloc always properly aligned */
if (ctx == NULL) return 0 ;
#else
LZ4_stream_t ctxBody;
LZ4_stream_t* const ctx = &ctxBody;
#endif
int result = LZ4_compress_destSize_extState_internal(ctx, src, dst, srcSizePtr, targetDstSize, 1 );
#if (LZ4_HEAPMODE)
FREEMEM(ctx);
#endif
return result;
}
/*-******************************
* Streaming functions
********************************/
#if !defined (LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
LZ4_stream_t* LZ4_createStream(void )
{
LZ4_stream_t* const lz4s = (LZ4_stream_t*)ALLOC(sizeof (LZ4_stream_t));
LZ4_STATIC_ASSERT(sizeof (LZ4_stream_t) >= sizeof (LZ4_stream_t_internal));
DEBUGLOG(4 , "LZ4_createStream %p" , lz4s);
if (lz4s == NULL) return NULL;
LZ4_initStream(lz4s, sizeof (*lz4s));
return lz4s;
}
#endif
static size_t LZ4_stream_t_alignment(void )
{
#if LZ4_ALIGN_TEST
typedef struct { char c; LZ4_stream_t t; } t_a;
return sizeof (t_a) - sizeof (LZ4_stream_t);
#else
return 1 ; /* effectively disabled */
#endif
}
LZ4_stream_t* LZ4_initStream (void * buffer, size_t size)
{
DEBUGLOG(5 , "LZ4_initStream" );
if (buffer == NULL) { return NULL; }
if (size < sizeof (LZ4_stream_t)) { return NULL; }
if (!LZ4_isAligned(buffer, LZ4_stream_t_alignment())) return NULL;
MEM_INIT(buffer, 0 , sizeof (LZ4_stream_t_internal));
return (LZ4_stream_t*)buffer;
}
/* resetStream is now deprecated,
* prefer initStream() which is more general */
void LZ4_resetStream (LZ4_stream_t* LZ4_stream)
{
DEBUGLOG(5 , "LZ4_resetStream (ctx:%p)" , LZ4_stream);
MEM_INIT(LZ4_stream, 0 , sizeof (LZ4_stream_t_internal));
}
void LZ4_resetStream_fast(LZ4_stream_t* ctx) {
LZ4_prepareTable(&(ctx->internal_donotuse), 0 , byU32);
}
#if !defined (LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
int LZ4_freeStream (LZ4_stream_t* LZ4_stream)
{
if (!LZ4_stream) return 0 ; /* support free on NULL */
DEBUGLOG(5 , "LZ4_freeStream %p" , LZ4_stream);
FREEMEM(LZ4_stream);
return (0 );
}
#endif
typedef enum { _ld_fast, _ld_slow } LoadDict_mode_e;
#define HASH_UNIT sizeof (reg_t)
int LZ4_loadDict_internal(LZ4_stream_t* LZ4_dict,
const char * dictionary, int dictSize,
LoadDict_mode_e _ld)
{
LZ4_stream_t_internal* const dict = &LZ4_dict->internal_donotuse;
const tableType_t tableType = byU32;
const BYTE* p = (const BYTE*)dictionary;
const BYTE* const dictEnd = p + dictSize;
U32 idx32;
DEBUGLOG(4 , "LZ4_loadDict (%i bytes from %p into %p)" , dictSize, dictionary, LZ4_dict);
/* It's necessary to reset the context,
* and not just continue it with prepareTable ( )
* to avoid any risk of generating overflowing matchIndex
* when compressing using this dictionary */
LZ4_resetStream(LZ4_dict);
/* We always increment the offset by 64 KB, since, if the dict is longer,
* we truncate it to the last 64 k , and if it ' s shorter , we still want to
* advance by a whole window length so we can provide the guarantee that
* there are only valid offsets in the window , which allows an optimization
* in LZ4_compress_fast_continue ( ) where it uses noDictIssue even when the
* dictionary isn't a full 64k. */
dict->currentOffset += 64 KB;
if (dictSize < (int )HASH_UNIT) {
return 0 ;
}
if ((dictEnd - p) > 64 KB) p = dictEnd - 64 KB;
dict->dictionary = p;
dict->dictSize = (U32)(dictEnd - p);
dict->tableType = (U32)tableType;
idx32 = dict->currentOffset - dict->dictSize;
while (p <= dictEnd-HASH_UNIT) {
U32 const h = LZ4_hashPosition(p, tableType);
/* Note: overwriting => favors positions end of dictionary */
LZ4_putIndexOnHash(idx32, h, dict->hashTable, tableType);
p+=3 ; idx32+=3 ;
}
if (_ld == _ld_slow) {
/* Fill hash table with additional references, to improve compression capability */
p = dict->dictionary;
idx32 = dict->currentOffset - dict->dictSize;
while (p <= dictEnd-HASH_UNIT) {
U32 const h = LZ4_hashPosition(p, tableType);
U32 const limit = dict->currentOffset - 64 KB;
if (LZ4_getIndexOnHash(h, dict->hashTable, tableType) <= limit) {
/* Note: not overwriting => favors positions beginning of dictionary */
LZ4_putIndexOnHash(idx32, h, dict->hashTable, tableType);
}
p++; idx32++;
}
}
return (int )dict->dictSize;
}
int LZ4_loadDict(LZ4_stream_t* LZ4_dict, const char * dictionary, int dictSize)
{
return LZ4_loadDict_internal(LZ4_dict, dictionary, dictSize, _ld_fast);
}
int LZ4_loadDictSlow(LZ4_stream_t* LZ4_dict, const char * dictionary, int dictSize)
{
return LZ4_loadDict_internal(LZ4_dict, dictionary, dictSize, _ld_slow);
}
void LZ4_attach_dictionary(LZ4_stream_t* workingStream, const LZ4_stream_t* dictionaryStream)
{
const LZ4_stream_t_internal* dictCtx = (dictionaryStream == NULL) ? NULL :
&(dictionaryStream->internal_donotuse);
DEBUGLOG(4 , "LZ4_attach_dictionary (%p, %p, size %u)" ,
workingStream, dictionaryStream,
dictCtx != NULL ? dictCtx->dictSize : 0 );
if (dictCtx != NULL) {
/* If the current offset is zero, we will never look in the
* external dictionary context , since there is no value a table
* entry can take that indicate a miss . In that case , we need
* to bump the offset to something non - zero .
*/
if (workingStream->internal_donotuse.currentOffset == 0 ) {
workingStream->internal_donotuse.currentOffset = 64 KB;
}
/* Don't actually attach an empty dictionary.
*/
if (dictCtx->dictSize == 0 ) {
dictCtx = NULL;
}
}
workingStream->internal_donotuse.dictCtx = dictCtx;
}
static void LZ4_renormDictT(LZ4_stream_t_internal* LZ4_dict, int nextSize)
{
assert(nextSize >= 0 );
if (LZ4_dict->currentOffset + (unsigned )nextSize > 0 x80000000) { /* potential ptrdiff_t overflow (32-bits mode) */
/* rescale hash table */
U32 const delta = LZ4_dict->currentOffset - 64 KB;
const BYTE* dictEnd = LZ4_dict->dictionary + LZ4_dict->dictSize;
int i;
DEBUGLOG(4 , "LZ4_renormDictT" );
for (i=0 ; i<LZ4_HASH_SIZE_U32; i++) {
if (LZ4_dict->hashTable[i] < delta) LZ4_dict->hashTable[i]=0 ;
else LZ4_dict->hashTable[i] -= delta;
}
LZ4_dict->currentOffset = 64 KB;
if (LZ4_dict->dictSize > 64 KB) LZ4_dict->dictSize = 64 KB;
LZ4_dict->dictionary = dictEnd - LZ4_dict->dictSize;
}
}
int LZ4_compress_fast_continue (LZ4_stream_t* LZ4_stream,
const char * source, char * dest,
int inputSize, int maxOutputSize,
int acceleration)
{
const tableType_t tableType = byU32;
LZ4_stream_t_internal* const streamPtr = &LZ4_stream->internal_donotuse;
const char * dictEnd = streamPtr->dictSize ? (const char *)streamPtr->dictionary + streamPtr->dictSize : NULL;
DEBUGLOG(5 , "LZ4_compress_fast_continue (inputSize=%i, dictSize=%u)" , inputSize, streamPtr->dictSize);
LZ4_renormDictT(streamPtr, inputSize); /* fix index overflow */
if (acceleration < 1 ) acceleration = LZ4_ACCELERATION_DEFAULT;
if (acceleration > LZ4_ACCELERATION_MAX) acceleration = LZ4_ACCELERATION_MAX;
/* invalidate tiny dictionaries */
if ( (streamPtr->dictSize < 4 ) /* tiny dictionary : not enough for a hash */
&& (dictEnd != source) /* prefix mode */
&& (inputSize > 0 ) /* tolerance : don't lose history, in case next invocation would use prefix mode */
&& (streamPtr->dictCtx == NULL) /* usingDictCtx */
) {
DEBUGLOG(5 , "LZ4_compress_fast_continue: dictSize(%u) at addr:%p is too small" , streamPtr->dictSize, streamPtr->dictionary);
/* remove dictionary existence from history, to employ faster prefix mode */
streamPtr->dictSize = 0 ;
streamPtr->dictionary = (const BYTE*)source;
dictEnd = source;
}
/* Check overlapping input/dictionary space */
{ const char * const sourceEnd = source + inputSize;
if ((sourceEnd > (const char *)streamPtr->dictionary) && (sourceEnd < dictEnd)) {
streamPtr->dictSize = (U32)(dictEnd - sourceEnd);
if (streamPtr->dictSize > 64 KB) streamPtr->dictSize = 64 KB;
if (streamPtr->dictSize < 4 ) streamPtr->dictSize = 0 ;
streamPtr->dictionary = (const BYTE*)dictEnd - streamPtr->dictSize;
}
}
/* prefix mode : source data follows dictionary */
if (dictEnd == source) {
if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset))
return LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, withPrefix64k, dictSmall, acceleration);
else
return LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, withPrefix64k, noDictIssue, acceleration);
}
/* external dictionary mode */
{ int result;
if (streamPtr->dictCtx) {
/* We depend here on the fact that dictCtx'es (produced by
* LZ4_loadDict ) guarantee that their tables contain no references
* to offsets between dictCtx - > currentOffset - 64 KB and
* dictCtx - > currentOffset - dictCtx - > dictSize . This makes it safe
* to use noDictIssue even when the dict isn ' t a full 64 KB .
*/
if (inputSize > 4 KB) {
/* For compressing large blobs, it is faster to pay the setup
* cost to copy the dictionary ' s tables into the active context ,
* so that the compression loop is only looking into one table .
*/
LZ4_memcpy(streamPtr, streamPtr->dictCtx, sizeof (*streamPtr));
result = LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, usingExtDict, noDictIssue, acceleration);
} else {
result = LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, usingDictCtx, noDictIssue, acceleration);
}
} else { /* small data <= 4 KB */
if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset)) {
result = LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, usingExtDict, dictSmall, acceleration);
} else {
result = LZ4_compress_generic(streamPtr, source, dest, inputSize, NULL, maxOutputSize, limitedOutput, tableType, usingExtDict, noDictIssue, acceleration);
}
}
streamPtr->dictionary = (const BYTE*)source;
streamPtr->dictSize = (U32)inputSize;
return result;
}
}
/* Hidden debug function, to force-test external dictionary mode */
int LZ4_compress_forceExtDict (LZ4_stream_t* LZ4_dict, const char * source, char * dest, int srcSize)
{
LZ4_stream_t_internal* const streamPtr = &LZ4_dict->internal_donotuse;
int result;
LZ4_renormDictT(streamPtr, srcSize);
if ((streamPtr->dictSize < 64 KB) && (streamPtr->dictSize < streamPtr->currentOffset)) {
result = LZ4_compress_generic(streamPtr, source, dest, srcSize, NULL, 0 , notLimited, byU32, usingExtDict, dictSmall, 1 );
} else {
result = LZ4_compress_generic(streamPtr, source, dest, srcSize, NULL, 0 , notLimited, byU32, usingExtDict, noDictIssue, 1 );
}
streamPtr->dictionary = (const BYTE*)source;
streamPtr->dictSize = (U32)srcSize;
return result;
}
/*! LZ4_saveDict() :
* If previously compressed data block is not guaranteed to remain available at its memory location ,
* save it into a safer place ( char * safeBuffer ) .
* Note : no need to call LZ4_loadDict ( ) afterwards , dictionary is immediately usable ,
* one can therefore call LZ4_compress_fast_continue ( ) right after .
* @ return : saved dictionary size in bytes ( necessarily < = dictSize ) , or 0 if error .
*/
int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char * safeBuffer, int dictSize)
{
LZ4_stream_t_internal* const dict = &LZ4_dict->internal_donotuse;
DEBUGLOG(5 , "LZ4_saveDict : dictSize=%i, safeBuffer=%p" , dictSize, safeBuffer);
if ((U32)dictSize > 64 KB) { dictSize = 64 KB; } /* useless to define a dictionary > 64 KB */
if ((U32)dictSize > dict->dictSize) { dictSize = (int )dict->dictSize; }
if (safeBuffer == NULL) assert(dictSize == 0 );
if (dictSize > 0 ) {
const BYTE* const previousDictEnd = dict->dictionary + dict->dictSize;
assert(dict->dictionary);
LZ4_memmove(safeBuffer, previousDictEnd - dictSize, (size_t)dictSize);
}
dict->dictionary = (const BYTE*)safeBuffer;
dict->dictSize = (U32)dictSize;
return dictSize;
}
/*-*******************************
* Decompression functions
********************************/
typedef enum { decode_full_block = 0 , partial_decode = 1 } earlyEnd_directive;
#undef MIN
#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
/* variant for decompress_unsafe()
* does not know end of input
* presumes input is well formed
* note : will consume at least one byte */
static size_t read_long_length_no_check(const BYTE** pp)
{
size_t b, l = 0 ;
do { b = **pp; (*pp)++; l += b; } while (b==255 );
DEBUGLOG(6 , "read_long_length_no_check: +length=%zu using %zu input bytes" , l, l/255 + 1 )
return l;
}
/* core decoder variant for LZ4_decompress_fast*()
* for legacy support only : these entry points are deprecated .
* - Presumes input is correctly formed ( no defense vs malformed inputs )
* - Does not know input size ( presume input buffer is " large enough " )
* - Decompress a full block ( only )
* @ return : nb of bytes read from input .
* Note : this variant is not optimized for speed , just for maintenance .
* the goal is to remove support of decompress_fast * ( ) variants by v2 . 0
**/
LZ4_FORCE_INLINE int
LZ4_decompress_unsafe_generic(
const BYTE* const istart,
BYTE* const ostart,
int decompressedSize,
size_t prefixSize,
const BYTE* const dictStart, /* only if dict==usingExtDict */
const size_t dictSize /* note: =0 if dictStart==NULL */
)
{
const BYTE* ip = istart;
BYTE* op = (BYTE*)ostart;
BYTE* const oend = ostart + decompressedSize;
const BYTE* const prefixStart = ostart - prefixSize;
DEBUGLOG(5 , "LZ4_decompress_unsafe_generic" );
if (dictStart == NULL) assert(dictSize == 0 );
while (1 ) {
/* start new sequence */
unsigned token = *ip++;
/* literals */
{ size_t ll = token >> ML_BITS;
if (ll==15 ) {
/* long literal length */
ll += read_long_length_no_check(&ip);
}
if ((size_t)(oend-op) < ll) return -1 ; /* output buffer overflow */
LZ4_memmove(op, ip, ll); /* support in-place decompression */
op += ll;
ip += ll;
if ((size_t)(oend-op) < MFLIMIT) {
if (op==oend) break ; /* end of block */
DEBUGLOG(5 , "invalid: literals end at distance %zi from end of block" , oend-op);
/* incorrect end of block :
* last match must start at least MFLIMIT==12 bytes before end of output block */
return -1 ;
} }
/* match */
{ size_t ml = token & 15 ;
size_t const offset = LZ4_readLE16(ip);
ip+=2 ;
if (ml==15 ) {
/* long literal length */
ml += read_long_length_no_check(&ip);
}
ml += MINMATCH;
if ((size_t)(oend-op) < ml) return -1 ; /* output buffer overflow */
{ const BYTE* match = op - offset;
/* out of range */
if (offset > (size_t)(op - prefixStart) + dictSize) {
DEBUGLOG(6 , "offset out of range" );
return -1 ;
}
/* check special case : extDict */
if (offset > (size_t)(op - prefixStart)) {
/* extDict scenario */
const BYTE* const dictEnd = dictStart + dictSize;
const BYTE* extMatch = dictEnd - (offset - (size_t)(op-prefixStart));
size_t const extml = (size_t)(dictEnd - extMatch);
if (extml > ml) {
/* match entirely within extDict */
LZ4_memmove(op, extMatch, ml);
op += ml;
ml = 0 ;
} else {
/* match split between extDict & prefix */
LZ4_memmove(op, extMatch, extml);
op += extml;
ml -= extml;
}
match = prefixStart;
}
/* match copy - slow variant, supporting overlap copy */
{ size_t u;
for (u=0 ; u<ml; u++) {
op[u] = match[u];
} } }
op += ml;
if ((size_t)(oend-op) < LASTLITERALS) {
DEBUGLOG(5 , "invalid: match ends at distance %zi from end of block" , oend-op);
/* incorrect end of block :
* last match must stop at least LASTLITERALS==5 bytes before end of output block */
return -1 ;
}
} /* match */
} /* main loop */
return (int )(ip - istart);
}
/* Read the variable-length literal or match length.
*
* @ ip : input pointer
* @ ilimit : position after which if length is not decoded , the input is necessarily corrupted .
* @ initial_check - check ip > = ipmax before start of loop . Returns initial_error if so .
* @ error ( output ) - error code . Must be set to 0 before call .
**/
typedef size_t Rvl_t;
static const Rvl_t rvl_error = (Rvl_t)(-1 );
LZ4_FORCE_INLINE Rvl_t
read_variable_length(const BYTE** ip, const BYTE* ilimit,
int initial_check)
{
Rvl_t s, length = 0 ;
assert(ip != NULL);
assert(*ip != NULL);
assert(ilimit != NULL);
if (initial_check && unlikely((*ip) >= ilimit)) { /* read limit reached */
return rvl_error;
}
s = **ip;
(*ip)++;
length += s;
if (unlikely((*ip) > ilimit)) { /* read limit reached */
return rvl_error;
}
/* accumulator overflow detection (32-bit mode only) */
if ((sizeof (length) < 8 ) && unlikely(length > ((Rvl_t)(-1 )/2 )) ) {
return rvl_error;
}
if (likely(s != 255 )) return length;
do {
s = **ip;
(*ip)++;
length += s;
if (unlikely((*ip) > ilimit)) { /* read limit reached */
return rvl_error;
}
/* accumulator overflow detection (32-bit mode only) */
if ((sizeof (length) < 8 ) && unlikely(length > ((Rvl_t)(-1 )/2 )) ) {
return rvl_error;
}
} while (s == 255 );
return length;
}
/*! LZ4_decompress_generic() :
* This generic decompression function covers all use cases .
* It shall be instantiated several times , using different sets of directives .
* Note that it is important for performance that this function really get inlined ,
* in order to remove useless branches during compilation optimization .
*/
LZ4_FORCE_INLINE int
LZ4_decompress_generic(
const char * const src,
char * const dst,
int srcSize,
int outputSize, /* If endOnInput==endOnInputSize, this value is `dstCapacity` */
earlyEnd_directive partialDecoding, /* full, partial */
dict_directive dict, /* noDict, withPrefix64k, usingExtDict */
const BYTE* const lowPrefix, /* always <= dst, == dst when no prefix */
const BYTE* const dictStart, /* only if dict==usingExtDict */
const size_t dictSize /* note : = 0 if noDict */
)
{
if ((src == NULL) || (outputSize < 0 )) { return -1 ; }
{ const BYTE* ip = (const BYTE*) src;
const BYTE* const iend = ip + srcSize;
BYTE* op = (BYTE*) dst;
BYTE* const oend = op + outputSize;
BYTE* cpy;
const BYTE* const dictEnd = (dictStart == NULL) ? NULL : dictStart + dictSize;
const int checkOffset = (dictSize < (int )(64 KB));
/* Set up the "end" pointers for the shortcut. */
const BYTE* const shortiend = iend - 14 /*maxLL*/ - 2 /*offset*/;
const BYTE* const shortoend = oend - 14 /*maxLL*/ - 18 /*maxML*/;
const BYTE* match;
size_t offset;
unsigned token;
size_t length;
DEBUGLOG(5 , "LZ4_decompress_generic (srcSize:%i, dstSize:%i)" , srcSize, outputSize);
/* Special cases */
assert(lowPrefix <= op);
if (unlikely(outputSize==0 )) {
/* Empty output buffer */
if (partialDecoding) return 0 ;
return ((srcSize==1 ) && (*ip==0 )) ? 0 : -1 ;
}
if (unlikely(srcSize==0 )) { return -1 ; }
/* LZ4_FAST_DEC_LOOP:
* designed for modern OoO performance cpus ,
* where copying reliably 32 - bytes is preferable to an unpredictable branch .
* note : fast loop may show a regression for some client arm chips. */
#if LZ4_FAST_DEC_LOOP
if ((oend - op) < FASTLOOP_SAFE_DISTANCE) {
DEBUGLOG(6 , "move to safe decode loop" );
goto safe_decode;
}
/* Fast loop : decode sequences as long as output < oend-FASTLOOP_SAFE_DISTANCE */
DEBUGLOG(6 , "using fast decode loop" );
while (1 ) {
/* Main fastloop assertion: We can always wildcopy FASTLOOP_SAFE_DISTANCE */
assert(oend - op >= FASTLOOP_SAFE_DISTANCE);
assert(ip < iend);
token = *ip++;
length = token >> ML_BITS; /* literal length */
DEBUGLOG(7 , "blockPos%6u: litLength token = %u" , (unsigned )(op-(BYTE*)dst), (unsigned )length);
/* decode literal length */
if (length == RUN_MASK) {
size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1 );
if (addl == rvl_error) {
DEBUGLOG(6 , "error reading long literal length" );
goto _output_error;
}
length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */
if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
/* copy literals */
LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
if ((op+length>oend-32 ) || (ip+length>iend-32 )) { goto safe_literal_copy; }
LZ4_wildCopy32(op, ip, op+length);
ip += length; op += length;
} else if (ip <= iend-(16 + 1 /*max lit + offset + nextToken*/)) {
/* We don't need to check oend, since we check it once for each loop below */
DEBUGLOG(7 , "copy %u bytes in a 16-bytes stripe" , (unsigned )length);
/* Literals can only be <= 14, but hope compilers optimize better when copy by a register size */
LZ4_memcpy(op, ip, 16 );
ip += length; op += length;
} else {
goto safe_literal_copy;
}
/* get offset */
offset = LZ4_readLE16(ip); ip+=2 ;
DEBUGLOG(6 , "blockPos%6u: offset = %u" , (unsigned )(op-(BYTE*)dst), (unsigned )offset);
match = op - offset;
assert(match <= op); /* overflow check */
/* get matchlength */
length = token & ML_MASK;
DEBUGLOG(7 , " match length token = %u (len==%u)" , (unsigned )length, (unsigned )length+MINMATCH);
if (length == ML_MASK) {
size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1 , 0 );
if (addl == rvl_error) {
DEBUGLOG(5 , "error reading long match length" );
goto _output_error;
}
length += addl;
length += MINMATCH;
DEBUGLOG(7 , " long match length == %u" , (unsigned )length);
if (unlikely((uptrval)(op)+length<(uptrval)op)) { goto _output_error; } /* overflow detection */
if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) {
goto safe_match_copy;
}
} else {
length += MINMATCH;
if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) {
DEBUGLOG(7 , "moving to safe_match_copy (ml==%u)" , (unsigned )length);
goto safe_match_copy;
}
/* Fastpath check: skip LZ4_wildCopy32 when true */
if ((dict == withPrefix64k) || (match >= lowPrefix)) {
if (offset >= 8 ) {
assert(match >= lowPrefix);
assert(match <= op);
assert(op + 18 <= oend);
LZ4_memcpy(op, match, 8 );
LZ4_memcpy(op+8 , match+8 , 8 );
LZ4_memcpy(op+16 , match+16 , 2 );
op += length;
continue ;
} } }
if ( checkOffset && (unlikely(match + dictSize < lowPrefix)) ) {
DEBUGLOG(5 , "Error : pos=%zi, offset=%zi => outside buffers" , op-lowPrefix, op-match);
goto _output_error;
}
/* match starting within external dictionary */
if ((dict==usingExtDict) && (match < lowPrefix)) {
assert(dictEnd != NULL);
if (unlikely(op+length > oend-LASTLITERALS)) {
if (partialDecoding) {
DEBUGLOG(7 , "partialDecoding: dictionary match, close to dstEnd" );
length = MIN(length, (size_t)(oend-op));
} else {
DEBUGLOG(6 , "end-of-block condition violated" )
goto _output_error;
} }
if (length <= (size_t)(lowPrefix-match)) {
/* match fits entirely within external dictionary : just copy */
LZ4_memmove(op, dictEnd - (lowPrefix-match), length);
op += length;
} else {
/* match stretches into both external dictionary and current block */
size_t const copySize = (size_t)(lowPrefix - match);
size_t const restSize = length - copySize;
LZ4_memcpy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (size_t)(op - lowPrefix)) { /* overlap copy */
BYTE* const endOfMatch = op + restSize;
const BYTE* copyFrom = lowPrefix;
while (op < endOfMatch) { *op++ = *copyFrom++; }
} else {
LZ4_memcpy(op, lowPrefix, restSize);
op += restSize;
} }
continue ;
}
/* copy match within block */
cpy = op + length;
assert((op <= oend) && (oend-op >= 32 ));
if (unlikely(offset<16 )) {
LZ4_memcpy_using_offset(op, match, cpy, offset);
} else {
LZ4_wildCopy32(op, match, cpy);
}
op = cpy; /* wildcopy correction */
}
safe_decode:
#endif
/* Main Loop : decode remaining sequences where output < FASTLOOP_SAFE_DISTANCE */
DEBUGLOG(6 , "using safe decode loop" );
while (1 ) {
assert(ip < iend);
token = *ip++;
length = token >> ML_BITS; /* literal length */
DEBUGLOG(7 , "blockPos%6u: litLength token = %u" , (unsigned )(op-(BYTE*)dst), (unsigned )length);
/* A two-stage shortcut for the most common case:
* 1 ) If the literal length is 0 . . 14 , and there is enough space ,
* enter the shortcut and copy 16 bytes on behalf of the literals
* ( in the fast mode , only 8 bytes can be safely copied this way ) .
* 2 ) Further if the match length is 4 . . 18 , copy 18 bytes in a similar
* manner ; but we ensure that there ' s enough space in the output for
* those 18 bytes earlier , upon entering the shortcut ( in other words ,
* there is a combined check for both stages ) .
*/
if ( (length != RUN_MASK)
/* strictly "less than" on input, to re-enter the loop with at least one byte */
&& likely((ip < shortiend) & (op <= shortoend)) ) {
/* Copy the literals */
LZ4_memcpy(op, ip, 16 );
op += length; ip += length;
/* The second stage: prepare for match copying, decode full info.
* If it doesn't work out, the info won't be wasted. */
length = token & ML_MASK; /* match length */
DEBUGLOG(7 , "blockPos%6u: matchLength token = %u (len=%u)" , (unsigned )(op-(BYTE*)dst), (unsigned )length, (unsigned )length + 4 );
offset = LZ4_readLE16(ip); ip += 2 ;
match = op - offset;
assert(match <= op); /* check overflow */
/* Do not deal with overlapping matches. */
if ( (length != ML_MASK)
&& (offset >= 8 )
&& (dict==withPrefix64k || match >= lowPrefix) ) {
/* Copy the match. */
LZ4_memcpy(op + 0 , match + 0 , 8 );
LZ4_memcpy(op + 8 , match + 8 , 8 );
LZ4_memcpy(op +16 , match +16 , 2 );
op += length + MINMATCH;
/* Both stages worked, load the next token. */
continue ;
}
/* The second stage didn't work out, but the info is ready.
* Propel it right to the point of match copying. */
goto _copy_match;
}
/* decode literal length */
if (length == RUN_MASK) {
size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1 );
if (addl == rvl_error) { goto _output_error; }
length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */
if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
}
#if LZ4_FAST_DEC_LOOP
safe_literal_copy:
#endif
/* copy literals */
cpy = op+length;
LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2 +1 +LASTLITERALS))) {
/* We've either hit the input parsing restriction or the output parsing restriction.
* In the normal scenario , decoding a full block , it must be the last sequence ,
* otherwise it ' s an error ( invalid input or dimensions ) .
* In partialDecoding scenario , it ' s necessary to ensure there is no buffer overflow .
*/
if (partialDecoding) {
/* Since we are partial decoding we may be in this block because of the output parsing
* restriction , which is not valid since the output buffer is allowed to be undersized .
*/
DEBUGLOG(7 , "partialDecoding: copying literals, close to input or output end" )
DEBUGLOG(7 , "partialDecoding: literal length = %u" , (unsigned )length);
DEBUGLOG(7 , "partialDecoding: remaining space in dstBuffer : %i" , (int )(oend - op));
DEBUGLOG(7 , "partialDecoding: remaining space in srcBuffer : %i" , (int )(iend - ip));
/* Finishing in the middle of a literals segment,
* due to lack of input .
*/
if (ip+length > iend) {
length = (size_t)(iend-ip);
cpy = op + length;
}
/* Finishing in the middle of a literals segment,
* due to lack of output space .
*/
if (cpy > oend) {
cpy = oend;
assert(op<=oend);
length = (size_t)(oend-op);
}
} else {
/* We must be on the last sequence (or invalid) because of the parsing limitations
* so check that we exactly consume the input and don ' t overrun the output buffer .
*/
if ((ip+length != iend) || (cpy > oend)) {
DEBUGLOG(5 , "should have been last run of literals" )
DEBUGLOG(5 , "ip(%p) + length(%i) = %p != iend (%p)" , ip, (int )length, ip+length, iend);
DEBUGLOG(5 , "or cpy(%p) > (oend-MFLIMIT)(%p)" , cpy, oend-MFLIMIT);
DEBUGLOG(5 , "after writing %u bytes / %i bytes available" , (unsigned )(op-(BYTE*)dst), outputSize);
goto _output_error;
}
}
LZ4_memmove(op, ip, length); /* supports overlapping memory regions, for in-place decompression scenarios */
ip += length;
op += length;
/* Necessarily EOF when !partialDecoding.
* When partialDecoding , it is EOF if we ' ve either
* filled the output buffer or
* can ' t proceed with reading an offset for following match .
*/
if (!partialDecoding || (cpy == oend) || (ip >= (iend-2 ))) {
break ;
}
} else {
LZ4_wildCopy8(op, ip, cpy); /* can overwrite up to 8 bytes beyond cpy */
ip += length; op = cpy;
}
/* get offset */
offset = LZ4_readLE16(ip); ip+=2 ;
match = op - offset;
/* get matchlength */
length = token & ML_MASK;
DEBUGLOG(7 , "blockPos%6u: matchLength token = %u" , (unsigned )(op-(BYTE*)dst), (unsigned )length);
_copy_match:
if (length == ML_MASK) {
size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1 , 0 );
if (addl == rvl_error) { goto _output_error; }
length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)op)) goto _output_error; /* overflow detection */
}
length += MINMATCH;
#if LZ4_FAST_DEC_LOOP
safe_match_copy:
#endif
if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) goto _output_error; /* Error : offset outside buffers */
/* match starting within external dictionary */
if ((dict==usingExtDict) && (match < lowPrefix)) {
assert(dictEnd != NULL);
if (unlikely(op+length > oend-LASTLITERALS)) {
if (partialDecoding) length = MIN(length, (size_t)(oend-op));
else goto _output_error; /* doesn't respect parsing restriction */
}
if (length <= (size_t)(lowPrefix-match)) {
/* match fits entirely within external dictionary : just copy */
LZ4_memmove(op, dictEnd - (lowPrefix-match), length);
op += length;
} else {
/* match stretches into both external dictionary and current block */
size_t const copySize = (size_t)(lowPrefix - match);
size_t const restSize = length - copySize;
LZ4_memcpy(op, dictEnd - copySize, copySize);
op += copySize;
if (restSize > (size_t)(op - lowPrefix)) { /* overlap copy */
BYTE* const endOfMatch = op + restSize;
const BYTE* copyFrom = lowPrefix;
while (op < endOfMatch) *op++ = *copyFrom++;
} else {
LZ4_memcpy(op, lowPrefix, restSize);
op += restSize;
} }
continue ;
}
assert(match >= lowPrefix);
/* copy match within block */
cpy = op + length;
/* partialDecoding : may end anywhere within the block */
assert(op<=oend);
if (partialDecoding && (cpy > oend-MATCH_SAFEGUARD_DISTANCE)) {
size_t const mlen = MIN(length, (size_t)(oend-op));
const BYTE* const matchEnd = match + mlen;
BYTE* const copyEnd = op + mlen;
if (matchEnd > op) { /* overlap copy */
while (op < copyEnd) { *op++ = *match++; }
} else {
LZ4_memcpy(op, match, mlen);
}
op = copyEnd;
if (op == oend) { break ; }
continue ;
}
if (unlikely(offset<8 )) {
LZ4_write32(op, 0 ); /* silence msan warning when offset==0 */
op[0 ] = match[0 ];
op[1 ] = match[1 ];
op[2 ] = match[2 ];
op[3 ] = match[3 ];
match += inc32table[offset];
LZ4_memcpy(op+4 , match, 4 );
match -= dec64table[offset];
} else {
LZ4_memcpy(op, match, 8 );
match += 8 ;
}
op += 8 ;
if (unlikely(cpy > oend-MATCH_SAFEGUARD_DISTANCE)) {
BYTE* const oCopyLimit = oend - (WILDCOPYLENGTH-1 );
if (cpy > oend-LASTLITERALS) { goto _output_error; } /* Error : last LASTLITERALS bytes must be literals (uncompressed) */
if (op < oCopyLimit) {
LZ4_wildCopy8(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
while (op < cpy) { *op++ = *match++; }
} else {
LZ4_memcpy(op, match, 8 );
if (length > 16 ) { LZ4_wildCopy8(op+8 , match+8 , cpy); }
}
op = cpy; /* wildcopy correction */
}
/* end of decoding */
DEBUGLOG(5 , "decoded %i bytes" , (int ) (((char *)op)-dst));
return (int ) (((char *)op)-dst); /* Nb of output bytes decoded */
/* Overflow error detected */
_output_error:
return (int ) (-(((const char *)ip)-src))-1 ;
}
}
/*===== Instantiate the API decoding functions. =====*/
LZ4_FORCE_O2
int LZ4_decompress_safe(const char * source, char * dest, int compressedSize, int maxDecompressedSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize,
decode_full_block, noDict,
(BYTE*)dest, NULL, 0 );
}
LZ4_FORCE_O2
int LZ4_decompress_safe_partial(const char * src, char * dst, int compressedSize, int targetOutputSize, int dstCapacity)
{
dstCapacity = MIN(targetOutputSize, dstCapacity);
return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
partial_decode,
noDict, (BYTE*)dst, NULL, 0 );
}
LZ4_FORCE_O2
int LZ4_decompress_fast(const char * source, char * dest, int originalSize)
{
DEBUGLOG(5 , "LZ4_decompress_fast" );
return LZ4_decompress_unsafe_generic(
(const BYTE*)source, (BYTE*)dest, originalSize,
0 , NULL, 0 );
}
/*===== Instantiate a few more decoding cases, used more than once. =====*/
LZ4_FORCE_O2 /* Exported, an obsolete API function. */
int LZ4_decompress_safe_withPrefix64k(const char * source, char * dest, int compressedSize, int maxOutputSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
decode_full_block, withPrefix64k,
(BYTE*)dest - 64 KB, NULL, 0 );
}
LZ4_FORCE_O2
static int LZ4_decompress_safe_partial_withPrefix64k(const char * source, char * dest, int compressedSize, int targetOutputSize, int dstCapacity)
{
dstCapacity = MIN(targetOutputSize, dstCapacity);
return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity,
partial_decode, withPrefix64k,
(BYTE*)dest - 64 KB, NULL, 0 );
}
/* Another obsolete API function, paired with the previous one. */
int LZ4_decompress_fast_withPrefix64k(const char * source, char * dest, int originalSize)
{
return LZ4_decompress_unsafe_generic(
(const BYTE*)source, (BYTE*)dest, originalSize,
64 KB, NULL, 0 );
}
LZ4_FORCE_O2
static int LZ4_decompress_safe_withSmallPrefix(const char * source, char * dest, int compressedSize, int maxOutputSize,
size_t prefixSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
decode_full_block, noDict,
(BYTE*)dest-prefixSize, NULL, 0 );
}
LZ4_FORCE_O2
static int LZ4_decompress_safe_partial_withSmallPrefix(const char * source, char * dest, int compressedSize, int targetOutputSize, int dstCapacity,
size_t prefixSize)
{
dstCapacity = MIN(targetOutputSize, dstCapacity);
return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity,
partial_decode, noDict,
(BYTE*)dest-prefixSize, NULL, 0 );
}
LZ4_FORCE_O2
int LZ4_decompress_safe_forceExtDict(const char * source, char * dest,
int compressedSize, int maxOutputSize,
const void * dictStart, size_t dictSize)
{
DEBUGLOG(5 , "LZ4_decompress_safe_forceExtDict" );
return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
decode_full_block, usingExtDict,
(BYTE*)dest, (const BYTE*)dictStart, dictSize);
}
LZ4_FORCE_O2
int LZ4_decompress_safe_partial_forceExtDict(const char * source, char * dest,
int compressedSize, int targetOutputSize, int dstCapacity,
const void * dictStart, size_t dictSize)
{
dstCapacity = MIN(targetOutputSize, dstCapacity);
return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity,
partial_decode, usingExtDict,
(BYTE*)dest, (const BYTE*)dictStart, dictSize);
}
LZ4_FORCE_O2
static int LZ4_decompress_fast_extDict(const char * source, char * dest, int originalSize,
const void * dictStart, size_t dictSize)
{
return LZ4_decompress_unsafe_generic(
(const BYTE*)source, (BYTE*)dest, originalSize,
0 , (const BYTE*)dictStart, dictSize);
}
/* The "double dictionary" mode, for use with e.g. ring buffers: the first part
* of the dictionary is passed as prefix , and the second via dictStart + dictSize .
* These routines are used only once , in LZ4_decompress_ * _ continue ( ) .
*/
LZ4_FORCE_INLINE
int LZ4_decompress_safe_doubleDict(const char * source, char * dest, int compressedSize, int maxOutputSize,
size_t prefixSize, const void * dictStart, size_t dictSize)
{
return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
decode_full_block, usingExtDict,
(BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize);
}
/*===== streaming decompression functions =====*/
#if !defined (LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
LZ4_streamDecode_t* LZ4_createStreamDecode(void )
{
LZ4_STATIC_ASSERT(sizeof (LZ4_streamDecode_t) >= sizeof (LZ4_streamDecode_t_internal));
return (LZ4_streamDecode_t*) ALLOC_AND_ZERO(sizeof (LZ4_streamDecode_t));
}
int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
{
if (LZ4_stream == NULL) { return 0 ; } /* support free on NULL */
FREEMEM(LZ4_stream);
return 0 ;
}
#endif
/*! LZ4_setStreamDecode() :
* Use this function to instruct where to find the dictionary .
* This function is not necessary if previous data is still available where it was decoded .
* Loading a size of 0 is allowed ( same effect as no dictionary ) .
* @ return : 1 if OK , 0 if error
*/
int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char * dictionary, int dictSize)
{
LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
lz4sd->prefixSize = (size_t)dictSize;
if (dictSize) {
assert(dictionary != NULL);
lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
} else {
lz4sd->prefixEnd = (const BYTE*) dictionary;
}
lz4sd->externalDict = NULL;
lz4sd->extDictSize = 0 ;
return 1 ;
}
/*! LZ4_decoderRingBufferSize() :
* when setting a ring buffer for streaming decompression ( optional scenario ) ,
* provides the minimum size of this ring buffer
* to be compatible with any source respecting maxBlockSize condition .
* Note : in a ring buffer scenario ,
* blocks are presumed decompressed next to each other .
* When not enough space remains for next block ( remainingSize < maxBlockSize ) ,
* decoding resumes from beginning of ring buffer .
* @ return : minimum ring buffer size ,
* or 0 if there is an error ( invalid maxBlockSize ) .
*/
int LZ4_decoderRingBufferSize(int maxBlockSize)
{
if (maxBlockSize < 0 ) return 0 ;
if (maxBlockSize > LZ4_MAX_INPUT_SIZE) return 0 ;
if (maxBlockSize < 16 ) maxBlockSize = 16 ;
return LZ4_DECODER_RING_BUFFER_SIZE(maxBlockSize);
}
/*
* _ continue ( ) :
These decoding functions allow decompression of multiple blocks in " streaming " mode .
Previously decoded blocks must still be available at the memory position where they were decoded .
If it ' s not possible , save the relevant part of decoded data into a safe buffer ,
and indicate where it stands using LZ4_setStreamDecode ( )
*/
LZ4_FORCE_O2
int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char * source, char * dest, int compressedSize, int maxOutputSize)
{
LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
int result;
if (lz4sd->prefixSize == 0 ) {
/* The first call, no dictionary yet. */
assert(lz4sd->extDictSize == 0 );
result = LZ4_decompress_safe(source, dest, compressedSize, maxOutputSize);
if (result <= 0 ) return result;
lz4sd->prefixSize = (size_t)result;
lz4sd->prefixEnd = (BYTE*)dest + result;
} else if (lz4sd->prefixEnd == (BYTE*)dest) {
/* They're rolling the current segment. */
if (lz4sd->prefixSize >= 64 KB - 1 )
result = LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize);
else if (lz4sd->extDictSize == 0 )
result = LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize,
lz4sd->prefixSize);
else
result = LZ4_decompress_safe_doubleDict(source, dest, compressedSize, maxOutputSize,
lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0 ) return result;
lz4sd->prefixSize += (size_t)result;
lz4sd->prefixEnd += result;
} else {
/* The buffer wraps around, or they're switching to another buffer. */
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
result = LZ4_decompress_safe_forceExtDict(source, dest, compressedSize, maxOutputSize,
lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0 ) return result;
lz4sd->prefixSize = (size_t)result;
lz4sd->prefixEnd = (BYTE*)dest + result;
}
return result;
}
LZ4_FORCE_O2 int
LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode,
const char * source, char * dest, int originalSize)
{
LZ4_streamDecode_t_internal* const lz4sd =
(assert(LZ4_streamDecode!=NULL), &LZ4_streamDecode->internal_donotuse);
int result;
DEBUGLOG(5 , "LZ4_decompress_fast_continue (toDecodeSize=%i)" , originalSize);
assert(originalSize >= 0 );
if (lz4sd->prefixSize == 0 ) {
DEBUGLOG(5 , "first invocation : no prefix nor extDict" );
assert(lz4sd->extDictSize == 0 );
result = LZ4_decompress_fast(source, dest, originalSize);
if (result <= 0 ) return result;
lz4sd->prefixSize = (size_t)originalSize;
lz4sd->prefixEnd = (BYTE*)dest + originalSize;
} else if (lz4sd->prefixEnd == (BYTE*)dest) {
DEBUGLOG(5 , "continue using existing prefix" );
result = LZ4_decompress_unsafe_generic(
(const BYTE*)source, (BYTE*)dest, originalSize,
lz4sd->prefixSize,
lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0 ) return result;
lz4sd->prefixSize += (size_t)originalSize;
lz4sd->prefixEnd += originalSize;
} else {
DEBUGLOG(5 , "prefix becomes extDict" );
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
result = LZ4_decompress_fast_extDict(source, dest, originalSize,
lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0 ) return result;
lz4sd->prefixSize = (size_t)originalSize;
lz4sd->prefixEnd = (BYTE*)dest + originalSize;
}
return result;
}
/*
Advanced decoding functions :
* _ usingDict ( ) :
These decoding functions work the same as " _ continue " ones ,
the dictionary must be explicitly provided within parameters
*/
int LZ4_decompress_safe_usingDict(const char * source, char * dest, int compressedSize, int maxOutputSize, const char * dictStart, int dictSize)
{
if (dictSize==0 )
return LZ4_decompress_safe(source, dest, compressedSize, maxOutputSize);
if (dictStart+dictSize == dest) {
if (dictSize >= 64 KB - 1 ) {
return LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize);
}
assert(dictSize >= 0 );
return LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize, (size_t)dictSize);
}
assert(dictSize >= 0 );
return LZ4_decompress_safe_forceExtDict(source, dest, compressedSize, maxOutputSize, dictStart, (size_t)dictSize);
}
int LZ4_decompress_safe_partial_usingDict(const char * source, char * dest, int compressedSize, int targetOutputSize, int dstCapacity, const char * dictStart, int dictSize)
{
if (dictSize==0 )
return LZ4_decompress_safe_partial(source, dest, compressedSize, targetOutputSize, dstCapacity);
if (dictStart+dictSize == dest) {
if (dictSize >= 64 KB - 1 ) {
return LZ4_decompress_safe_partial_withPrefix64k(source, dest, compressedSize, targetOutputSize, dstCapacity);
}
assert(dictSize >= 0 );
return LZ4_decompress_safe_partial_withSmallPrefix(source, dest, compressedSize, targetOutputSize, dstCapacity, (size_t)dictSize);
}
assert(dictSize >= 0 );
return LZ4_decompress_safe_partial_forceExtDict(source, dest, compressedSize, targetOutputSize, dstCapacity, dictStart, (size_t)dictSize);
}
int LZ4_decompress_fast_usingDict(const char * source, char * dest, int originalSize, const char * dictStart, int dictSize)
{
if (dictSize==0 || dictStart+dictSize == dest)
return LZ4_decompress_unsafe_generic(
(const BYTE*)source, (BYTE*)dest, originalSize,
(size_t)dictSize, NULL, 0 );
assert(dictSize >= 0 );
return LZ4_decompress_fast_extDict(source, dest, originalSize, dictStart, (size_t)dictSize);
}
/*=*************************************************
* Obsolete Functions
***************************************************/
/* obsolete compression functions */
int LZ4_compress_limitedOutput(const char * source, char * dest, int inputSize, int maxOutputSize)
{
return LZ4_compress_default(source, dest, inputSize, maxOutputSize);
}
int LZ4_compress(const char * src, char * dest, int srcSize)
{
return LZ4_compress_default(src, dest, srcSize, LZ4_compressBound(srcSize));
}
int LZ4_compress_limitedOutput_withState (void * state, const char * src, char * dst, int srcSize, int dstSize)
{
return LZ4_compress_fast_extState(state, src, dst, srcSize, dstSize, 1 );
}
int LZ4_compress_withState (void * state, const char * src, char * dst, int srcSize)
{
return LZ4_compress_fast_extState(state, src, dst, srcSize, LZ4_compressBound(srcSize), 1 );
}
int LZ4_compress_limitedOutput_continue (LZ4_stream_t* LZ4_stream, const char * src, char * dst, int srcSize, int dstCapacity)
{
return LZ4_compress_fast_continue(LZ4_stream, src, dst, srcSize, dstCapacity, 1 );
}
int LZ4_compress_continue (LZ4_stream_t* LZ4_stream, const char * source, char * dest, int inputSize)
{
return LZ4_compress_fast_continue(LZ4_stream, source, dest, inputSize, LZ4_compressBound(inputSize), 1 );
}
/*
These decompression functions are deprecated and should no longer be used .
They are only provided here for compatibility with older user programs .
- LZ4_uncompress is totally equivalent to LZ4_decompress_fast
- LZ4_uncompress_unknownOutputSize is totally equivalent to LZ4_decompress_safe
*/
int LZ4_uncompress (const char * source, char * dest, int outputSize)
{
return LZ4_decompress_fast(source, dest, outputSize);
}
int LZ4_uncompress_unknownOutputSize (const char * source, char * dest, int isize, int maxOutputSize)
{
return LZ4_decompress_safe(source, dest, isize, maxOutputSize);
}
/* Obsolete Streaming functions */
int LZ4_sizeofStreamState(void ) { return sizeof (LZ4_stream_t); }
int LZ4_resetStreamState(void * state, char * inputBuffer)
{
(void )inputBuffer;
LZ4_resetStream((LZ4_stream_t*)state);
return 0 ;
}
#if !defined (LZ4_STATIC_LINKING_ONLY_DISABLE_MEMORY_ALLOCATION)
void * LZ4_create (char * inputBuffer)
{
(void )inputBuffer;
return LZ4_createStream();
}
#endif
char * LZ4_slideInputBuffer (void * state)
{
/* avoid const char * -> char * conversion warning */
return (char *)(uptrval)((LZ4_stream_t*)state)->internal_donotuse.dictionary;
}
#endif /* LZ4_COMMONDEFS_ONLY */
Messung V0.5 in Prozent C=89 H=93 G=90
¤ Dauer der Verarbeitung: 0.87 Sekunden
(vorverarbeitet am 2026-08-22)
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