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src.rivoreo.one / lz4 / 481a37fe472e88e276a90967984ce92abf0cff5e / . / lib / lz4frame.c
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/*
* LZ4 auto-framing library
* Copyright (C) 2011-2016, 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
*/
/* LZ4F is a stand-alone API to create LZ4-compressed Frames
* in full conformance with specification v1.6.1 .
* This library rely upon memory management capabilities (malloc, free)
* provided either by <stdlib.h>,
* or redirected towards another library of user's choice
* (see Memory Routines below).
*/
/*-************************************
* Compiler Options
**************************************/
#ifdef _MSC_VER /* Visual Studio */
# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
#endif
/*-************************************
* Tuning parameters
**************************************/
/*
* LZ4F_HEAPMODE :
* Select how default compression functions will allocate memory for their hash table,
* in memory stack (0:default, fastest), or in memory heap (1:requires malloc()).
*/
#ifndef LZ4F_HEAPMODE
# define LZ4F_HEAPMODE 0
#endif
/*-************************************
* Memory routines
**************************************/
/*
* User may redirect invocations of
* malloc(), calloc() and free()
* towards another library or solution of their choice
* by modifying below section.
*/
#include <stdlib.h> /* malloc, calloc, free */
#define ALLOC(s) malloc(s)
#ifndef LZ4_SRC_INCLUDED /* avoid redefinition when sources are coalesced */
# define ALLOC_AND_ZERO(s) calloc(1,(s))
#endif
#define FREEMEM(p) free(p)
#include <string.h> /* memset, memcpy, memmove */
#ifndef LZ4_SRC_INCLUDED /* avoid redefinition when sources are coalesced */
# define MEM_INIT memset
#endif
/*-************************************
* Library declarations
**************************************/
#define LZ4F_STATIC_LINKING_ONLY
#include "lz4frame.h"
#define LZ4_STATIC_LINKING_ONLY
#include "lz4.h"
#define LZ4_HC_STATIC_LINKING_ONLY
#include "lz4hc.h"
#define XXH_STATIC_LINKING_ONLY
#include "xxhash.h"
/*-************************************
* Debug
**************************************/
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=1)
# include <assert.h>
#else
# ifndef assert
# define assert(condition) ((void)0)
# endif
#endif
#define LZ4F_STATIC_ASSERT(c) { enum { LZ4F_static_assert = 1/(int)(!!(c)) }; } /* use only *after* variable declarations */
#if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2) && !defined(DEBUGLOG)
# include <stdio.h>
static int g_debuglog_enable = 1;
# define DEBUGLOG(l, ...) { \
if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) { \
fprintf(stderr, __FILE__ ": "); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, " \n"); \
} }
#else
# define DEBUGLOG(l, ...) {} /* disabled */
#endif
/*-************************************
* Basic Types
**************************************/
#if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
# include <stdint.h>
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef int32_t S32;
typedef uint64_t U64;
#else
typedef unsigned char BYTE;
typedef unsigned short U16;
typedef unsigned int U32;
typedef signed int S32;
typedef unsigned long long U64;
#endif
/* unoptimized version; solves endianess & alignment issues */
static U32 LZ4F_readLE32 (const void* src)
{
const BYTE* const srcPtr = (const BYTE*)src;
U32 value32 = srcPtr[0];
value32 += ((U32)srcPtr[1])<< 8;
value32 += ((U32)srcPtr[2])<<16;
value32 += ((U32)srcPtr[3])<<24;
return value32;
}
static void LZ4F_writeLE32 (void* dst, U32 value32)
{
BYTE* const dstPtr = (BYTE*)dst;
dstPtr[0] = (BYTE)value32;
dstPtr[1] = (BYTE)(value32 >> 8);
dstPtr[2] = (BYTE)(value32 >> 16);
dstPtr[3] = (BYTE)(value32 >> 24);
}
static U64 LZ4F_readLE64 (const void* src)
{
const BYTE* const srcPtr = (const BYTE*)src;
U64 value64 = srcPtr[0];
value64 += ((U64)srcPtr[1]<<8);
value64 += ((U64)srcPtr[2]<<16);
value64 += ((U64)srcPtr[3]<<24);
value64 += ((U64)srcPtr[4]<<32);
value64 += ((U64)srcPtr[5]<<40);
value64 += ((U64)srcPtr[6]<<48);
value64 += ((U64)srcPtr[7]<<56);
return value64;
}
static void LZ4F_writeLE64 (void* dst, U64 value64)
{
BYTE* const dstPtr = (BYTE*)dst;
dstPtr[0] = (BYTE)value64;
dstPtr[1] = (BYTE)(value64 >> 8);
dstPtr[2] = (BYTE)(value64 >> 16);
dstPtr[3] = (BYTE)(value64 >> 24);
dstPtr[4] = (BYTE)(value64 >> 32);
dstPtr[5] = (BYTE)(value64 >> 40);
dstPtr[6] = (BYTE)(value64 >> 48);
dstPtr[7] = (BYTE)(value64 >> 56);
}
/*-************************************
* Constants
**************************************/
#ifndef LZ4_SRC_INCLUDED /* avoid double definition */
# define KB *(1<<10)
# define MB *(1<<20)
# define GB *(1<<30)
#endif
#define _1BIT 0x01
#define _2BITS 0x03
#define _3BITS 0x07
#define _4BITS 0x0F
#define _8BITS 0xFF
#define LZ4F_MAGIC_SKIPPABLE_START 0x184D2A50U
#define LZ4F_MAGICNUMBER 0x184D2204U
#define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U
#define LZ4F_BLOCKSIZEID_DEFAULT LZ4F_max64KB
static const size_t minFHSize = LZ4F_HEADER_SIZE_MIN; /* 7 */
static const size_t maxFHSize = LZ4F_HEADER_SIZE_MAX; /* 19 */
static const size_t BHSize = 4; /* block header : size, and compress flag */
static const size_t BFSize = 4; /* block footer : checksum (optional) */
/*-************************************
* Structures and local types
**************************************/
typedef struct LZ4F_cctx_s
{
LZ4F_preferences_t prefs;
U32 version;
U32 cStage;
const LZ4F_CDict* cdict;
size_t maxBlockSize;
size_t maxBufferSize;
BYTE* tmpBuff;
BYTE* tmpIn;
size_t tmpInSize;
U64 totalInSize;
XXH32_state_t xxh;
void* lz4CtxPtr;
U16 lz4CtxAlloc; /* sized for: 0 = none, 1 = lz4 ctx, 2 = lz4hc ctx */
U16 lz4CtxState; /* in use as: 0 = none, 1 = lz4 ctx, 2 = lz4hc ctx */
} LZ4F_cctx_t;
/*-************************************
* Error management
**************************************/
#define LZ4F_GENERATE_STRING(STRING) #STRING,
static const char* LZ4F_errorStrings[] = { LZ4F_LIST_ERRORS(LZ4F_GENERATE_STRING) };
unsigned LZ4F_isError(LZ4F_errorCode_t code)
{
return (code > (LZ4F_errorCode_t)(-LZ4F_ERROR_maxCode));
}
const char* LZ4F_getErrorName(LZ4F_errorCode_t code)
{
static const char* codeError = "Unspecified error code";
if (LZ4F_isError(code)) return LZ4F_errorStrings[-(int)(code)];
return codeError;
}
LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult)
{
if (!LZ4F_isError(functionResult)) return LZ4F_OK_NoError;
return (LZ4F_errorCodes)(-(ptrdiff_t)functionResult);
}
static LZ4F_errorCode_t err0r(LZ4F_errorCodes code)
{
/* A compilation error here means sizeof(ptrdiff_t) is not large enough */
LZ4F_STATIC_ASSERT(sizeof(ptrdiff_t) >= sizeof(size_t));
return (LZ4F_errorCode_t)-(ptrdiff_t)code;
}
unsigned LZ4F_getVersion(void) { return LZ4F_VERSION; }
int LZ4F_compressionLevel_max(void) { return LZ4HC_CLEVEL_MAX; }
size_t LZ4F_getBlockSize(unsigned blockSizeID)
{
static const size_t blockSizes[4] = { 64 KB, 256 KB, 1 MB, 4 MB };
if (blockSizeID == 0) blockSizeID = LZ4F_BLOCKSIZEID_DEFAULT;
if (blockSizeID < LZ4F_max64KB || blockSizeID > LZ4F_max4MB)
return err0r(LZ4F_ERROR_maxBlockSize_invalid);
blockSizeID -= LZ4F_max64KB;
return blockSizes[blockSizeID];
}
/*-************************************
* Private functions
**************************************/
#define MIN(a,b) ( (a) < (b) ? (a) : (b) )
static BYTE LZ4F_headerChecksum (const void* header, size_t length)
{
U32 const xxh = XXH32(header, length, 0);
return (BYTE)(xxh >> 8);
}
/*-************************************
* Simple-pass compression functions
**************************************/
static LZ4F_blockSizeID_t LZ4F_optimalBSID(const LZ4F_blockSizeID_t requestedBSID,
const size_t srcSize)
{
LZ4F_blockSizeID_t proposedBSID = LZ4F_max64KB;
size_t maxBlockSize = 64 KB;
while (requestedBSID > proposedBSID) {
if (srcSize <= maxBlockSize)
return proposedBSID;
proposedBSID = (LZ4F_blockSizeID_t)((int)proposedBSID + 1);
maxBlockSize <<= 2;
}
return requestedBSID;
}
/*! LZ4F_compressBound_internal() :
* Provides dstCapacity given a srcSize to guarantee operation success in worst case situations.
* prefsPtr is optional : if NULL is provided, preferences will be set to cover worst case scenario.
* @return is always the same for a srcSize and prefsPtr, so it can be relied upon to size reusable buffers.
* When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations.
*/
static size_t LZ4F_compressBound_internal(size_t srcSize,
const LZ4F_preferences_t* preferencesPtr,
size_t alreadyBuffered)
{
LZ4F_preferences_t prefsNull;
MEM_INIT(&prefsNull, 0, sizeof(prefsNull));
prefsNull.frameInfo.contentChecksumFlag = LZ4F_contentChecksumEnabled; /* worst case */
{ const LZ4F_preferences_t* const prefsPtr = (preferencesPtr==NULL) ? &prefsNull : preferencesPtr;
U32 const flush = prefsPtr->autoFlush | (srcSize==0);
LZ4F_blockSizeID_t const blockID = prefsPtr->frameInfo.blockSizeID;
size_t const blockSize = LZ4F_getBlockSize(blockID);
size_t const maxBuffered = blockSize - 1;
size_t const bufferedSize = MIN(alreadyBuffered, maxBuffered);
size_t const maxSrcSize = srcSize + bufferedSize;
unsigned const nbFullBlocks = (unsigned)(maxSrcSize / blockSize);
size_t const partialBlockSize = maxSrcSize & (blockSize-1);
size_t const lastBlockSize = flush ? partialBlockSize : 0;
unsigned const nbBlocks = nbFullBlocks + (lastBlockSize>0);
size_t const blockCRCSize = BFSize * prefsPtr->frameInfo.blockChecksumFlag;
size_t const frameEnd = BHSize + (prefsPtr->frameInfo.contentChecksumFlag*BFSize);
return ((BHSize + blockCRCSize) * nbBlocks) +
(blockSize * nbFullBlocks) + lastBlockSize + frameEnd;
}
}
size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefs;
size_t const headerSize = maxFHSize; /* max header size, including optional fields */
if (preferencesPtr!=NULL) prefs = *preferencesPtr;
else MEM_INIT(&prefs, 0, sizeof(prefs));
prefs.autoFlush = 1;
return headerSize + LZ4F_compressBound_internal(srcSize, &prefs, 0);;
}
/*! LZ4F_compressFrame_usingCDict() :
* Compress srcBuffer using a dictionary, in a single step.
* cdict can be NULL, in which case, no dictionary is used.
* dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
* The LZ4F_preferences_t structure is optional : you may provide NULL as argument,
* however, it's the only way to provide a dictID, so it's not recommended.
* @return : number of bytes written into dstBuffer,
* or an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressFrame_usingCDict(LZ4F_cctx* cctx,
void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_CDict* cdict,
const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefs;
LZ4F_compressOptions_t options;
BYTE* const dstStart = (BYTE*) dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* const dstEnd = dstStart + dstCapacity;
if (preferencesPtr!=NULL)
prefs = *preferencesPtr;
else
MEM_INIT(&prefs, 0, sizeof(prefs));
if (prefs.frameInfo.contentSize != 0)
prefs.frameInfo.contentSize = (U64)srcSize; /* auto-correct content size if selected (!=0) */
prefs.frameInfo.blockSizeID = LZ4F_optimalBSID(prefs.frameInfo.blockSizeID, srcSize);
prefs.autoFlush = 1;
if (srcSize <= LZ4F_getBlockSize(prefs.frameInfo.blockSizeID))
prefs.frameInfo.blockMode = LZ4F_blockIndependent; /* only one block => no need for inter-block link */
MEM_INIT(&options, 0, sizeof(options));
options.stableSrc = 1;
if (dstCapacity < LZ4F_compressFrameBound(srcSize, &prefs)) /* condition to guarantee success */
return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
{ size_t const headerSize = LZ4F_compressBegin_usingCDict(cctx, dstBuffer, dstCapacity, cdict, &prefs); /* write header */
if (LZ4F_isError(headerSize)) return headerSize;
dstPtr += headerSize; /* header size */ }
assert(dstEnd >= dstPtr);
{ size_t const cSize = LZ4F_compressUpdate(cctx, dstPtr, (size_t)(dstEnd-dstPtr), srcBuffer, srcSize, &options);
if (LZ4F_isError(cSize)) return cSize;
dstPtr += cSize; }
assert(dstEnd >= dstPtr);
{ size_t const tailSize = LZ4F_compressEnd(cctx, dstPtr, (size_t)(dstEnd-dstPtr), &options); /* flush last block, and generate suffix */
if (LZ4F_isError(tailSize)) return tailSize;
dstPtr += tailSize; }
assert(dstEnd >= dstStart);
return (size_t)(dstPtr - dstStart);
}
/*! LZ4F_compressFrame() :
* Compress an entire srcBuffer into a valid LZ4 frame, in a single step.
* dstBuffer MUST be >= LZ4F_compressFrameBound(srcSize, preferencesPtr).
* The LZ4F_preferences_t structure is optional : you can provide NULL as argument. All preferences will be set to default.
* @return : number of bytes written into dstBuffer.
* or an error code if it fails (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressFrame(void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_preferences_t* preferencesPtr)
{
size_t result;
#if (LZ4F_HEAPMODE)
LZ4F_cctx_t *cctxPtr;
result = LZ4F_createCompressionContext(&cctxPtr, LZ4F_VERSION);
if (LZ4F_isError(result)) return result;
#else
LZ4F_cctx_t cctx;
LZ4_stream_t lz4ctx;
LZ4F_cctx_t *cctxPtr = &cctx;
DEBUGLOG(4, "LZ4F_compressFrame");
MEM_INIT(&cctx, 0, sizeof(cctx));
cctx.version = LZ4F_VERSION;
cctx.maxBufferSize = 5 MB; /* mess with real buffer size to prevent dynamic allocation; works only because autoflush==1 & stableSrc==1 */
if (preferencesPtr == NULL ||
preferencesPtr->compressionLevel < LZ4HC_CLEVEL_MIN)
{
LZ4_initStream(&lz4ctx, sizeof(lz4ctx));
cctxPtr->lz4CtxPtr = &lz4ctx;
cctxPtr->lz4CtxAlloc = 1;
cctxPtr->lz4CtxState = 1;
}
#endif
result = LZ4F_compressFrame_usingCDict(cctxPtr, dstBuffer, dstCapacity,
srcBuffer, srcSize,
NULL, preferencesPtr);
#if (LZ4F_HEAPMODE)
LZ4F_freeCompressionContext(cctxPtr);
#else
if (preferencesPtr != NULL &&
preferencesPtr->compressionLevel >= LZ4HC_CLEVEL_MIN)
{
FREEMEM(cctxPtr->lz4CtxPtr);
}
#endif
return result;
}
/*-***************************************************
* Dictionary compression
*****************************************************/
struct LZ4F_CDict_s {
void* dictContent;
LZ4_stream_t* fastCtx;
LZ4_streamHC_t* HCCtx;
}; /* typedef'd to LZ4F_CDict within lz4frame_static.h */
/*! LZ4F_createCDict() :
* When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
* LZ4F_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
* LZ4F_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
* `dictBuffer` can be released after LZ4F_CDict creation, since its content is copied within CDict
* @return : digested dictionary for compression, or NULL if failed */
LZ4F_CDict* LZ4F_createCDict(const void* dictBuffer, size_t dictSize)
{
const char* dictStart = (const char*)dictBuffer;
LZ4F_CDict* cdict = (LZ4F_CDict*) ALLOC(sizeof(*cdict));
DEBUGLOG(4, "LZ4F_createCDict");
if (!cdict) return NULL;
if (dictSize > 64 KB) {
dictStart += dictSize - 64 KB;
dictSize = 64 KB;
}
cdict->dictContent = ALLOC(dictSize);
cdict->fastCtx = LZ4_createStream();
cdict->HCCtx = LZ4_createStreamHC();
if (!cdict->dictContent || !cdict->fastCtx || !cdict->HCCtx) {
LZ4F_freeCDict(cdict);
return NULL;
}
memcpy(cdict->dictContent, dictStart, dictSize);
LZ4_loadDict (cdict->fastCtx, (const char*)cdict->dictContent, (int)dictSize);
LZ4_setCompressionLevel(cdict->HCCtx, LZ4HC_CLEVEL_DEFAULT);
LZ4_loadDictHC(cdict->HCCtx, (const char*)cdict->dictContent, (int)dictSize);
return cdict;
}
void LZ4F_freeCDict(LZ4F_CDict* cdict)
{
if (cdict==NULL) return; /* support free on NULL */
FREEMEM(cdict->dictContent);
LZ4_freeStream(cdict->fastCtx);
LZ4_freeStreamHC(cdict->HCCtx);
FREEMEM(cdict);
}
/*-*********************************
* Advanced compression functions
***********************************/
/*! LZ4F_createCompressionContext() :
* The first thing to do is to create a compressionContext object, which will be used in all compression operations.
* This is achieved using LZ4F_createCompressionContext(), which takes as argument a version and an LZ4F_preferences_t structure.
* The version provided MUST be LZ4F_VERSION. It is intended to track potential incompatible differences between different binaries.
* The function will provide a pointer to an allocated LZ4F_compressionContext_t object.
* If the result LZ4F_errorCode_t is not OK_NoError, there was an error during context creation.
* Object can release its memory using LZ4F_freeCompressionContext();
*/
LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_compressionContext_t* LZ4F_compressionContextPtr, unsigned version)
{
LZ4F_cctx_t* const cctxPtr = (LZ4F_cctx_t*)ALLOC_AND_ZERO(sizeof(LZ4F_cctx_t));
if (cctxPtr==NULL) return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->version = version;
cctxPtr->cStage = 0; /* Next stage : init stream */
*LZ4F_compressionContextPtr = (LZ4F_compressionContext_t)cctxPtr;
return LZ4F_OK_NoError;
}
LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_compressionContext_t LZ4F_compressionContext)
{
LZ4F_cctx_t* const cctxPtr = (LZ4F_cctx_t*)LZ4F_compressionContext;
if (cctxPtr != NULL) { /* support free on NULL */
FREEMEM(cctxPtr->lz4CtxPtr); /* works because LZ4_streamHC_t and LZ4_stream_t are simple POD types */
FREEMEM(cctxPtr->tmpBuff);
FREEMEM(LZ4F_compressionContext);
}
return LZ4F_OK_NoError;
}
/**
* This function prepares the internal LZ4(HC) stream for a new compression,
* resetting the context and attaching the dictionary, if there is one.
*
* It needs to be called at the beginning of each independent compression
* stream (i.e., at the beginning of a frame in blockLinked mode, or at the
* beginning of each block in blockIndependent mode).
*/
static void LZ4F_initStream(void* ctx,
const LZ4F_CDict* cdict,
int level,
LZ4F_blockMode_t blockMode) {
if (level < LZ4HC_CLEVEL_MIN) {
if (cdict != NULL || blockMode == LZ4F_blockLinked) {
/* In these cases, we will call LZ4_compress_fast_continue(),
* which needs an already reset context. Otherwise, we'll call a
* one-shot API. The non-continued APIs internally perform their own
* resets at the beginning of their calls, where they know what
* tableType they need the context to be in. So in that case this
* would be misguided / wasted work. */
LZ4_resetStream_fast((LZ4_stream_t*)ctx);
}
LZ4_attach_dictionary((LZ4_stream_t *)ctx, cdict ? cdict->fastCtx : NULL);
} else {
LZ4_resetStreamHC_fast((LZ4_streamHC_t*)ctx, level);
LZ4_attach_HC_dictionary((LZ4_streamHC_t *)ctx, cdict ? cdict->HCCtx : NULL);
}
}
/*! LZ4F_compressBegin_usingCDict() :
* init streaming compression and writes frame header into dstBuffer.
* dstBuffer must be >= LZ4F_HEADER_SIZE_MAX bytes.
* @return : number of bytes written into dstBuffer for the header
* or an error code (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressBegin_usingCDict(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const LZ4F_CDict* cdict,
const LZ4F_preferences_t* preferencesPtr)
{
LZ4F_preferences_t prefNull;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
BYTE* headerStart;
if (dstCapacity < maxFHSize) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
MEM_INIT(&prefNull, 0, sizeof(prefNull));
if (preferencesPtr == NULL) preferencesPtr = &prefNull;
cctxPtr->prefs = *preferencesPtr;
/* Ctx Management */
{ U16 const ctxTypeID = (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) ? 1 : 2;
if (cctxPtr->lz4CtxAlloc < ctxTypeID) {
FREEMEM(cctxPtr->lz4CtxPtr);
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) {
cctxPtr->lz4CtxPtr = LZ4_createStream();
} else {
cctxPtr->lz4CtxPtr = LZ4_createStreamHC();
}
if (cctxPtr->lz4CtxPtr == NULL)
return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->lz4CtxAlloc = ctxTypeID;
cctxPtr->lz4CtxState = ctxTypeID;
} else if (cctxPtr->lz4CtxState != ctxTypeID) {
/* otherwise, a sufficient buffer is allocated, but we need to
* reset it to the correct context type */
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN) {
LZ4_initStream((LZ4_stream_t *) cctxPtr->lz4CtxPtr, sizeof (LZ4_stream_t));
} else {
LZ4_initStreamHC((LZ4_streamHC_t *) cctxPtr->lz4CtxPtr, sizeof(LZ4_streamHC_t));
LZ4_setCompressionLevel((LZ4_streamHC_t *) cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel);
}
cctxPtr->lz4CtxState = ctxTypeID;
}
}
/* Buffer Management */
if (cctxPtr->prefs.frameInfo.blockSizeID == 0)
cctxPtr->prefs.frameInfo.blockSizeID = LZ4F_BLOCKSIZEID_DEFAULT;
cctxPtr->maxBlockSize = LZ4F_getBlockSize(cctxPtr->prefs.frameInfo.blockSizeID);
{ size_t const requiredBuffSize = preferencesPtr->autoFlush ?
((cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) ? 64 KB : 0) : /* only needs past data up to window size */
cctxPtr->maxBlockSize + ((cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) ? 128 KB : 0);
if (cctxPtr->maxBufferSize < requiredBuffSize) {
cctxPtr->maxBufferSize = 0;
FREEMEM(cctxPtr->tmpBuff);
cctxPtr->tmpBuff = (BYTE*)ALLOC_AND_ZERO(requiredBuffSize);
if (cctxPtr->tmpBuff == NULL) return err0r(LZ4F_ERROR_allocation_failed);
cctxPtr->maxBufferSize = requiredBuffSize;
} }
cctxPtr->tmpIn = cctxPtr->tmpBuff;
cctxPtr->tmpInSize = 0;
(void)XXH32_reset(&(cctxPtr->xxh), 0);
/* context init */
cctxPtr->cdict = cdict;
if (cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked) {
/* frame init only for blockLinked : blockIndependent will be init at each block */
LZ4F_initStream(cctxPtr->lz4CtxPtr, cdict, cctxPtr->prefs.compressionLevel, LZ4F_blockLinked);
}
if (preferencesPtr->compressionLevel >= LZ4HC_CLEVEL_MIN) {
LZ4_favorDecompressionSpeed((LZ4_streamHC_t*)cctxPtr->lz4CtxPtr, (int)preferencesPtr->favorDecSpeed);
}
/* Magic Number */
LZ4F_writeLE32(dstPtr, LZ4F_MAGICNUMBER);
dstPtr += 4;
headerStart = dstPtr;
/* FLG Byte */
*dstPtr++ = (BYTE)(((1 & _2BITS) << 6) /* Version('01') */
+ ((cctxPtr->prefs.frameInfo.blockMode & _1BIT ) << 5)
+ ((cctxPtr->prefs.frameInfo.blockChecksumFlag & _1BIT ) << 4)
+ ((unsigned)(cctxPtr->prefs.frameInfo.contentSize > 0) << 3)
+ ((cctxPtr->prefs.frameInfo.contentChecksumFlag & _1BIT ) << 2)
+ (cctxPtr->prefs.frameInfo.dictID > 0) );
/* BD Byte */
*dstPtr++ = (BYTE)((cctxPtr->prefs.frameInfo.blockSizeID & _3BITS) << 4);
/* Optional Frame content size field */
if (cctxPtr->prefs.frameInfo.contentSize) {
LZ4F_writeLE64(dstPtr, cctxPtr->prefs.frameInfo.contentSize);
dstPtr += 8;
cctxPtr->totalInSize = 0;
}
/* Optional dictionary ID field */
if (cctxPtr->prefs.frameInfo.dictID) {
LZ4F_writeLE32(dstPtr, cctxPtr->prefs.frameInfo.dictID);
dstPtr += 4;
}
/* Header CRC Byte */
*dstPtr = LZ4F_headerChecksum(headerStart, (size_t)(dstPtr - headerStart));
dstPtr++;
cctxPtr->cStage = 1; /* header written, now request input data block */
return (size_t)(dstPtr - dstStart);
}
/*! LZ4F_compressBegin() :
* init streaming compression and writes frame header into dstBuffer.
* dstBuffer must be >= LZ4F_HEADER_SIZE_MAX bytes.
* preferencesPtr can be NULL, in which case default parameters are selected.
* @return : number of bytes written into dstBuffer for the header
* or an error code (can be tested using LZ4F_isError())
*/
size_t LZ4F_compressBegin(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const LZ4F_preferences_t* preferencesPtr)
{
return LZ4F_compressBegin_usingCDict(cctxPtr, dstBuffer, dstCapacity,
NULL, preferencesPtr);
}
/* LZ4F_compressBound() :
* @return minimum capacity of dstBuffer for a given srcSize to handle worst case scenario.
* LZ4F_preferences_t structure is optional : if NULL, preferences will be set to cover worst case scenario.
* This function cannot fail.
*/
size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr)
{
return LZ4F_compressBound_internal(srcSize, preferencesPtr, (size_t)-1);
}
typedef int (*compressFunc_t)(void* ctx, const char* src, char* dst, int srcSize, int dstSize, int level, const LZ4F_CDict* cdict);
/*! LZ4F_makeBlock():
* compress a single block, add header and optional checksum.
* assumption : dst buffer capacity is >= BHSize + srcSize + crcSize
*/
static size_t LZ4F_makeBlock(void* dst,
const void* src, size_t srcSize,
compressFunc_t compress, void* lz4ctx, int level,
const LZ4F_CDict* cdict,
LZ4F_blockChecksum_t crcFlag)
{
BYTE* const cSizePtr = (BYTE*)dst;
U32 cSize = (U32)compress(lz4ctx, (const char*)src, (char*)(cSizePtr+BHSize),
(int)(srcSize), (int)(srcSize-1),
level, cdict);
if (cSize == 0) { /* compression failed */
cSize = (U32)srcSize;
LZ4F_writeLE32(cSizePtr, cSize | LZ4F_BLOCKUNCOMPRESSED_FLAG);
memcpy(cSizePtr+BHSize, src, srcSize);
} else {
LZ4F_writeLE32(cSizePtr, cSize);
}
if (crcFlag) {
U32 const crc32 = XXH32(cSizePtr+BHSize, cSize, 0); /* checksum of compressed data */
LZ4F_writeLE32(cSizePtr+BHSize+cSize, crc32);
}
return BHSize + cSize + ((U32)crcFlag)*BFSize;
}
static int LZ4F_compressBlock(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
int const acceleration = (level < 0) ? -level + 1 : 1;
LZ4F_initStream(ctx, cdict, level, LZ4F_blockIndependent);
if (cdict) {
return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
} else {
return LZ4_compress_fast_extState_fastReset(ctx, src, dst, srcSize, dstCapacity, acceleration);
}
}
static int LZ4F_compressBlock_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
int const acceleration = (level < 0) ? -level + 1 : 1;
(void)cdict; /* init once at beginning of frame */
return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
}
static int LZ4F_compressBlockHC(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
LZ4F_initStream(ctx, cdict, level, LZ4F_blockIndependent);
if (cdict) {
return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity);
}
return LZ4_compress_HC_extStateHC_fastReset(ctx, src, dst, srcSize, dstCapacity, level);
}
static int LZ4F_compressBlockHC_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
{
(void)level; (void)cdict; /* init once at beginning of frame */
return LZ4_compress_HC_continue((LZ4_streamHC_t*)ctx, src, dst, srcSize, dstCapacity);
}
static compressFunc_t LZ4F_selectCompression(LZ4F_blockMode_t blockMode, int level)
{
if (level < LZ4HC_CLEVEL_MIN) {
if (blockMode == LZ4F_blockIndependent) return LZ4F_compressBlock;
return LZ4F_compressBlock_continue;
}
if (blockMode == LZ4F_blockIndependent) return LZ4F_compressBlockHC;
return LZ4F_compressBlockHC_continue;
}
static int LZ4F_localSaveDict(LZ4F_cctx_t* cctxPtr)
{
if (cctxPtr->prefs.compressionLevel < LZ4HC_CLEVEL_MIN)
return LZ4_saveDict ((LZ4_stream_t*)(cctxPtr->lz4CtxPtr), (char*)(cctxPtr->tmpBuff), 64 KB);
return LZ4_saveDictHC ((LZ4_streamHC_t*)(cctxPtr->lz4CtxPtr), (char*)(cctxPtr->tmpBuff), 64 KB);
}
typedef enum { notDone, fromTmpBuffer, fromSrcBuffer } LZ4F_lastBlockStatus;
/*! LZ4F_compressUpdate() :
* LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary.
* dstBuffer MUST be >= LZ4F_compressBound(srcSize, preferencesPtr).
* LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
* @return : the number of bytes written into dstBuffer. It can be zero, meaning input data was just buffered.
* or an error code if it fails (which can be tested using LZ4F_isError())
*/
size_t LZ4F_compressUpdate(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const void* srcBuffer, size_t srcSize,
const LZ4F_compressOptions_t* compressOptionsPtr)
{
LZ4F_compressOptions_t cOptionsNull;
size_t const blockSize = cctxPtr->maxBlockSize;
const BYTE* srcPtr = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcPtr + srcSize;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
LZ4F_lastBlockStatus lastBlockCompressed = notDone;
compressFunc_t const compress = LZ4F_selectCompression(cctxPtr->prefs.frameInfo.blockMode, cctxPtr->prefs.compressionLevel);
DEBUGLOG(4, "LZ4F_compressUpdate (srcSize=%zu)", srcSize);
if (cctxPtr->cStage != 1) return err0r(LZ4F_ERROR_GENERIC);
if (dstCapacity < LZ4F_compressBound_internal(srcSize, &(cctxPtr->prefs), cctxPtr->tmpInSize))
return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
MEM_INIT(&cOptionsNull, 0, sizeof(cOptionsNull));
if (compressOptionsPtr == NULL) compressOptionsPtr = &cOptionsNull;
/* complete tmp buffer */
if (cctxPtr->tmpInSize > 0) { /* some data already within tmp buffer */
size_t const sizeToCopy = blockSize - cctxPtr->tmpInSize;
if (sizeToCopy > srcSize) {
/* add src to tmpIn buffer */
memcpy(cctxPtr->tmpIn + cctxPtr->tmpInSize, srcBuffer, srcSize);
srcPtr = srcEnd;
cctxPtr->tmpInSize += srcSize;
/* still needs some CRC */
} else {
/* complete tmpIn block and then compress it */
lastBlockCompressed = fromTmpBuffer;
memcpy(cctxPtr->tmpIn + cctxPtr->tmpInSize, srcBuffer, sizeToCopy);
srcPtr += sizeToCopy;
dstPtr += LZ4F_makeBlock(dstPtr,
cctxPtr->tmpIn, blockSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict,
cctxPtr->prefs.frameInfo.blockChecksumFlag);
if (cctxPtr->prefs.frameInfo.blockMode==LZ4F_blockLinked) cctxPtr->tmpIn += blockSize;
cctxPtr->tmpInSize = 0;
}
}
while ((size_t)(srcEnd - srcPtr) >= blockSize) {
/* compress full blocks */
lastBlockCompressed = fromSrcBuffer;
dstPtr += LZ4F_makeBlock(dstPtr,
srcPtr, blockSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict,
cctxPtr->prefs.frameInfo.blockChecksumFlag);
srcPtr += blockSize;
}
if ((cctxPtr->prefs.autoFlush) && (srcPtr < srcEnd)) {
/* compress remaining input < blockSize */
lastBlockCompressed = fromSrcBuffer;
dstPtr += LZ4F_makeBlock(dstPtr,
srcPtr, (size_t)(srcEnd - srcPtr),
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict,
cctxPtr->prefs.frameInfo.blockChecksumFlag);
srcPtr = srcEnd;
}
/* preserve dictionary if necessary */
if ((cctxPtr->prefs.frameInfo.blockMode==LZ4F_blockLinked) && (lastBlockCompressed==fromSrcBuffer)) {
if (compressOptionsPtr->stableSrc) {
cctxPtr->tmpIn = cctxPtr->tmpBuff;
} else {
int const realDictSize = LZ4F_localSaveDict(cctxPtr);
if (realDictSize==0) return err0r(LZ4F_ERROR_GENERIC);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
}
/* keep tmpIn within limits */
if ((cctxPtr->tmpIn + blockSize) > (cctxPtr->tmpBuff + cctxPtr->maxBufferSize) /* necessarily LZ4F_blockLinked && lastBlockCompressed==fromTmpBuffer */
&& !(cctxPtr->prefs.autoFlush))
{
int const realDictSize = LZ4F_localSaveDict(cctxPtr);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
/* some input data left, necessarily < blockSize */
if (srcPtr < srcEnd) {
/* fill tmp buffer */
size_t const sizeToCopy = (size_t)(srcEnd - srcPtr);
memcpy(cctxPtr->tmpIn, srcPtr, sizeToCopy);
cctxPtr->tmpInSize = sizeToCopy;
}
if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled)
(void)XXH32_update(&(cctxPtr->xxh), srcBuffer, srcSize);
cctxPtr->totalInSize += srcSize;
return (size_t)(dstPtr - dstStart);
}
/*! LZ4F_flush() :
* When compressed data must be sent immediately, without waiting for a block to be filled,
* invoke LZ4_flush(), which will immediately compress any remaining data stored within LZ4F_cctx.
* The result of the function is the number of bytes written into dstBuffer.
* It can be zero, this means there was no data left within LZ4F_cctx.
* The function outputs an error code if it fails (can be tested using LZ4F_isError())
* LZ4F_compressOptions_t* is optional. NULL is a valid argument.
*/
size_t LZ4F_flush(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const LZ4F_compressOptions_t* compressOptionsPtr)
{
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
compressFunc_t compress;
if (cctxPtr->tmpInSize == 0) return 0; /* nothing to flush */
if (cctxPtr->cStage != 1) return err0r(LZ4F_ERROR_GENERIC);
if (dstCapacity < (cctxPtr->tmpInSize + BHSize + BFSize))
return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
(void)compressOptionsPtr; /* not yet useful */
/* select compression function */
compress = LZ4F_selectCompression(cctxPtr->prefs.frameInfo.blockMode, cctxPtr->prefs.compressionLevel);
/* compress tmp buffer */
dstPtr += LZ4F_makeBlock(dstPtr,
cctxPtr->tmpIn, cctxPtr->tmpInSize,
compress, cctxPtr->lz4CtxPtr, cctxPtr->prefs.compressionLevel,
cctxPtr->cdict,
cctxPtr->prefs.frameInfo.blockChecksumFlag);
assert(((void)"flush overflows dstBuffer!", (size_t)(dstPtr - dstStart) <= dstCapacity));
if (cctxPtr->prefs.frameInfo.blockMode == LZ4F_blockLinked)
cctxPtr->tmpIn += cctxPtr->tmpInSize;
cctxPtr->tmpInSize = 0;
/* keep tmpIn within limits */
if ((cctxPtr->tmpIn + cctxPtr->maxBlockSize) > (cctxPtr->tmpBuff + cctxPtr->maxBufferSize)) { /* necessarily LZ4F_blockLinked */
int const realDictSize = LZ4F_localSaveDict(cctxPtr);
cctxPtr->tmpIn = cctxPtr->tmpBuff + realDictSize;
}
return (size_t)(dstPtr - dstStart);
}
/*! LZ4F_compressEnd() :
* When you want to properly finish the compressed frame, just call LZ4F_compressEnd().
* It will flush whatever data remained within compressionContext (like LZ4_flush())
* but also properly finalize the frame, with an endMark and an (optional) checksum.
* LZ4F_compressOptions_t structure is optional : you can provide NULL as argument.
* @return: the number of bytes written into dstBuffer (necessarily >= 4 (endMark size))
* or an error code if it fails (can be tested using LZ4F_isError())
* The context can then be used again to compress a new frame, starting with LZ4F_compressBegin().
*/
size_t LZ4F_compressEnd(LZ4F_cctx* cctxPtr,
void* dstBuffer, size_t dstCapacity,
const LZ4F_compressOptions_t* compressOptionsPtr)
{
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* dstPtr = dstStart;
size_t const flushSize = LZ4F_flush(cctxPtr, dstBuffer, dstCapacity, compressOptionsPtr);
if (LZ4F_isError(flushSize)) return flushSize;
dstPtr += flushSize;
assert(flushSize <= dstCapacity);
dstCapacity -= flushSize;
if (dstCapacity < 4) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
LZ4F_writeLE32(dstPtr, 0);
dstPtr += 4; /* endMark */
if (cctxPtr->prefs.frameInfo.contentChecksumFlag == LZ4F_contentChecksumEnabled) {
U32 const xxh = XXH32_digest(&(cctxPtr->xxh));
if (dstCapacity < 8) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall);
LZ4F_writeLE32(dstPtr, xxh);
dstPtr+=4; /* content Checksum */
}
cctxPtr->cStage = 0; /* state is now re-usable (with identical preferences) */
cctxPtr->maxBufferSize = 0; /* reuse HC context */
if (cctxPtr->prefs.frameInfo.contentSize) {
if (cctxPtr->prefs.frameInfo.contentSize != cctxPtr->totalInSize)
return err0r(LZ4F_ERROR_frameSize_wrong);
}
return (size_t)(dstPtr - dstStart);
}
/*-***************************************************
* Frame Decompression
*****************************************************/
typedef enum {
dstage_getFrameHeader=0, dstage_storeFrameHeader,
dstage_init,
dstage_getBlockHeader, dstage_storeBlockHeader,
dstage_copyDirect, dstage_getBlockChecksum,
dstage_getCBlock, dstage_storeCBlock,
dstage_flushOut,
dstage_getSuffix, dstage_storeSuffix,
dstage_getSFrameSize, dstage_storeSFrameSize,
dstage_skipSkippable
} dStage_t;
struct LZ4F_dctx_s {
LZ4F_frameInfo_t frameInfo;
U32 version;
dStage_t dStage;
U64 frameRemainingSize;
size_t maxBlockSize;
size_t maxBufferSize;
BYTE* tmpIn;
size_t tmpInSize;
size_t tmpInTarget;
BYTE* tmpOutBuffer;
const BYTE* dict;
size_t dictSize;
BYTE* tmpOut;
size_t tmpOutSize;
size_t tmpOutStart;
XXH32_state_t xxh;
XXH32_state_t blockChecksum;
BYTE header[LZ4F_HEADER_SIZE_MAX];
}; /* typedef'd to LZ4F_dctx in lz4frame.h */
/*! LZ4F_createDecompressionContext() :
* Create a decompressionContext object, which will track all decompression operations.
* Provides a pointer to a fully allocated and initialized LZ4F_decompressionContext object.
* Object can later be released using LZ4F_freeDecompressionContext().
* @return : if != 0, there was an error during context creation.
*/
LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** LZ4F_decompressionContextPtr, unsigned versionNumber)
{
LZ4F_dctx* const dctx = (LZ4F_dctx*)ALLOC_AND_ZERO(sizeof(LZ4F_dctx));
if (dctx==NULL) return err0r(LZ4F_ERROR_GENERIC);
dctx->version = versionNumber;
*LZ4F_decompressionContextPtr = dctx;
return LZ4F_OK_NoError;
}
LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx)
{
LZ4F_errorCode_t result = LZ4F_OK_NoError;
if (dctx != NULL) { /* can accept NULL input, like free() */
result = (LZ4F_errorCode_t)dctx->dStage;
FREEMEM(dctx->tmpIn);
FREEMEM(dctx->tmpOutBuffer);
FREEMEM(dctx);
}
return result;
}
/*==--- Streaming Decompression operations ---==*/
void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx)
{
dctx->dStage = dstage_getFrameHeader;
dctx->dict = NULL;
dctx->dictSize = 0;
}
/*! LZ4F_decodeHeader() :
* input : `src` points at the **beginning of the frame**
* output : set internal values of dctx, such as
* dctx->frameInfo and dctx->dStage.
* Also allocates internal buffers.
* @return : nb Bytes read from src (necessarily <= srcSize)
* or an error code (testable with LZ4F_isError())
*/
static size_t LZ4F_decodeHeader(LZ4F_dctx* dctx, const void* src, size_t srcSize)
{
unsigned blockMode, blockChecksumFlag, contentSizeFlag, contentChecksumFlag, dictIDFlag, blockSizeID;
size_t frameHeaderSize;
const BYTE* srcPtr = (const BYTE*)src;
/* need to decode header to get frameInfo */
if (srcSize < minFHSize) return err0r(LZ4F_ERROR_frameHeader_incomplete); /* minimal frame header size */
MEM_INIT(&(dctx->frameInfo), 0, sizeof(dctx->frameInfo));
/* special case : skippable frames */
if ((LZ4F_readLE32(srcPtr) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START) {
dctx->frameInfo.frameType = LZ4F_skippableFrame;
if (src == (void*)(dctx->header)) {
dctx->tmpInSize = srcSize;
dctx->tmpInTarget = 8;
dctx->dStage = dstage_storeSFrameSize;
return srcSize;
} else {
dctx->dStage = dstage_getSFrameSize;
return 4;
}
}
/* control magic number */
if (LZ4F_readLE32(srcPtr) != LZ4F_MAGICNUMBER)
return err0r(LZ4F_ERROR_frameType_unknown);
dctx->frameInfo.frameType = LZ4F_frame;
/* Flags */
{ U32 const FLG = srcPtr[4];
U32 const version = (FLG>>6) & _2BITS;
blockChecksumFlag = (FLG>>4) & _1BIT;
blockMode = (FLG>>5) & _1BIT;
contentSizeFlag = (FLG>>3) & _1BIT;
contentChecksumFlag = (FLG>>2) & _1BIT;
dictIDFlag = FLG & _1BIT;
/* validate */
if (((FLG>>1)&_1BIT) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bit */
if (version != 1) return err0r(LZ4F_ERROR_headerVersion_wrong); /* Version Number, only supported value */
}
/* Frame Header Size */
frameHeaderSize = minFHSize + (contentSizeFlag?8:0) + (dictIDFlag?4:0);
if (srcSize < frameHeaderSize) {
/* not enough input to fully decode frame header */
if (srcPtr != dctx->header)
memcpy(dctx->header, srcPtr, srcSize);
dctx->tmpInSize = srcSize;
dctx->tmpInTarget = frameHeaderSize;
dctx->dStage = dstage_storeFrameHeader;
return srcSize;
}
{ U32 const BD = srcPtr[5];
blockSizeID = (BD>>4) & _3BITS;
/* validate */
if (((BD>>7)&_1BIT) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bit */
if (blockSizeID < 4) return err0r(LZ4F_ERROR_maxBlockSize_invalid); /* 4-7 only supported values for the time being */
if (((BD>>0)&_4BITS) != 0) return err0r(LZ4F_ERROR_reservedFlag_set); /* Reserved bits */
}
/* check header */
assert(frameHeaderSize > 5);
{ BYTE const HC = LZ4F_headerChecksum(srcPtr+4, frameHeaderSize-5);
if (HC != srcPtr[frameHeaderSize-1])
return err0r(LZ4F_ERROR_headerChecksum_invalid);
}
/* save */
dctx->frameInfo.blockMode = (LZ4F_blockMode_t)blockMode;
dctx->frameInfo.blockChecksumFlag = (LZ4F_blockChecksum_t)blockChecksumFlag;
dctx->frameInfo.contentChecksumFlag = (LZ4F_contentChecksum_t)contentChecksumFlag;
dctx->frameInfo.blockSizeID = (LZ4F_blockSizeID_t)blockSizeID;
dctx->maxBlockSize = LZ4F_getBlockSize(blockSizeID);
if (contentSizeFlag)
dctx->frameRemainingSize =
dctx->frameInfo.contentSize = LZ4F_readLE64(srcPtr+6);
if (dictIDFlag)
dctx->frameInfo.dictID = LZ4F_readLE32(srcPtr + frameHeaderSize - 5);
dctx->dStage = dstage_init;
return frameHeaderSize;
}
/*! LZ4F_headerSize() :
* @return : size of frame header
* or an error code, which can be tested using LZ4F_isError()
*/
size_t LZ4F_headerSize(const void* src, size_t srcSize)
{
if (src == NULL) return err0r(LZ4F_ERROR_srcPtr_wrong);
/* minimal srcSize to determine header size */
if (srcSize < LZ4F_MIN_SIZE_TO_KNOW_HEADER_LENGTH)
return err0r(LZ4F_ERROR_frameHeader_incomplete);
/* special case : skippable frames */
if ((LZ4F_readLE32(src) & 0xFFFFFFF0U) == LZ4F_MAGIC_SKIPPABLE_START)
return 8;
/* control magic number */
if (LZ4F_readLE32(src) != LZ4F_MAGICNUMBER)
return err0r(LZ4F_ERROR_frameType_unknown);
/* Frame Header Size */
{ BYTE const FLG = ((const BYTE*)src)[4];
U32 const contentSizeFlag = (FLG>>3) & _1BIT;
U32 const dictIDFlag = FLG & _1BIT;
return minFHSize + (contentSizeFlag?8:0) + (dictIDFlag?4:0);
}
}
/*! LZ4F_getFrameInfo() :
* This function extracts frame parameters (max blockSize, frame checksum, etc.).
* Usage is optional. Objective is to provide relevant information for allocation purposes.
* This function works in 2 situations :
* - At the beginning of a new frame, in which case it will decode this information from `srcBuffer`, and start the decoding process.
* Amount of input data provided must be large enough to successfully decode the frame header.
* A header size is variable, but is guaranteed to be <= LZ4F_HEADER_SIZE_MAX bytes. It's possible to provide more input data than this minimum.
* - After decoding has been started. In which case, no input is read, frame parameters are extracted from dctx.
* The number of bytes consumed from srcBuffer will be updated within *srcSizePtr (necessarily <= original value).
* Decompression must resume from (srcBuffer + *srcSizePtr).
* @return : an hint about how many srcSize bytes LZ4F_decompress() expects for next call,
* or an error code which can be tested using LZ4F_isError()
* note 1 : in case of error, dctx is not modified. Decoding operations can resume from where they stopped.
* note 2 : frame parameters are *copied into* an already allocated LZ4F_frameInfo_t structure.
*/
LZ4F_errorCode_t LZ4F_getFrameInfo(LZ4F_dctx* dctx,
LZ4F_frameInfo_t* frameInfoPtr,
const void* srcBuffer, size_t* srcSizePtr)
{
LZ4F_STATIC_ASSERT(dstage_getFrameHeader < dstage_storeFrameHeader);
if (dctx->dStage > dstage_storeFrameHeader) {
/* frameInfo already decoded */
size_t o=0, i=0;
*srcSizePtr = 0;
*frameInfoPtr = dctx->frameInfo;
/* returns : recommended nb of bytes for LZ4F_decompress() */
return LZ4F_decompress(dctx, NULL, &o, NULL, &i, NULL);
} else {
if (dctx->dStage == dstage_storeFrameHeader) {
/* frame decoding already started, in the middle of header => automatic fail */
*srcSizePtr = 0;
return err0r(LZ4F_ERROR_frameDecoding_alreadyStarted);
} else {
size_t const hSize = LZ4F_headerSize(srcBuffer, *srcSizePtr);
if (LZ4F_isError(hSize)) { *srcSizePtr=0; return hSize; }
if (*srcSizePtr < hSize) {
*srcSizePtr=0;
return err0r(LZ4F_ERROR_frameHeader_incomplete);
}
{ size_t decodeResult = LZ4F_decodeHeader(dctx, srcBuffer, hSize);
if (LZ4F_isError(decodeResult)) {
*srcSizePtr = 0;
} else {
*srcSizePtr = decodeResult;
decodeResult = BHSize; /* block header size */
}
*frameInfoPtr = dctx->frameInfo;
return decodeResult;
} } }
}
/* LZ4F_updateDict() :
* only used for LZ4F_blockLinked mode */
static void LZ4F_updateDict(LZ4F_dctx* dctx,
const BYTE* dstPtr, size_t dstSize, const BYTE* dstBufferStart,
unsigned withinTmp)
{
if (dctx->dictSize==0)
dctx->dict = (const BYTE*)dstPtr; /* priority to dictionary continuity */
if (dctx->dict + dctx->dictSize == dstPtr) { /* dictionary continuity, directly within dstBuffer */
dctx->dictSize += dstSize;
return;
}
assert(dstPtr >= dstBufferStart);
if ((size_t)(dstPtr - dstBufferStart) + dstSize >= 64 KB) { /* history in dstBuffer becomes large enough to become dictionary */
dctx->dict = (const BYTE*)dstBufferStart;
dctx->dictSize = (size_t)(dstPtr - dstBufferStart) + dstSize;
return;
}
assert(dstSize < 64 KB); /* if dstSize >= 64 KB, dictionary would be set into dstBuffer directly */
/* dstBuffer does not contain whole useful history (64 KB), so it must be saved within tmpOut */
if ((withinTmp) && (dctx->dict == dctx->tmpOutBuffer)) { /* continue history within tmpOutBuffer */
/* withinTmp expectation : content of [dstPtr,dstSize] is same as [dict+dictSize,dstSize], so we just extend it */
assert(dctx->dict + dctx->dictSize == dctx->tmpOut + dctx->tmpOutStart);
dctx->dictSize += dstSize;
return;
}
if (withinTmp) { /* copy relevant dict portion in front of tmpOut within tmpOutBuffer */
size_t const preserveSize = (size_t)(dctx->tmpOut - dctx->tmpOutBuffer);
size_t copySize = 64 KB - dctx->tmpOutSize;
const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize - dctx->tmpOutStart;
if (dctx->tmpOutSize > 64 KB) copySize = 0;
if (copySize > preserveSize) copySize = preserveSize;
memcpy(dctx->tmpOutBuffer + preserveSize - copySize, oldDictEnd - copySize, copySize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = preserveSize + dctx->tmpOutStart + dstSize;
return;
}
if (dctx->dict == dctx->tmpOutBuffer) { /* copy dst into tmp to complete dict */
if (dctx->dictSize + dstSize > dctx->maxBufferSize) { /* tmp buffer not large enough */
size_t const preserveSize = 64 KB - dstSize;
memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - preserveSize, preserveSize);
dctx->dictSize = preserveSize;
}
memcpy(dctx->tmpOutBuffer + dctx->dictSize, dstPtr, dstSize);
dctx->dictSize += dstSize;
return;
}
/* join dict & dest into tmp */
{ size_t preserveSize = 64 KB - dstSize;
if (preserveSize > dctx->dictSize) preserveSize = dctx->dictSize;
memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - preserveSize, preserveSize);
memcpy(dctx->tmpOutBuffer + preserveSize, dstPtr, dstSize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = preserveSize + dstSize;
}
}
/*! LZ4F_decompress() :
* Call this function repetitively to regenerate compressed data in srcBuffer.
* The function will attempt to decode up to *srcSizePtr bytes from srcBuffer
* into dstBuffer of capacity *dstSizePtr.
*
* The number of bytes regenerated into dstBuffer will be provided within *dstSizePtr (necessarily <= original value).
*
* The number of bytes effectively read from srcBuffer will be provided within *srcSizePtr (necessarily <= original value).
* If number of bytes read is < number of bytes provided, then decompression operation is not complete.
* Remaining data will have to be presented again in a subsequent invocation.
*
* The function result is an hint of the better srcSize to use for next call to LZ4F_decompress.
* Schematically, it's the size of the current (or remaining) compressed block + header of next block.
* Respecting the hint provides a small boost to performance, since it allows less buffer shuffling.
* Note that this is just a hint, and it's always possible to any srcSize value.
* When a frame is fully decoded, @return will be 0.
* If decompression failed, @return is an error code which can be tested using LZ4F_isError().
*/
size_t LZ4F_decompress(LZ4F_dctx* dctx,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const LZ4F_decompressOptions_t* decompressOptionsPtr)
{
LZ4F_decompressOptions_t optionsNull;
const BYTE* const srcStart = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcStart + *srcSizePtr;
const BYTE* srcPtr = srcStart;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* const dstEnd = dstStart + *dstSizePtr;
BYTE* dstPtr = dstStart;
const BYTE* selectedIn = NULL;
unsigned doAnotherStage = 1;
size_t nextSrcSizeHint = 1;
MEM_INIT(&optionsNull, 0, sizeof(optionsNull));
if (decompressOptionsPtr==NULL) decompressOptionsPtr = &optionsNull;
*srcSizePtr = 0;
*dstSizePtr = 0;
/* behaves as a state machine */
while (doAnotherStage) {
switch(dctx->dStage)
{
case dstage_getFrameHeader:
if ((size_t)(srcEnd-srcPtr) >= maxFHSize) { /* enough to decode - shortcut */
size_t const hSize = LZ4F_decodeHeader(dctx, srcPtr, (size_t)(srcEnd-srcPtr)); /* will update dStage appropriately */
if (LZ4F_isError(hSize)) return hSize;
srcPtr += hSize;
break;
}
dctx->tmpInSize = 0;
if (srcEnd-srcPtr == 0) return minFHSize; /* 0-size input */
dctx->tmpInTarget = minFHSize; /* minimum size to decode header */
dctx->dStage = dstage_storeFrameHeader;
/* fall-through */
case dstage_storeFrameHeader:
{ size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize, (size_t)(srcEnd - srcPtr));
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
}
if (dctx->tmpInSize < dctx->tmpInTarget) {
nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize) + BHSize; /* rest of header + nextBlockHeader */
doAnotherStage = 0; /* not enough src data, ask for some more */
break;
}
{ size_t const hSize = LZ4F_decodeHeader(dctx, dctx->header, dctx->tmpInTarget); /* will update dStage appropriately */
if (LZ4F_isError(hSize)) return hSize;
}
break;
case dstage_init:
if (dctx->frameInfo.contentChecksumFlag) (void)XXH32_reset(&(dctx->xxh), 0);
/* internal buffers allocation */
{ size_t const bufferNeeded = dctx->maxBlockSize
+ ((dctx->frameInfo.blockMode==LZ4F_blockLinked) ? 128 KB : 0);
if (bufferNeeded > dctx->maxBufferSize) { /* tmp buffers too small */
dctx->maxBufferSize = 0; /* ensure allocation will be re-attempted on next entry*/
FREEMEM(dctx->tmpIn);
dctx->tmpIn = (BYTE*)ALLOC(dctx->maxBlockSize + BFSize /* block checksum */);
if (dctx->tmpIn == NULL)
return err0r(LZ4F_ERROR_allocation_failed);
FREEMEM(dctx->tmpOutBuffer);
dctx->tmpOutBuffer= (BYTE*)ALLOC(bufferNeeded);
if (dctx->tmpOutBuffer== NULL)
return err0r(LZ4F_ERROR_allocation_failed);
dctx->maxBufferSize = bufferNeeded;
} }
dctx->tmpInSize = 0;
dctx->tmpInTarget = 0;
dctx->tmpOut = dctx->tmpOutBuffer;
dctx->tmpOutStart = 0;
dctx->tmpOutSize = 0;
dctx->dStage = dstage_getBlockHeader;
/* fall-through */
case dstage_getBlockHeader:
if ((size_t)(srcEnd - srcPtr) >= BHSize) {
selectedIn = srcPtr;
srcPtr += BHSize;
} else {
/* not enough input to read cBlockSize field */
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeBlockHeader;
}
if (dctx->dStage == dstage_storeBlockHeader) /* can be skipped */
case dstage_storeBlockHeader:
{ size_t const remainingInput = (size_t)(srcEnd - srcPtr);
size_t const wantedData = BHSize - dctx->tmpInSize;
size_t const sizeToCopy = MIN(wantedData, remainingInput);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < BHSize) { /* not enough input for cBlockSize */
nextSrcSizeHint = BHSize - dctx->tmpInSize;
doAnotherStage = 0;
break;
}
selectedIn = dctx->tmpIn;
} /* if (dctx->dStage == dstage_storeBlockHeader) */
/* decode block header */
{ size_t const nextCBlockSize = LZ4F_readLE32(selectedIn) & 0x7FFFFFFFU;
size_t const crcSize = dctx->frameInfo.blockChecksumFlag * BFSize;
if (nextCBlockSize==0) { /* frameEnd signal, no more block */
dctx->dStage = dstage_getSuffix;
break;
}
if (nextCBlockSize > dctx->maxBlockSize)
return err0r(LZ4F_ERROR_maxBlockSize_invalid);
if (LZ4F_readLE32(selectedIn) & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
/* next block is uncompressed */
dctx->tmpInTarget = nextCBlockSize;
if (dctx->frameInfo.blockChecksumFlag) {
(void)XXH32_reset(&dctx->blockChecksum, 0);
}
dctx->dStage = dstage_copyDirect;
break;
}
/* next block is a compressed block */
dctx->tmpInTarget = nextCBlockSize + crcSize;
dctx->dStage = dstage_getCBlock;
if (dstPtr==dstEnd) {
nextSrcSizeHint = BHSize + nextCBlockSize + crcSize;
doAnotherStage = 0;
}
break;
}
case dstage_copyDirect: /* uncompressed block */
{ size_t const minBuffSize = MIN((size_t)(srcEnd-srcPtr), (size_t)(dstEnd-dstPtr));
size_t const sizeToCopy = MIN(dctx->tmpInTarget, minBuffSize);
memcpy(dstPtr, srcPtr, sizeToCopy);
if (dctx->frameInfo.blockChecksumFlag) {
(void)XXH32_update(&dctx->blockChecksum, srcPtr, sizeToCopy);
}
if (dctx->frameInfo.contentChecksumFlag)
(void)XXH32_update(&dctx->xxh, srcPtr, sizeToCopy);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= sizeToCopy;
/* history management (linked blocks only)*/
if (dctx->frameInfo.blockMode == LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 0);
srcPtr += sizeToCopy;
dstPtr += sizeToCopy;
if (sizeToCopy == dctx->tmpInTarget) { /* all done */
if (dctx->frameInfo.blockChecksumFlag) {
dctx->tmpInSize = 0;
dctx->dStage = dstage_getBlockChecksum;
} else
dctx->dStage = dstage_getBlockHeader; /* new block */
break;
}
dctx->tmpInTarget -= sizeToCopy; /* need to copy more */
nextSrcSizeHint = dctx->tmpInTarget +
+(dctx->frameInfo.blockChecksumFlag ? BFSize : 0)
+ BHSize /* next header size */;
doAnotherStage = 0;
break;
}
/* check block checksum for recently transferred uncompressed block */
case dstage_getBlockChecksum:
{ const void* crcSrc;
if ((srcEnd-srcPtr >= 4) && (dctx->tmpInSize==0)) {
crcSrc = srcPtr;
srcPtr += 4;
} else {
size_t const stillToCopy = 4 - dctx->tmpInSize;
size_t const sizeToCopy = MIN(stillToCopy, (size_t)(srcEnd-srcPtr));
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
if (dctx->tmpInSize < 4) { /* all input consumed */
doAnotherStage = 0;
break;
}
crcSrc = dctx->header;
}
{ U32 const readCRC = LZ4F_readLE32(crcSrc);
U32 const calcCRC = XXH32_digest(&dctx->blockChecksum);
if (readCRC != calcCRC)
return err0r(LZ4F_ERROR_blockChecksum_invalid);
} }
dctx->dStage = dstage_getBlockHeader; /* new block */
break;
case dstage_getCBlock:
if ((size_t)(srcEnd-srcPtr) < dctx->tmpInTarget) {
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeCBlock;
break;
}
/* input large enough to read full block directly */
selectedIn = srcPtr;
srcPtr += dctx->tmpInTarget;
if (0) /* jump over next block */
case dstage_storeCBlock:
{ size_t const wantedData = dctx->tmpInTarget - dctx->tmpInSize;
size_t const inputLeft = (size_t)(srcEnd-srcPtr);
size_t const sizeToCopy = MIN(wantedData, inputLeft);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
if (dctx->tmpInSize < dctx->tmpInTarget) { /* need more input */
nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize)
+ (dctx->frameInfo.blockChecksumFlag ? BFSize : 0)
+ BHSize /* next header size */;
doAnotherStage = 0;
break;
}
selectedIn = dctx->tmpIn;
}
/* At this stage, input is large enough to decode a block */
if (dctx->frameInfo.blockChecksumFlag) {
dctx->tmpInTarget -= 4;
assert(selectedIn != NULL); /* selectedIn is defined at this stage (either srcPtr, or dctx->tmpIn) */
{ U32 const readBlockCrc = LZ4F_readLE32(selectedIn + dctx->tmpInTarget);
U32 const calcBlockCrc = XXH32(selectedIn, dctx->tmpInTarget, 0);
if (readBlockCrc != calcBlockCrc)
return err0r(LZ4F_ERROR_blockChecksum_invalid);
} }
if ((size_t)(dstEnd-dstPtr) >= dctx->maxBlockSize) {
const char* dict = (const char*)dctx->dict;
size_t dictSize = dctx->dictSize;
int decodedSize;
if (dict && dictSize > 1 GB) {
/* the dictSize param is an int, avoid truncation / sign issues */
dict += dictSize - 64 KB;
dictSize = 64 KB;
}
/* enough capacity in `dst` to decompress directly there */
decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dstPtr,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
dict, (int)dictSize);
if (decodedSize < 0) return err0r(LZ4F_ERROR_GENERIC); /* decompression failed */
if (dctx->frameInfo.contentChecksumFlag)
XXH32_update(&(dctx->xxh), dstPtr, (size_t)decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= (size_t)decodedSize;
/* dictionary management */
if (dctx->frameInfo.blockMode==LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, (size_t)decodedSize, dstStart, 0);
dstPtr += decodedSize;
dctx->dStage = dstage_getBlockHeader;
break;
}
/* not enough place into dst : decode into tmpOut */
/* ensure enough place for tmpOut */
if (dctx->frameInfo.blockMode == LZ4F_blockLinked) {
if (dctx->dict == dctx->tmpOutBuffer) {
if (dctx->dictSize > 128 KB) {
memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - 64 KB, 64 KB);
dctx->dictSize = 64 KB;
}
dctx->tmpOut = dctx->tmpOutBuffer + dctx->dictSize;
} else { /* dict not within tmp */
size_t const reservedDictSpace = MIN(dctx->dictSize, 64 KB);
dctx->tmpOut = dctx->tmpOutBuffer + reservedDictSpace;
} }
/* Decode block */
{ const char* dict = (const char*)dctx->dict;
size_t dictSize = dctx->dictSize;
int decodedSize;
if (dict && dictSize > 1 GB) {
/* the dictSize param is an int, avoid truncation / sign issues */
dict += dictSize - 64 KB;
dictSize = 64 KB;
}
decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dctx->tmpOut,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
dict, (int)dictSize);
if (decodedSize < 0) /* decompression failed */
return err0r(LZ4F_ERROR_decompressionFailed);
if (dctx->frameInfo.contentChecksumFlag)
XXH32_update(&(dctx->xxh), dctx->tmpOut, (size_t)decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= (size_t)decodedSize;
dctx->tmpOutSize = (size_t)decodedSize;
dctx->tmpOutStart = 0;
dctx->dStage = dstage_flushOut;
}
/* fall-through */
case dstage_flushOut: /* flush decoded data from tmpOut to dstBuffer */
{ size_t const sizeToCopy = MIN(dctx->tmpOutSize - dctx->tmpOutStart, (size_t)(dstEnd-dstPtr));
memcpy(dstPtr, dctx->tmpOut + dctx->tmpOutStart, sizeToCopy);
/* dictionary management */
if (dctx->frameInfo.blockMode == LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 1 /*withinTmp*/);
dctx->tmpOutStart += sizeToCopy;
dstPtr += sizeToCopy;
if (dctx->tmpOutStart == dctx->tmpOutSize) { /* all flushed */
dctx->dStage = dstage_getBlockHeader; /* get next block */
break;
}
/* could not flush everything : stop there, just request a block header */
doAnotherStage = 0;
nextSrcSizeHint = BHSize;
break;
}
case dstage_getSuffix:
if (dctx->frameRemainingSize)
return err0r(LZ4F_ERROR_frameSize_wrong); /* incorrect frame size decoded */
if (!dctx->frameInfo.contentChecksumFlag) { /* no checksum, frame is completed */
nextSrcSizeHint = 0;
LZ4F_resetDecompressionContext(dctx);
doAnotherStage = 0;
break;
}
if ((srcEnd - srcPtr) < 4) { /* not enough size for entire CRC */
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeSuffix;
} else {
selectedIn = srcPtr;
srcPtr += 4;
}
if (dctx->dStage == dstage_storeSuffix) /* can be skipped */
case dstage_storeSuffix:
{ size_t const remainingInput = (size_t)(srcEnd - srcPtr);
size_t const wantedData = 4 - dctx->tmpInSize;
size_t const sizeToCopy = MIN(wantedData, remainingInput);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < 4) { /* not enough input to read complete suffix */
nextSrcSizeHint = 4 - dctx->tmpInSize;
doAnotherStage=0;
break;
}
selectedIn = dctx->tmpIn;
} /* if (dctx->dStage == dstage_storeSuffix) */
/* case dstage_checkSuffix: */ /* no direct entry, avoid initialization risks */
{ U32 const readCRC = LZ4F_readLE32(selectedIn);
U32 const resultCRC = XXH32_digest(&(dctx->xxh));
if (readCRC != resultCRC)
return err0r(LZ4F_ERROR_contentChecksum_invalid);
nextSrcSizeHint = 0;
LZ4F_resetDecompressionContext(dctx);
doAnotherStage = 0;
break;
}
case dstage_getSFrameSize:
if ((srcEnd - srcPtr) >= 4) {
selectedIn = srcPtr;
srcPtr += 4;
} else {
/* not enough input to read cBlockSize field */
dctx->tmpInSize = 4;
dctx->tmpInTarget = 8;
dctx->dStage = dstage_storeSFrameSize;
}
if (dctx->dStage == dstage_storeSFrameSize)
case dstage_storeSFrameSize:
{ size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize,
(size_t)(srcEnd - srcPtr) );
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < dctx->tmpInTarget) {
/* not enough input to get full sBlockSize; wait for more */
nextSrcSizeHint = dctx->tmpInTarget - dctx->tmpInSize;
doAnotherStage = 0;
break;
}
selectedIn = dctx->header + 4;
} /* if (dctx->dStage == dstage_storeSFrameSize) */
/* case dstage_decodeSFrameSize: */ /* no direct entry */
{ size_t const SFrameSize = LZ4F_readLE32(selectedIn);
dctx->frameInfo.contentSize = SFrameSize;
dctx->tmpInTarget = SFrameSize;
dctx->dStage = dstage_skipSkippable;
break;
}
case dstage_skipSkippable:
{ size_t const skipSize = MIN(dctx->tmpInTarget, (size_t)(srcEnd-srcPtr));
srcPtr += skipSize;
dctx->tmpInTarget -= skipSize;
doAnotherStage = 0;
nextSrcSizeHint = dctx->tmpInTarget;
if (nextSrcSizeHint) break; /* still more to skip */
/* frame fully skipped : prepare context for a new frame */
LZ4F_resetDecompressionContext(dctx);
break;
}
} /* switch (dctx->dStage) */
} /* while (doAnotherStage) */
/* preserve history within tmp whenever necessary */
LZ4F_STATIC_ASSERT((unsigned)dstage_init == 2);
if ( (dctx->frameInfo.blockMode==LZ4F_blockLinked) /* next block will use up to 64KB from previous ones */
&& (dctx->dict != dctx->tmpOutBuffer) /* dictionary is not already within tmp */
&& (!decompressOptionsPtr->stableDst) /* cannot rely on dst data to remain there for next call */
&& ((unsigned)(dctx->dStage)-2 < (unsigned)(dstage_getSuffix)-2) ) /* valid stages : [init ... getSuffix[ */
{
if (dctx->dStage == dstage_flushOut) {
size_t const preserveSize = (size_t)(dctx->tmpOut - dctx->tmpOutBuffer);
size_t copySize = 64 KB - dctx->tmpOutSize;
const BYTE* oldDictEnd = dctx->dict + dctx->dictSize - dctx->tmpOutStart;
if (dctx->tmpOutSize > 64 KB) copySize = 0;
if (copySize > preserveSize) copySize = preserveSize;
if (copySize > 0)
memcpy(dctx->tmpOutBuffer + preserveSize - copySize, oldDictEnd - copySize, copySize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = preserveSize + dctx->tmpOutStart;
} else {
const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize;
size_t const newDictSize = MIN(dctx->dictSize, 64 KB);
if (newDictSize > 0)
memcpy(dctx->tmpOutBuffer, oldDictEnd - newDictSize, newDictSize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = newDictSize;
dctx->tmpOut = dctx->tmpOutBuffer + newDictSize;
}
}
*srcSizePtr = (size_t)(srcPtr - srcStart);
*dstSizePtr = (size_t)(dstPtr - dstStart);
return nextSrcSizeHint;
}
/*! LZ4F_decompress_usingDict() :
* Same as LZ4F_decompress(), using a predefined dictionary.
* Dictionary is used "in place", without any preprocessing.
* It must remain accessible throughout the entire frame decoding.
*/
size_t LZ4F_decompress_usingDict(LZ4F_dctx* dctx,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const void* dict, size_t dictSize,
const LZ4F_decompressOptions_t* decompressOptionsPtr)
{
if (dctx->dStage <= dstage_init) {
dctx->dict = (const BYTE*)dict;
dctx->dictSize = dictSize;
}
return LZ4F_decompress(dctx, dstBuffer, dstSizePtr,
srcBuffer, srcSizePtr,
decompressOptionsPtr);
}