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first version supporting legacy streams (transparent decoding)

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This commit is contained in:
Yann Collet
2016-08-28 07:43:34 -07:00
parent bbd5bb75a6
commit 4bf317dd00
5 changed files with 215 additions and 31 deletions
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lib/legacy/zstd_legacy.h
+163 -23
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@@ -42,6 +42,7 @@ extern "C" {
***************************************/
#include "mem.h" /* MEM_STATIC */
#include "error_private.h" /* ERROR */
#include "zstd.h" /* ZSTD_inBuffer, ZSTD_outBuffer */
#include "zstd_v01.h"
#include "zstd_v02.h"
#include "zstd_v03.h"
@@ -76,32 +77,30 @@ MEM_STATIC unsigned ZSTD_isLegacy(const void* src, size_t srcSize)
MEM_STATIC unsigned long long ZSTD_getDecompressedSize_legacy(const void* src, size_t srcSize)
{
if (srcSize < 4) return 0;
{ U32 const version = ZSTD_isLegacy(src, srcSize);
if (version < 5) return 0; /* no decompressed size in frame header, or not a legacy format */
if (version==5) {
ZSTDv05_parameters fParams;
size_t const frResult = ZSTDv05_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.srcSize;
}
if (version==6) {
ZSTDv06_frameParams fParams;
size_t const frResult = ZSTDv06_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.frameContentSize;
}
if (version==7) {
ZSTDv07_frameParams fParams;
size_t const frResult = ZSTDv07_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.frameContentSize;
}
return 0; /* should not be possible */
U32 const version = ZSTD_isLegacy(src, srcSize);
if (version < 5) return 0; /* no decompressed size in frame header, or not a legacy format */
if (version==5) {
ZSTDv05_parameters fParams;
size_t const frResult = ZSTDv05_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.srcSize;
}
if (version==6) {
ZSTDv06_frameParams fParams;
size_t const frResult = ZSTDv06_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.frameContentSize;
}
if (version==7) {
ZSTDv07_frameParams fParams;
size_t const frResult = ZSTDv07_getFrameParams(&fParams, src, srcSize);
if (frResult != 0) return 0;
return fParams.frameContentSize;
}
return 0; /* should not be possible */
}
MEM_STATIC size_t ZSTD_decompressLegacy(
void* dst, size_t dstCapacity,
const void* src, size_t compressedSize,
@@ -148,6 +147,147 @@ MEM_STATIC size_t ZSTD_decompressLegacy(
}
MEM_STATIC void* ZSTD_createLegacyStreamContext(U32 version)
{
switch(version)
{
default :
case 1 :
case 2 :
case 3 :
return NULL;
case 4 : return ZBUFFv04_createDCtx();
case 5 : return ZBUFFv05_createDCtx();
case 6 : return ZBUFFv06_createDCtx();
case 7 : return ZBUFFv07_createDCtx();
}
}
MEM_STATIC size_t ZSTD_freeLegacyStreamContext(void* legacyContext, U32 version)
{
switch(version)
{
default :
case 1 :
case 2 :
case 3 :
return ERROR(version_unsupported);
case 4 : return ZBUFFv04_freeDCtx((ZBUFFv04_DCtx*)legacyContext);
case 5 : return ZBUFFv05_freeDCtx((ZBUFFv05_DCtx*)legacyContext);
case 6 : return ZBUFFv06_freeDCtx((ZBUFFv06_DCtx*)legacyContext);
case 7 : return ZBUFFv07_freeDCtx((ZBUFFv07_DCtx*)legacyContext);
}
}
MEM_STATIC void ZSTD_initLegacyStream(void* legacyContext, U32 version,
const void* dict, size_t dictSize)
{
switch(version)
{
default :
case 1 :
case 2 :
case 3 :
return;
case 4 :
{
ZBUFFv04_DCtx* dctx = (ZBUFFv04_DCtx*) legacyContext;
ZBUFFv04_decompressInit(dctx);
ZBUFFv04_decompressWithDictionary(dctx, dict, dictSize);
return;
}
case 5 :
{
ZBUFFv05_DCtx* dctx = (ZBUFFv05_DCtx*) legacyContext;
ZBUFFv05_decompressInitDictionary(dctx, dict, dictSize);
return;
}
case 6 :
{
ZBUFFv06_DCtx* dctx = (ZBUFFv06_DCtx*) legacyContext;
ZBUFFv06_decompressInitDictionary(dctx, dict, dictSize);
return;
}
case 7 :
{
ZBUFFv07_DCtx* dctx = (ZBUFFv07_DCtx*) legacyContext;
ZBUFFv07_decompressInitDictionary(dctx, dict, dictSize);
return;
}
}
}
MEM_STATIC size_t ZSTD_decompressLegacyStream(void** legacyContext, U32 version,
ZSTD_outBuffer* output, ZSTD_inBuffer* input,
const void* dict, size_t dictSize)
{
if (*legacyContext == NULL) {
*legacyContext = ZSTD_createLegacyStreamContext(version);
if (*legacyContext==NULL) return ERROR(memory_allocation);
ZSTD_initLegacyStream(*legacyContext, version, dict, dictSize);
}
switch(version)
{
default :
case 1 :
case 2 :
case 3 :
return ERROR(version_unsupported);
case 4 :
{
ZBUFFv04_DCtx* dctx = (ZBUFFv04_DCtx*) (*legacyContext);
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv04_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
case 5 :
{
ZBUFFv05_DCtx* dctx = (ZBUFFv05_DCtx*) (*legacyContext);
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv05_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
case 6 :
{
ZBUFFv06_DCtx* dctx = (ZBUFFv06_DCtx*) (*legacyContext);
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv06_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
case 7 :
{
ZBUFFv07_DCtx* dctx = (ZBUFFv07_DCtx*) (*legacyContext);
const void* src = (const char*)input->src + input->pos;
size_t readSize = input->size - input->pos;
void* dst = (char*)output->dst + output->pos;
size_t decodedSize = output->size - output->pos;
size_t const hintSize = ZBUFFv07_decompressContinue(dctx, dst, &decodedSize, src, &readSize);
output->pos += decodedSize;
input->pos += readSize;
return hintSize;
}
}
}
#if defined (__cplusplus)
}