ClickHouse/contrib/libzstd/include/zstd/legacy/zstd_legacy.h
2016-10-25 10:14:12 +03:00

140 lines
4.1 KiB
C++

/**
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
/// Milovidov: we had only used version 6 in ClickHouse.
#ifndef ZSTD_LEGACY_H
#define ZSTD_LEGACY_H
#if defined (__cplusplus)
extern "C" {
#endif
/* *************************************
* Includes
***************************************/
#include "mem.h" /* MEM_STATIC */
#include "error_private.h" /* ERROR */
#include "zstd.h" /* ZSTD_inBuffer, ZSTD_outBuffer */
#include "zstd_v06.h"
/** ZSTD_isLegacy() :
@return : > 0 if supported by legacy decoder. 0 otherwise.
return value is the version.
*/
MEM_STATIC unsigned ZSTD_isLegacy(const void* src, size_t srcSize)
{
U32 magicNumberLE;
if (srcSize<4) return 0;
magicNumberLE = MEM_readLE32(src);
switch(magicNumberLE)
{
case ZSTDv06_MAGICNUMBER : return 6;
default : return 0;
}
}
MEM_STATIC unsigned long long ZSTD_getDecompressedSize_legacy(const void* src, size_t srcSize)
{
U32 const version = ZSTD_isLegacy(src, srcSize);
if (version==6) {
ZSTDv06_frameParams fParams;
size_t const frResult = ZSTDv06_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,
const void* dict,size_t dictSize)
{
U32 const version = ZSTD_isLegacy(src, compressedSize);
switch(version)
{
case 6 :
{ size_t result;
ZSTDv06_DCtx* const zd = ZSTDv06_createDCtx();
if (zd==NULL) return ERROR(memory_allocation);
result = ZSTDv06_decompress_usingDict(zd, dst, dstCapacity, src, compressedSize, dict, dictSize);
ZSTDv06_freeDCtx(zd);
return result;
}
default :
return ERROR(prefix_unknown);
}
}
MEM_STATIC size_t ZSTD_freeLegacyStreamContext(void* legacyContext, U32 version)
{
switch(version)
{
default :
return ERROR(version_unsupported);
case 6 : return ZBUFFv06_freeDCtx((ZBUFFv06_DCtx*)legacyContext);
}
}
MEM_STATIC size_t ZSTD_initLegacyStream(void** legacyContext, U32 prevVersion, U32 newVersion,
const void* dict, size_t dictSize)
{
if (prevVersion != newVersion) ZSTD_freeLegacyStreamContext(*legacyContext, prevVersion);
switch(newVersion)
{
default :
return 0;
case 6 :
{
ZBUFFv06_DCtx* dctx = (prevVersion != newVersion) ? ZBUFFv06_createDCtx() : (ZBUFFv06_DCtx*)*legacyContext;
if (dctx==NULL) return ERROR(memory_allocation);
ZBUFFv06_decompressInitDictionary(dctx, dict, dictSize);
*legacyContext = dctx;
return 0;
}
}
}
MEM_STATIC size_t ZSTD_decompressLegacyStream(void* legacyContext, U32 version,
ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{
switch(version)
{
default :
return ERROR(version_unsupported);
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;
}
}
}
#if defined (__cplusplus)
}
#endif
#endif /* ZSTD_LEGACY_H */