ddidderr/zstd-rs
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introduced dictionary format

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This commit is contained in:
Yann Collet
2016-01-26 03:14:20 +01:00
parent bc4c8aa4b7
commit b923f65076
9 changed files with 245 additions and 118 deletions
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lib/zstd_decompress.c
+62 -6
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@@ -126,6 +126,7 @@ struct ZSTD_DCtx_s
U32 LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
U32 OffTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
U32 MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
U32 hufTableX4[HUF_DTABLE_SIZE(HufLog)];
const void* previousDstEnd;
const void* base;
const void* vBase;
@@ -138,7 +139,7 @@ struct ZSTD_DCtx_s
const BYTE* litPtr;
size_t litBufSize;
size_t litSize;
BYTE litBuffer[BLOCKSIZE + 8 /* margin for wildcopy */];
BYTE litBuffer[BLOCKSIZE + WILDCOPY_OVERLENGTH];
BYTE headerBuffer[ZSTD_frameHeaderSize_max];
}; /* typedef'd to ZSTD_DCtx within "zstd_static.h" */
@@ -150,6 +151,7 @@ size_t ZSTD_resetDCtx(ZSTD_DCtx* dctx)
dctx->base = NULL;
dctx->vBase = NULL;
dctx->dictEnd = NULL;
dctx->hufTableX4[0] = HufLog;
return 0;
}
@@ -333,6 +335,27 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
dctx->litSize = litSize;
return litCSize + lhSize;
}
case IS_PCH:
{
size_t errorCode;
size_t litSize, litCSize;
U32 lhSize = ((istart[0]) >> 4) & 3;
if (lhSize != 1) /* only case supported for now : small litSize, single stream */
return ERROR(corruption_detected);
/* 2 - 2 - 10 - 10 */
lhSize=3;
litSize = ((istart[0] & 15) << 6) + (istart[1] >> 2);
litCSize = ((istart[1] & 3) << 8) + istart[2];
errorCode = HUF_decompress1X4_usingDTable(dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->hufTableX4);
if (HUF_isError(errorCode)) return ERROR(corruption_detected);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = BLOCKSIZE+WILDCOPY_OVERLENGTH;
dctx->litSize = litSize;
return litCSize + lhSize;
}
case IS_RAW:
{
size_t litSize;
@@ -386,12 +409,12 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
if (litSize > BLOCKSIZE) return ERROR(corruption_detected);
memset(dctx->litBuffer, istart[lhSize], litSize);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = BLOCKSIZE+8;
dctx->litBufSize = BLOCKSIZE+WILDCOPY_OVERLENGTH;
dctx->litSize = litSize;
return lhSize+1;
}
default: /* IS_PCH */
return ERROR(corruption_detected); /* not yet nominal case */
default:
return ERROR(corruption_detected); /* impossible */
}
}
@@ -794,7 +817,8 @@ size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
ZSTD_resetDCtx(dctx);
if (dict)
{
ZSTD_decompress_insertDictionary(dctx, dict, dictSize);
size_t errorCode = ZSTD_decompress_insertDictionary(dctx, dict, dictSize);
if (ZSTD_isError(errorCode)) return ERROR(dictionary_corrupted);
dctx->dictEnd = dctx->previousDstEnd;
dctx->vBase = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
dctx->base = dst;
@@ -979,10 +1003,42 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, co
}
void ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
static void ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
dctx->dictEnd = dctx->previousDstEnd;
dctx->vBase = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
dctx->base = dict;
dctx->previousDstEnd = (const char*)dict + dictSize;
}
static size_t ZSTD_loadEntropy(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
size_t hSize = HUF_readDTableX4(dctx->hufTableX4, dict, dictSize);
if (HUF_isError(hSize)) return ERROR(dictionary_corrupted);
return hSize;
}
size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
size_t eSize;
U32 magic = MEM_readLE32(dict);
if (magic != ZSTD_DICT_MAGIC) {
/* pure content mode */
ZSTD_refDictContent(dctx, dict, dictSize);
return 0;
}
/* load entropy tables */
dict = (const char*)dict + 4;
dictSize -= 4;
eSize = ZSTD_loadEntropy(dctx, dict, dictSize);
if (ZSTD_isError(eSize)) return ERROR(dictionary_corrupted);
/* reference dictionary content */
dict = (const char*)dict + eSize;
dictSize -= eSize;
ZSTD_refDictContent(dctx, dict, dictSize);
return 0;
}