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Refactor buildSequencesStatistics() to avoid pointer increment for superblocks

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senhuang42 2021-01-08 15:50:19 -05:00 committed by Sen Huang
parent e2bb215117
commit eb1ee8686d
3 changed files with 49 additions and 42 deletions
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79
lib/compress/zstd_compress.c
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@ -2204,18 +2204,18 @@ static int ZSTD_useBlockSplitting(const ZSTD_CCtx_params* cctxParams)
/* ZSTD_buildSequencesStatistics():
* Returns the size of the statistics for a given set of sequences, or a ZSTD error code,
* Also modifies LLtype, Offtype, MLtype, and lastNCount to the appropriate values.
*/
MEM_STATIC size_t
ZSTD_buildSequencesStatistics(seqStore_t* seqStorePtr, size_t nbSeq,
U32* LLtype, U32* Offtype, U32* MLtype, BYTE** lastNCount,
const ZSTD_fseCTables_t* prevEntropy, ZSTD_fseCTables_t* nextEntropy,
BYTE* dst, const BYTE* const dstEnd,
ZSTD_strategy strategy, BYTE** lastNCount, ZSTD_fseCTablesMetadata_t* fseMetadata,
ZSTD_strategy strategy,
void* entropyWorkspace, size_t entropyWkspSize) {
U32 LLtype, Offtype, MLtype; /* compressed, raw or rle */
BYTE* const ostart = dst;
const BYTE* const oend = dstEnd;
BYTE* op = ostart;
BYTE* seqHead = op++;
unsigned* const countWorkspace = (unsigned*)entropyWorkspace;
@ -2229,34 +2229,31 @@ ZSTD_buildSequencesStatistics(seqStore_t* seqStorePtr, size_t nbSeq,
/* convert length/distances into codes */
ZSTD_seqToCodes(seqStorePtr);
assert(op <= oend);
assert(LLtype && Offtype && MLtype);
/* build CTable for Literal Lengths */
{ unsigned max = MaxLL;
size_t const mostFrequent = HIST_countFast_wksp(countWorkspace, &max, llCodeTable, nbSeq, entropyWorkspace, entropyWkspSize); /* can't fail */
DEBUGLOG(5, "Building LL table");
nextEntropy->litlength_repeatMode = prevEntropy->litlength_repeatMode;
LLtype = ZSTD_selectEncodingType(&nextEntropy->litlength_repeatMode,
*LLtype = ZSTD_selectEncodingType(&nextEntropy->litlength_repeatMode,
countWorkspace, max, mostFrequent, nbSeq,
LLFSELog, prevEntropy->litlengthCTable,
LL_defaultNorm, LL_defaultNormLog,
ZSTD_defaultAllowed, strategy);
assert(set_basic < set_compressed && set_rle < set_compressed);
assert(!(LLtype < set_compressed && nextEntropy->litlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
assert(!(*LLtype < set_compressed && nextEntropy->litlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
{ size_t const countSize = ZSTD_buildCTable(
op, (size_t)(oend - op),
CTable_LitLength, LLFSELog, (symbolEncodingType_e)LLtype,
CTable_LitLength, LLFSELog, (symbolEncodingType_e)*LLtype,
countWorkspace, max, llCodeTable, nbSeq,
LL_defaultNorm, LL_defaultNormLog, MaxLL,
prevEntropy->litlengthCTable,
sizeof(prevEntropy->litlengthCTable),
entropyWorkspace, entropyWkspSize);
FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for LitLens failed");
if (LLtype == set_compressed)
if (*LLtype == set_compressed)
*lastNCount = op;
op += countSize;
if (fseMetadata) {
if (LLtype == set_compressed) fseMetadata->lastCountSize = countSize;
fseMetadata->llType = (symbolEncodingType_e) LLtype;
}
assert(op <= oend);
} }
/* build CTable for Offsets */
@ -2267,28 +2264,24 @@ ZSTD_buildSequencesStatistics(seqStore_t* seqStorePtr, size_t nbSeq,
ZSTD_defaultPolicy_e const defaultPolicy = (max <= DefaultMaxOff) ? ZSTD_defaultAllowed : ZSTD_defaultDisallowed;
DEBUGLOG(5, "Building OF table");
nextEntropy->offcode_repeatMode = prevEntropy->offcode_repeatMode;
Offtype = ZSTD_selectEncodingType(&nextEntropy->offcode_repeatMode,
*Offtype = ZSTD_selectEncodingType(&nextEntropy->offcode_repeatMode,
countWorkspace, max, mostFrequent, nbSeq,
OffFSELog, prevEntropy->offcodeCTable,
OF_defaultNorm, OF_defaultNormLog,
defaultPolicy, strategy);
assert(!(Offtype < set_compressed && nextEntropy->offcode_repeatMode != FSE_repeat_none)); /* We don't copy tables */
assert(!(*Offtype < set_compressed && nextEntropy->offcode_repeatMode != FSE_repeat_none)); /* We don't copy tables */
{ size_t const countSize = ZSTD_buildCTable(
op, (size_t)(oend - op),
CTable_OffsetBits, OffFSELog, (symbolEncodingType_e)Offtype,
CTable_OffsetBits, OffFSELog, (symbolEncodingType_e)*Offtype,
countWorkspace, max, ofCodeTable, nbSeq,
OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
prevEntropy->offcodeCTable,
sizeof(prevEntropy->offcodeCTable),
entropyWorkspace, entropyWkspSize);
FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for Offsets failed");
if (Offtype == set_compressed)
if (*Offtype == set_compressed)
*lastNCount = op;
op += countSize;
if (fseMetadata) {
if (Offtype == set_compressed) fseMetadata->lastCountSize = countSize;
fseMetadata->ofType = (symbolEncodingType_e) Offtype;
}
assert(op <= oend);
} }
/* build CTable for MatchLengths */
@ -2297,32 +2290,26 @@ ZSTD_buildSequencesStatistics(seqStore_t* seqStorePtr, size_t nbSeq,
countWorkspace, &max, mlCodeTable, nbSeq, entropyWorkspace, entropyWkspSize); /* can't fail */
DEBUGLOG(5, "Building ML table (remaining space : %i)", (int)(oend-op));
nextEntropy->matchlength_repeatMode = prevEntropy->matchlength_repeatMode;
MLtype = ZSTD_selectEncodingType(&nextEntropy->matchlength_repeatMode,
*MLtype = ZSTD_selectEncodingType(&nextEntropy->matchlength_repeatMode,
countWorkspace, max, mostFrequent, nbSeq,
MLFSELog, prevEntropy->matchlengthCTable,
ML_defaultNorm, ML_defaultNormLog,
ZSTD_defaultAllowed, strategy);
assert(!(MLtype < set_compressed && nextEntropy->matchlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
assert(!(*MLtype < set_compressed && nextEntropy->matchlength_repeatMode != FSE_repeat_none)); /* We don't copy tables */
{ size_t const countSize = ZSTD_buildCTable(
op, (size_t)(oend - op),
CTable_MatchLength, MLFSELog, (symbolEncodingType_e)MLtype,
CTable_MatchLength, MLFSELog, (symbolEncodingType_e)*MLtype,
countWorkspace, max, mlCodeTable, nbSeq,
ML_defaultNorm, ML_defaultNormLog, MaxML,
prevEntropy->matchlengthCTable,
sizeof(prevEntropy->matchlengthCTable),
entropyWorkspace, entropyWkspSize);
FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for MatchLengths failed");
if (MLtype == set_compressed)
if (*MLtype == set_compressed)
*lastNCount = op;
op += countSize;
if (fseMetadata) {
if (MLtype == set_compressed) fseMetadata->lastCountSize = countSize;
fseMetadata->mlType = (symbolEncodingType_e) MLtype;
}
assert(op <= oend);
} }
*seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
return op-ostart;
}
@ -2353,6 +2340,7 @@ ZSTD_entropyCompressSequences_internal(seqStore_t* seqStorePtr,
BYTE* const oend = ostart + dstCapacity;
BYTE* op = ostart;
BYTE* lastNCount = NULL;
BYTE* seqHead;
entropyWorkspace = count + (MaxSeq + 1);
entropyWkspSize -= (MaxSeq + 1) * sizeof(*count);
@ -2398,13 +2386,22 @@ ZSTD_entropyCompressSequences_internal(seqStore_t* seqStorePtr,
return (size_t)(op - ostart);
}
{
U32 LLtype;
U32 Offtype;
U32 MLtype;
seqHead = op++;
/* build stats for sequences */
entropyStatisticsSize = ZSTD_buildSequencesStatistics(seqStorePtr,
nbSeq, &prevEntropy->fse, &nextEntropy->fse, op, oend,
strategy, &lastNCount, NULL /* no fseMetadata needed */,
entropyStatisticsSize = ZSTD_buildSequencesStatistics(seqStorePtr, nbSeq,
&LLtype, &Offtype, &MLtype, &lastNCount,
&prevEntropy->fse, &nextEntropy->fse,
op, oend,
strategy,
entropyWorkspace, entropyWkspSize);
FORWARD_IF_ERROR(entropyStatisticsSize, "FSE statistics building failed!");
*seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
op += entropyStatisticsSize;
}
{ size_t const bitstreamSize = ZSTD_encodeSequences(
op, (size_t)(oend - op),
@ -2890,13 +2887,23 @@ static size_t ZSTD_buildBlockEntropyStats_sequences(seqStore_t* seqStorePtr,
BYTE* const oend = ostart + sizeof(fseMetadata->fseTablesBuffer);
BYTE* op = ostart;
BYTE* lastNCount = NULL;
size_t hSize;
U32 LLtype;
U32 Offtype;
U32 MLtype;
DEBUGLOG(5, "ZSTD_buildBlockEntropyStats_sequences (nbSeq=%zu)", nbSeq);
ZSTD_memset(workspace, 0, wkspSize);
fseMetadata->lastCountSize = 0;
return ZSTD_buildSequencesStatistics(seqStorePtr, nbSeq, prevEntropy, nextEntropy, op, oend,
strategy, &lastNCount, fseMetadata,
hSize = ZSTD_buildSequencesStatistics(seqStorePtr, nbSeq,
&LLtype, &Offtype, &MLtype, &lastNCount,
prevEntropy, nextEntropy, op, oend,
strategy,
workspace, wkspSize);
fseMetadata->lastNCount = lastNCount;
fseMetadata->llType = (symbolEncodingType_e) LLtype;
fseMetadata->ofType = (symbolEncodingType_e) Offtype;
fseMetadata->mlType = (symbolEncodingType_e) MLtype;
return hSize;
}

2
lib/compress/zstd_compress_internal.h
View File

@ -107,7 +107,7 @@ typedef struct {
symbolEncodingType_e mlType;
BYTE fseTablesBuffer[ZSTD_MAX_FSE_HEADERS_SIZE];
size_t fseTablesSize;
size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_compressSubBlock_sequences() */
BYTE* lastNCount; /* This is to account for bug in 1.3.4. More detail in ZSTD_compressSubBlock_sequences() */
} ZSTD_fseCTablesMetadata_t;
typedef struct {

4
lib/compress/zstd_compress_superblock.c
View File

@ -500,9 +500,9 @@ static size_t ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables
* block, since it isn't worth optimizing.
*/
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
if (writeEntropy && fseMetadata->lastCountSize && fseMetadata->lastCountSize + bitstreamSize < 4) {
if (writeEntropy && fseMetadata->lastNCount && (op - fseMetadata->lastNCount) < 4) {
/* NCountSize >= 2 && bitstreamSize > 0 ==> lastCountSize == 3 */
assert(fseMetadata->lastCountSize + bitstreamSize == 3);
assert(op - fseMetadata->lastNCount == 3);
DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.3.4 by "
"emitting an uncompressed block.");
return 0;