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[libzstd] Increase MaxOff

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This commit is contained in:
Nick Terrell 2017-09-18 16:54:53 -07:00
parent bdc83f523b
commit bbe77212ef
4 changed files with 65 additions and 30 deletions
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7
lib/common/zstd_internal.h
View File

@ -123,7 +123,8 @@ typedef enum { set_basic, set_rle, set_compressed, set_repeat } symbolEncodingTy
#define MaxLit ((1<<Litbits) - 1)
#define MaxML 52
#define MaxLL 35
#define MaxOff 28
#define DefaultMaxOff 28
#define MaxOff 31
#define MaxSeq MAX(MaxLL, MaxML) /* Assumption : MaxOff < MaxLL,MaxML */
#define MLFSELog 9
#define LLFSELog 9
@ -149,8 +150,8 @@ static const S16 ML_defaultNorm[MaxML+1] = { 1, 4, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1,
#define ML_DEFAULTNORMLOG 6 /* for static allocation */
static const U32 ML_defaultNormLog = ML_DEFAULTNORMLOG;
static const S16 OF_defaultNorm[MaxOff+1] = { 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,-1,-1,-1,-1,-1 };
static const S16 OF_defaultNorm[DefaultMaxOff+1] = { 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1,-1,-1,-1,-1,-1 };
#define OF_DEFAULTNORMLOG 5 /* for static allocation */
static const U32 OF_defaultNormLog = OF_DEFAULTNORMLOG;

33
lib/compress/zstd_compress.c
View File

@ -1250,20 +1250,30 @@ void ZSTD_seqToCodes(const seqStore_t* seqStorePtr)
mlCodeTable[seqStorePtr->longLengthPos] = MaxML;
}
MEM_STATIC symbolEncodingType_e ZSTD_selectEncodingType(FSE_repeat* repeatMode,
size_t const mostFrequent, size_t nbSeq, U32 defaultNormLog)
typedef enum {
ZSTD_defaultDisallowed = 0,
ZSTD_defaultAllowed = 1
} ZSTD_defaultPolicy_e;
MEM_STATIC symbolEncodingType_e ZSTD_selectEncodingType(
FSE_repeat* repeatMode, size_t const mostFrequent, size_t nbSeq,
U32 defaultNormLog, ZSTD_defaultPolicy_e const isDefaultAllowed)
{
#define MIN_SEQ_FOR_DYNAMIC_FSE 64
#define MAX_SEQ_FOR_STATIC_FSE 1000
if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
ZSTD_STATIC_ASSERT(ZSTD_defaultDisallowed == 0 && ZSTD_defaultAllowed != 0);
if ((mostFrequent == nbSeq) && (!isDefaultAllowed || nbSeq > 2)) {
/* Prefer set_basic over set_rle when there are 2 or less symbols,
* since RLE uses 1 byte, but set_basic uses 5-6 bits per symbol.
* If basic encoding isn't possible, always choose RLE.
*/
*repeatMode = FSE_repeat_check;
return set_rle;
}
if ((*repeatMode == FSE_repeat_valid) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
if (isDefaultAllowed && (*repeatMode == FSE_repeat_valid) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
return set_repeat;
}
if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (defaultNormLog-1)))) {
if (isDefaultAllowed && ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (defaultNormLog-1))))) {
*repeatMode = FSE_repeat_valid;
return set_basic;
}
@ -1299,6 +1309,7 @@ MEM_STATIC size_t ZSTD_buildCTable(void* dst, size_t dstCapacity,
count[codeTable[nbSeq-1]]--;
nbSeq_1--;
}
assert(nbSeq_1 > 1);
CHECK_F(FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max));
{ size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
if (FSE_isError(NCountSize)) return NCountSize;
@ -1436,7 +1447,7 @@ MEM_STATIC size_t ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
/* CTable for Literal Lengths */
{ U32 max = MaxLL;
size_t const mostFrequent = FSE_countFast_wksp(count, &max, llCodeTable, nbSeq, entropy->workspace);
LLtype = ZSTD_selectEncodingType(&entropy->litlength_repeatMode, mostFrequent, nbSeq, LL_defaultNormLog);
LLtype = ZSTD_selectEncodingType(&entropy->litlength_repeatMode, mostFrequent, nbSeq, LL_defaultNormLog, ZSTD_defaultAllowed);
{ size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_LitLength, LLFSELog, (symbolEncodingType_e)LLtype,
count, max, llCodeTable, nbSeq, LL_defaultNorm, LL_defaultNormLog, MaxLL,
entropy->workspace, sizeof(entropy->workspace));
@ -1446,9 +1457,11 @@ MEM_STATIC size_t ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
/* CTable for Offsets */
{ U32 max = MaxOff;
size_t const mostFrequent = FSE_countFast_wksp(count, &max, ofCodeTable, nbSeq, entropy->workspace);
Offtype = ZSTD_selectEncodingType(&entropy->offcode_repeatMode, mostFrequent, nbSeq, OF_defaultNormLog);
/* We can only use the basic table if max <= DefaultMaxOff, otherwise the offsets are too large */
ZSTD_defaultPolicy_e const defaultPolicy = max <= DefaultMaxOff ? ZSTD_defaultAllowed : ZSTD_defaultDisallowed;
Offtype = ZSTD_selectEncodingType(&entropy->offcode_repeatMode, mostFrequent, nbSeq, OF_defaultNormLog, defaultPolicy);
{ size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_OffsetBits, OffFSELog, (symbolEncodingType_e)Offtype,
count, max, ofCodeTable, nbSeq, OF_defaultNorm, OF_defaultNormLog, MaxOff,
count, max, ofCodeTable, nbSeq, OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
entropy->workspace, sizeof(entropy->workspace));
if (ZSTD_isError(countSize)) return countSize;
op += countSize;
@ -1456,7 +1469,7 @@ MEM_STATIC size_t ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
/* CTable for MatchLengths */
{ U32 max = MaxML;
size_t const mostFrequent = FSE_countFast_wksp(count, &max, mlCodeTable, nbSeq, entropy->workspace);
MLtype = ZSTD_selectEncodingType(&entropy->matchlength_repeatMode, mostFrequent, nbSeq, ML_defaultNormLog);
MLtype = ZSTD_selectEncodingType(&entropy->matchlength_repeatMode, mostFrequent, nbSeq, ML_defaultNormLog, ZSTD_defaultAllowed);
{ size_t const countSize = ZSTD_buildCTable(op, oend - op, CTable_MatchLength, MLFSELog, (symbolEncodingType_e)MLtype,
count, max, mlCodeTable, nbSeq, ML_defaultNorm, ML_defaultNormLog, MaxML,
entropy->workspace, sizeof(entropy->workspace));

53
lib/decompress/zstd_decompress.c
View File

@ -862,6 +862,15 @@ size_t ZSTD_execSequenceLast7(BYTE* op,
typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e;
/* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum
* offset bits. But we can only read at most (STREAM_ACCUMULATOR_MIN_32 - 1)
* bits before reloading. This value is the maximum number of bytes we read
* after reloading when we are decoding long offets.
*/
#define LONG_OFFSETS_MAX_EXTRA_BITS_32 \
(ZSTD_WINDOWLOG_MAX_32 > STREAM_ACCUMULATOR_MIN_32 \
? ZSTD_WINDOWLOG_MAX_32 - STREAM_ACCUMULATOR_MIN_32 \
: 0)
static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)
{
@ -869,7 +878,7 @@ static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e l
U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= MaxOff, by table construction */
U32 const llBits = LL_bits[llCode];
U32 const mlBits = ML_bits[mlCode];
@ -896,7 +905,7 @@ static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e l
0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D,
0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD,
0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD };
0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
/* sequence */
{ size_t offset;
@ -904,8 +913,10 @@ static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e l
offset = 0;
else {
ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
if (longOffsets) {
int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN);
ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 2);
assert(ofBits <= MaxOff);
if (MEM_32bits() && longOffsets) {
U32 const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN_32-1);
offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
@ -936,13 +947,17 @@ static seq_t ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e l
seq.matchLength = ML_base[mlCode]
+ ((mlCode>31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
if (MEM_32bits() && (mlBits+llBits>24)) BIT_reloadDStream(&seqState->DStream);
if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
BIT_reloadDStream(&seqState->DStream);
if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
BIT_reloadDStream(&seqState->DStream);
/* Verify that there is enough bits to read the rest of the data in 64-bit mode. */
ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
seq.litLength = LL_base[llCode]
+ ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
if ( MEM_32bits()
|| (totalBits > 64 - 7 - (LLFSELog+MLFSELog+OffFSELog)) )
BIT_reloadDStream(&seqState->DStream);
if (MEM_32bits())
BIT_reloadDStream(&seqState->DStream);
DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u",
(U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset);
@ -1102,7 +1117,6 @@ static size_t ZSTD_decompressSequences(
}
HINT_INLINE
seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const longOffsets)
{
@ -1110,7 +1124,7 @@ seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const long
U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= MaxOff, by table construction */
U32 const llBits = LL_bits[llCode];
U32 const mlBits = ML_bits[mlCode];
@ -1137,7 +1151,7 @@ seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const long
0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D,
0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD,
0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD };
0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
/* sequence */
{ size_t offset;
@ -1145,8 +1159,10 @@ seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const long
offset = 0;
else {
ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
if (longOffsets) {
int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN);
ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 2);
assert(ofBits <= MaxOff);
if (MEM_32bits() && longOffsets) {
U32 const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN_32-1);
offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
@ -1176,11 +1192,16 @@ seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const long
}
seq.matchLength = ML_base[mlCode] + ((mlCode>31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
if (MEM_32bits() && (mlBits+llBits>24)) BIT_reloadDStream(&seqState->DStream);
if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
BIT_reloadDStream(&seqState->DStream);
if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
BIT_reloadDStream(&seqState->DStream);
/* Verify that there is enough bits to read the rest of the data in 64-bit mode. */
ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
seq.litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
if (MEM_32bits() ||
(totalBits > 64 - 7 - (LLFSELog+MLFSELog+OffFSELog)) ) BIT_reloadDStream(&seqState->DStream);
if (MEM_32bits())
BIT_reloadDStream(&seqState->DStream);
{ size_t const pos = seqState->pos + seq.litLength;
seq.match = seqState->base + pos - seq.offset; /* single memory segment */

2
tests/decodecorpus.c
View File

@ -881,7 +881,7 @@ static size_t writeSequences(U32* seed, frame_t* frame, seqStore_t* seqStorePtr,
frame->stats.offsetSymbolSet, 28)) {
Offtype = set_repeat;
} else if (!(RAND(seed) & 3)) {
FSE_buildCTable_wksp(CTable_OffsetBits, OF_defaultNorm, MaxOff, OF_defaultNormLog, scratchBuffer, sizeof(scratchBuffer));
FSE_buildCTable_wksp(CTable_OffsetBits, OF_defaultNorm, DefaultMaxOff, OF_defaultNormLog, scratchBuffer, sizeof(scratchBuffer));
Offtype = set_basic;
} else {
size_t nbSeq_1 = nbSeq;