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Merge pull request #829 from facebook/fix828

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fixed decompression bug reported by @Etsukata (#828)
This commit is contained in:
Yann Collet
2017-09-01 14:28:52 -07:00
committed by GitHub
parent ab40a56fa3 ed7ace38e9
commit e7615bacc3
4 changed files with 21 additions and 34 deletions
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1
NEWS
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@@ -1,6 +1,7 @@
v1.3.2
license : changed /examples license to BSD + GPLv2
license : fix a few header files to reflect new license (#825)
fix : 32-bits build can now decode large offsets (levels 21+)
fix : a rare compression bug when compression generates very large distances (only possible at --ultra -22)
build: better compatibility with reproducible builds, by Bernhard M. Wiedemann (@bmwiedemann) (#818)

8
lib/common/threading.c
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@@ -14,12 +14,8 @@
* This file will hold wrapper for systems, which do not support pthreads
*/
/* When ZSTD_MULTITHREAD is not defined, this file would become an empty translation unit.
* Include some ISO C header code to prevent this and portably avoid related warnings.
* (Visual C++: C4206 / GCC: -Wpedantic / Clang: -Wempty-translation-unit)
*/
#include <stddef.h>
/* create fake symbol to avoid empty trnaslation unit warning */
int g_ZSTD_threading_useles_symbol;
#if defined(ZSTD_MULTITHREAD) && defined(_WIN32)

32
lib/decompress/zstd_decompress.c
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@@ -1088,7 +1088,10 @@ static size_t ZSTD_decompressSequences(
}
FORCE_INLINE_TEMPLATE seq_t ZSTD_decodeSequenceLong_generic(seqState_t* seqState, int const longOffsets)
typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e;
HINT_INLINE
seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const longOffsets)
{
seq_t seq;
@@ -1180,13 +1183,6 @@ FORCE_INLINE_TEMPLATE seq_t ZSTD_decodeSequenceLong_generic(seqState_t* seqState
return seq;
}
static seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, unsigned const windowSize) {
if (ZSTD_highbit32(windowSize) > STREAM_ACCUMULATOR_MIN) {
return ZSTD_decodeSequenceLong_generic(seqState, 1);
} else {
return ZSTD_decodeSequenceLong_generic(seqState, 0);
}
}
HINT_INLINE
size_t ZSTD_execSequenceLong(BYTE* op,
@@ -1202,11 +1198,9 @@ size_t ZSTD_execSequenceLong(BYTE* op,
const BYTE* match = sequence.match;
/* check */
#if 1
if (oMatchEnd>oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
if (iLitEnd > litLimit) return ERROR(corruption_detected); /* over-read beyond lit buffer */
if (oLitEnd>oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
#endif
/* copy Literals */
ZSTD_copy8(op, *litPtr);
@@ -1216,7 +1210,6 @@ size_t ZSTD_execSequenceLong(BYTE* op,
*litPtr = iLitEnd; /* update for next sequence */
/* copy Match */
#if 1
if (sequence.offset > (size_t)(oLitEnd - base)) {
/* offset beyond prefix */
if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
@@ -1236,8 +1229,8 @@ size_t ZSTD_execSequenceLong(BYTE* op,
return sequenceLength;
}
} }
/* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
#endif
assert(op <= oend_w);
assert(sequence.matchLength >= MINMATCH);
/* match within prefix */
if (sequence.offset < 8) {
@@ -1285,9 +1278,12 @@ static size_t ZSTD_decompressSequencesLong(
const BYTE* const base = (const BYTE*) (dctx->base);
const BYTE* const vBase = (const BYTE*) (dctx->vBase);
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
unsigned const windowSize32 = (unsigned)dctx->fParams.windowSize;
int nbSeq;
unsigned long long const regularWindowSizeMax = 1ULL << STREAM_ACCUMULATOR_MIN;
ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (dctx->fParams.windowSize >= regularWindowSizeMax));
ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
/* Build Decoding Tables */
{ size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
if (ZSTD_isError(seqHSize)) return seqHSize;
@@ -1315,13 +1311,13 @@ static size_t ZSTD_decompressSequencesLong(
/* prepare in advance */
for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && seqNb<seqAdvance; seqNb++) {
sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, windowSize32);
sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, isLongOffset);
}
if (seqNb<seqAdvance) return ERROR(corruption_detected);
/* decode and decompress */
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && seqNb<nbSeq ; seqNb++) {
seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, windowSize32);
seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, isLongOffset);
size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
PREFETCH(sequence.match);
@@ -1369,10 +1365,6 @@ static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
ip += litCSize;
srcSize -= litCSize;
}
if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as it's performance detrimental */
/* likely because of register pressure */
/* if that's the correct cause, then 32-bits ARM should be affected differently */
/* it would be good to test this on ARM real hardware, to see if prefetch version improves speed */
if (dctx->fParams.windowSize > (1<<23))
return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);

4
programs/bench.c
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@@ -373,10 +373,8 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
blockTable[blockNb].cPtr, blockTable[blockNb].cSize,
ddict);
if (ZSTD_isError(regenSize)) {
DISPLAY("ZSTD_decompress_usingDDict() failed on block %u of size %u : %s \n",
EXM_THROW(2, "ZSTD_decompress_usingDDict() failed on block %u of size %u : %s \n",
blockNb, (U32)blockTable[blockNb].cSize, ZSTD_getErrorName(regenSize));
clockLoop = 0; /* force immediate test end */
break;
}
blockTable[blockNb].resSize = regenSize;
}