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path: root/thirdparty/zstd/decompress/zstd_decompress.c
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Diffstat (limited to 'thirdparty/zstd/decompress/zstd_decompress.c')
-rw-r--r--thirdparty/zstd/decompress/zstd_decompress.c72
1 files changed, 41 insertions, 31 deletions
diff --git a/thirdparty/zstd/decompress/zstd_decompress.c b/thirdparty/zstd/decompress/zstd_decompress.c
index 96fc609089..a59d944112 100644
--- a/thirdparty/zstd/decompress/zstd_decompress.c
+++ b/thirdparty/zstd/decompress/zstd_decompress.c
@@ -827,9 +827,9 @@ typedef struct {
FSE_DState_t stateOffb;
FSE_DState_t stateML;
size_t prevOffset[ZSTD_REP_NUM];
- const BYTE* base;
+ const BYTE* prefixStart;
+ const BYTE* dictEnd;
size_t pos;
- uPtrDiff gotoDict;
} seqState_t;
@@ -1224,8 +1224,9 @@ seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const long
BIT_reloadDStream(&seqState->DStream);
{ size_t const pos = seqState->pos + seq.litLength;
- seq.match = seqState->base + pos - seq.offset; /* single memory segment */
- if (seq.offset > pos) seq.match += seqState->gotoDict; /* separate memory segment */
+ const BYTE* const matchBase = (seq.offset > pos) ? seqState->dictEnd : seqState->prefixStart;
+ seq.match = matchBase + pos - seq.offset; /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted.
+ * No consequence though : no memory access will occur, overly large offset will be detected in ZSTD_execSequenceLong() */
seqState->pos = pos + seq.matchLength;
}
@@ -1243,7 +1244,7 @@ HINT_INLINE
size_t ZSTD_execSequenceLong(BYTE* op,
BYTE* const oend, seq_t sequence,
const BYTE** litPtr, const BYTE* const litLimit,
- const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
+ const BYTE* const prefixStart, const BYTE* const dictStart, const BYTE* const dictEnd)
{
BYTE* const oLitEnd = op + sequence.litLength;
size_t const sequenceLength = sequence.litLength + sequence.matchLength;
@@ -1253,21 +1254,21 @@ size_t ZSTD_execSequenceLong(BYTE* op,
const BYTE* match = sequence.match;
/* check */
- if (oMatchEnd>oend) return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
+ 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);
+ if (oLitEnd > oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, prefixStart, dictStart, dictEnd);
/* copy Literals */
- ZSTD_copy8(op, *litPtr);
+ ZSTD_copy8(op, *litPtr); /* note : op <= oLitEnd <= oend_w == oend - 8 */
if (sequence.litLength > 8)
ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
op = oLitEnd;
*litPtr = iLitEnd; /* update for next sequence */
/* copy Match */
- if (sequence.offset > (size_t)(oLitEnd - base)) {
+ if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
/* offset beyond prefix */
- if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
+ if (sequence.offset > (size_t)(oLitEnd - dictStart)) return ERROR(corruption_detected);
if (match + sequence.matchLength <= dictEnd) {
memmove(oLitEnd, match, sequence.matchLength);
return sequenceLength;
@@ -1277,7 +1278,7 @@ size_t ZSTD_execSequenceLong(BYTE* op,
memmove(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
- match = base;
+ match = prefixStart;
if (op > oend_w || sequence.matchLength < MINMATCH) {
U32 i;
for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
@@ -1331,8 +1332,8 @@ static size_t ZSTD_decompressSequencesLong(
BYTE* op = ostart;
const BYTE* litPtr = dctx->litPtr;
const BYTE* const litEnd = litPtr + dctx->litSize;
- const BYTE* const base = (const BYTE*) (dctx->base);
- const BYTE* const vBase = (const BYTE*) (dctx->vBase);
+ const BYTE* const prefixStart = (const BYTE*) (dctx->base);
+ const BYTE* const dictStart = (const BYTE*) (dctx->vBase);
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
int nbSeq;
@@ -1353,9 +1354,9 @@ static size_t ZSTD_decompressSequencesLong(
int seqNb;
dctx->fseEntropy = 1;
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
- seqState.base = base;
- seqState.pos = (size_t)(op-base);
- seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast to avoid undefined behaviour */
+ seqState.prefixStart = prefixStart;
+ seqState.pos = (size_t)(op-prefixStart);
+ seqState.dictEnd = dictEnd;
CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend-ip), corruption_detected);
FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
@@ -1370,9 +1371,9 @@ static size_t ZSTD_decompressSequencesLong(
/* decode and decompress */
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && seqNb<nbSeq ; seqNb++) {
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);
+ size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
- PREFETCH(sequence.match);
+ PREFETCH(sequence.match); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
sequences[seqNb&STOSEQ_MASK] = sequence;
op += oneSeqSize;
}
@@ -1381,7 +1382,7 @@ static size_t ZSTD_decompressSequencesLong(
/* finish queue */
seqNb -= seqAdvance;
for ( ; seqNb<nbSeq ; seqNb++) {
- size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb&STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
+ size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb&STOSEQ_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
op += oneSeqSize;
}
@@ -2450,14 +2451,16 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
return ZSTD_decompressLegacyStream(zds->legacyContext, legacyVersion, output, input);
}
#endif
- return hSize; /* error */
+ return hSize; /* error */
}
if (hSize != 0) { /* need more input */
size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */
- if (toLoad > (size_t)(iend-ip)) { /* not enough input to load full header */
- if (iend-ip > 0) {
- memcpy(zds->headerBuffer + zds->lhSize, ip, iend-ip);
- zds->lhSize += iend-ip;
+ size_t const remainingInput = (size_t)(iend-ip);
+ assert(iend >= ip);
+ if (toLoad > remainingInput) { /* not enough input to load full header */
+ if (remainingInput > 0) {
+ memcpy(zds->headerBuffer + zds->lhSize, ip, remainingInput);
+ zds->lhSize += remainingInput;
}
input->pos = input->size;
return (MAX(ZSTD_frameHeaderSize_min, hSize) - zds->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
@@ -2472,8 +2475,10 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
&& (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) {
size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend-istart);
if (cSize <= (size_t)(iend-istart)) {
+ /* shortcut : using single-pass mode */
size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, oend-op, istart, cSize, zds->ddict);
if (ZSTD_isError(decompressedSize)) return decompressedSize;
+ DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()")
ip = istart + cSize;
op += decompressedSize;
zds->expected = 0;
@@ -2496,8 +2501,9 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
}
/* control buffer memory usage */
- DEBUGLOG(4, "Control max buffer memory usage (max %u KB)",
- (U32)(zds->maxWindowSize >> 10));
+ DEBUGLOG(4, "Control max memory usage (%u KB <= max %u KB)",
+ (U32)(zds->fParams.windowSize >>10),
+ (U32)(zds->maxWindowSize >> 10) );
zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
if (zds->fParams.windowSize > zds->maxWindowSize) return ERROR(frameParameter_windowTooLarge);
@@ -2555,17 +2561,21 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
/* fall-through */
case zdss_load:
{ size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds);
- size_t const toLoad = neededInSize - zds->inPos; /* should always be <= remaining space within inBuff */
+ size_t const toLoad = neededInSize - zds->inPos;
+ int const isSkipFrame = ZSTD_isSkipFrame(zds);
size_t loadedSize;
- if (toLoad > zds->inBuffSize - zds->inPos) return ERROR(corruption_detected); /* should never happen */
- loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend-ip);
+ if (isSkipFrame) {
+ loadedSize = MIN(toLoad, (size_t)(iend-ip));
+ } else {
+ if (toLoad > zds->inBuffSize - zds->inPos) return ERROR(corruption_detected); /* should never happen */
+ loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend-ip);
+ }
ip += loadedSize;
zds->inPos += loadedSize;
if (loadedSize < toLoad) { someMoreWork = 0; break; } /* not enough input, wait for more */
/* decode loaded input */
- { const int isSkipFrame = ZSTD_isSkipFrame(zds);
- size_t const decodedSize = ZSTD_decompressContinue(zds,
+ { size_t const decodedSize = ZSTD_decompressContinue(zds,
zds->outBuff + zds->outStart, zds->outBuffSize - zds->outStart,
zds->inBuff, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 05:08:50 +0000