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Merge pull request #2777 from terrelln/oss-fuzz-fix

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[rsyncable] Fix test failures
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Nick Terrell 2021-09-14 13:20:22 -07:00 committed by GitHub
commit 2fabd370bb
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1 changed files with 17 additions and 19 deletions
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36
lib/compress/zstdmt_compress.c
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@ -1705,24 +1705,32 @@ findSynchronizationPoint(ZSTDMT_CCtx const* mtctx, ZSTD_inBuffer const input)
*/
return syncPoint;
/* Initialize the loop variables. */
if (mtctx->inBuff.filled < RSYNC_MIN_BLOCK_SIZE - RSYNC_LENGTH) {
if (mtctx->inBuff.filled < RSYNC_MIN_BLOCK_SIZE) {
/* We don't need to scan the first RSYNC_MIN_BLOCK_SIZE positions
* because they can't possibly be a sync point. So we can start
* part way through the input buffer.
*/
pos = RSYNC_MIN_BLOCK_SIZE - mtctx->inBuff.filled;
assert(pos <= input.size - input.pos /* validated earlier */);
assert(pos >= RSYNC_LENGTH);
prev = istart + pos - RSYNC_LENGTH;
hash = ZSTD_rollingHash_compute(prev, RSYNC_LENGTH);
} else if (mtctx->inBuff.filled >= RSYNC_LENGTH) {
/* We have enough bytes buffered to initialize the hash.
if (pos >= RSYNC_LENGTH) {
prev = istart + pos - RSYNC_LENGTH;
hash = ZSTD_rollingHash_compute(prev, RSYNC_LENGTH);
} else {
assert(mtctx->inBuff.filled >= RSYNC_LENGTH);
prev = (BYTE const*)mtctx->inBuff.buffer.start + mtctx->inBuff.filled - RSYNC_LENGTH;
hash = ZSTD_rollingHash_compute(prev + pos, (RSYNC_LENGTH - pos));
hash = ZSTD_rollingHash_append(hash, istart, pos);
}
} else {
/* We have enough bytes buffered to initialize the hash,
* and are have processed enough bytes to find a sync point.
* Start scanning at the beginning of the input.
*/
assert(mtctx->inBuff.filled >= RSYNC_MIN_BLOCK_SIZE);
assert(RSYNC_MIN_BLOCK_SIZE >= RSYNC_LENGTH);
pos = 0;
prev = (BYTE const*)mtctx->inBuff.buffer.start + mtctx->inBuff.filled - RSYNC_LENGTH;
hash = ZSTD_rollingHash_compute(prev, RSYNC_LENGTH);
if ((hash & hitMask) == hitMask && mtctx->inBuff.filled >= RSYNC_MIN_BLOCK_SIZE) {
if ((hash & hitMask) == hitMask) {
/* We're already at a sync point so don't load any more until
* we're able to flush this sync point.
* This likely happened because the job table was full so we
@ -1732,16 +1740,6 @@ findSynchronizationPoint(ZSTDMT_CCtx const* mtctx, ZSTD_inBuffer const input)
syncPoint.flush = 1;
return syncPoint;
}
} else {
/* We don't have enough bytes buffered to initialize the hash, but
* we know we have at least RSYNC_LENGTH bytes total.
* Start scanning after the first RSYNC_LENGTH bytes less the bytes
* already buffered.
*/
pos = RSYNC_LENGTH - mtctx->inBuff.filled;
prev = (BYTE const*)mtctx->inBuff.buffer.start - pos;
hash = ZSTD_rollingHash_compute(mtctx->inBuff.buffer.start, mtctx->inBuff.filled);
hash = ZSTD_rollingHash_append(hash, istart, pos);
}
/* Starting with the hash of the previous RSYNC_LENGTH bytes, roll
* through the input. If we hit a synchronization point, then cut the
@ -1753,7 +1751,7 @@ findSynchronizationPoint(ZSTDMT_CCtx const* mtctx, ZSTD_inBuffer const input)
*/
for (; pos < syncPoint.toLoad; ++pos) {
BYTE const toRemove = pos < RSYNC_LENGTH ? prev[pos] : istart[pos - RSYNC_LENGTH];
/* if (pos >= RSYNC_LENGTH) assert(ZSTD_rollingHash_compute(istart + pos - RSYNC_LENGTH, RSYNC_LENGTH) == hash); */
assert(pos < RSYNC_LENGTH || ZSTD_rollingHash_compute(istart + pos - RSYNC_LENGTH, RSYNC_LENGTH) == hash);
hash = ZSTD_rollingHash_rotate(hash, toRemove, istart[pos], primePower);
assert(mtctx->inBuff.filled + pos >= RSYNC_MIN_BLOCK_SIZE);
if ((hash & hitMask) == hitMask) {