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a bugfix for backward matches

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This commit is contained in:
inikep 2016-02-06 15:18:26 +01:00
parent dbade7c263
commit da730ff092
1 changed files with 42 additions and 44 deletions
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86
lib/zstd_opt.c
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@ -185,20 +185,22 @@ size_t ZSTD_insertBtAndGetAllMatches (
U32 nbCompares, const U32 mls,
U32 extDict, ZSTD_match_t* matches, size_t bestLength)
{
U32* const hashTable = zc->hashTable;
const BYTE* const base = zc->base;
const U32 current = (U32)(ip-base);
const U32 hashLog = zc->params.hashLog;
const size_t h = ZSTD_hashPtr(ip, hashLog, mls);
U32* const hashTable = zc->hashTable;
U32 matchIndex = hashTable[h];
if (matchIndex >= current) return 0;
U32* const bt = zc->contentTable;
const U32 btLog = zc->params.contentLog - 1;
const U32 btMask= (1 << btLog) - 1;
U32 matchIndex = hashTable[h];
size_t commonLengthSmaller=0, commonLengthLarger=0;
const BYTE* const base = zc->base;
const BYTE* const dictBase = zc->dictBase;
const U32 dictLimit = zc->dictLimit;
const BYTE* const dictEnd = dictBase + dictLimit;
const BYTE* const prefixStart = base + dictLimit;
const U32 current = (U32)(ip-base);
const U32 btLow = btMask >= current ? 0 : current - btMask;
const U32 windowLow = zc->lowLimit;
U32* smallerPtr = bt + 2*(current&btMask);
@ -285,6 +287,8 @@ FORCE_INLINE size_t ZSTD_BtGetAllMatches_selectMLS (
const BYTE* ip, const BYTE* const iLowLimit, const BYTE* const iHighLimit,
const U32 maxNbAttempts, const U32 matchLengthSearch, ZSTD_match_t* matches, size_t minml)
{
if (iLowLimit) {}; // skip warnings
switch(matchLengthSearch)
{
default :
@ -320,6 +324,7 @@ size_t ZSTD_HcGetAllMatches_generic (
/* HC4 match finder */
matchIndex = ZSTD_insertAndFindFirstIndex (zc, ip, mls);
if (matchIndex >= current) return 0;
while ((matchIndex>lowLimit) && (nbAttempts)) {
size_t currentMl=0;
@ -329,7 +334,6 @@ size_t ZSTD_HcGetAllMatches_generic (
match = base + matchIndex;
if (match[minml] == ip[minml]) /* potentially better */
currentMl = ZSTD_count(ip, match, iHighLimit);
if (currentMl > 0) {
while ((match-back > base) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
currentMl += back;
@ -338,6 +342,10 @@ size_t ZSTD_HcGetAllMatches_generic (
match = dictBase + matchIndex;
if (MEM_read32(match) == MEM_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
currentMl = ZSTD_count_2segments(ip+MINMATCH, match+MINMATCH, iHighLimit, dictEnd, prefixStart) + MINMATCH;
if (currentMl > 0) {
while ((match-back > dictBase) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
currentMl += back;
}
}
/* save best solution */
@ -576,19 +584,22 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
if (!opt[cur].off && opt[cur].mlen != 1) {
mlen = ZSTD_count(inr, inr - opt[cur].rep2, iend); // check rep2
ZSTD_LOG_PARSER("%d: try REP2 rep2=%d mlen=%d\n", (int)(inr-base), opt[cur].rep2, mlen);
}
else {
mlen = ZSTD_count(inr, inr - opt[cur].rep, iend); // check rep
ZSTD_LOG_PARSER("%d: try REP1 rep=%d mlen=%d\n", (int)(inr-base), opt[cur].rep, mlen);
}
size_t cur_rep;
best_mlen = 0;
if (mlen >= MINMATCH)
if (!opt[cur].off && opt[cur].mlen != 1) {
cur_rep = opt[cur].rep2;
ZSTD_LOG_PARSER("%d: try REP2 rep2=%d mlen=%d\n", (int)(inr-base), cur_rep, mlen);
}
else {
cur_rep = opt[cur].rep;
ZSTD_LOG_PARSER("%d: try REP1 rep=%d mlen=%d\n", (int)(inr-base), cur_rep, mlen);
}
if (MEM_read32(inr) == MEM_read32(inr - cur_rep)) // check rep
{
mlen = ZSTD_count(inr+MINMATCH, inr+MINMATCH - cur_rep, iend) + MINMATCH;
ZSTD_LOG_PARSER("%d: Found REP mlen=%d off=%d rep=%d opt[%d].off=%d\n", (int)(inr-base), mlen, 0, opt[cur].rep, cur, opt[cur].off);
if (mlen > sufficient_len || cur + mlen >= ZSTD_OPT_NUM)
@ -666,6 +677,8 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
best_mlen = (cur2 + matches[i].len < ZSTD_OPT_NUM) ? matches[i].len : ZSTD_OPT_NUM - cur2;
ZSTD_LOG_PARSER("%d: Found1 cur=%d cur2=%d mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(inr-base), cur, cur2, matches[i].len, matches[i].off, best_mlen, last_pos);
if (mlen < matches[i].back + 1)
mlen = matches[i].back + 1;
while (mlen <= best_mlen)
{
@ -739,7 +752,7 @@ _storeSequence: // cur, last_pos, best_mlen, best_off have to be set
size_t litLength = ip - anchor;
ZSTD_LOG_ENCODE("%d/%d: BEFORE_ENCODE literals=%d mlen=%d off=%d rep1=%d rep2=%d\n", (int)(ip-base), (int)(iend-base), (int)(litLength), (int)mlen, (int)(offset), (int)rep_1, (int)rep_2);
ZSTD_LOG_ENCODE("%d/%d: ENCODE1 literals=%d mlen=%d off=%d rep1=%d rep2=%d\n", (int)(ip-base), (int)(iend-base), (int)(litLength), (int)mlen, (int)(offset), (int)rep_1, (int)rep_2);
if (offset)
{
@ -756,7 +769,7 @@ _storeSequence: // cur, last_pos, best_mlen, best_off have to be set
}
}
ZSTD_LOG_ENCODE("%d/%d: ENCODE literals=%d mlen=%d off=%d rep1=%d rep2=%d\n", (int)(ip-base), (int)(iend-base), (int)(litLength), (int)mlen, (int)(offset), (int)rep_1, (int)rep_2);
ZSTD_LOG_ENCODE("%d/%d: ENCODE2 literals=%d mlen=%d off=%d rep1=%d rep2=%d\n", (int)(ip-base), (int)(iend-base), (int)(litLength), (int)mlen, (int)(offset), (int)rep_1, (int)rep_2);
// printf("orig="); print_hex_text(ip, mlen, 0);
// printf("match="); print_hex_text(ip-offset, mlen, 0);
@ -766,33 +779,18 @@ _storeSequence: // cur, last_pos, best_mlen, best_off have to be set
ml2 = ZSTD_count(ip, ip-offset, iend);
else
ml2 = ZSTD_count(ip, ip-rep_1, iend);
if (ml2 < mlen && ml2 < MINMATCH)
{
printf("%d: ERROR iend=%d mlen=%d offset=%d ml2=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset, (int)ml2);
exit(0);
}
if (ip < anchor)
{
printf("%d: ERROR ip < anchor iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset);
exit(0);
}
if (ip - offset < base)
{
printf("%d: ERROR ip - offset < base iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset);
exit(0);
}
if (mlen < MINMATCH)
{
printf("%d: ERROR mlen < MINMATCH iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset);
exit(0);
}
if (ip + mlen > iend)
{
printf("%d: ERROR ip + mlen >= iend iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset);
exit(0);
}
if (ml2 < mlen && ml2 < MINMATCH) {
printf("%d: ERROR iend=%d mlen=%d offset=%d ml2=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset, (int)ml2); exit(0); }
if (ip < anchor) {
printf("%d: ERROR ip < anchor iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset); exit(0); }
if (ip - offset < ctx->base) {
printf("%d: ERROR ip - offset < base iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset); exit(0); }
if ((int)offset >= (1 << ctx->params.windowLog)) {
printf("%d: offset >= (1 << params.windowLog) iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset); exit(0); }
if (mlen < MINMATCH) {
printf("%d: ERROR mlen < MINMATCH iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset); exit(0); }
if (ip + mlen > iend) {
printf("%d: ERROR ip + mlen >= iend iend=%d mlen=%d offset=%d\n", (int)(ip - base), (int)(iend - ip), (int)mlen, (int)offset); exit(0); }
#endif
ZSTD_updatePrice(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);