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authorYann Collet <cyan@fb.com>2017-11-03 08:18:12 (GMT)
committerYann Collet <cyan@fb.com>2017-11-03 08:18:12 (GMT)
commit81667a1e966469de0f307bfda141ccb6e89a3115 (patch)
treea23759ffd11979f1b11482267024ff74f67176db /lib/lz4opt.h
parent82c1aed41927d0d3400ab91f975c2e163ecdcc1d (diff)
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removed code and reference to binary tree match finder
reduced size of LZ4HC state
Diffstat (limited to 'lib/lz4opt.h')
-rw-r--r--lib/lz4opt.h124
1 files changed, 2 insertions, 122 deletions
diff --git a/lib/lz4opt.h b/lib/lz4opt.h
index c754865..841e00c 100644
--- a/lib/lz4opt.h
+++ b/lib/lz4opt.h
@@ -62,7 +62,7 @@ LZ4_FORCE_INLINE int LZ4HC_literalsPrice(int const litlen)
/* requires mlen >= MINMATCH */
LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen)
{
- int price = 2 + 1; /* 16-bit offset + token */
+ int price = 1 + 2 ; /* token + 16-bit offset */
price += LZ4HC_literalsPrice(litlen);
@@ -74,126 +74,8 @@ LZ4_FORCE_INLINE int LZ4HC_sequencePrice(int litlen, int mlen)
/*-*************************************
-* Binary Tree search
+* Match finder
***************************************/
-LZ4_FORCE_INLINE int LZ4HC_BinTree_InsertAndGetAllMatches (
- LZ4HC_CCtx_internal* ctx,
- const BYTE* const ip,
- const BYTE* const iHighLimit,
- size_t best_mlen,
- LZ4HC_match_t* matches,
- int* matchNum)
-{
- U16* const chainTable = ctx->chainTable;
- U32* const HashTable = ctx->hashTable;
- const BYTE* const base = ctx->base;
- const U32 dictLimit = ctx->dictLimit;
- const U32 current = (U32)(ip - base);
- const U32 lowLimit = (ctx->lowLimit + MAX_DISTANCE > current) ? ctx->lowLimit : current - (MAX_DISTANCE - 1);
- const BYTE* const dictBase = ctx->dictBase;
- const BYTE* match;
- int nbAttempts = ctx->searchNum;
- int mnum = 0;
- U16 *ptr0, *ptr1, delta0, delta1;
- U32 matchIndex;
- size_t matchLength = 0;
- U32* HashPos;
-
- if (ip + MINMATCH > iHighLimit) return 1;
-
- /* HC4 match finder */
- HashPos = &HashTable[LZ4HC_hashPtr(ip)];
- matchIndex = *HashPos;
- *HashPos = current;
-
- ptr0 = &DELTANEXTMAXD(current*2+1);
- ptr1 = &DELTANEXTMAXD(current*2);
- delta0 = delta1 = (U16)(current - matchIndex);
-
- while ((matchIndex < current) && (matchIndex>=lowLimit) && (nbAttempts)) {
- nbAttempts--;
- if (matchIndex >= dictLimit) {
- match = base + matchIndex;
- matchLength = LZ4_count(ip, match, iHighLimit);
- } else {
- const BYTE* vLimit = ip + (dictLimit - matchIndex);
- match = dictBase + matchIndex;
- if (vLimit > iHighLimit) vLimit = iHighLimit;
- matchLength = LZ4_count(ip, match, vLimit);
- if ((ip+matchLength == vLimit) && (vLimit < iHighLimit))
- matchLength += LZ4_count(ip+matchLength, base+dictLimit, iHighLimit);
- if (matchIndex+matchLength >= dictLimit)
- match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
- }
-
- if (matchLength > best_mlen) {
- best_mlen = matchLength;
- if (matches) {
- if (matchIndex >= dictLimit)
- matches[mnum].off = (int)(ip - match);
- else
- matches[mnum].off = (int)(ip - (base + matchIndex)); /* virtual matchpos */
- matches[mnum].len = (int)matchLength;
- mnum++;
- }
- if (best_mlen > LZ4_OPT_NUM) break;
- }
-
- if (ip+matchLength >= iHighLimit) /* equal : no way to know if inf or sup */
- break; /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */
-
- DEBUGLOG(6, "ip :%016llX", (U64)ip);
- DEBUGLOG(6, "match:%016llX", (U64)match);
- if (*(ip+matchLength) < *(match+matchLength)) {
- *ptr0 = delta0;
- ptr0 = &DELTANEXTMAXD(matchIndex*2);
- if (*ptr0 == (U16)-1) break;
- delta0 = *ptr0;
- delta1 += delta0;
- matchIndex -= delta0;
- } else {
- *ptr1 = delta1;
- ptr1 = &DELTANEXTMAXD(matchIndex*2+1);
- if (*ptr1 == (U16)-1) break;
- delta1 = *ptr1;
- delta0 += delta1;
- matchIndex -= delta1;
- }
- }
-
- *ptr0 = (U16)-1;
- *ptr1 = (U16)-1;
- if (matchNum) *matchNum = mnum;
- /* if (best_mlen > 8) return best_mlen-8; */
- if (!matchNum) return 1;
- return 1;
-}
-
-
-LZ4_FORCE_INLINE void LZ4HC_updateBinTree(LZ4HC_CCtx_internal* ctx, const BYTE* const ip, const BYTE* const iHighLimit)
-{
- const BYTE* const base = ctx->base;
- const U32 target = (U32)(ip - base);
- U32 idx = ctx->nextToUpdate;
- while(idx < target)
- idx += LZ4HC_BinTree_InsertAndGetAllMatches(ctx, base+idx, iHighLimit, 8, NULL, NULL);
-}
-
-
-/** Tree updater, providing best match */
-LZ4_FORCE_INLINE int LZ4HC_BinTree_GetAllMatches (
- LZ4HC_CCtx_internal* ctx,
- const BYTE* const ip, const BYTE* const iHighLimit,
- size_t best_mlen, LZ4HC_match_t* matches, const int fullUpdate)
-{
- int mnum = 0;
- if (ip < ctx->base + ctx->nextToUpdate) return 0; /* skipped area */
- if (fullUpdate) LZ4HC_updateBinTree(ctx, ip, iHighLimit);
- best_mlen = LZ4HC_BinTree_InsertAndGetAllMatches(ctx, ip, iHighLimit, best_mlen, matches, &mnum);
- ctx->nextToUpdate = (U32)(ip - ctx->base + best_mlen);
- return mnum;
-}
-
LZ4_FORCE_INLINE
int LZ4HC_FindLongerMatch(LZ4HC_CCtx_internal* const ctx, /* Index table will be updated */
@@ -257,7 +139,6 @@ static int LZ4HC_compress_optimal (
int best_mlen, best_off;
int cur, last_match_pos = 0;
- //int const nb_matches_initial = LZ4HC_BinTree_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate);
int const nb_matches_initial = LZ4HC_HashChain_GetAllMatches(ctx, ip, matchlimit, MINMATCH-1, matches, fullUpdate);
if (!nb_matches_initial) { ip++; continue; }
@@ -323,7 +204,6 @@ static int LZ4HC_compress_optimal (
}
DEBUGLOG(7, "search at rPos:%u", cur);
- //nb_matches = LZ4HC_BinTree_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate);
if (fullUpdate)
nb_matches = LZ4HC_HashChain_GetAllMatches(ctx, curPtr, matchlimit, MINMATCH-1, matches, fullUpdate);
else