Revert "Revert "ZSTD_compressBlock_opt_extDict_generic""

This reverts commit 2b714dfd26.
2025-10-31 00:27:46 +02:00 · 2016-02-09 23:00:41 +01:00
parent 2b714dfd26
commit be77f3342d
2 changed files with 492 additions and 6 deletions
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -1927,12 +1927,12 @@ static void ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx* ctx, const void* src,

 static void ZSTD_compressBlock_opt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
-    ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
+    ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 0, 2);
 }

 static void ZSTD_compressBlock_opt_bt_extDict(ZSTD_CCtx* ctx, const void* src, size_t srcSize)
 {
-    ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
+    ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 1, 2);
 }


@@ -2106,10 +2106,12 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t
    case ZSTD_greedy:
    case ZSTD_lazy:
    case ZSTD_lazy2:
+    case ZSTD_opt:
        ZSTD_insertAndFindFirstIndex (zc, iend-8, zc->params.searchLength);
        break;

    case ZSTD_btlazy2:
+    case ZSTD_opt_bt:
        ZSTD_updateTree(zc, iend-8, iend, 1 << zc->params.searchLog, zc->params.searchLength);
        break;

--- a/lib/zstd_opt.c
+++ b/lib/zstd_opt.c
@@ -178,6 +178,9 @@ MEM_STATIC void ZSTD_updatePrice(seqStore_t* seqStorePtr, U32 litLength, const B



+/* *************************************
+*  Binary Tree search
+***************************************/
 FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
 U32 ZSTD_insertBtAndGetAllMatches (
                        ZSTD_CCtx* zc,
@@ -298,7 +301,39 @@ FORCE_INLINE U32 ZSTD_BtGetAllMatches_selectMLS (
    }
 }

+/** Tree updater, providing best match */
+FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
+size_t ZSTD_BtGetAllMatches_extDict (
+                        ZSTD_CCtx* zc,
+                        const BYTE* const ip, const BYTE* const iLimit,
+                        const U32 maxNbAttempts, const U32 mls, ZSTD_match_t* matches, U32 minml)
+{
+    if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
+    ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
+    return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 1, matches, minml);
+}

+
+FORCE_INLINE U32 ZSTD_BtGetAllMatches_selectMLS_extDict (
+                        ZSTD_CCtx* zc,   /* Index table will be updated */
+                        const BYTE* ip, const BYTE* const iLowLimit, const BYTE* const iHighLimit,
+                        const U32 maxNbAttempts, const U32 matchLengthSearch, ZSTD_match_t* matches, U32 minml)
+{
+    if (iLowLimit) {}; // skip warnings
+
+    switch(matchLengthSearch)
+    {
+    default :
+    case 4 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 4, matches, minml);
+    case 5 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 5, matches, minml);
+    case 6 : return ZSTD_BtGetAllMatches_extDict(zc, ip, iHighLimit, maxNbAttempts, 6, matches, minml);
+    }
+}
+
+
+/* ***********************
+*  Hash Chain
+*************************/
 FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
 U32 ZSTD_HcGetAllMatches_generic (
                        ZSTD_CCtx* zc,   /* Index table will be updated */
@@ -313,6 +348,7 @@ U32 ZSTD_HcGetAllMatches_generic (
    const U32 dictLimit = zc->dictLimit;
    const BYTE* const prefixStart = base + dictLimit;
    const BYTE* const dictEnd = dictBase + dictLimit;
+    const BYTE* const dictStart  = dictBase + zc->lowLimit;
    const U32 lowLimit = zc->lowLimit;
    const U32 current = (U32)(ip-base);
    const U32 minChain = current > chainSize ? current - chainSize : 0;
@@ -343,7 +379,7 @@ U32 ZSTD_HcGetAllMatches_generic (
            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 */
+                while ((match-back > dictStart) && (ip-back > iLowLimit) && (ip[-back-1] == match[-back-1])) back++; /* backward match extension */
                currentMl += back;
            }
        }
@@ -381,6 +417,19 @@ FORCE_INLINE U32 ZSTD_HcGetAllMatches_selectMLS (
    }
 }

+FORCE_INLINE U32 ZSTD_HcGetAllMatches_selectMLS_extDict (
+                        ZSTD_CCtx* zc,
+                        const BYTE* ip, const BYTE* const iLowLimit, const BYTE* const iHighLimit,
+                        const U32 maxNbAttempts, const U32 matchLengthSearch, ZSTD_match_t* matches, U32 minml)
+{
+    switch(matchLengthSearch)
+    {
+    default :
+    case 4 : return ZSTD_HcGetAllMatches_generic(zc, ip, iLowLimit, iHighLimit, maxNbAttempts, 4, 1, matches, minml);
+    case 5 : return ZSTD_HcGetAllMatches_generic(zc, ip, iLowLimit, iHighLimit, maxNbAttempts, 5, 1, matches, minml);
+    case 6 : return ZSTD_HcGetAllMatches_generic(zc, ip, iLowLimit, iHighLimit, maxNbAttempts, 6, 1, matches, minml);
+    }
+}


 /* *******************************
@@ -465,9 +514,9 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
       ZSTD_LOG_PARSER("%d: match_num=%d last_pos=%d\n", (int)(ip-base), match_num, last_pos);
       if (!last_pos && !match_num) { ip++; continue; }

-        opt[0].rep = rep_1;
-        opt[0].rep2 = rep_2;
-        opt[0].mlen = 1;
+       opt[0].rep = rep_1;
+       opt[0].rep2 = rep_2;
+       opt[0].mlen = 1;

       if (match_num && matches[match_num-1].len > sufficient_len)
       {
@@ -804,3 +853,438 @@ _storeSequence: // cur, last_pos, best_mlen, best_off have to be set



+FORCE_INLINE
+void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
+                                     const void* src, size_t srcSize,
+                                     const U32 searchMethod, const U32 depth)
+{
+    seqStore_t* seqStorePtr = &(ctx->seqStore);
+    const BYTE* const istart = (const BYTE*)src;
+    const BYTE* ip = istart;
+    const BYTE* anchor = istart;
+    const BYTE* const iend = istart + srcSize;
+    const BYTE* const ilimit = iend - 8;
+    const BYTE* const base = ctx->base;
+    const U32 dictLimit = ctx->dictLimit;
+    const BYTE* const prefixStart = base + dictLimit;
+    const BYTE* const dictBase = ctx->dictBase;
+    const BYTE* const dictEnd  = dictBase + dictLimit;
+
+    U32 rep_2=REPCODE_STARTVALUE, rep_1=REPCODE_STARTVALUE;
+    const U32 maxSearches = 1U << ctx->params.searchLog;
+    const U32 mls = ctx->params.searchLength;
+
+    typedef U32 (*getAllMatches_f)(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iLowLimit, const BYTE* iHighLimit,
+                        U32 maxNbAttempts, U32 matchLengthSearch, ZSTD_match_t* matches, U32 minml);
+    getAllMatches_f getAllMatches = searchMethod ? ZSTD_BtGetAllMatches_selectMLS_extDict : ZSTD_HcGetAllMatches_selectMLS_extDict;
+
+    ZSTD_optimal_t opt[ZSTD_OPT_NUM+4];
+    ZSTD_match_t matches[ZSTD_OPT_NUM+1];
+    const uint8_t *inr;
+    U32 skip_num, cur, cur2, match_num, last_pos, litlen, price;
+
+    const U32 sufficient_len = ctx->params.sufficientLength;
+    const U32 faster_get_matches = (ctx->params.strategy == ZSTD_opt); 
+
+
+    /* init */
+    ZSTD_resetSeqStore(seqStorePtr);
+    if ((ip - prefixStart) < REPCODE_STARTVALUE) ip += REPCODE_STARTVALUE;
+
+
+    /* Match Loop */
+    while (ip < ilimit) {
+        U32 mlen=0;
+        U32 best_mlen=0;
+        U32 best_off=0;
+        U32 current = (U32)(ip-base);
+        memset(opt, 0, sizeof(ZSTD_optimal_t));
+        last_pos = 0;
+        inr = ip;
+        opt[0].litlen = (U32)(ip - anchor);
+
+
+        /* check repCode */
+        {
+            const U32 repIndex = (U32)(current+1 - rep_1);
+            const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
+            const BYTE* const repMatch = repBase + repIndex;
+            if ((U32)((dictLimit-1) - repIndex) >= 3)   /* intentional overflow */
+            if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
+                /* repcode detected we should take it */
+                const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
+                mlen = (U32)ZSTD_count_2segments(ip+1+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + MINMATCH;
+                
+                ZSTD_LOG_PARSER("%d: start try REP rep=%d mlen=%d\n", (int)(ip-base), (int)rep_1, (int)mlen);
+                if (depth==0 || mlen > sufficient_len || mlen >= ZSTD_OPT_NUM) {
+                    ip+=1; best_mlen = mlen; best_off = 0; cur = 0; last_pos = 1;
+                    goto _storeSequence;
+                }
+
+                litlen = opt[0].litlen + 1;
+                do
+                {
+                    price = ZSTD_getPrice(seqStorePtr, litlen, anchor, 0, mlen - MINMATCH);
+                    if (mlen + 1 > last_pos || price < opt[mlen + 1].price)
+                        SET_PRICE(mlen + 1, mlen, 0, litlen, price);
+                    mlen--;
+                }
+                while (mlen >= MINMATCH);
+            }
+        }
+
+       best_mlen = (last_pos) ? last_pos : MINMATCH;
+        
+       if (faster_get_matches && last_pos)
+           match_num = 0;
+       else
+           match_num = getAllMatches(ctx, ip, ip, iend, maxSearches, mls, matches, best_mlen); /* first search (depth 0) */
+
+       ZSTD_LOG_PARSER("%d: match_num=%d last_pos=%d\n", (int)(ip-base), match_num, last_pos);
+       if (!last_pos && !match_num) { ip++; continue; }
+
+       opt[0].rep = rep_1;
+       opt[0].rep2 = rep_2;
+       opt[0].mlen = 1;
+
+       if (match_num && matches[match_num-1].len > sufficient_len)
+       {
+            best_mlen = matches[match_num-1].len;
+            best_off = matches[match_num-1].off;
+            cur = 0;
+            last_pos = 1;
+            goto _storeSequence;
+       }
+
+       // set prices using matches at position = 0
+       for (U32 i = 0; i < match_num; i++)
+       {
+           mlen = (i>0) ? matches[i-1].len+1 : best_mlen;
+           best_mlen = (matches[i].len < ZSTD_OPT_NUM) ? matches[i].len : ZSTD_OPT_NUM;
+           ZSTD_LOG_PARSER("%d: start Found mlen=%d off=%d best_mlen=%d last_pos=%d\n", (int)(ip-base), matches[i].len, matches[i].off, (int)best_mlen, (int)last_pos);
+           litlen = opt[0].litlen;
+           while (mlen <= best_mlen)
+           {
+                price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[i].off, mlen - MINMATCH);
+                if (mlen > last_pos || price < opt[mlen].price)
+                    SET_PRICE(mlen, mlen, matches[i].off, litlen, price);
+                mlen++;
+           }
+        }
+
+        if (last_pos < MINMATCH) { 
+     //     ip += ((ip-anchor) >> g_searchStrength) + 1;   /* jump faster over incompressible sections */
+            ip++; continue; 
+        }
+
+
+        // check further positions
+        for (skip_num = 0, cur = 1; cur <= last_pos; cur++)
+        { 
+           inr = ip + cur;
+
+           if (opt[cur-1].mlen == 1)
+           {
+                litlen = opt[cur-1].litlen + 1;
+                if (cur > litlen)
+                {
+                    price = opt[cur - litlen].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr-litlen);
+                    ZSTD_LOG_TRY_PRICE("%d: TRY1 opt[%d].price=%d price=%d cur=%d litlen=%d\n", (int)(inr-base), cur - litlen, opt[cur - litlen].price, price, cur, litlen);
+                }
+                else
+                    price = ZSTD_getLiteralPrice(seqStorePtr, litlen, anchor);
+           }
+           else
+           {
+                litlen = 1;
+                price = opt[cur - 1].price + ZSTD_getLiteralPrice(seqStorePtr, litlen, inr-1);                  
+                ZSTD_LOG_TRY_PRICE("%d: TRY3 price=%d cur=%d litlen=%d litonly=%d\n", (int)(inr-base), price, cur, litlen, (int)ZSTD_getLiteralPrice(seqStorePtr, litlen, inr-1));
+           }
+           
+           ZSTD_LOG_TRY_PRICE("%d: TRY4 price=%d opt[%d].price=%d\n", (int)(inr-base), price, cur, opt[cur].price);
+
+           if (cur > last_pos || price <= opt[cur].price) // || ((price == opt[cur].price) && (opt[cur-1].mlen == 1) && (cur != litlen)))
+                SET_PRICE(cur, 1, 0, litlen, price);
+
+           if (cur == last_pos) break;
+
+           if (inr > ilimit) // last match must start at a minimum distance of 8 from oend
+               continue;
+
+            mlen = opt[cur].mlen;
+            
+            if (opt[cur-mlen].off)
+            {
+                opt[cur].rep2 = opt[cur-mlen].rep;
+                opt[cur].rep = opt[cur-mlen].off;
+                ZSTD_LOG_PARSER("%d: COPYREP1 cur=%d mlen=%d rep=%d rep2=%d\n", (int)(inr-base), cur, mlen, opt[cur].rep, opt[cur].rep2);
+            }
+            else
+            {
+                if (cur!=mlen && opt[cur-mlen].litlen == 0) 
+                {
+                    opt[cur].rep2 = opt[cur-mlen].rep;
+                    opt[cur].rep = opt[cur-mlen].rep2;
+                    ZSTD_LOG_PARSER("%d: COPYREP2 cur=%d mlen=%d rep=%d rep2=%d\n", (int)(inr-base), cur, mlen, opt[cur].rep, opt[cur].rep2);
+                }
+                else
+                {
+                    opt[cur].rep2 = opt[cur-mlen].rep2;
+                    opt[cur].rep = opt[cur-mlen].rep;
+                    ZSTD_LOG_PARSER("%d: COPYREP3 cur=%d mlen=%d rep=%d rep2=%d\n", (int)(inr-base), cur, mlen, opt[cur].rep, opt[cur].rep2);
+                }
+            }
+
+           ZSTD_LOG_PARSER("%d: CURRENT price[%d/%d]=%d off=%d mlen=%d litlen=%d rep=%d rep2=%d\n", (int)(inr-base), cur, last_pos, opt[cur].price, opt[cur].off, opt[cur].mlen, opt[cur].litlen, opt[cur].rep, opt[cur].rep2); 
+
+
+
+           size_t cur_rep;
+           best_mlen = 0;
+
+           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);   
+           }
+
+           const U32 repIndex = (U32)(current+cur - cur_rep);
+           const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
+           const BYTE* const repMatch = repBase + repIndex;
+           if ((U32)((dictLimit-1) - repIndex) >= 3)   /* intentional overflow */
+           if (MEM_read32(inr) == MEM_read32(repMatch)) {
+                /* repcode detected */
+                const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
+                mlen = (U32)ZSTD_count_2segments(inr+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + 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)
+                {
+                    best_mlen = mlen;
+                    best_off = 0;
+                    ZSTD_LOG_PARSER("%d: REP sufficient_len=%d best_mlen=%d best_off=%d last_pos=%d\n", (int)(inr-base), sufficient_len, best_mlen, best_off, last_pos);
+                    last_pos = cur + 1;
+                    goto _storeSequence;
+                 }
+
+                if (opt[cur].mlen == 1)
+                {
+                    litlen = opt[cur].litlen;
+
+                    if (cur > litlen)
+                    {
+                        price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, 0, mlen - MINMATCH);
+                        ZSTD_LOG_TRY_PRICE("%d: TRY5 opt[%d].price=%d price=%d cur=%d litlen=%d\n", (int)(inr-base), cur - litlen, opt[cur - litlen].price, price, cur, litlen);
+                    }
+                    else
+                        price = ZSTD_getPrice(seqStorePtr, litlen, anchor, 0, mlen - MINMATCH);
+                }
+                else
+                {
+                    litlen = 0;
+                    price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, 0, mlen - MINMATCH);
+                    ZSTD_LOG_TRY_PRICE("%d: TRY7 price=%d cur=%d litlen=0 getprice=%d\n", (int)(inr-base), price, cur, (int)ZSTD_getPrice(seqStorePtr, 0, NULL, 0, mlen - MINMATCH));
+                }
+
+                best_mlen = mlen;
+                if (faster_get_matches)
+                    skip_num = best_mlen;
+
+                ZSTD_LOG_PARSER("%d: Found REP mlen=%d off=%d price=%d litlen=%d price[%d]=%d\n", (int)(inr-base), mlen, 0, price, litlen, cur - litlen, opt[cur - litlen].price);
+
+                do
+                {
+                    if (cur + mlen > last_pos || price <= opt[cur + mlen].price) // || ((price == opt[cur + mlen].price) && (opt[cur].mlen == 1) && (cur != litlen))) // at equal price prefer REP instead of MATCH
+                        SET_PRICE(cur + mlen, mlen, 0, litlen, price);
+                    mlen--;
+                }
+                while (mlen >= MINMATCH);
+            }
+
+
+            if (faster_get_matches && skip_num > 0)
+            {
+                skip_num--; 
+                continue;
+            }
+
+
+            best_mlen = (best_mlen > MINMATCH) ? best_mlen : MINMATCH;      
+
+            match_num = getAllMatches(ctx, inr, ip, iend, maxSearches, mls, matches, best_mlen); 
+            ZSTD_LOG_PARSER("%d: ZSTD_GetAllMatches match_num=%d\n", (int)(inr-base), match_num);
+
+
+            if (match_num > 0 && matches[match_num-1].len > sufficient_len)
+            {
+                cur -= matches[match_num-1].back;
+                best_mlen = matches[match_num-1].len;
+                best_off = matches[match_num-1].off;
+                last_pos = cur + 1;
+                goto _storeSequence;
+            }
+
+
+            // set prices using matches at position = cur
+            for (U32 i = 0; i < match_num; i++)
+            {
+                mlen = (i>0) ? matches[i-1].len+1 : best_mlen;
+                cur2 = cur - matches[i].back;
+                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)
+                {
+                    if (opt[cur2].mlen == 1)
+                    {
+                        litlen = opt[cur2].litlen;
+                        if (cur2 > litlen)
+                            price = opt[cur2 - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, ip+cur2-litlen, matches[i].off, mlen - MINMATCH);
+                        else
+                            price = ZSTD_getPrice(seqStorePtr, litlen, anchor, matches[i].off, mlen - MINMATCH);
+                    }
+                    else
+                    {
+                        litlen = 0;
+                        price = opt[cur2].price + ZSTD_getPrice(seqStorePtr, 0, NULL, matches[i].off, mlen - MINMATCH);
+                    }
+
+                    ZSTD_LOG_PARSER("%d: Found2 pred=%d mlen=%d best_mlen=%d off=%d price=%d litlen=%d price[%d]=%d\n", (int)(inr-base), matches[i].back, mlen, best_mlen, matches[i].off, price, litlen, cur - litlen, opt[cur - litlen].price);
+                    ZSTD_LOG_TRY_PRICE("%d: TRY8 price=%d opt[%d].price=%d\n", (int)(inr-base), price, cur2 + mlen, opt[cur2 + mlen].price);
+
+                    if (cur2 + mlen > last_pos || (price < opt[cur2 + mlen].price))
+                        SET_PRICE(cur2 + mlen, mlen, matches[i].off, litlen, price);
+
+                    mlen++;
+                }
+            }
+        } //  for (skip_num = 0, cur = 1; cur <= last_pos; cur++)
+
+
+        best_mlen = opt[last_pos].mlen;
+        best_off = opt[last_pos].off;
+        cur = last_pos - best_mlen;
+   //     printf("%d: start=%d best_mlen=%d best_off=%d cur=%d\n", (int)(ip - base), (int)(start - ip), (int)best_mlen, (int)best_off, cur);
+
+        /* store sequence */
+_storeSequence: // cur, last_pos, best_mlen, best_off have to be set
+        for (U32 i = 1; i <= last_pos; i++)
+            ZSTD_LOG_PARSER("%d: price[%d/%d]=%d off=%d mlen=%d litlen=%d rep=%d rep2=%d\n", (int)(ip-base+i), i, last_pos, opt[i].price, opt[i].off, opt[i].mlen, opt[i].litlen, opt[i].rep, opt[i].rep2);
+        ZSTD_LOG_PARSER("%d: cur=%d/%d best_mlen=%d best_off=%d rep=%d\n", (int)(ip-base+cur), (int)cur, (int)last_pos, (int)best_mlen, (int)best_off, opt[cur].rep); 
+
+        opt[0].mlen = 1;
+        U32 offset;
+
+        while (1)
+        {
+            mlen = opt[cur].mlen;
+            ZSTD_LOG_PARSER("%d: cur=%d mlen=%d\n", (int)(ip-base), cur, mlen);
+            offset = opt[cur].off;
+            opt[cur].mlen = best_mlen; 
+            opt[cur].off = best_off;
+            best_mlen = mlen;
+            best_off = offset; 
+            if (mlen > cur)
+                break;
+            cur -= mlen;
+        }
+          
+        for (U32 i = 0; i <= last_pos;)
+        {
+            ZSTD_LOG_PARSER("%d: price2[%d/%d]=%d off=%d mlen=%d litlen=%d rep=%d rep2=%d\n", (int)(ip-base+i), i, last_pos, opt[i].price, opt[i].off, opt[i].mlen, opt[i].litlen, opt[i].rep, opt[i].rep2);
+            i += opt[i].mlen;
+        }
+
+        cur = 0;
+
+        while (cur < last_pos)
+        {
+            ZSTD_LOG_PARSER("%d: price3[%d/%d]=%d off=%d mlen=%d litlen=%d rep=%d rep2=%d\n", (int)(ip-base+cur), cur, last_pos, opt[cur].price, opt[cur].off, opt[cur].mlen, opt[cur].litlen, opt[cur].rep, opt[cur].rep2);
+            mlen = opt[cur].mlen;
+            if (mlen == 1) { ip++; cur++; continue; }
+            offset = opt[cur].off;
+            cur += mlen;
+
+
+            U32 litLength = (U32)(ip - anchor);
+            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)
+            {
+                rep_2 = rep_1;
+                rep_1 = offset;
+            }
+            else
+            {
+                if (litLength == 0) 
+                {
+                    best_off = rep_2;
+                    rep_2 = rep_1;
+                    rep_1 = best_off;
+                }
+            }
+
+            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);
+ 
+#if ZSTD_OPT_DEBUG >= 5
+            int ml2;
+            if (offset)
+                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 < 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);
+            ZSTD_storeSeq(seqStorePtr, litLength, anchor, offset, mlen-MINMATCH);
+            anchor = ip = ip + mlen;
+        }
+
+
+        // check immediate repcode
+        while (anchor <= ilimit) {
+            const U32 repIndex = (U32)((anchor-base) - rep_2);
+            const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
+            const BYTE* const repMatch = repBase + repIndex;
+            if ((U32)((dictLimit-1) - repIndex) >= 3)   /* intentional overflow */
+            if (MEM_read32(anchor) == MEM_read32(repMatch)) {
+                /* repcode detected we should take it */
+                const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
+                mlen = (U32)ZSTD_count_2segments(anchor+MINMATCH, repMatch+MINMATCH, iend, repEnd, prefixStart) + MINMATCH;
+                offset = rep_2; rep_2 = rep_1; rep_1 = offset;   /* swap offset history */
+                ZSTD_LOG_ENCODE("%d/%d: ENCODE REP literals=%d mlen=%d off=%d rep1=%d rep2=%d\n", (int)(anchor-base), (int)(iend-base), (int)(0), (int)best_mlen, (int)(0), (int)rep_1, (int)rep_2);
+                ZSTD_updatePrice(seqStorePtr, 0, anchor, 0, mlen-MINMATCH);
+                ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, mlen-MINMATCH);
+                anchor += mlen;
+                ip = anchor;
+                continue;   /* faster when present ... (?) */
+            }
+            break;
+        }
+    }
+
+    /* Last Literals */
+    {
+        U32 lastLLSize = (U32)(iend - anchor);
+        ZSTD_LOG_ENCODE("%d: lastLLSize literals=%d\n", (int)(ip-base), (int)(lastLLSize));
+        memcpy(seqStorePtr->lit, anchor, lastLLSize);
+        seqStorePtr->lit += lastLLSize;
+    }
+}