From: Przemyslaw Skibinski <inikep@gmail.com>
Date: Fri, 21 Oct 2016 09:19:00 +0000 (+0200)
Subject: improved ZSTD_compressBlock_opt_extDict_generic
X-Git-Tag: v1.1.1~23^2~3
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4732074a71cf80811aee608dbd24368a854719c2;p=thirdparty%2Fzstd.git

improved ZSTD_compressBlock_opt_extDict_generic
---

diff --git a/lib/compress/zstd_opt.h b/lib/compress/zstd_opt.h
index 8a436df42..5e4cb7c27 100644
--- a/lib/compress/zstd_opt.h
+++ b/lib/compress/zstd_opt.h
@@ -16,6 +16,7 @@
 
 
 #define ZSTD_FREQ_DIV   5
+#define ZSTD_MAX_PRICE  (1<<30)
 
 /*-*************************************
 *  Price functions for optimal parser
@@ -171,7 +172,7 @@ MEM_STATIC void ZSTD_updatePrice(seqStore_t* seqStorePtr, U32 litLength, const B
 
 #define SET_PRICE(pos, mlen_, offset_, litlen_, price_)   \
     {                                                 \
-        while (last_pos < pos)  { opt[last_pos+1].price = 1<<30; last_pos++; } \
+        while (last_pos < pos)  { opt[last_pos+1].price = ZSTD_MAX_PRICE; last_pos++; } \
         opt[pos].mlen = mlen_;                         \
         opt[pos].off = offset_;                        \
         opt[pos].litlen = litlen_;                     \
@@ -495,7 +496,7 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
                 opt[cur].rep[0] = ((opt[cur].off==ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur-mlen].rep[0] - 1) : (opt[cur-mlen].rep[opt[cur].off]);
            }
 
-           best_mlen = minMatch;
+            best_mlen = minMatch;
             {   U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
                 for (i=(opt[cur].mlen != 1); i<last_i; i++) {  /* check rep */
                     const S32 repCur = ((i==ZSTD_REP_MOVE_OPT) && (opt[cur].mlen != 1)) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
@@ -509,7 +510,6 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
                        }
 
                        best_off = i - (opt[cur].mlen != 1);
-
                        if (mlen > best_mlen) best_mlen = mlen;
 
                        do {
@@ -762,8 +762,7 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
                 opt[cur].rep[0] = ((opt[cur].off==ZSTD_REP_MOVE_OPT) && (mlen != 1)) ? (opt[cur-mlen].rep[0] - 1) : (opt[cur-mlen].rep[opt[cur].off]);
             }
 
-            best_mlen = 0;
-
+            best_mlen = minMatch;
             {   U32 i, last_i = ZSTD_REP_CHECK + (mlen != 1);
                 for (i = (mlen != 1); i<last_i; i++) {
                     const S32 repCur = ((i==ZSTD_REP_MOVE_OPT) && (opt[cur].mlen != 1)) ? (opt[cur].rep[0] - 1) : opt[cur].rep[i];
@@ -783,20 +782,20 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
                         }
 
                         best_off = i - (opt[cur].mlen != 1);
-                        if (opt[cur].mlen == 1) {
-                            litlen = opt[cur].litlen;
-                            if (cur > litlen) {
-                                price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, best_off, mlen - MINMATCH);
-                            } else
-                                price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH);
-                        } else {
-                            litlen = 0;
-                            price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH);
-                        }
-
-                        best_mlen = mlen;
+                        if (mlen > best_mlen) best_mlen = mlen;
 
                         do {
+                            if (opt[cur].mlen == 1) {
+                                litlen = opt[cur].litlen;
+                                if (cur > litlen) {
+                                    price = opt[cur - litlen].price + ZSTD_getPrice(seqStorePtr, litlen, inr-litlen, best_off, mlen - MINMATCH);
+                                } else
+                                    price = ZSTD_getPrice(seqStorePtr, litlen, anchor, best_off, mlen - MINMATCH);
+                            } else {
+                                litlen = 0;
+                                price = opt[cur].price + ZSTD_getPrice(seqStorePtr, 0, NULL, best_off, mlen - MINMATCH);
+                            }
+
                             if (cur + mlen > last_pos || price <= opt[cur + mlen].price)
                                 SET_PRICE(cur + mlen, mlen, i, litlen, price);
                             mlen--;
@@ -812,8 +811,6 @@ void ZSTD_compressBlock_opt_extDict_generic(ZSTD_CCtx* ctx,
                 goto _storeSequence;
             }
 
-            best_mlen = (best_mlen > minMatch) ? best_mlen : minMatch;
-
             /* set prices using matches at position = cur */
             for (u = 0; u < match_num; u++) {
                 mlen = (u>0) ? matches[u-1].len+1 : best_mlen;