cache literal prices for ZSTD_btopt

diff --git a/lib/zstd_internal.h b/lib/zstd_internal.h
index 31a99cbde83606ef85b8a0b60f54c477116cf38f..9c888e7798f2feaeba4dea2fca08ad11cefc2774 100644 (file)
--- a/lib/zstd_internal.h
+++ b/lib/zstd_internal.h
@@ -242,6 +242,9 @@ typedef struct {
     U32  log2litSum;
     U32  log2offCodeSum;
     U32  factor;
+    U32  cachedPrice;
+    U32  cachedLitLength;
+    const BYTE* cachedLiterals;
     ZSTD_stats_t stats;
 } seqStore_t;
 

diff --git a/lib/zstd_opt.h b/lib/zstd_opt.h
index 4f6e4c8e9bba4247420b5527c862942a177e3dd1..efda97e523cbaf0f46b9c7971408789d6124b724 100644 (file)
--- a/lib/zstd_opt.h
+++ b/lib/zstd_opt.h
@@ -54,6 +54,8 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr)
     unsigned u;
 
     if (ssPtr->litLengthSum == 0) {
+        ssPtr->cachedLiterals = NULL;
+        ssPtr->cachedPrice = ssPtr->cachedLitLength = 0;
         ssPtr->litSum = (2<<Litbits);
         ssPtr->litLengthSum = MaxLL+1;
         ssPtr->matchLengthSum = MaxML+1;
@@ -98,17 +100,41 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr)
 }
 
 
-FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* seqStorePtr, U32 litLength, const BYTE* literals)
+FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* ssPtr, U32 litLength, const BYTE* literals)
 {
     U32 price, u;
 
     if (litLength == 0)
-        return seqStorePtr->log2litLengthSum - ZSTD_highbit(seqStorePtr->litLengthFreq[0]+1);
+        return ssPtr->log2litLengthSum - ZSTD_highbit(ssPtr->litLengthFreq[0]+1);
 
     /* literals */
-    price = litLength * seqStorePtr->log2litSum;
+#define ZSTD_CACHE_LITPRICES
+#ifdef ZSTD_CACHE_LITPRICES
+    if (ssPtr->cachedLiterals == literals) {
+     //   if (ssPtr->cachedLitLength > litLength) printf("ERROR: ssPtr->cachedLitLength > litLength\n"); 
+        U32 additional = litLength - ssPtr->cachedLitLength;
+        const BYTE* literals2 = ssPtr->cachedLiterals + ssPtr->cachedLitLength;
+        price = ssPtr->cachedPrice + additional * ssPtr->log2litSum;
+        for (u=0; u < additional; u++)
+            price -= ZSTD_highbit(ssPtr->litFreq[literals2[u]]+1);
+        ssPtr->cachedPrice = price;
+        ssPtr->cachedLitLength = litLength;
+    } else {
+        price = litLength * ssPtr->log2litSum;
+        for (u=0; u < litLength; u++)
+            price -= ZSTD_highbit(ssPtr->litFreq[literals[u]]+1);
+
+        if (litLength >= 12) {
+            ssPtr->cachedLiterals = literals;
+            ssPtr->cachedPrice = price;
+            ssPtr->cachedLitLength = litLength;
+        }
+    }
+#else
+    price = litLength * ssPtr->log2litSum;
     for (u=0; u < litLength; u++)
-        price -= ZSTD_highbit(seqStorePtr->litFreq[literals[u]]+1);
+        price -= ZSTD_highbit(ssPtr->litFreq[literals[u]]+1);
+#endif
 
     /* literal Length */
     {   static const BYTE LL_Code[64] = {  0,  1,  2,  3,  4,  5,  6,  7,
@@ -121,7 +147,7 @@ FORCE_INLINE U32 ZSTD_getLiteralPrice(seqStore_t* seqStorePtr, U32 litLength, co
                                           24, 24, 24, 24, 24, 24, 24, 24 };
         const BYTE LL_deltaCode = 19;
         const BYTE llCode = (litLength>63) ? (BYTE)ZSTD_highbit(litLength) + LL_deltaCode : LL_Code[litLength];
-        price += LL_bits[llCode] + seqStorePtr->log2litLengthSum - ZSTD_highbit(seqStorePtr->litLengthFreq[llCode]+1);
+        price += LL_bits[llCode] + ssPtr->log2litLengthSum - ZSTD_highbit(ssPtr->litLengthFreq[llCode]+1);
     }
 
     return price;
@@ -465,7 +491,11 @@ void ZSTD_compressBlock_opt_generic(ZSTD_CCtx* ctx,
         memset(opt, 0, sizeof(ZSTD_optimal_t));
         last_pos = 0;
         inr = ip;
+#ifdef ZSTD_CACHE_LITPRICES
+        litstart = anchor;
+#else
         litstart = ((U32)(ip - anchor) > 128) ? ip - 128 : anchor;
+#endif
         opt[0].litlen = (U32)(ip - litstart);
 
         /* check repCode */