ZSTD_REP_NUM

lib/zstd_compress.c

@@ -627,8 +627,10 @@ size_t ZSTD_compressSequences(ZSTD_CCtx* zc,
     /* CTable for Offset codes */
     {   /* create Offset codes */
         size_t i; for (i=0; i<nbSeq; i++) {
-            offCodeTable[i] = (BYTE)ZSTD_highbit(offsetTable[i]) + 1;
-            if (offsetTable[i]==0) offCodeTable[i]=0;
+            if (offsetTable[i] < ZSTD_REP_NUM) 
+                offCodeTable[i] = 0;
+            else
+                offCodeTable[i] = (BYTE)ZSTD_highbit(offsetTable[i]) + 1;
         }
     }
     max = MaxOff;
@@ -774,7 +776,7 @@ MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const B
     else *(seqStorePtr->litLength++) = (BYTE)litLength;
 
     /* match offset */
-    *(seqStorePtr->offset++) = (U32)offsetCode;
+    *(seqStorePtr->offset++) = (U32)offsetCode + ZSTD_REP_NUM - 1;
 
     /* match Length */
     if (matchCode >= MaxML) {

lib/zstd_decompress.c

@@ -657,8 +657,10 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
         offset = offsetPrefix[offsetCode] + BIT_readBits(&(seqState->DStream), nbBits);
         if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
         if (offsetCode==0) offset = prevOffset;   /* repcode, cmove */
+        else offset -= ZSTD_REP_NUM - 1;
         if (offsetCode | !litLength) seqState->prevOffset = seq->offset;   /* cmove */
         FSE_decodeSymbol(&(seqState->stateOffb), &(seqState->DStream));    /* update */
+//    printf("offsetCode=%d nbBits=%d offset=%d\n", offsetCode, nbBits, (int)offset); fflush(stdout);
     }
 
     /* Literal length update */

lib/zstd_internal.h

@@ -66,6 +66,7 @@
 
 #define ZSTD_OPT_NUM    (1<<12)
 #define ZSTD_DICT_MAGIC  0xEC30A435
+#define ZSTD_REP_NUM    4
 
 #define KB *(1 <<10)
 #define MB *(1 <<20)