minor refactoring

diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c
index 51157306b74d0735939e7e15d50efcd365bb9de5..0bb04ea0287df13ddfcd8df787e376409b3117eb 100644 (file)
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -1093,12 +1093,23 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc, const BYTE* const ip, const U32 mls, co
 }
 
 
+static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
+{
+    const BYTE* const base = zc->base;
+    const U32 target = (U32)(ip - base);
+    U32 idx = zc->nextToUpdate;
+
+    for( ; idx < target ; )
+        idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0);
+}
+
 FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
 size_t ZSTD_insertBtAndFindBestMatch (
                         ZSTD_CCtx* zc,
                         const BYTE* const ip, const BYTE* const iend,
                         size_t* offsetPtr,
-                        U32 nbCompares, const U32 mls)
+                        U32 nbCompares, const U32 mls,
+                        U32 extDict)
 {
     U32* const hashTable = zc->hashTable;
     const U32 hashLog = zc->params.hashLog;
@@ -1109,6 +1120,10 @@ size_t ZSTD_insertBtAndFindBestMatch (
     U32 matchIndex  = hashTable[h];
     size_t commonLengthSmaller=0, commonLengthLarger=0;
     const BYTE* const base = zc->base;
+    const BYTE* const dictBase = zc->dictBase;
+    const U32 dictLimit = zc->dictLimit;
+    const BYTE* const dictEnd = dictBase + dictLimit;
+    const BYTE* const prefixStart = base + dictLimit;
     const U32 current = (U32)(ip-base);
     const U32 btLow = btMask >= current ? 0 : current - btMask;
     const U32 windowLow = zc->lowLimit;
@@ -1123,11 +1138,22 @@ size_t ZSTD_insertBtAndFindBestMatch (
     while (nbCompares-- && (matchIndex > windowLow))
     {
         U32* nextPtr = bt + 2*(matchIndex & btMask);
-        const BYTE* match = base + matchIndex;
         size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
+        const BYTE* match;
 
-        if (match[matchLength] == ip[matchLength])
-            matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
+        if ((!extDict) || (matchIndex+matchLength >= dictLimit))
+        {
+            match = base + matchIndex;
+            if (match[matchLength] == ip[matchLength])
+                matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
+        }
+        else
+        {
+            match = dictBase + matchIndex;
+            matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
+            if (matchIndex+matchLength >= dictLimit)
+                               match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
+        }
 
         if (matchLength > bestLength)
         {
@@ -1166,17 +1192,6 @@ size_t ZSTD_insertBtAndFindBestMatch (
 }
 
 
-static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
-{
-    const BYTE* const base = zc->base;
-    const U32 target = (U32)(ip - base);
-    U32 idx = zc->nextToUpdate;
-
-    for( ; idx < target ; )
-        idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0);
-}
-
-
 /** Tree updater, providing best match */
 FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
 size_t ZSTD_BtFindBestMatch (
@@ -1187,7 +1202,7 @@ size_t ZSTD_BtFindBestMatch (
 {
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
     ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
-    return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls);
+    return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
 }
 
 
@@ -1218,93 +1233,6 @@ static void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const B
 }
 
 
-FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
-size_t ZSTD_insertBtAndFindBestMatch_extDict (
-                        ZSTD_CCtx* zc,
-                        const BYTE* const ip, const BYTE* const iend,
-                        size_t* offsetPtr,
-                        U32 nbCompares, const U32 mls)
-{
-    U32* const hashTable = zc->hashTable;
-    const U32 hashLog = zc->params.hashLog;
-    const size_t h  = ZSTD_hashPtr(ip, hashLog, mls);
-    U32* const bt   = zc->contentTable;
-    const U32 btLog = zc->params.contentLog - 1;
-    const U32 btMask= (1 << btLog) - 1;
-    U32 matchIndex  = hashTable[h];
-    size_t commonLengthSmaller=0, commonLengthLarger=0;
-    const BYTE* const base = zc->base;
-    const BYTE* const dictBase = zc->dictBase;
-    const U32 dictLimit = zc->dictLimit;
-    const BYTE* const dictEnd = dictBase + dictLimit;
-    const BYTE* const prefixStart = base + dictLimit;
-    const U32 current = (U32)(ip-base);
-    const U32 btLow = btMask >= current ? 0 : current - btMask;
-    const U32 windowLow = zc->lowLimit;
-    U32* smallerPtr = bt + 2*(current&btMask);
-    U32* largerPtr  = bt + 2*(current&btMask) + 1;
-    size_t bestLength = 0;
-    U32 matchEndIdx = current+8;
-    U32 dummy32;   /* to be nullified at the end */
-
-    hashTable[h] = current;   /* Update Hash Table */
-
-    while (nbCompares-- && (matchIndex > windowLow))
-    {
-        U32* nextPtr = bt + 2*(matchIndex & btMask);
-        size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
-        const BYTE* match;
-
-        if (matchIndex+matchLength >= dictLimit)
-        {
-            match = base + matchIndex;
-            if (match[matchLength] == ip[matchLength])
-                matchLength += ZSTD_count(ip+matchLength+1, match+matchLength+1, iend) +1;
-        }
-        else
-        {
-            match = dictBase + matchIndex;
-            matchLength += ZSTD_count_2segments(ip+matchLength, match+matchLength, iend, dictEnd, prefixStart);
-            if (matchIndex+matchLength >= dictLimit)
-                               match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
-        }
-
-        if (matchLength > bestLength)
-        {
-            if (matchLength > matchEndIdx - matchIndex)
-                matchEndIdx = matchIndex + (U32)matchLength;
-            if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit(current-matchIndex+1) - ZSTD_highbit((U32)offsetPtr[0]+1)) )
-                bestLength = matchLength, *offsetPtr = current - matchIndex;
-            if (ip+matchLength == iend)   /* equal : no way to know if inf or sup */
-                break;   /* drop, to guarantee consistency (miss a little bit of compression) */
-        }
-
-        if (match[matchLength] < ip[matchLength])
-        {
-            /* match is smaller than current */
-            *smallerPtr = matchIndex;             /* update smaller idx */
-            commonLengthSmaller = matchLength;    /* all smaller will now have at least this guaranteed common length */
-            if (matchIndex <= btLow) { smallerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
-            smallerPtr = nextPtr+1;               /* new "smaller" => larger of match */
-            matchIndex = nextPtr[1];              /* new matchIndex larger than previous (closer to current) */
-        }
-        else
-        {
-            /* match is larger than current */
-            *largerPtr = matchIndex;
-            commonLengthLarger = matchLength;
-            if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
-            largerPtr = nextPtr;
-            matchIndex = nextPtr[0];
-        }
-    }
-
-    *smallerPtr = *largerPtr = 0;
-
-    zc->nextToUpdate = (matchEndIdx > current + 8) ? matchEndIdx - 8 : current+1;
-    return bestLength;
-}
-
 /** Tree updater, providing best match */
 FORCE_INLINE /* inlining is important to hardwire a hot branch (template emulation) */
 size_t ZSTD_BtFindBestMatch_extDict (
@@ -1315,7 +1243,7 @@ size_t ZSTD_BtFindBestMatch_extDict (
 {
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
     ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
-    return ZSTD_insertBtAndFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls);
+    return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
 }