Fix Off-By-One Error in Counting DDS Search Attempts

This caused us to double-search the first position and fail to search the
last position in the chain, slowing down search and making it less effective.

diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index 0ee9f6506cf04928c9f9e4be00b594afca1e34a3..5e38e49cc6937ff59577b26ad70dc635ee755af0 100644 (file)
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -575,7 +575,7 @@ size_t ZSTD_HcFindBestMatch_generic (
         const U32 ddsMinChain = ddsSize > ddsChainSize ? ddsSize - ddsChainSize : 0;
         const U32 bucketSize           = (1 << DD_BLOG);
 
-        U32 attemptNb = 0;
+        U32 attemptNb = 1;
 
         matchIndex = dms->hashTable[ddsIdx];
 
@@ -603,7 +603,7 @@ size_t ZSTD_HcFindBestMatch_generic (
                 break;
             }
 
-            if (attemptNb < bucketSize - 1) {
+            if (attemptNb < bucketSize) {
                 matchIndex = dms->hashTable[ddsIdx + attemptNb];
             } else {
                 matchIndex = dms->chainTable[matchIndex & ddsChainMask];