[lib] Fix repcode validation in no dict mode

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index ff8a00e6b3b2aded7efb2f2ccf1a276a7306a330..528ee9e5df658a5e5964354228cf646d03787728 100644 (file)
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -3278,6 +3278,7 @@ size_t ZSTD_compress_usingDict(ZSTD_CCtx* cctx,
 {
     ZSTD_parameters const params = ZSTD_getParams_internal(compressionLevel, srcSize, dict ? dictSize : 0);
     ZSTD_CCtx_params cctxParams = ZSTD_assignParamsToCCtxParams(&cctx->requestedParams, &params);
+    DEBUGLOG(4, "ZSTD_compress_usingDict (srcSize=%u)", (unsigned)srcSize);
     assert(params.fParams.contentSizeFlag == 1);
     return ZSTD_compress_advanced_internal(cctx, dst, dstCapacity, src, srcSize, dict, dictSize, &cctxParams);
 }
@@ -4053,6 +4054,7 @@ size_t ZSTD_compress2(ZSTD_CCtx* cctx,
                       void* dst, size_t dstCapacity,
                       const void* src, size_t srcSize)
 {
+    DEBUGLOG(4, "ZSTD_compress2 (srcSize=%u)", (unsigned)srcSize);
     ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
     {   size_t oPos = 0;
         size_t iPos = 0;

diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index 8a16c371a691316fceed540efe179a0021db9308..db73f6ce21f2ca597b18c6ba825c6496c6e9f2bd 100644 (file)
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -970,6 +970,9 @@ MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window,
     return contiguous;
 }
 
+/**
+ * Returns the lowest allowed match index. It may either be in the ext-dict or the prefix.
+ */
 MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t* ms, U32 current, unsigned windowLog)
 {
     U32    const maxDistance = 1U << windowLog;
@@ -980,6 +983,19 @@ MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t* ms, U32 current
     return matchLowest;
 }
 
+/**
+ * Returns the lowest allowed match index in the prefix.
+ */
+MEM_STATIC U32 ZSTD_getLowestPrefixIndex(const ZSTD_matchState_t* ms, U32 current, unsigned windowLog)
+{
+    U32    const maxDistance = 1U << windowLog;
+    U32    const lowestValid = ms->window.dictLimit;
+    U32    const withinWindow = (current - lowestValid > maxDistance) ? current - maxDistance : lowestValid;
+    U32    const isDictionary = (ms->loadedDictEnd != 0);
+    U32    const matchLowest = isDictionary ? lowestValid : withinWindow;
+    return matchLowest;
+}
+
 
 
 /* debug functions */

diff --git a/lib/compress/zstd_double_fast.c b/lib/compress/zstd_double_fast.c
index 2306a0d8c465edc14ccb0391429d68611c703de9..27eed66cfedd3167fa3410a25d59eff2eb2ac55e 100644 (file)
--- a/lib/compress/zstd_double_fast.c
+++ b/lib/compress/zstd_double_fast.c
@@ -63,10 +63,8 @@ size_t ZSTD_compressBlock_doubleFast_generic(
     const BYTE* ip = istart;
     const BYTE* anchor = istart;
     const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
-    const U32 lowestValid = ms->window.dictLimit;
-    const U32 maxDistance = 1U << cParams->windowLog;
     /* presumes that, if there is a dictionary, it must be using Attach mode */
-    const U32 prefixLowestIndex = (endIndex - lowestValid > maxDistance) ? endIndex - maxDistance : lowestValid;
+    const U32 prefixLowestIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
     const BYTE* const prefixLowest = base + prefixLowestIndex;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - HASH_READ_SIZE;
@@ -104,13 +102,15 @@ size_t ZSTD_compressBlock_doubleFast_generic(
 
     /* if a dictionary is attached, it must be within window range */
     if (dictMode == ZSTD_dictMatchState) {
-        assert(lowestValid + maxDistance >= endIndex);
+        assert(ms->window.dictLimit + (1U << cParams->windowLog) >= endIndex);
     }
 
     /* init */
     ip += (dictAndPrefixLength == 0);
     if (dictMode == ZSTD_noDict) {
-        U32 const maxRep = (U32)(ip - prefixLowest);
+        U32 const current = (U32)(ip - base);
+        U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
+        U32 const maxRep = current - windowLow;
         if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
     }

diff --git a/lib/compress/zstd_fast.c b/lib/compress/zstd_fast.c
index 81c7cd2c80832e52527e8dfbd64751cea672f37e..9906e4ba287655df2f0b430ef345f7c0e96b65d8 100644 (file)
--- a/lib/compress/zstd_fast.c
+++ b/lib/compress/zstd_fast.c
@@ -61,9 +61,7 @@ ZSTD_compressBlock_fast_generic(
     const BYTE* ip1;
     const BYTE* anchor = istart;
     const U32   endIndex = (U32)((size_t)(istart - base) + srcSize);
-    const U32   maxDistance = 1U << cParams->windowLog;
-    const U32   validStartIndex = ms->window.dictLimit;
-    const U32   prefixStartIndex = (endIndex - validStartIndex > maxDistance) ? endIndex - maxDistance : validStartIndex;
+    const U32   prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
     const BYTE* const prefixStart = base + prefixStartIndex;
     const BYTE* const iend = istart + srcSize;
     const BYTE* const ilimit = iend - HASH_READ_SIZE;
@@ -74,7 +72,9 @@ ZSTD_compressBlock_fast_generic(
     DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
     ip0 += (ip0 == prefixStart);
     ip1 = ip0 + 1;
-    {   U32 const maxRep = (U32)(ip0 - prefixStart);
+    {   U32 const current = (U32)(ip0 - base);
+        U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, cParams->windowLog);
+        U32 const maxRep = current - windowLow;
         if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
     }

diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index 65ad2f27f8c271284e081541c7e76d64cb9a7a91..55bf23c89cff8fff4d21a098ccb629758d6e3d1f 100644 (file)
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -662,10 +662,14 @@ ZSTD_compressBlock_lazy_generic(
                                      0;
     const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest));
 
+    DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u)", (U32)dictMode);
+
     /* init */
     ip += (dictAndPrefixLength == 0);
     if (dictMode == ZSTD_noDict) {
-        U32 const maxRep = (U32)(ip - prefixLowest);
+        U32 const current = (U32)(ip - base);
+        U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, current, ms->cParams.windowLog);
+        U32 const maxRep = current - windowLow;
         if (offset_2 > maxRep) savedOffset = offset_2, offset_2 = 0;
         if (offset_1 > maxRep) savedOffset = offset_1, offset_1 = 0;
     }