diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c
index 4858831e3..50979ce58 100644
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -147,13 +147,14 @@ void ZSTD_validateParams(ZSTD_parameters* params)
     const U32 btPlus = (params->strategy == ZSTD_btlazy2) || (params->strategy == ZSTD_btopt);
     const U32 searchLengthMax = (params->strategy == ZSTD_fast) ? ZSTD_SEARCHLENGTH_MAX : ZSTD_SEARCHLENGTH_MAX-1;
     const U32 searchLengthMin = (params->strategy == ZSTD_btopt) ? ZSTD_SEARCHLENGTH_MIN : ZSTD_SEARCHLENGTH_MIN+1;
+    const U32 hashLog3Min = (params->strategy == ZSTD_btopt) ? ZSTD_HASHLOG3_MIN : 0;
 
     /* validate params */
     if (MEM_32bits()) if (params->windowLog > 25) params->windowLog = 25;   /* 32 bits mode cannot flush > 24 bits */
     CLAMP(params->windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
     CLAMP(params->contentLog, ZSTD_CONTENTLOG_MIN, ZSTD_CONTENTLOG_MAX);
     CLAMP(params->hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
-    CLAMP(params->hashLog3, ZSTD_HASHLOG3_MIN, ZSTD_HASHLOG3_MAX);
+    CLAMP(params->hashLog3, hashLog3Min, ZSTD_HASHLOG3_MAX);
     CLAMP(params->searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
     CLAMP(params->searchLength, searchLengthMin, searchLengthMax);
     CLAMP(params->targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
@@ -164,8 +165,8 @@ void ZSTD_validateParams(ZSTD_parameters* params)
         U32 srcLog = ZSTD_highbit((U32)(params->srcSize)-1) + 1;
         if (params->windowLog > srcLog) params->windowLog = srcLog;
     }
-    if (params->windowLog   < ZSTD_WINDOWLOG_ABSOLUTEMIN) params->windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
-    if (params->contentLog  > params->windowLog+btPlus) params->contentLog = params->windowLog+btPlus;   /* <= ZSTD_CONTENTLOG_MAX */
+    if (params->windowLog  < ZSTD_WINDOWLOG_ABSOLUTEMIN) params->windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN;  /* required for frame header */
+    if (params->contentLog > params->windowLog+btPlus) params->contentLog = params->windowLog+btPlus;   /* <= ZSTD_CONTENTLOG_MAX */
 }
 
 
@@ -174,10 +175,14 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
 {   /* note : params considered validated here */
     const size_t blockSize = MIN(BLOCKSIZE, (size_t)1 << params.windowLog);
     /* reserve table memory */
-    const U32 contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog;
+    const U32    contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog;
+    const U32    divider = (params.searchLength==3) ? 3 : 4;
+    const size_t maxNbSeq = blockSize / divider;
+    const size_t tokenSpace = blockSize + 8*maxNbSeq;
     const size_t tableSpace = ((1 << contentLog) + (1 << params.hashLog) + (1 << params.hashLog3)) * sizeof(U32);
-    const size_t neededSpace = tableSpace + (256*sizeof(U32)) + (3*blockSize)
-        + ((params.strategy == ZSTD_btopt) ? ((1<<MLbits) + (1<<LLbits) + (1<<Offbits) + (1<<Litbits))*sizeof(U32) + (ZSTD_OPT_NUM+1)*(sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t)) : 0);
+    const size_t optSpace   = ((1<<MLbits) + (1<<LLbits) + (1<<Offbits) + (1<<Litbits))*sizeof(U32) + (ZSTD_OPT_NUM+1)*(sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
+    const size_t neededSpace = tableSpace + (256*sizeof(U32)) /* huffTable */ + tokenSpace
+                           + ((params.strategy == ZSTD_btopt) ? optSpace : 0);
 
     if (zc->workSpaceSize < neededSpace) {
         free(zc->workSpace);
@@ -204,13 +209,13 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
     zc->blockSize = blockSize;
 
     zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer);
-    zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart) + blockSize;
-    zc->seqStore.litStart = zc->seqStore.offCodeStart + (blockSize>>2);
+    zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart + maxNbSeq);
+    zc->seqStore.litStart = zc->seqStore.offCodeStart + maxNbSeq;
     zc->seqStore.litLengthStart =  zc->seqStore.litStart + blockSize;
-    zc->seqStore.matchLengthStart = zc->seqStore.litLengthStart + (blockSize>>2);
-    zc->seqStore.dumpsStart = zc->seqStore.matchLengthStart + (blockSize>>2);
+    zc->seqStore.matchLengthStart = zc->seqStore.litLengthStart + maxNbSeq;
+    zc->seqStore.dumpsStart = zc->seqStore.matchLengthStart + maxNbSeq;
     if (params.strategy == ZSTD_btopt) {
-        zc->seqStore.litFreq = (U32*)((void*)(zc->seqStore.dumpsStart + (blockSize>>2)));
+        zc->seqStore.litFreq = (U32*)((void*)(zc->seqStore.dumpsStart + maxNbSeq));
         zc->seqStore.litLengthFreq = zc->seqStore.litFreq + (1<<Litbits);
         zc->seqStore.matchLengthFreq = zc->seqStore.litLengthFreq + (1<<LLbits);
         zc->seqStore.offCodeFreq = zc->seqStore.matchLengthFreq + (1<<MLbits);
@@ -227,9 +232,9 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
 }
 
 
-/*! ZSTD_copyCCtx
-*   Duplicate an existing context @srcCCtx into another one @dstCCtx.
-*   Only works during stage 0 (i.e. before first call to ZSTD_compressContinue())
+/*! ZSTD_copyCCtx() :
+*   Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
+*   Only works during stage 0 (i.e. before first call to ZSTD_compressContinue()).
 *   @return : 0, or an error code */
 size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx)
 {
@@ -2363,7 +2368,7 @@ static const ZSTD_parameters ZSTD_defaultParameters[4][ZSTD_MAX_CLEVEL+1] = {
     {  0, 17, 18, 17,  0,  7,  4,128, ZSTD_btopt   },  /* level 16 */
     {  0, 17, 18, 17,  0,  8,  4,128, ZSTD_btopt   },  /* level 17 */
     {  0, 17, 18, 17,  0,  8,  4,256, ZSTD_btopt   },  /* level 18 */
-    {  0, 17, 18, 17,  0,  9,  4,256, ZSTD_btopt   },  /* level 19 */
+    {  0, 17, 18, 17, 16,  9,  3,256, ZSTD_btopt   },  /* level 19 */
     {  0, 17, 18, 17,  0, 10,  4,512, ZSTD_btopt   },  /* level 20 */
     {  0, 17, 18, 17,  0, 11,  4,512, ZSTD_btopt   },  /* level 21 */
     {  0, 17, 18, 17,  0, 11,  4,512, ZSTD_btopt   },  /* level 21-2 */
@@ -2384,22 +2389,22 @@ static const ZSTD_parameters ZSTD_defaultParameters[4][ZSTD_MAX_CLEVEL+1] = {
     {  0, 14, 14, 14,  0,  6,  4,  4, ZSTD_lazy2   },  /* level  7.*/
     {  0, 14, 14, 14,  0,  7,  4,  4, ZSTD_lazy2   },  /* level  8.*/
     {  0, 14, 15, 14,  0,  6,  4,  4, ZSTD_btlazy2 },  /* level  9.*/
-    {  0, 14, 15, 14,  0,  3,  3,  6, ZSTD_btopt   },  /* level 10.*/
-    {  0, 14, 15, 14,  0,  6,  3,  8, ZSTD_btopt   },  /* level 11.*/
-    {  0, 14, 15, 14,  0,  6,  3, 16, ZSTD_btopt   },  /* level 12.*/
-    {  0, 14, 15, 14,  0,  6,  3, 24, ZSTD_btopt   },  /* level 13.*/
-    {  0, 14, 15, 15,  0,  6,  3, 48, ZSTD_btopt   },  /* level 14.*/
-    {  0, 14, 15, 15,  0,  6,  3, 64, ZSTD_btopt   },  /* level 15.*/
-    {  0, 14, 15, 15,  0,  6,  3, 96, ZSTD_btopt   },  /* level 16.*/
-    {  0, 14, 15, 15,  0,  6,  3,128, ZSTD_btopt   },  /* level 17.*/
-    {  0, 14, 15, 15,  0,  6,  3,256, ZSTD_btopt   },  /* level 18.*/
-    {  0, 14, 15, 15,  0,  7,  3,256, ZSTD_btopt   },  /* level 19.*/
-    {  0, 14, 15, 15,  0,  8,  3,256, ZSTD_btopt   },  /* level 20.*/
-    {  0, 14, 15, 15,  0,  9,  3,256, ZSTD_btopt   },  /* level 21.*/
-    {  0, 14, 15, 15,  0, 10,  3,256, ZSTD_btopt   },  /* level 22.*/
-    {  0, 14, 15, 15,  0, 11,  3,256, ZSTD_btopt   },  /* level 23.*/
-    {  0, 14, 15, 15,  0, 12,  3,256, ZSTD_btopt   },  /* level 24.*/
-    {  0, 14, 15, 15,  0, 13,  3,256, ZSTD_btopt   },  /* level 25.*/
+    {  0, 14, 15, 14, 16,  3,  3,  6, ZSTD_btopt   },  /* level 10.*/
+    {  0, 14, 15, 14, 16,  6,  3,  8, ZSTD_btopt   },  /* level 11.*/
+    {  0, 14, 15, 14, 16,  6,  3, 16, ZSTD_btopt   },  /* level 12.*/
+    {  0, 14, 15, 14, 16,  6,  3, 24, ZSTD_btopt   },  /* level 13.*/
+    {  0, 14, 15, 15, 16,  6,  3, 48, ZSTD_btopt   },  /* level 14.*/
+    {  0, 14, 15, 15, 16,  6,  3, 64, ZSTD_btopt   },  /* level 15.*/
+    {  0, 14, 15, 15, 16,  6,  3, 96, ZSTD_btopt   },  /* level 16.*/
+    {  0, 14, 15, 15, 16,  6,  3,128, ZSTD_btopt   },  /* level 17.*/
+    {  0, 14, 15, 15, 16,  6,  3,256, ZSTD_btopt   },  /* level 18.*/
+    {  0, 14, 15, 15, 16,  7,  3,256, ZSTD_btopt   },  /* level 19.*/
+    {  0, 14, 15, 15, 16,  8,  3,256, ZSTD_btopt   },  /* level 20.*/
+    {  0, 14, 15, 15, 16,  9,  3,256, ZSTD_btopt   },  /* level 21.*/
+    {  0, 14, 15, 15, 16, 10,  3,256, ZSTD_btopt   },  /* level 22.*/
+    {  0, 14, 15, 15, 16, 11,  3,256, ZSTD_btopt   },  /* level 23.*/
+    {  0, 14, 15, 15, 16, 12,  3,256, ZSTD_btopt   },  /* level 24.*/
+    {  0, 14, 15, 15, 16, 13,  3,256, ZSTD_btopt   },  /* level 25.*/
 },
 };
 
diff --git a/lib/zstd_decompress.c b/lib/zstd_decompress.c
index c4338bcc2..844aa976e 100644
--- a/lib/zstd_decompress.c
+++ b/lib/zstd_decompress.c
@@ -822,7 +822,8 @@ static size_t ZSTD_decompressSequences(
             nbSeq--;
             ZSTD_decodeSequence(&sequence, &seqState, mls);
             oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litLimit_8, base, vBase, dictEnd);
-            if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
+            if (ZSTD_isError(oneSeqSize))
+                return oneSeqSize;
             op += oneSeqSize;
         }
 
diff --git a/programs/fuzzer.c b/programs/fuzzer.c
index 7cbfd7940..697695b38 100644
--- a/programs/fuzzer.c
+++ b/programs/fuzzer.c
@@ -196,22 +196,6 @@ static int basicUnitTests(U32 seed, double compressibility)
     if (result != (size_t)-ZSTD_error_srcSize_wrong) goto _output_error;
     DISPLAYLEVEL(4, "OK \n");
 
-    /* All zeroes test (#137 verif) */
-    #define ZEROESLENGTH 100
-    DISPLAYLEVEL(4, "test%3i : compress %u zeroes : ", testNb++, ZEROESLENGTH);
-    memset(CNBuffer, 0, ZEROESLENGTH);
-    result = ZSTD_compress(compressedBuffer, ZSTD_compressBound(ZEROESLENGTH), CNBuffer, ZEROESLENGTH, 1);
-    if (ZSTD_isError(result)) goto _output_error;
-    cSize = result;
-    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/ZEROESLENGTH*100);
-
-    DISPLAYLEVEL(4, "test%3i : decompress %u zeroes : ", testNb++, ZEROESLENGTH);
-    result = ZSTD_decompress(decodedBuffer, ZEROESLENGTH, compressedBuffer, cSize);
-    if (ZSTD_isError(result)) goto _output_error;
-    if (result != ZEROESLENGTH) goto _output_error;
-    DISPLAYLEVEL(4, "OK \n");
-
-
     /* Dictionary and Duplication tests */
     {
         ZSTD_CCtx* ctxOrig = ZSTD_createCCtx();
@@ -344,6 +328,58 @@ static int basicUnitTests(U32 seed, double compressibility)
         DISPLAYLEVEL(4, "OK \n");
     }
 
+    /* All zeroes test (#137 verif) */
+    #define ZEROESLENGTH 100
+    DISPLAYLEVEL(4, "test%3i : compress %u zeroes : ", testNb++, ZEROESLENGTH);
+    memset(CNBuffer, 0, ZEROESLENGTH);
+    result = ZSTD_compress(compressedBuffer, ZSTD_compressBound(ZEROESLENGTH), CNBuffer, ZEROESLENGTH, 1);
+    if (ZSTD_isError(result)) goto _output_error;
+    cSize = result;
+    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/ZEROESLENGTH*100);
+
+    DISPLAYLEVEL(4, "test%3i : decompress %u zeroes : ", testNb++, ZEROESLENGTH);
+    result = ZSTD_decompress(decodedBuffer, ZEROESLENGTH, compressedBuffer, cSize);
+    if (ZSTD_isError(result)) goto _output_error;
+    if (result != ZEROESLENGTH) goto _output_error;
+    DISPLAYLEVEL(4, "OK \n");
+
+    /* nbSeq limit test */
+    {
+        #define _3BYTESTESTLENGTH 131000
+        #define NB3BYTESSEQLOG   9
+        #define NB3BYTESSEQ     (1 << NB3BYTESSEQLOG)
+        #define NB3BYTESSEQMASK (NB3BYTESSEQ-1)
+        BYTE _3BytesSeqs[NB3BYTESSEQ][3];
+        U32 r = 1;
+        int i;
+
+        for (i=0; i < NB3BYTESSEQ; i++) {
+            _3BytesSeqs[i][0] = (BYTE)(FUZ_rand(&r) & 255);
+            _3BytesSeqs[i][1] = (BYTE)(FUZ_rand(&r) & 255);
+            _3BytesSeqs[i][2] = (BYTE)(FUZ_rand(&r) & 255);
+        }
+
+        for (i=0; i < _3BYTESTESTLENGTH; ) {
+            U32 id = FUZ_rand(&r) & NB3BYTESSEQMASK;
+            ((BYTE*)CNBuffer)[i+0] = _3BytesSeqs[id][0];
+            ((BYTE*)CNBuffer)[i+1] = _3BytesSeqs[id][1];
+            ((BYTE*)CNBuffer)[i+2] = _3BytesSeqs[id][2];
+            i += 3;
+        }
+
+        DISPLAYLEVEL(4, "test%3i : compress lots 3-bytes sequences : ", testNb++);
+        result = ZSTD_compress(compressedBuffer, ZSTD_compressBound(_3BYTESTESTLENGTH), CNBuffer, _3BYTESTESTLENGTH, 19);
+        if (ZSTD_isError(result)) goto _output_error;
+        cSize = result;
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/_3BYTESTESTLENGTH*100);
+
+        DISPLAYLEVEL(4, "test%3i : decompress lots 3-bytes sequence : ", testNb++);
+        result = ZSTD_decompress(decodedBuffer, _3BYTESTESTLENGTH, compressedBuffer, cSize);
+        if (ZSTD_isError(result)) goto _output_error;
+        if (result != _3BYTESTESTLENGTH) goto _output_error;
+        DISPLAYLEVEL(4, "OK \n");
+    }
+
 _end:
     free(CNBuffer);
     free(compressedBuffer);