diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index b9e0ec44d..8a0b46e09 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -59,18 +59,16 @@ ZSTD_CCtx* ZSTD_createCCtx(void)
 
 ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
 {
-    ZSTD_CCtx* cctx;
-
-    if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
-
-    cctx = (ZSTD_CCtx*) ZSTD_calloc(sizeof(ZSTD_CCtx), customMem);
-    if (!cctx) return NULL;
-    cctx->customMem = customMem;
-    cctx->requestedParams.compressionLevel = ZSTD_CLEVEL_DEFAULT;
-    cctx->requestedParams.fParams.contentSizeFlag = 1;
     ZSTD_STATIC_ASSERT(zcss_init==0);
     ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1));
-    return cctx;
+    if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
+    {   ZSTD_CCtx* const cctx = (ZSTD_CCtx*)ZSTD_calloc(sizeof(ZSTD_CCtx), customMem);
+        if (!cctx) return NULL;
+        cctx->customMem = customMem;
+        cctx->requestedParams.compressionLevel = ZSTD_CLEVEL_DEFAULT;
+        cctx->requestedParams.fParams.contentSizeFlag = 1;
+        return cctx;
+    }
 }
 
 ZSTD_CCtx* ZSTD_initStaticCCtx(void *workspace, size_t workspaceSize)
@@ -95,13 +93,10 @@ size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return 0;   /* support free on NULL */
     if (cctx->staticSize) return ERROR(memory_allocation);   /* not compatible with static CCtx */
-    ZSTD_free(cctx->workSpace, cctx->customMem);
-    cctx->workSpace = NULL;
-    ZSTD_freeCDict(cctx->cdictLocal);
-    cctx->cdictLocal = NULL;
+    ZSTD_free(cctx->workSpace, cctx->customMem); cctx->workSpace = NULL;
+    ZSTD_freeCDict(cctx->cdictLocal); cctx->cdictLocal = NULL;
 #ifdef ZSTD_MULTITHREAD
-    ZSTDMT_freeCCtx(cctx->mtctx);
-    cctx->mtctx = NULL;
+    ZSTDMT_freeCCtx(cctx->mtctx); cctx->mtctx = NULL;
 #endif
     ZSTD_free(cctx, cctx->customMem);
     return 0;   /* reserved as a potential error code in the future */
@@ -122,10 +117,6 @@ static size_t ZSTD_sizeof_mtctx(const ZSTD_CCtx* cctx)
 size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return 0;   /* support sizeof on NULL */
-    DEBUGLOG(3, "sizeof(*cctx) : %u", (U32)sizeof(*cctx));
-    DEBUGLOG(3, "workSpaceSize (including streaming buffers): %u", (U32)cctx->workSpaceSize);
-    DEBUGLOG(3, "inner cdict : %u", (U32)ZSTD_sizeof_CDict(cctx->cdictLocal));
-    DEBUGLOG(3, "inner MTCTX : %u", (U32)ZSTD_sizeof_mtctx(cctx));
     return sizeof(*cctx) + cctx->workSpaceSize
            + ZSTD_sizeof_CDict(cctx->cdictLocal)
            + ZSTD_sizeof_mtctx(cctx);
@@ -696,12 +687,23 @@ size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
     return ZSTD_estimateCCtxSize_usingCCtxParams(&params);
 }
 
-size_t ZSTD_estimateCCtxSize(int compressionLevel)
+static size_t ZSTD_estimateCCtxSize_internal(int compressionLevel)
 {
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
     return ZSTD_estimateCCtxSize_usingCParams(cParams);
 }
 
+size_t ZSTD_estimateCCtxSize(int compressionLevel)
+{
+    int level;
+    size_t memBudget = 0;
+    for (level=1; level<=compressionLevel; level++) {
+        size_t const newMB = ZSTD_estimateCCtxSize_internal(level);
+        if (newMB > memBudget) memBudget = newMB;
+    }
+    return memBudget;
+}
+
 size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
 {
     if (params->nbThreads > 1) { return ERROR(GENERIC); }
@@ -721,11 +723,21 @@ size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams)
     return ZSTD_estimateCStreamSize_usingCCtxParams(&params);
 }
 
-size_t ZSTD_estimateCStreamSize(int compressionLevel) {
+static size_t ZSTD_estimateCStreamSize_internal(int compressionLevel) {
     ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
     return ZSTD_estimateCStreamSize_usingCParams(cParams);
 }
 
+size_t ZSTD_estimateCStreamSize(int compressionLevel) {
+    int level;
+    size_t memBudget = 0;
+    for (level=1; level<=compressionLevel; level++) {
+        size_t const newMB = ZSTD_estimateCStreamSize_internal(level);
+        if (newMB > memBudget) memBudget = newMB;
+    }
+    return memBudget;
+}
+
 static U32 ZSTD_equivalentCParams(ZSTD_compressionParameters cParams1,
                                   ZSTD_compressionParameters cParams2)
 {
@@ -761,9 +773,9 @@ static U32 ZSTD_sufficientBuff(size_t bufferSize1, size_t blockSize1,
     size_t const windowSize2 = MAX(1, (size_t)MIN(((U64)1 << cParams2.windowLog), pledgedSrcSize));
     size_t const blockSize2 = MIN(ZSTD_BLOCKSIZE_MAX, windowSize2);
     size_t const neededBufferSize2 = (buffPol2==ZSTDb_buffered) ? windowSize2 + blockSize2 : 0;
-    DEBUGLOG(4, "ZSTD_sufficientBuff: windowSize2=%u from wlog=%u",
+    DEBUGLOG(4, "ZSTD_sufficientBuff: is windowSize2=%u <= wlog1=%u",
                 (U32)windowSize2, cParams2.windowLog);
-    DEBUGLOG(4, "ZSTD_sufficientBuff: blockSize2 %u <=? blockSize1 %u",
+    DEBUGLOG(4, "ZSTD_sufficientBuff: is blockSize2=%u <= blockSize1=%u",
                 (U32)blockSize2, (U32)blockSize1);
     return (blockSize2 <= blockSize1) /* seqStore space depends on blockSize */
          & (neededBufferSize2 <= bufferSize1);
@@ -786,10 +798,12 @@ static U32 ZSTD_equivalentParams(ZSTD_CCtx_params params1,
  *  reuse CCtx without reset (note : requires no dictionary) */
 static size_t ZSTD_continueCCtx(ZSTD_CCtx* cctx, ZSTD_CCtx_params params, U64 pledgedSrcSize)
 {
-    U32 const end = (U32)(cctx->nextSrc - cctx->base);
+    size_t const endT = (size_t)(cctx->nextSrc - cctx->base);
+    U32 const end = (U32)endT;
     size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params.cParams.windowLog), pledgedSrcSize));
     size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, windowSize);
-    DEBUGLOG(4, "ZSTD_continueCCtx");
+    DEBUGLOG(4, "ZSTD_continueCCtx: re-use context in place");
+    assert(endT < (3U<<30));
 
     cctx->blockSize = blockSize;   /* previous block size could be different even for same windowLog, due to pledgedSrcSize */
     cctx->appliedParams = params;
@@ -921,12 +935,12 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
         zc->entropy->offcode_repeatMode = FSE_repeat_none;
         zc->entropy->matchlength_repeatMode = FSE_repeat_none;
         zc->entropy->litlength_repeatMode = FSE_repeat_none;
-        zc->nextToUpdate = 1;
-        zc->nextSrc = NULL;
         zc->base = NULL;
         zc->dictBase = NULL;
-        zc->dictLimit = 0;
         zc->lowLimit = 0;
+        zc->dictLimit = 0;
+        zc->nextToUpdate = 1;
+        zc->nextSrc = NULL;
         { int i; for (i=0; i<ZSTD_REP_NUM; i++) zc->seqStore.rep[i] = repStartValue[i]; }
         zc->hashLog3 = hashLog3;
         zc->optState.litLengthSum = 0;
@@ -934,7 +948,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
         ptr = zc->entropy + 1;
 
         /* opt parser space */
-        if ((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btultra)) {
+        if ((params.cParams.strategy == ZSTD_btopt) | (params.cParams.strategy == ZSTD_btultra)) {
             DEBUGLOG(4, "reserving optimal parser space");
             assert(((size_t)ptr & 3) == 0);  /* ensure ptr is properly aligned */
             zc->optState.litFreq = (U32*)ptr;
@@ -1085,15 +1099,31 @@ size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long
 }
 
 
+#define ZSTD_ROWSIZE 16
+/*! ZSTD_reduceTable_internal() :
+ *  reduce table indexes by `reducerValue`
+ *  presume table size is a multiple of ZSTD_ROWSIZE.
+ *  Helps auto-vectorization */
+static void ZSTD_reduceTable_internal (U32* const table, int const nbRows, U32 const reducerValue)
+{
+    int cellNb = 0;
+    int rowNb;
+    for (rowNb=0 ; rowNb < nbRows ; rowNb++) {
+        int column;
+        for (column=0; column<ZSTD_ROWSIZE; column++) {
+            if (table[cellNb] < reducerValue) table[cellNb] = 0;
+            else table[cellNb] -= reducerValue;
+            cellNb++;
+    }   }
+}
+
 /*! ZSTD_reduceTable() :
  *  reduce table indexes by `reducerValue` */
 static void ZSTD_reduceTable (U32* const table, U32 const size, U32 const reducerValue)
 {
-    U32 u;
-    for (u=0 ; u < size ; u++) {
-        if (table[u] < reducerValue) table[u] = 0;
-        else table[u] -= reducerValue;
-    }
+    assert((size & (ZSTD_ROWSIZE-1)) == 0);  /* multiple of ZSTD_ROWSIZE */
+    assert(size < (1U<<31));   /* can be casted to int */
+    ZSTD_reduceTable_internal(table, size/ZSTD_ROWSIZE, reducerValue);
 }
 
 /*! ZSTD_ldm_reduceTable() :
@@ -1112,19 +1142,25 @@ static void ZSTD_ldm_reduceTable(ldmEntry_t* const table, U32 const size,
 *   rescale all indexes to avoid future overflow (indexes are U32) */
 static void ZSTD_reduceIndex (ZSTD_CCtx* zc, const U32 reducerValue)
 {
-    { U32 const hSize = (U32)1 << zc->appliedParams.cParams.hashLog;
-      ZSTD_reduceTable(zc->hashTable, hSize, reducerValue); }
+    {   U32 const hSize = (U32)1 << zc->appliedParams.cParams.hashLog;
+        ZSTD_reduceTable(zc->hashTable, hSize, reducerValue);
+    }
 
-    { U32 const chainSize = (zc->appliedParams.cParams.strategy == ZSTD_fast) ? 0 : ((U32)1 << zc->appliedParams.cParams.chainLog);
-      ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue); }
+    if (zc->appliedParams.cParams.strategy != ZSTD_fast) {
+        U32 const chainSize = (U32)1 << zc->appliedParams.cParams.chainLog;
+        if (zc->appliedParams.cParams.strategy == ZSTD_btlazy2)
+            ZSTD_preserveUnsortedMark(zc->chainTable, chainSize, reducerValue);
+        ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue);
+    }
 
-    { U32 const h3Size = (zc->hashLog3) ? (U32)1 << zc->hashLog3 : 0;
-      ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue); }
+    if (zc->hashLog3) {
+        U32 const h3Size = (U32)1 << zc->hashLog3;
+        ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue);
+    }
 
-    { if (zc->appliedParams.ldmParams.enableLdm) {
-          U32 const ldmHSize = (U32)1 << zc->appliedParams.ldmParams.hashLog;
-          ZSTD_ldm_reduceTable(zc->ldmState.hashTable, ldmHSize, reducerValue);
-      }
+    if (zc->appliedParams.ldmParams.enableLdm) {
+        U32 const ldmHSize = (U32)1 << zc->appliedParams.ldmParams.hashLog;
+        ZSTD_ldm_reduceTable(zc->ldmState.hashTable, ldmHSize, reducerValue);
     }
 }
 
@@ -1632,9 +1668,12 @@ static void ZSTD_resetSeqStore(seqStore_t* ssPtr)
     ssPtr->longLengthID = 0;
 }
 
-static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
+static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
+                                        void* dst, size_t dstCapacity,
+                                        const void* src, size_t srcSize)
 {
-    DEBUGLOG(5, "ZSTD_compressBlock_internal : dstCapacity = %u", (U32)dstCapacity);
+    DEBUGLOG(5, "ZSTD_compressBlock_internal (dstCapacity=%u) (dictLimit=%u, nextToUpdate=%u)",
+                (U32)dstCapacity, zc->dictLimit, zc->nextToUpdate);
     if (srcSize < MIN_CBLOCK_SIZE+ZSTD_blockHeaderSize+1)
         return 0;   /* don't even attempt compression below a certain srcSize */
     ZSTD_resetSeqStore(&(zc->seqStore));
@@ -1726,13 +1765,17 @@ static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
             cctx->dictLimit -= correction;
             if (cctx->nextToUpdate < correction) cctx->nextToUpdate = 0;
             else cctx->nextToUpdate -= correction;
-            DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x\n", correction, cctx->lowLimit);
+            DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x", correction, cctx->lowLimit);
         }
         /* enforce maxDist */
         if ((U32)(ip+blockSize - cctx->base) > cctx->loadedDictEnd + maxDist) {
             U32 const newLowLimit = (U32)(ip+blockSize - cctx->base) - maxDist;
             if (cctx->lowLimit < newLowLimit) cctx->lowLimit = newLowLimit;
+            if (cctx->dictLimit < cctx->lowLimit)
+                DEBUGLOG(5, "ZSTD_compress_frameChunk : update dictLimit from %u to %u ",
+                    cctx->dictLimit, cctx->lowLimit);
             if (cctx->dictLimit < cctx->lowLimit) cctx->dictLimit = cctx->lowLimit;
+            if (cctx->nextToUpdate < cctx->lowLimit) cctx->nextToUpdate = cctx->lowLimit;
         }
 
         {   size_t cSize = ZSTD_compressBlock_internal(cctx,
@@ -1835,8 +1878,9 @@ static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,
 
     /* Check if blocks follow each other */
     if (src != cctx->nextSrc) {
-        /* not contiguous */
         size_t const distanceFromBase = (size_t)(cctx->nextSrc - cctx->base);
+        DEBUGLOG(5, "ZSTD_compressContinue_internal: non contiguous blocks, new segment starts at %u",
+                    cctx->dictLimit);
         cctx->lowLimit = cctx->dictLimit;
         assert(distanceFromBase == (size_t)(U32)distanceFromBase);  /* should never overflow */
         cctx->dictLimit = (U32)distanceFromBase;
@@ -1868,6 +1912,7 @@ size_t ZSTD_compressContinue (ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize)
 {
+    DEBUGLOG(5, "ZSTD_compressContinue (srcSize=%u)", (U32)srcSize);
     return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1 /* frame mode */, 0 /* last chunk */);
 }
 
@@ -1921,7 +1966,7 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t
             ZSTD_insertAndFindFirstIndex(zc, iend-HASH_READ_SIZE, zc->appliedParams.cParams.searchLength);
         break;
 
-    case ZSTD_btlazy2:
+    case ZSTD_btlazy2:   /* we want the dictionary table fully sorted */
     case ZSTD_btopt:
     case ZSTD_btultra:
         if (srcSize >= HASH_READ_SIZE)
@@ -2129,10 +2174,10 @@ size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx,
 
 size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel)
 {
-    ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, dictSize);
+    ZSTD_parameters const params = ZSTD_getParams(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize);
     ZSTD_CCtx_params const cctxParams =
             ZSTD_assignParamsToCCtxParams(cctx->requestedParams, params);
-    DEBUGLOG(4, "ZSTD_compressBegin_usingDict");
+    DEBUGLOG(4, "ZSTD_compressBegin_usingDict (dictSize=%u)", (U32)dictSize);
     return ZSTD_compressBegin_internal(cctx, dict, dictSize, ZSTD_dm_auto, NULL,
                                        cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, ZSTDb_not_buffered);
 }
@@ -2184,7 +2229,6 @@ static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
     return op-ostart;
 }
 
-
 size_t ZSTD_compressEnd (ZSTD_CCtx* cctx,
                          void* dst, size_t dstCapacity,
                    const void* src, size_t srcSize)
@@ -2260,6 +2304,7 @@ size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, co
 
 size_t ZSTD_compressCCtx (ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel)
 {
+    DEBUGLOG(4, "ZSTD_compressCCtx (srcSize=%u)", (U32)srcSize);
     return ZSTD_compress_usingDict(ctx, dst, dstCapacity, src, srcSize, NULL, 0, compressionLevel);
 }
 
@@ -2869,7 +2914,7 @@ size_t ZSTD_compress_generic (ZSTD_CCtx* cctx,
         if (params.nbThreads > 1) {
             if (cctx->mtctx == NULL || (params.nbThreads != ZSTDMT_getNbThreads(cctx->mtctx))) {
                 DEBUGLOG(4, "ZSTD_compress_generic: creating new mtctx for nbThreads=%u (previous: %u)",
-                            params.nbThreads, (U32)ZSTDMT_getNbThreads(cctx->mtctx));
+                            params.nbThreads, (unsigned)ZSTDMT_getNbThreads(cctx->mtctx));
                 ZSTDMT_freeCCtx(cctx->mtctx);
                 cctx->mtctx = ZSTDMT_createCCtx_advanced(params.nbThreads, cctx->customMem);
                 if (cctx->mtctx == NULL) return ERROR(memory_allocation);
@@ -2971,9 +3016,9 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
     { 21, 19, 21,  4,  5, 16, ZSTD_lazy2   },  /* level 10 */
     { 22, 20, 22,  4,  5, 16, ZSTD_lazy2   },  /* level 11 */
     { 22, 20, 22,  5,  5, 16, ZSTD_lazy2   },  /* level 12 */
-    { 22, 21, 22,  5,  5, 16, ZSTD_lazy2   },  /* level 13 */
-    { 22, 21, 22,  6,  5, 16, ZSTD_lazy2   },  /* level 14 */
-    { 22, 21, 22,  4,  5, 16, ZSTD_btlazy2 },  /* level 15 */
+    { 22, 21, 22,  4,  5, 16, ZSTD_btlazy2 },  /* level 13 */
+    { 22, 21, 22,  5,  5, 16, ZSTD_btlazy2 },  /* level 14 */
+    { 22, 22, 22,  6,  5, 16, ZSTD_btlazy2 },  /* level 15 */
     { 22, 21, 22,  4,  5, 48, ZSTD_btopt   },  /* level 16 */
     { 23, 22, 22,  4,  4, 48, ZSTD_btopt   },  /* level 17 */
     { 23, 22, 22,  5,  3, 64, ZSTD_btopt   },  /* level 18 */
@@ -3062,41 +3107,14 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
 },
 };
 
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
-/* This function just controls
- * the monotonic memory budget increase of ZSTD_defaultCParameters[0].
- * Run once, on first ZSTD_getCParams() usage, if ZSTD_DEBUG is enabled
- */
-MEM_STATIC void ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget(void)
-{
-    int level;
-    for (level=1; level<ZSTD_maxCLevel(); level++) {
-        ZSTD_compressionParameters const c1 = ZSTD_defaultCParameters[0][level];
-        ZSTD_compressionParameters const c2 = ZSTD_defaultCParameters[0][level+1];
-        assert(c1.windowLog <= c2.windowLog);
-#       define ZSTD_TABLECOST(h,c) ((1<<(h)) + (1<<(c)))
-        assert(ZSTD_TABLECOST(c1.hashLog, c1.chainLog) <= ZSTD_TABLECOST(c2.hashLog, c2.chainLog));
-    }
-}
-#endif
-
 /*! ZSTD_getCParams() :
-*   @return ZSTD_compressionParameters structure for a selected compression level, `srcSize` and `dictSize`.
+*  @return ZSTD_compressionParameters structure for a selected compression level, srcSize and dictSize.
 *   Size values are optional, provide 0 if not known or unused */
 ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize)
 {
     size_t const addedSize = srcSizeHint ? 0 : 500;
     U64 const rSize = srcSizeHint+dictSize ? srcSizeHint+dictSize+addedSize : (U64)-1;
     U32 const tableID = (rSize <= 256 KB) + (rSize <= 128 KB) + (rSize <= 16 KB);   /* intentional underflow for srcSizeHint == 0 */
-
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
-    static int g_monotonicTest = 1;
-    if (g_monotonicTest) {
-        ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget();
-        g_monotonicTest=0;
-    }
-#endif
-
     DEBUGLOG(4, "ZSTD_getCParams: cLevel=%i, srcSize=%u, dictSize=%u => table %u",
                 compressionLevel, (U32)srcSizeHint, (U32)dictSize, tableID);
     if (compressionLevel <= 0) compressionLevel = ZSTD_CLEVEL_DEFAULT;   /* 0 == default; no negative compressionLevel yet */
diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index 6d4804961..1d575804a 100644
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -15,76 +15,117 @@
 /*-*************************************
 *  Binary Tree search
 ***************************************/
-/** ZSTD_insertBt1() : add one or multiple positions to tree.
- *  ip : assumed <= iend-8 .
- * @return : nb of positions added */
-static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
-                const BYTE* const ip, const BYTE* const iend,
-                U32 nbCompares, U32 const mls, U32 const extDict)
+#define ZSTD_DUBT_UNSORTED_MARK 1   /* note : index 1 will now be confused with "unsorted" if sorted as larger than its predecessor.
+                                       It's not a big deal though : the candidate will just be considered unsorted, and be sorted again.
+                                       Additionnally, candidate position 1 will be lost.
+                                       But candidate 1 cannot hide a large tree of candidates, so it's a moderate loss.
+                                       The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be misdhandled by a table re-use using a different strategy */
+
+/*! ZSTD_preserveUnsortedMark() :
+ *  pre-emptively increase value of ZSTD_DUBT_UNSORTED_MARK before ZSTD_reduceTable()
+ *  so that combined operation preserves its value.
+ *  Without it, ZSTD_DUBT_UNSORTED_MARK==1 would be squashed to 0.
+ *  As a consequence, the list of unsorted elements would stop on the first element,
+ *  removing candidates, resulting in a negligible loss to compression ratio
+ *  (since overflow protection with ZSTD_reduceTable() is relatively rare).
+ *  Another potential risk is that a position will be promoted from *unsorted*
+ *  to *sorted=>smaller:0*, meaning the next candidate will be considered smaller.
+ *  This could be wrong, and result in data corruption.
+ *  On second thought, this corruption might be impossible,
+ *  because unsorted elements are always at the beginning of the list,
+ *  and squashing to zero reduce the list to a single element,
+ *  which needs to be sorted anyway.
+ *  I haven't spent much thoughts into this possible scenario,
+ *  and just felt it was safer to implement ZSTD_preserveUnsortedMark() */
+void ZSTD_preserveUnsortedMark (U32* const table, U32 const size, U32 const reducerValue)
+{
+    U32 u;
+    for (u=0; u<size; u++)
+        if (table[u] == ZSTD_DUBT_UNSORTED_MARK)
+            table[u] = ZSTD_DUBT_UNSORTED_MARK + reducerValue;
+}
+
+void ZSTD_updateDUBT(ZSTD_CCtx* zc,
+                const BYTE* ip, const BYTE* iend,
+                U32 mls)
+{
+    U32* const hashTable = zc->hashTable;
+    U32  const hashLog = zc->appliedParams.cParams.hashLog;
+
+    U32* const bt = zc->chainTable;
+    U32  const btLog  = zc->appliedParams.cParams.chainLog - 1;
+    U32  const btMask = (1 << btLog) - 1;
+
+    const BYTE* const base = zc->base;
+    U32 const target = (U32)(ip - base);
+    U32 idx = zc->nextToUpdate;
+
+    if (idx != target)
+        DEBUGLOG(7, "ZSTD_updateDUBT, from %u to %u (dictLimit:%u)",
+                    idx, target, zc->dictLimit);
+    assert(ip + 8 <= iend);   /* condition for ZSTD_hashPtr */
+    (void)iend;
+
+    assert(idx >= zc->dictLimit);   /* condition for valid base+idx */
+    for ( ; idx < target ; idx++) {
+        size_t const h  = ZSTD_hashPtr(base + idx, hashLog, mls);   /* assumption : ip + 8 <= iend */
+        U32    const matchIndex = hashTable[h];
+
+        U32*   const nextCandidatePtr = bt + 2*(idx&btMask);
+        U32*   const sortMarkPtr  = nextCandidatePtr + 1;
+
+        DEBUGLOG(8, "ZSTD_updateDUBT: insert %u", idx);
+        hashTable[h] = idx;   /* Update Hash Table */
+        *nextCandidatePtr = matchIndex;   /* update BT like a chain */
+        *sortMarkPtr = ZSTD_DUBT_UNSORTED_MARK;
+    }
+    zc->nextToUpdate = target;
+}
+
+
+/** ZSTD_insertDUBT1() :
+ *  sort one already inserted but unsorted position
+ *  assumption : current >= btlow == (current - btmask)
+ *  doesn't fail */
+static void ZSTD_insertDUBT1(ZSTD_CCtx* zc,
+                 U32 current, const BYTE* inputEnd,
+                 U32 nbCompares, U32 btLow, int extDict)
 {
-    U32*   const hashTable = zc->hashTable;
-    U32    const hashLog = zc->appliedParams.cParams.hashLog;
-    size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
     U32*   const bt = zc->chainTable;
     U32    const btLog  = zc->appliedParams.cParams.chainLog - 1;
     U32    const 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 ip = (current>=dictLimit) ? base + current : dictBase + current;
+    const BYTE* const iend = (current>=dictLimit) ? inputEnd : dictBase + dictLimit;
     const BYTE* const dictEnd = dictBase + dictLimit;
     const BYTE* const prefixStart = base + dictLimit;
     const BYTE* match;
-    const U32 current = (U32)(ip-base);
-    const U32 btLow = btMask >= current ? 0 : current - btMask;
     U32* smallerPtr = bt + 2*(current&btMask);
     U32* largerPtr  = smallerPtr + 1;
+    U32 matchIndex = *smallerPtr;
     U32 dummy32;   /* to be nullified at the end */
     U32 const windowLow = zc->lowLimit;
-    U32 matchEndIdx = current+8+1;
-    size_t bestLength = 8;
-#ifdef ZSTD_C_PREDICT
-    U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0);
-    U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1);
-    predictedSmall += (predictedSmall>0);
-    predictedLarge += (predictedLarge>0);
-#endif /* ZSTD_C_PREDICT */
 
-    DEBUGLOG(8, "ZSTD_insertBt1 (%u)", current);
-
-    assert(ip <= iend-8);   /* required for h calculation */
-    hashTable[h] = current;   /* Update Hash Table */
+    DEBUGLOG(8, "ZSTD_insertDUBT1(%u) (dictLimit=%u, lowLimit=%u)",
+                current, dictLimit, windowLow);
+    assert(current >= btLow);
+    assert(ip < iend);   /* condition for ZSTD_count */
 
     while (nbCompares-- && (matchIndex > windowLow)) {
         U32* const nextPtr = bt + 2*(matchIndex & btMask);
         size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
         assert(matchIndex < current);
 
-#ifdef ZSTD_C_PREDICT   /* note : can create issues when hlog small <= 11 */
-        const U32* predictPtr = bt + 2*((matchIndex-1) & btMask);   /* written this way, as bt is a roll buffer */
-        if (matchIndex == predictedSmall) {
-            /* no need to check length, result known */
-            *smallerPtr = matchIndex;
-            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) */
-            predictedSmall = predictPtr[1] + (predictPtr[1]>0);
-            continue;
-        }
-        if (matchIndex == predictedLarge) {
-            *largerPtr = matchIndex;
-            if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
-            largerPtr = nextPtr;
-            matchIndex = nextPtr[0];
-            predictedLarge = predictPtr[0] + (predictPtr[0]>0);
-            continue;
-        }
-#endif
-
-        if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
-            assert(matchIndex+matchLength >= dictLimit);   /* might be wrong if extDict is incorrectly set to 0 */
-            match = base + matchIndex;
+        if ( (!extDict)
+          || (matchIndex+matchLength >= dictLimit)  /* both in current segment*/
+          || (current < dictLimit) /* both in extDict */) {
+            const BYTE* const mBase = !extDict || ((matchIndex+matchLength) >= dictLimit) ? base : dictBase;
+            assert( (matchIndex+matchLength >= dictLimit)   /* might be wrong if extDict is incorrectly set to 0 */
+                 || (current < dictLimit) );
+            match = mBase + matchIndex;
             matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
         } else {
             match = dictBase + matchIndex;
@@ -93,11 +134,8 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
                 match = base + matchIndex;   /* to prepare for next usage of match[matchLength] */
         }
 
-        if (matchLength > bestLength) {
-            bestLength = matchLength;
-            if (matchLength > matchEndIdx - matchIndex)
-                matchEndIdx = matchIndex + (U32)matchLength;
-        }
+        DEBUGLOG(8, "ZSTD_insertDUBT1: comparing %u with %u : found %u common bytes ",
+                    current, matchIndex, (U32)matchLength);
 
         if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
             break;   /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
@@ -108,6 +146,8 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
             *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 searching */
+            DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is smaller : next => %u",
+                        matchIndex, btLow, nextPtr[1]);
             smallerPtr = nextPtr+1;               /* new "candidate" => larger than match, which was smaller than target */
             matchIndex = nextPtr[1];              /* new matchIndex, larger than previous and closer to current */
         } else {
@@ -115,125 +155,145 @@ static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
             *largerPtr = matchIndex;
             commonLengthLarger = matchLength;
             if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
+            DEBUGLOG(8, "ZSTD_insertDUBT1: %u (>btLow=%u) is larger => %u",
+                        matchIndex, btLow, nextPtr[0]);
             largerPtr = nextPtr;
             matchIndex = nextPtr[0];
     }   }
 
     *smallerPtr = *largerPtr = 0;
-    if (bestLength > 384) return MIN(192, (U32)(bestLength - 384));   /* speed optimization */
-    assert(matchEndIdx > current + 8);
-    return matchEndIdx - (current + 8);
-}
-
-FORCE_INLINE_TEMPLATE
-void ZSTD_updateTree_internal(ZSTD_CCtx* zc,
-                const BYTE* const ip, const BYTE* const iend,
-                const U32 nbCompares, const U32 mls, const U32 extDict)
-{
-    const BYTE* const base = zc->base;
-    U32 const target = (U32)(ip - base);
-    U32 idx = zc->nextToUpdate;
-    DEBUGLOG(7, "ZSTD_updateTree_internal, from %u to %u  (extDict:%u)",
-                idx, target, extDict);
-
-    while(idx < target)
-        idx += ZSTD_insertBt1(zc, base+idx, iend, nbCompares, mls, extDict);
-    zc->nextToUpdate = target;
-}
-
-void ZSTD_updateTree(ZSTD_CCtx* zc,
-                const BYTE* const ip, const BYTE* const iend,
-                const U32 nbCompares, const U32 mls)
-{
-    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 0 /*extDict*/);
-}
-
-void ZSTD_updateTree_extDict(ZSTD_CCtx* zc,
-                const BYTE* const ip, const BYTE* const iend,
-                const U32 nbCompares, const U32 mls)
-{
-    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 1 /*extDict*/);
 }
 
 
-static size_t ZSTD_insertBtAndFindBestMatch (
-                        ZSTD_CCtx* zc,
-                        const BYTE* const ip, const BYTE* const iend,
-                        size_t* offsetPtr,
-                        U32 nbCompares, const U32 mls,
-                        U32 extDict)
+static size_t ZSTD_DUBT_findBestMatch (
+                            ZSTD_CCtx* zc,
+                            const BYTE* const ip, const BYTE* const iend,
+                            size_t* offsetPtr,
+                            U32 nbCompares, const U32 mls,
+                            U32 extDict)
 {
     U32*   const hashTable = zc->hashTable;
     U32    const hashLog = zc->appliedParams.cParams.hashLog;
     size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
+    U32          matchIndex  = hashTable[h];
+
+    const BYTE* const base = zc->base;
+    U32    const current = (U32)(ip-base);
+    U32    const windowLow = zc->lowLimit;
+
     U32*   const bt = zc->chainTable;
     U32    const btLog  = zc->appliedParams.cParams.chainLog - 1;
     U32    const 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;
-    U32 matchEndIdx = current+8+1;
-    U32 dummy32;   /* to be nullified at the end */
-    size_t bestLength = 0;
+    U32    const btLow = (btMask >= current) ? 0 : current - btMask;
+    U32    const unsortLimit = MAX(btLow, windowLow);
 
+    U32*         nextCandidate = bt + 2*(matchIndex&btMask);
+    U32*         unsortedMark = bt + 2*(matchIndex&btMask) + 1;
+    U32          nbCandidates = nbCompares;
+    U32          previousCandidate = 0;
+
+    DEBUGLOG(7, "ZSTD_DUBT_findBestMatch (%u) ", current);
     assert(ip <= iend-8);   /* required for h calculation */
-    hashTable[h] = current;   /* Update Hash Table */
 
-    while (nbCompares-- && (matchIndex > windowLow)) {
-        U32* const nextPtr = bt + 2*(matchIndex & btMask);
-        size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
-        const BYTE* match;
+    /* reach end of unsorted candidates list */
+    while ( (matchIndex > unsortLimit)
+         && (*unsortedMark == ZSTD_DUBT_UNSORTED_MARK)
+         && (nbCandidates > 1) ) {
+        DEBUGLOG(8, "ZSTD_DUBT_findBestMatch: candidate %u is unsorted",
+                    matchIndex);
+        *unsortedMark = previousCandidate;
+        previousCandidate = matchIndex;
+        matchIndex = *nextCandidate;
+        nextCandidate = bt + 2*(matchIndex&btMask);
+        unsortedMark = bt + 2*(matchIndex&btMask) + 1;
+        nbCandidates --;
+    }
 
-        if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
-            match = base + matchIndex;
-            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
-        } 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 ( (matchIndex > unsortLimit)
+      && (*unsortedMark==ZSTD_DUBT_UNSORTED_MARK) ) {
+        DEBUGLOG(7, "ZSTD_DUBT_findBestMatch: nullify last unsorted candidate %u",
+                    matchIndex);
+        *nextCandidate = *unsortedMark = 0;   /* nullify next candidate if it's still unsorted (note : simplification, detrimental to compression ratio, beneficial for speed) */
+    }
 
-        if (matchLength > bestLength) {
-            if (matchLength > matchEndIdx - matchIndex)
-                matchEndIdx = matchIndex + (U32)matchLength;
-            if ( (4*(int)(matchLength-bestLength)) > (int)(ZSTD_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
-                bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + 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) */
+    /* batch sort stacked candidates */
+    matchIndex = previousCandidate;
+    while (matchIndex) {  /* will end on matchIndex == 0 */
+        U32* const nextCandidateIdxPtr = bt + 2*(matchIndex&btMask) + 1;
+        U32 const nextCandidateIdx = *nextCandidateIdxPtr;
+        ZSTD_insertDUBT1(zc, matchIndex, iend,
+                         nbCandidates, unsortLimit, extDict);
+        matchIndex = nextCandidateIdx;
+        nbCandidates++;
+    }
+
+    /* find longest match */
+    {   size_t commonLengthSmaller=0, commonLengthLarger=0;
+        const BYTE* const dictBase = zc->dictBase;
+        const U32 dictLimit = zc->dictLimit;
+        const BYTE* const dictEnd = dictBase + dictLimit;
+        const BYTE* const prefixStart = base + dictLimit;
+        U32* smallerPtr = bt + 2*(current&btMask);
+        U32* largerPtr  = bt + 2*(current&btMask) + 1;
+        U32 matchEndIdx = current+8+1;
+        U32 dummy32;   /* to be nullified at the end */
+        size_t bestLength = 0;
+
+        matchIndex  = hashTable[h];
+        hashTable[h] = current;   /* Update Hash Table */
+
+        while (nbCompares-- && (matchIndex > windowLow)) {
+            U32* const nextPtr = bt + 2*(matchIndex & btMask);
+            size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
+            const BYTE* match;
+
+            if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
+                match = base + matchIndex;
+                matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
+            } 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_highbit32(current-matchIndex+1) - ZSTD_highbit32((U32)offsetPtr[0]+1)) )
+                    bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + 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;
+
+        assert(matchEndIdx > current+8); /* ensure nextToUpdate is increased */
+        zc->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
+        if (bestLength >= MINMATCH) {
+            U32 const mIndex = current - ((U32)*offsetPtr - ZSTD_REP_MOVE); (void)mIndex;
+            DEBUGLOG(8, "ZSTD_DUBT_findBestMatch(%u) : found match of length %u and offsetCode %u (pos %u)",
+                        current, (U32)bestLength, (U32)*offsetPtr, mIndex);
         }
-
-        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;
-
-    assert(matchEndIdx > current+8);
-    zc->nextToUpdate = matchEndIdx - 8;   /* skip repetitive patterns */
-    return bestLength;
+        return bestLength;
+    }
 }
 
 
@@ -244,9 +304,10 @@ static size_t ZSTD_BtFindBestMatch (
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 mls)
 {
+    DEBUGLOG(7, "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, 0);
+    ZSTD_updateDUBT(zc, ip, iLimit, mls);
+    return ZSTD_DUBT_findBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
 }
 
 
@@ -274,9 +335,10 @@ static size_t ZSTD_BtFindBestMatch_extDict (
                         size_t* offsetPtr,
                         const U32 maxNbAttempts, const U32 mls)
 {
+    DEBUGLOG(7, "ZSTD_BtFindBestMatch_extDict");
     if (ip < zc->base + zc->nextToUpdate) return 0;   /* skipped area */
-    ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
-    return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
+    ZSTD_updateDUBT(zc, ip, iLimit, mls);
+    return ZSTD_DUBT_findBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
 }
 
 
diff --git a/lib/compress/zstd_lazy.h b/lib/compress/zstd_lazy.h
index 74e1fd697..5c02f1661 100644
--- a/lib/compress/zstd_lazy.h
+++ b/lib/compress/zstd_lazy.h
@@ -18,9 +18,9 @@ extern "C" {
 #include "mem.h"    /* U32 */
 #include "zstd.h"   /* ZSTD_CCtx, size_t */
 
-U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls);
-void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls);
-void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls);
+U32 ZSTD_insertAndFindFirstIndex (ZSTD_CCtx* zc, const BYTE* ip, U32 mls);   /* used in ZSTD_loadDictionaryContent() */
+void ZSTD_updateDUBT(ZSTD_CCtx* zc, const BYTE* ip, const BYTE* iend, U32 mls);  /* used in ZSTD_loadDictionaryContent() */
+void ZSTD_preserveUnsortedMark (U32* const table, U32 const size, U32 const reducerValue);  /*! used in ZSTD_reduceIndex(). pre-emptively increase value of ZSTD_DUBT_UNSORTED_MARK */
 
 size_t ZSTD_compressBlock_btlazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_lazy2(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c
index 7171ff537..04824ccf2 100644
--- a/lib/compress/zstd_opt.c
+++ b/lib/compress/zstd_opt.c
@@ -10,7 +10,6 @@
 
 #include "zstd_compress_internal.h"
 #include "zstd_opt.h"
-#include "zstd_lazy.h"   /* ZSTD_updateTree, ZSTD_updateTree_extDict */
 
 
 #define ZSTD_LITFREQ_ADD    2   /* scaling factor for litFreq, so that frequencies adapt faster to new stats. Also used for matchSum (?) */
@@ -265,6 +264,147 @@ static U32 ZSTD_insertAndFindFirstIndexHash3 (ZSTD_CCtx* const cctx, const BYTE*
 /*-*************************************
 *  Binary Tree search
 ***************************************/
+/** ZSTD_insertBt1() : add one or multiple positions to tree.
+ *  ip : assumed <= iend-8 .
+ * @return : nb of positions added */
+static U32 ZSTD_insertBt1(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                U32 nbCompares, U32 const mls, U32 const extDict)
+{
+    U32*   const hashTable = zc->hashTable;
+    U32    const hashLog = zc->appliedParams.cParams.hashLog;
+    size_t const h  = ZSTD_hashPtr(ip, hashLog, mls);
+    U32*   const bt = zc->chainTable;
+    U32    const btLog  = zc->appliedParams.cParams.chainLog - 1;
+    U32    const 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 BYTE* match;
+    const U32 current = (U32)(ip-base);
+    const U32 btLow = btMask >= current ? 0 : current - btMask;
+    U32* smallerPtr = bt + 2*(current&btMask);
+    U32* largerPtr  = smallerPtr + 1;
+    U32 dummy32;   /* to be nullified at the end */
+    U32 const windowLow = zc->lowLimit;
+    U32 matchEndIdx = current+8+1;
+    size_t bestLength = 8;
+#ifdef ZSTD_C_PREDICT
+    U32 predictedSmall = *(bt + 2*((current-1)&btMask) + 0);
+    U32 predictedLarge = *(bt + 2*((current-1)&btMask) + 1);
+    predictedSmall += (predictedSmall>0);
+    predictedLarge += (predictedLarge>0);
+#endif /* ZSTD_C_PREDICT */
+
+    DEBUGLOG(8, "ZSTD_insertBt1 (%u)", current);
+
+    assert(ip <= iend-8);   /* required for h calculation */
+    hashTable[h] = current;   /* Update Hash Table */
+
+    while (nbCompares-- && (matchIndex > windowLow)) {
+        U32* const nextPtr = bt + 2*(matchIndex & btMask);
+        size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger);   /* guaranteed minimum nb of common bytes */
+        assert(matchIndex < current);
+
+#ifdef ZSTD_C_PREDICT   /* note : can create issues when hlog small <= 11 */
+        const U32* predictPtr = bt + 2*((matchIndex-1) & btMask);   /* written this way, as bt is a roll buffer */
+        if (matchIndex == predictedSmall) {
+            /* no need to check length, result known */
+            *smallerPtr = matchIndex;
+            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) */
+            predictedSmall = predictPtr[1] + (predictPtr[1]>0);
+            continue;
+        }
+        if (matchIndex == predictedLarge) {
+            *largerPtr = matchIndex;
+            if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop the search */
+            largerPtr = nextPtr;
+            matchIndex = nextPtr[0];
+            predictedLarge = predictPtr[0] + (predictPtr[0]>0);
+            continue;
+        }
+#endif
+
+        if ((!extDict) || (matchIndex+matchLength >= dictLimit)) {
+            assert(matchIndex+matchLength >= dictLimit);   /* might be wrong if extDict is incorrectly set to 0 */
+            match = base + matchIndex;
+            matchLength += ZSTD_count(ip+matchLength, match+matchLength, iend);
+        } 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) {
+            bestLength = matchLength;
+            if (matchLength > matchEndIdx - matchIndex)
+                matchEndIdx = matchIndex + (U32)matchLength;
+        }
+
+        if (ip+matchLength == iend) {   /* equal : no way to know if inf or sup */
+            break;   /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt tree */
+        }
+
+        if (match[matchLength] < ip[matchLength]) {  /* necessarily within buffer */
+            /* 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 searching */
+            smallerPtr = nextPtr+1;               /* new "candidate" => larger than match, which was smaller than target */
+            matchIndex = nextPtr[1];              /* new matchIndex, larger than previous and closer to current */
+        } else {
+            /* match is larger than current */
+            *largerPtr = matchIndex;
+            commonLengthLarger = matchLength;
+            if (matchIndex <= btLow) { largerPtr=&dummy32; break; }   /* beyond tree size, stop searching */
+            largerPtr = nextPtr;
+            matchIndex = nextPtr[0];
+    }   }
+
+    *smallerPtr = *largerPtr = 0;
+    if (bestLength > 384) return MIN(192, (U32)(bestLength - 384));   /* speed optimization */
+    assert(matchEndIdx > current + 8);
+    return matchEndIdx - (current + 8);
+}
+
+FORCE_INLINE_TEMPLATE
+void ZSTD_updateTree_internal(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                const U32 nbCompares, const U32 mls, const U32 extDict)
+{
+    const BYTE* const base = zc->base;
+    U32 const target = (U32)(ip - base);
+    U32 idx = zc->nextToUpdate;
+    DEBUGLOG(7, "ZSTD_updateTree_internal, from %u to %u  (extDict:%u)",
+                idx, target, extDict);
+
+    while(idx < target)
+        idx += ZSTD_insertBt1(zc, base+idx, iend, nbCompares, mls, extDict);
+    zc->nextToUpdate = target;
+}
+
+void ZSTD_updateTree(ZSTD_CCtx* zc,
+                const BYTE* ip, const BYTE* iend,
+                U32 nbCompares, U32 mls)
+{
+    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 0 /*extDict*/);
+}
+
+static void ZSTD_updateTree_extDict(ZSTD_CCtx* zc,
+                const BYTE* const ip, const BYTE* const iend,
+                const U32 nbCompares, const U32 mls)
+{
+    ZSTD_updateTree_internal(zc, ip, iend, nbCompares, mls, 1 /*extDict*/);
+}
+
+
 FORCE_INLINE_TEMPLATE
 U32 ZSTD_insertBtAndGetAllMatches (
                     ZSTD_CCtx* zc,
diff --git a/lib/compress/zstd_opt.h b/lib/compress/zstd_opt.h
index 82e810c29..b803a0f2e 100644
--- a/lib/compress/zstd_opt.h
+++ b/lib/compress/zstd_opt.h
@@ -15,8 +15,11 @@
 extern "C" {
 #endif
 
+#include "mem.h"    /* U32 */
 #include "zstd.h"   /* ZSTD_CCtx, size_t */
 
+void ZSTD_updateTree(ZSTD_CCtx* ctx, const BYTE* ip, const BYTE* iend, U32 nbCompares, U32 mls);  /* used in ZSTD_loadDictionaryContent() */
+
 size_t ZSTD_compressBlock_btopt(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 size_t ZSTD_compressBlock_btultra(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
 
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index a59d94411..ab6c2edc5 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -204,6 +204,7 @@ ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
 
 ZSTD_DCtx* ZSTD_createDCtx(void)
 {
+    DEBUGLOG(3, "ZSTD_createDCtx");
     return ZSTD_createDCtx_advanced(ZSTD_defaultCMem);
 }
 
@@ -2247,6 +2248,7 @@ size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
 
 ZSTD_DStream* ZSTD_createDStream(void)
 {
+    DEBUGLOG(3, "ZSTD_createDStream");
     return ZSTD_createDStream_advanced(ZSTD_defaultCMem);
 }
 
@@ -2273,6 +2275,7 @@ size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_MAX; }
 
 size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
 {
+    DEBUGLOG(4, "ZSTD_initDStream_usingDict");
     zds->streamStage = zdss_loadHeader;
     zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
     ZSTD_freeDDict(zds->ddictLocal);
@@ -2289,6 +2292,7 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
 /* note : this variant can't fail */
 size_t ZSTD_initDStream(ZSTD_DStream* zds)
 {
+    DEBUGLOG(4, "ZSTD_initDStream");
     return ZSTD_initDStream_usingDict(zds, NULL, 0);
 }
 
@@ -2304,6 +2308,7 @@ size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict)
 
 size_t ZSTD_resetDStream(ZSTD_DStream* zds)
 {
+    DEBUGLOG(4, "ZSTD_resetDStream");
     zds->streamStage = zdss_loadHeader;
     zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
     zds->legacyVersion = 0;
diff --git a/tests/fuzz/.gitignore b/tests/fuzz/.gitignore
index 4ff28de98..9409cf837 100644
--- a/tests/fuzz/.gitignore
+++ b/tests/fuzz/.gitignore
@@ -2,4 +2,7 @@
 corpora
 block_decompress
 block_round_trip
+simple_decompress
 simple_round_trip
+stream_decompress
+stream_round_trip
diff --git a/tests/fuzzer.c b/tests/fuzzer.c
index 024a583ba..3206d6e11 100644
--- a/tests/fuzzer.c
+++ b/tests/fuzzer.c
@@ -63,7 +63,7 @@ static UTIL_time_t g_displayClock = UTIL_TIME_INITIALIZER;
 #define DISPLAYUPDATE(l, ...) if (g_displayLevel>=l) { \
             if ((UTIL_clockSpanMicro(g_displayClock) > g_refreshRate) || (g_displayLevel>=4)) \
             { g_displayClock = UTIL_getTime(); DISPLAY(__VA_ARGS__); \
-            if (g_displayLevel>=4) fflush(stderr); } }
+            if (g_displayLevel>=4) fflush(stdout); } }
 
 
 #undef MIN
@@ -293,91 +293,91 @@ static int basicUnitTests(U32 seed, double compressibility)
     RDG_genBuffer(CNBuffer, CNBuffSize, compressibility, 0., seed);
 
     /* Basic tests */
-    DISPLAYLEVEL(4, "test%3i : ZSTD_getErrorName : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : ZSTD_getErrorName : ", testNb++);
     {   const char* errorString = ZSTD_getErrorName(0);
-        DISPLAYLEVEL(4, "OK : %s \n", errorString);
+        DISPLAYLEVEL(3, "OK : %s \n", errorString);
     }
 
-    DISPLAYLEVEL(4, "test%3i : ZSTD_getErrorName with wrong value : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : ZSTD_getErrorName with wrong value : ", testNb++);
     {   const char* errorString = ZSTD_getErrorName(499);
-        DISPLAYLEVEL(4, "OK : %s \n", errorString);
+        DISPLAYLEVEL(3, "OK : %s \n", errorString);
     }
 
 
-    DISPLAYLEVEL(4, "test%3i : compress %u bytes : ", testNb++, (U32)CNBuffSize);
+    DISPLAYLEVEL(3, "test%3i : compress %u bytes : ", testNb++, (U32)CNBuffSize);
     {   ZSTD_CCtx* cctx = ZSTD_createCCtx();
         if (cctx==NULL) goto _output_error;
         CHECKPLUS(r, ZSTD_compressCCtx(cctx,
                             compressedBuffer, compressedBufferSize,
                             CNBuffer, CNBuffSize, 1),
                   cSize=r );
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : size of cctx for level 1 : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : size of cctx for level 1 : ", testNb++);
         {   size_t const cctxSize = ZSTD_sizeof_CCtx(cctx);
-            DISPLAYLEVEL(4, "%u bytes \n", (U32)cctxSize);
+            DISPLAYLEVEL(3, "%u bytes \n", (U32)cctxSize);
         }
         ZSTD_freeCCtx(cctx);
     }
 
 
-    DISPLAYLEVEL(4, "test%3i : ZSTD_getFrameContentSize test : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : ZSTD_getFrameContentSize test : ", testNb++);
     {   unsigned long long const rSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
         if (rSize != CNBuffSize) goto _output_error;
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : ZSTD_findDecompressedSize test : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : ZSTD_findDecompressedSize test : ", testNb++);
     {   unsigned long long const rSize = ZSTD_findDecompressedSize(compressedBuffer, cSize);
         if (rSize != CNBuffSize) goto _output_error;
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+    DISPLAYLEVEL(3, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
     { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
       if (r != CNBuffSize) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
     {   size_t u;
         for (u=0; u<CNBuffSize; u++) {
             if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u]) goto _output_error;;
     }   }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
 
-    DISPLAYLEVEL(4, "test%3i : decompress with null dict : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress with null dict : ", testNb++);
     { size_t const r = ZSTD_decompress_usingDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, NULL, 0);
       if (r != CNBuffSize) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : decompress with null DDict : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress with null DDict : ", testNb++);
     { size_t const r = ZSTD_decompress_usingDDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, NULL);
       if (r != CNBuffSize) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : decompress with 1 missing byte : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress with 1 missing byte : ", testNb++);
     { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize-1);
       if (!ZSTD_isError(r)) goto _output_error;
       if (ZSTD_getErrorCode((size_t)r) != ZSTD_error_srcSize_wrong) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : decompress with 1 too much byte : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress with 1 too much byte : ", testNb++);
     { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize+1);
       if (!ZSTD_isError(r)) goto _output_error;
       if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%di : check CCtx size after compressing empty input : ", testNb++);
+    DISPLAYLEVEL(3, "test%3d : check CCtx size after compressing empty input : ", testNb++);
     {   ZSTD_CCtx* cctx = ZSTD_createCCtx();
         size_t const r = ZSTD_compressCCtx(cctx, compressedBuffer, compressedBufferSize, NULL, 0, 19);
         if (ZSTD_isError(r)) goto _output_error;
         if (ZSTD_sizeof_CCtx(cctx) > (1U << 20)) goto _output_error;
         ZSTD_freeCCtx(cctx);
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%di : re-use CCtx with expanding block size : ", testNb++);
+    DISPLAYLEVEL(3, "test%3d : re-use CCtx with expanding block size : ", testNb++);
     {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
         ZSTD_parameters const params = ZSTD_getParams(1, ZSTD_CONTENTSIZE_UNKNOWN, 0);
         assert(params.fParams.contentSizeFlag == 1);  /* block size will be adapted if pledgedSrcSize is enabled */
@@ -392,11 +392,11 @@ static int basicUnitTests(U32 seed, double compressibility)
         }
         ZSTD_freeCCtx(cctx);
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
     /* Static CCtx tests */
 #define STATIC_CCTX_LEVEL 3
-    DISPLAYLEVEL(4, "test%3i : create static CCtx for level %u :", testNb++, STATIC_CCTX_LEVEL);
+    DISPLAYLEVEL(3, "test%3i : create static CCtx for level %u :", testNb++, STATIC_CCTX_LEVEL);
     {   size_t const staticCCtxSize = ZSTD_estimateCStreamSize(STATIC_CCTX_LEVEL);
         void* const staticCCtxBuffer = malloc(staticCCtxSize);
         size_t const staticDCtxSize = ZSTD_estimateDCtxSize();
@@ -411,57 +411,57 @@ static int basicUnitTests(U32 seed, double compressibility)
         {   ZSTD_CCtx* staticCCtx = ZSTD_initStaticCCtx(staticCCtxBuffer, staticCCtxSize);
             ZSTD_DCtx* staticDCtx = ZSTD_initStaticDCtx(staticDCtxBuffer, staticDCtxSize);
             if ((staticCCtx==NULL) || (staticDCtx==NULL)) goto _output_error;
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init CCtx for level %u : ", testNb++, STATIC_CCTX_LEVEL);
+            DISPLAYLEVEL(3, "test%3i : init CCtx for level %u : ", testNb++, STATIC_CCTX_LEVEL);
             { size_t const r = ZSTD_compressBegin(staticCCtx, STATIC_CCTX_LEVEL);
               if (ZSTD_isError(r)) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : simple compression test with static CCtx : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : simple compression test with static CCtx : ", testNb++);
             CHECKPLUS(r, ZSTD_compressCCtx(staticCCtx,
                             compressedBuffer, compressedBufferSize,
                             CNBuffer, CNBuffSize, STATIC_CCTX_LEVEL),
                       cSize=r );
-            DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n",
+            DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n",
                             (U32)cSize, (double)cSize/CNBuffSize*100);
 
-            DISPLAYLEVEL(4, "test%3i : simple decompression test with static DCtx : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : simple decompression test with static DCtx : ", testNb++);
             { size_t const r = ZSTD_decompressDCtx(staticDCtx,
                                                 decodedBuffer, CNBuffSize,
                                                 compressedBuffer, cSize);
               if (r != CNBuffSize) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
             {   size_t u;
                 for (u=0; u<CNBuffSize; u++) {
                     if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u])
                         goto _output_error;;
             }   }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init CCtx for too large level (must fail) : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : init CCtx for too large level (must fail) : ", testNb++);
             { size_t const r = ZSTD_compressBegin(staticCCtx, ZSTD_maxCLevel());
               if (!ZSTD_isError(r)) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init CCtx for small level %u (should work again) : ", testNb++, 1);
+            DISPLAYLEVEL(3, "test%3i : init CCtx for small level %u (should work again) : ", testNb++, 1);
             { size_t const r = ZSTD_compressBegin(staticCCtx, 1);
               if (ZSTD_isError(r)) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init CStream for small level %u : ", testNb++, 1);
+            DISPLAYLEVEL(3, "test%3i : init CStream for small level %u : ", testNb++, 1);
             { size_t const r = ZSTD_initCStream(staticCCtx, 1);
               if (ZSTD_isError(r)) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init CStream with dictionary (should fail) : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : init CStream with dictionary (should fail) : ", testNb++);
             { size_t const r = ZSTD_initCStream_usingDict(staticCCtx, CNBuffer, 64 KB, 1);
               if (!ZSTD_isError(r)) goto _output_error; }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
 
-            DISPLAYLEVEL(4, "test%3i : init DStream (should fail) : ", testNb++);
+            DISPLAYLEVEL(3, "test%3i : init DStream (should fail) : ", testNb++);
             { size_t const r = ZSTD_initDStream(staticDCtx);
               if (ZSTD_isError(r)) goto _output_error; }
             {   ZSTD_outBuffer output = { decodedBuffer, CNBuffSize, 0 };
@@ -469,53 +469,52 @@ static int basicUnitTests(U32 seed, double compressibility)
                 size_t const r = ZSTD_decompressStream(staticDCtx, &output, &input);
                 if (!ZSTD_isError(r)) goto _output_error;
             }
-            DISPLAYLEVEL(4, "OK \n");
+            DISPLAYLEVEL(3, "OK \n");
         }
         free(staticCCtxBuffer);
         free(staticDCtxBuffer);
     }
 
 
-
     /* ZSTDMT simple MT compression test */
-    DISPLAYLEVEL(4, "test%3i : create ZSTDMT CCtx : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : create ZSTDMT CCtx : ", testNb++);
     {   ZSTDMT_CCtx* mtctx = ZSTDMT_createCCtx(2);
         if (mtctx==NULL) {
             DISPLAY("mtctx : mot enough memory, aborting \n");
             testResult = 1;
             goto _end;
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : compress %u bytes with 2 threads : ", testNb++, (U32)CNBuffSize);
+        DISPLAYLEVEL(3, "test%3i : compress %u bytes with 2 threads : ", testNb++, (U32)CNBuffSize);
         CHECKPLUS(r, ZSTDMT_compressCCtx(mtctx,
                                 compressedBuffer, compressedBufferSize,
                                 CNBuffer, CNBuffSize,
                                 1),
                   cSize=r );
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : decompressed size test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : decompressed size test : ", testNb++);
         {   unsigned long long const rSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
             if (rSize != CNBuffSize)  {
                 DISPLAY("ZSTD_getFrameContentSize incorrect : %u != %u \n", (U32)rSize, (U32)CNBuffSize);
                 goto _output_error;
         }   }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+        DISPLAYLEVEL(3, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
         { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
           if (r != CNBuffSize) goto _output_error; }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
         {   size_t u;
             for (u=0; u<CNBuffSize; u++) {
                 if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u]) goto _output_error;;
         }   }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : compress -T2 with checksum : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress -T2 with checksum : ", testNb++);
         {   ZSTD_parameters params = ZSTD_getParams(1, CNBuffSize, 0);
             params.fParams.checksumFlag = 1;
             params.fParams.contentSizeFlag = 1;
@@ -525,19 +524,19 @@ static int basicUnitTests(U32 seed, double compressibility)
                                     NULL, params, 3 /*overlapRLog*/),
                       cSize=r );
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+        DISPLAYLEVEL(3, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
         { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
           if (r != CNBuffSize) goto _output_error; }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
         ZSTDMT_freeCCtx(mtctx);
     }
 
 
     /* Simple API multiframe test */
-    DISPLAYLEVEL(4, "test%3i : compress multiple frames : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : compress multiple frames : ", testNb++);
     {   size_t off = 0;
         int i;
         int const segs = 4;
@@ -559,53 +558,53 @@ static int basicUnitTests(U32 seed, double compressibility)
         }
         cSize = off;
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : get decompressed size of multiple frames : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : get decompressed size of multiple frames : ", testNb++);
     {   unsigned long long const r = ZSTD_findDecompressedSize(compressedBuffer, cSize);
         if (r != CNBuffSize / 2) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : decompress multiple frames : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress multiple frames : ", testNb++);
     {   CHECK_V(r, ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize));
         if (r != CNBuffSize / 2) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
     if (memcmp(decodedBuffer, CNBuffer, CNBuffSize / 2) != 0) goto _output_error;
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
     /* Dictionary and CCtx Duplication tests */
     {   ZSTD_CCtx* const ctxOrig = ZSTD_createCCtx();
         ZSTD_CCtx* const ctxDuplicated = ZSTD_createCCtx();
         static const size_t dictSize = 551;
 
-        DISPLAYLEVEL(4, "test%3i : copy context too soon : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : copy context too soon : ", testNb++);
         { size_t const copyResult = ZSTD_copyCCtx(ctxDuplicated, ctxOrig, 0);
           if (!ZSTD_isError(copyResult)) goto _output_error; }   /* error must be detected */
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : load dictionary into context : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : load dictionary into context : ", testNb++);
         CHECK( ZSTD_compressBegin_usingDict(ctxOrig, CNBuffer, dictSize, 2) );
         CHECK( ZSTD_copyCCtx(ctxDuplicated, ctxOrig, 0) ); /* Begin_usingDict implies unknown srcSize, so match that */
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : compress with flat dictionary : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress with flat dictionary : ", testNb++);
         cSize = 0;
         CHECKPLUS(r, ZSTD_compressEnd(ctxOrig, compressedBuffer, compressedBufferSize,
                                            (const char*)CNBuffer + dictSize, CNBuffSize - dictSize),
                   cSize += r);
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : frame built with flat dictionary should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built with flat dictionary should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                        decodedBuffer, CNBuffSize,
                                        compressedBuffer, cSize,
                                        CNBuffer, dictSize),
                   if (r != CNBuffSize - dictSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : compress with duplicated context : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress with duplicated context : ", testNb++);
         {   size_t const cSizeOrig = cSize;
             cSize = 0;
             CHECKPLUS(r, ZSTD_compressEnd(ctxDuplicated, compressedBuffer, compressedBufferSize,
@@ -613,25 +612,25 @@ static int basicUnitTests(U32 seed, double compressibility)
                       cSize += r);
             if (cSize != cSizeOrig) goto _output_error;   /* should be identical ==> same size */
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : frame built with duplicated context should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built with duplicated context should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                            decodedBuffer, CNBuffSize,
                                            compressedBuffer, cSize,
                                            CNBuffer, dictSize),
                   if (r != CNBuffSize - dictSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : decompress with DDict : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : decompress with DDict : ", testNb++);
         {   ZSTD_DDict* const ddict = ZSTD_createDDict(CNBuffer, dictSize);
             size_t const r = ZSTD_decompress_usingDDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, ddict);
             if (r != CNBuffSize - dictSize) goto _output_error;
-            DISPLAYLEVEL(4, "OK (size of DDict : %u) \n", (U32)ZSTD_sizeof_DDict(ddict));
+            DISPLAYLEVEL(3, "OK (size of DDict : %u) \n", (U32)ZSTD_sizeof_DDict(ddict));
             ZSTD_freeDDict(ddict);
         }
 
-        DISPLAYLEVEL(4, "test%3i : decompress with static DDict : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : decompress with static DDict : ", testNb++);
         {   size_t const ddictBufferSize = ZSTD_estimateDDictSize(dictSize, ZSTD_dlm_byCopy);
             void* ddictBuffer = malloc(ddictBufferSize);
             if (ddictBuffer == NULL) goto _output_error;
@@ -640,10 +639,10 @@ static int basicUnitTests(U32 seed, double compressibility)
                 if (r != CNBuffSize - dictSize) goto _output_error;
             }
             free(ddictBuffer);
-            DISPLAYLEVEL(4, "OK (size of static DDict : %u) \n", (U32)ddictBufferSize);
+            DISPLAYLEVEL(3, "OK (size of static DDict : %u) \n", (U32)ddictBufferSize);
         }
 
-        DISPLAYLEVEL(4, "test%3i : check content size on duplicated context : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : check content size on duplicated context : ", testNb++);
         {   size_t const testSize = CNBuffSize / 3;
             {   ZSTD_parameters p = ZSTD_getParams(2, testSize, dictSize);
                 p.fParams.contentSizeFlag = 1;
@@ -658,7 +657,7 @@ static int basicUnitTests(U32 seed, double compressibility)
                 if (ZSTD_getFrameHeader(&zfh, compressedBuffer, cSize)) goto _output_error;
                 if ((zfh.frameContentSize != testSize) && (zfh.frameContentSize != 0)) goto _output_error;
         }   }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
         ZSTD_freeCCtx(ctxOrig);
         ZSTD_freeCCtx(ctxDuplicated);
@@ -681,89 +680,89 @@ static int basicUnitTests(U32 seed, double compressibility)
             goto _output_error;
         }
 
-        DISPLAYLEVEL(4, "test%3i : dictBuilder on cyclic data : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : dictBuilder on cyclic data : ", testNb++);
         assert(compressedBufferSize >= totalSampleSize);
         { U32 u; for (u=0; u<totalSampleSize; u++) ((BYTE*)decodedBuffer)[u] = (BYTE)u; }
         { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
         {   size_t const sDictSize = ZDICT_trainFromBuffer(dictBuffer, dictBufferCapacity,
                                          decodedBuffer, samplesSizes, nbSamples);
             if (ZDICT_isError(sDictSize)) goto _output_error;
-            DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)sDictSize);
+            DISPLAYLEVEL(3, "OK, created dictionary of size %u \n", (U32)sDictSize);
         }
 
-        DISPLAYLEVEL(4, "test%3i : dictBuilder : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : dictBuilder : ", testNb++);
         { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
         dictSize = ZDICT_trainFromBuffer(dictBuffer, dictBufferCapacity,
                                          CNBuffer, samplesSizes, nbSamples);
         if (ZDICT_isError(dictSize)) goto _output_error;
-        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);
+        DISPLAYLEVEL(3, "OK, created dictionary of size %u \n", (U32)dictSize);
 
-        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : check dictID : ", testNb++);
         dictID = ZDICT_getDictID(dictBuffer, dictSize);
         if (dictID==0) goto _output_error;
-        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+        DISPLAYLEVEL(3, "OK : %u \n", dictID);
 
-        DISPLAYLEVEL(4, "test%3i : compress with dictionary : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress with dictionary : ", testNb++);
         cSize = ZSTD_compress_usingDict(cctx, compressedBuffer, compressedBufferSize,
                                         CNBuffer, CNBuffSize,
                                         dictBuffer, dictSize, 4);
         if (ZSTD_isError(cSize)) goto _output_error;
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : retrieve dictID from dictionary : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : retrieve dictID from dictionary : ", testNb++);
         {   U32 const did = ZSTD_getDictID_fromDict(dictBuffer, dictSize);
             if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : retrieve dictID from frame : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : retrieve dictID from frame : ", testNb++);
         {   U32 const did = ZSTD_getDictID_fromFrame(compressedBuffer, cSize);
             if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                        decodedBuffer, CNBuffSize,
                                        compressedBuffer, cSize,
                                        dictBuffer, dictSize),
                   if (r != CNBuffSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : estimate CDict size : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : estimate CDict size : ", testNb++);
         {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             size_t const estimatedSize = ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byRef);
-            DISPLAYLEVEL(4, "OK : %u \n", (U32)estimatedSize);
+            DISPLAYLEVEL(3, "OK : %u \n", (U32)estimatedSize);
         }
 
-        DISPLAYLEVEL(4, "test%3i : compress with CDict ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress with CDict ", testNb++);
         {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize,
                                             ZSTD_dlm_byRef, ZSTD_dm_auto,
                                             cParams, ZSTD_defaultCMem);
-            DISPLAYLEVEL(4, "(size : %u) : ", (U32)ZSTD_sizeof_CDict(cdict));
+            DISPLAYLEVEL(3, "(size : %u) : ", (U32)ZSTD_sizeof_CDict(cdict));
             cSize = ZSTD_compress_usingCDict(cctx, compressedBuffer, compressedBufferSize,
                                                  CNBuffer, CNBuffSize, cdict);
             ZSTD_freeCDict(cdict);
             if (ZSTD_isError(cSize)) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : retrieve dictID from frame : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : retrieve dictID from frame : ", testNb++);
         {   U32 const did = ZSTD_getDictID_fromFrame(compressedBuffer, cSize);
             if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                        decodedBuffer, CNBuffSize,
                                        compressedBuffer, cSize,
                                        dictBuffer, dictSize),
                   if (r != CNBuffSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : compress with static CDict : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : compress with static CDict : ", testNb++);
         {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             size_t const cdictSize = ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byCopy);
             void* const cdictBuffer = malloc(cdictSize);
@@ -785,9 +784,9 @@ static int basicUnitTests(U32 seed, double compressibility)
             }   }
             free(cdictBuffer);
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : ZSTD_compress_usingCDict_advanced, no contentSize, no dictID : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : ZSTD_compress_usingCDict_advanced, no contentSize, no dictID : ", testNb++);
         {   ZSTD_frameParameters const fParams = { 0 /* frameSize */, 1 /* checksum */, 1 /* noDictID*/ };
             ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dm_auto, cParams, ZSTD_defaultCMem);
@@ -796,23 +795,23 @@ static int basicUnitTests(U32 seed, double compressibility)
             ZSTD_freeCDict(cdict);
             if (ZSTD_isError(cSize)) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : try retrieving contentSize from frame : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : try retrieving contentSize from frame : ", testNb++);
         {   U64 const contentSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
             if (contentSize != ZSTD_CONTENTSIZE_UNKNOWN) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK (unknown)\n");
+        DISPLAYLEVEL(3, "OK (unknown)\n");
 
-        DISPLAYLEVEL(4, "test%3i : frame built without dictID should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built without dictID should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                        decodedBuffer, CNBuffSize,
                                        compressedBuffer, cSize,
                                        dictBuffer, dictSize),
                   if (r != CNBuffSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : ZSTD_compress_advanced, no dictID : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : ZSTD_compress_advanced, no dictID : ", testNb++);
         {   ZSTD_parameters p = ZSTD_getParams(3, CNBuffSize, dictSize);
             p.fParams.noDictIDFlag = 1;
             cSize = ZSTD_compress_advanced(cctx, compressedBuffer, compressedBufferSize,
@@ -820,42 +819,42 @@ static int basicUnitTests(U32 seed, double compressibility)
                                            dictBuffer, dictSize, p);
             if (ZSTD_isError(cSize)) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
 
-        DISPLAYLEVEL(4, "test%3i : frame built without dictID should be decompressible : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : frame built without dictID should be decompressible : ", testNb++);
         CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
                                        decodedBuffer, CNBuffSize,
                                        compressedBuffer, cSize,
                                        dictBuffer, dictSize),
                   if (r != CNBuffSize) goto _output_error);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : dictionary containing only header should return error : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : dictionary containing only header should return error : ", testNb++);
         {
           const size_t ret = ZSTD_decompress_usingDict(
               dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize,
               "\x37\xa4\x30\xec\x11\x22\x33\x44", 8);
           if (ZSTD_getErrorCode(ret) != ZSTD_error_dictionary_corrupted) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a good dictionary : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a good dictionary : ", testNb++);
         {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dm_fullDict, cParams, ZSTD_defaultCMem);
             if (cdict==NULL) goto _output_error;
             ZSTD_freeCDict(cdict);
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a rawContent (must fail) : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a rawContent (must fail) : ", testNb++);
         {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
             ZSTD_CDict* const cdict = ZSTD_createCDict_advanced((const char*)dictBuffer+1, dictSize-1, ZSTD_dlm_byRef, ZSTD_dm_fullDict, cParams, ZSTD_defaultCMem);
             if (cdict!=NULL) goto _output_error;
             ZSTD_freeCDict(cdict);
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_auto should fail : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_auto should fail : ", testNb++);
         {
             size_t ret;
             MEM_writeLE32((char*)dictBuffer+2, ZSTD_MAGIC_DICTIONARY);
@@ -863,9 +862,9 @@ static int basicUnitTests(U32 seed, double compressibility)
                     cctx, (const char*)dictBuffer+2, dictSize-2, ZSTD_dlm_byRef, ZSTD_dm_auto);
             if (!ZSTD_isError(ret)) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_rawContent should pass : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_rawContent should pass : ", testNb++);
         {
             size_t ret;
             MEM_writeLE32((char*)dictBuffer+2, ZSTD_MAGIC_DICTIONARY);
@@ -873,9 +872,9 @@ static int basicUnitTests(U32 seed, double compressibility)
                     cctx, (const char*)dictBuffer+2, dictSize-2, ZSTD_dlm_byRef, ZSTD_dm_rawContent);
             if (ZSTD_isError(ret)) goto _output_error;
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Dictionary with non-default repcodes : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Dictionary with non-default repcodes : ", testNb++);
         { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
         dictSize = ZDICT_trainFromBuffer(dictBuffer, dictSize,
                                          CNBuffer, samplesSizes, nbSamples);
@@ -917,7 +916,7 @@ static int basicUnitTests(U32 seed, double compressibility)
             if (ZSTD_isError(dSize)) { DISPLAYLEVEL(5, "Decompression error %s : ", ZSTD_getErrorName(dSize)); goto _output_error; }
             if (memcmp(data, decodedBuffer, sizeof(data))) { DISPLAYLEVEL(5, "Data corruption : "); goto _output_error; }
         }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
         ZSTD_freeCCtx(cctx);
         free(dictBuffer);
@@ -942,7 +941,7 @@ static int basicUnitTests(U32 seed, double compressibility)
             goto _output_error;
         }
 
-        DISPLAYLEVEL(4, "test%3i : ZDICT_trainFromBuffer_cover : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : ZDICT_trainFromBuffer_cover : ", testNb++);
         { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
         memset(&params, 0, sizeof(params));
         params.d = 1 + (FUZ_rand(&seed) % 16);
@@ -951,26 +950,26 @@ static int basicUnitTests(U32 seed, double compressibility)
                                                CNBuffer, samplesSizes, nbSamples,
                                                params);
         if (ZDICT_isError(dictSize)) goto _output_error;
-        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);
+        DISPLAYLEVEL(3, "OK, created dictionary of size %u \n", (U32)dictSize);
 
-        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : check dictID : ", testNb++);
         dictID = ZDICT_getDictID(dictBuffer, dictSize);
         if (dictID==0) goto _output_error;
-        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+        DISPLAYLEVEL(3, "OK : %u \n", dictID);
 
-        DISPLAYLEVEL(4, "test%3i : ZDICT_optimizeTrainFromBuffer_cover : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : ZDICT_optimizeTrainFromBuffer_cover : ", testNb++);
         memset(&params, 0, sizeof(params));
         params.steps = 4;
         optDictSize = ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, optDictSize,
                                                           CNBuffer, samplesSizes,
                                                           nbSamples / 4, &params);
         if (ZDICT_isError(optDictSize)) goto _output_error;
-        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)optDictSize);
+        DISPLAYLEVEL(3, "OK, created dictionary of size %u \n", (U32)optDictSize);
 
-        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : check dictID : ", testNb++);
         dictID = ZDICT_getDictID(dictBuffer, optDictSize);
         if (dictID==0) goto _output_error;
-        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+        DISPLAYLEVEL(3, "OK : %u \n", dictID);
 
         ZSTD_freeCCtx(cctx);
         free(dictBuffer);
@@ -978,20 +977,20 @@ static int basicUnitTests(U32 seed, double compressibility)
     }
 
     /* Decompression defense tests */
-    DISPLAYLEVEL(4, "test%3i : Check input length for magic number : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : Check input length for magic number : ", testNb++);
     { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, CNBuffer, 3);   /* too small input */
       if (!ZSTD_isError(r)) goto _output_error;
       if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : Check magic Number : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : Check magic Number : ", testNb++);
     ((char*)(CNBuffer))[0] = 1;
     { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, CNBuffer, 4);
       if (!ZSTD_isError(r)) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
     /* content size verification test */
-    DISPLAYLEVEL(4, "test%3i : Content size verification : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : Content size verification : ", testNb++);
     {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
         size_t const srcSize = 5000;
         size_t const wrongSrcSize = (srcSize + 1000);
@@ -1001,7 +1000,7 @@ static int basicUnitTests(U32 seed, double compressibility)
         {   size_t const result = ZSTD_compressEnd(cctx, decodedBuffer, CNBuffSize, CNBuffer, srcSize);
             if (!ZSTD_isError(result)) goto _output_error;
             if (ZSTD_getErrorCode(result) != ZSTD_error_srcSize_wrong) goto _output_error;
-            DISPLAYLEVEL(4, "OK : %s \n", ZSTD_getErrorName(result));
+            DISPLAYLEVEL(3, "OK : %s \n", ZSTD_getErrorName(result));
         }
         ZSTD_freeCCtx(cctx);
     }
@@ -1011,7 +1010,7 @@ static int basicUnitTests(U32 seed, double compressibility)
         size_t const inputSize = CNBuffSize / 2;   /* won't cause pb with small dict size */
 
         /* basic block compression */
-        DISPLAYLEVEL(4, "test%3i : magic-less format test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : magic-less format test : ", testNb++);
         CHECK( ZSTD_CCtx_setParameter(cctx, ZSTD_p_format, ZSTD_f_zstd1_magicless) );
         {   ZSTD_inBuffer in = { CNBuffer, inputSize, 0 };
             ZSTD_outBuffer out = { compressedBuffer, ZSTD_compressBound(inputSize), 0 };
@@ -1020,15 +1019,15 @@ static int basicUnitTests(U32 seed, double compressibility)
             if (in.pos != in.size) goto _output_error;
             cSize = out.pos;
         }
-        DISPLAYLEVEL(4, "OK (compress : %u -> %u bytes)\n", (U32)inputSize, (U32)cSize);
+        DISPLAYLEVEL(3, "OK (compress : %u -> %u bytes)\n", (U32)inputSize, (U32)cSize);
 
-        DISPLAYLEVEL(4, "test%3i : decompress normally (should fail) : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : decompress normally (should fail) : ", testNb++);
         {   size_t const decodeResult = ZSTD_decompressDCtx(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize);
             if (ZSTD_getErrorCode(decodeResult) != ZSTD_error_prefix_unknown) goto _output_error;
-            DISPLAYLEVEL(4, "OK : %s \n", ZSTD_getErrorName(decodeResult));
+            DISPLAYLEVEL(3, "OK : %s \n", ZSTD_getErrorName(decodeResult));
         }
 
-        DISPLAYLEVEL(4, "test%3i : decompress with magic-less instruction : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : decompress with magic-less instruction : ", testNb++);
         ZSTD_DCtx_reset(dctx);
         CHECK( ZSTD_DCtx_setFormat(dctx, ZSTD_f_zstd1_magicless) );
         {   ZSTD_inBuffer in = { compressedBuffer, cSize, 0 };
@@ -1037,7 +1036,7 @@ static int basicUnitTests(U32 seed, double compressibility)
             if (result != 0) goto _output_error;
             if (in.pos != in.size) goto _output_error;
             if (out.pos != inputSize) goto _output_error;
-            DISPLAYLEVEL(4, "OK : regenerated %u bytes \n", (U32)out.pos);
+            DISPLAYLEVEL(3, "OK : regenerated %u bytes \n", (U32)out.pos);
         }
 
         ZSTD_freeCCtx(cctx);
@@ -1050,21 +1049,21 @@ static int basicUnitTests(U32 seed, double compressibility)
         size_t cSize2;
 
         /* basic block compression */
-        DISPLAYLEVEL(4, "test%3i : Block compression test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Block compression test : ", testNb++);
         CHECK( ZSTD_compressBegin(cctx, 5) );
         CHECK( ZSTD_getBlockSize(cctx) >= blockSize);
         cSize = ZSTD_compressBlock(cctx, compressedBuffer, ZSTD_compressBound(blockSize), CNBuffer, blockSize);
         if (ZSTD_isError(cSize)) goto _output_error;
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Block decompression test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Block decompression test : ", testNb++);
         CHECK( ZSTD_decompressBegin(dctx) );
         { CHECK_V(r, ZSTD_decompressBlock(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize) );
           if (r != blockSize) goto _output_error; }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
         /* dictionary block compression */
-        DISPLAYLEVEL(4, "test%3i : Dictionary Block compression test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Dictionary Block compression test : ", testNb++);
         CHECK( ZSTD_compressBegin_usingDict(cctx, CNBuffer, dictSize, 5) );
         cSize = ZSTD_compressBlock(cctx, compressedBuffer, ZSTD_compressBound(blockSize), (char*)CNBuffer+dictSize, blockSize);
         if (ZSTD_isError(cSize)) goto _output_error;
@@ -1074,16 +1073,16 @@ static int basicUnitTests(U32 seed, double compressibility)
         cSize2 = ZSTD_compressBlock(cctx, (char*)compressedBuffer+cSize+blockSize, ZSTD_compressBound(blockSize),
                                           (char*)CNBuffer+dictSize+2*blockSize, blockSize);
         if (ZSTD_isError(cSize2)) goto _output_error;
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
-        DISPLAYLEVEL(4, "test%3i : Dictionary Block decompression test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Dictionary Block decompression test : ", testNb++);
         CHECK( ZSTD_decompressBegin_usingDict(dctx, CNBuffer, dictSize) );
         { CHECK_V( r, ZSTD_decompressBlock(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize) );
           if (r != blockSize) goto _output_error; }
         ZSTD_insertBlock(dctx, (char*)decodedBuffer+blockSize, blockSize);   /* insert non-compressed block into dctx history */
         { CHECK_V( r, ZSTD_decompressBlock(dctx, (char*)decodedBuffer+2*blockSize, CNBuffSize, (char*)compressedBuffer+cSize+blockSize, cSize2) );
           if (r != blockSize) goto _output_error; }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
 
         ZSTD_freeCCtx(cctx);
     }
@@ -1091,7 +1090,7 @@ static int basicUnitTests(U32 seed, double compressibility)
 
     /* long rle test */
     {   size_t sampleSize = 0;
-        DISPLAYLEVEL(4, "test%3i : Long RLE test : ", testNb++);
+        DISPLAYLEVEL(3, "test%3i : Long RLE test : ", testNb++);
         RDG_genBuffer(CNBuffer, sampleSize, compressibility, 0., seed+1);
         memset((char*)CNBuffer+sampleSize, 'B', 256 KB - 1);
         sampleSize += 256 KB - 1;
@@ -1101,21 +1100,21 @@ static int basicUnitTests(U32 seed, double compressibility)
         if (ZSTD_isError(cSize)) goto _output_error;
         { CHECK_V(regenSize, ZSTD_decompress(decodedBuffer, sampleSize, compressedBuffer, cSize));
           if (regenSize!=sampleSize) goto _output_error; }
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
     }
 
     /* All zeroes test (test bug #137) */
     #define ZEROESLENGTH 100
-    DISPLAYLEVEL(4, "test%3i : compress %u zeroes : ", testNb++, ZEROESLENGTH);
+    DISPLAYLEVEL(3, "test%3i : compress %u zeroes : ", testNb++, ZEROESLENGTH);
     memset(CNBuffer, 0, ZEROESLENGTH);
     { CHECK_V(r, ZSTD_compress(compressedBuffer, ZSTD_compressBound(ZEROESLENGTH), CNBuffer, ZEROESLENGTH, 1) );
       cSize = r; }
-    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/ZEROESLENGTH*100);
+    DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/ZEROESLENGTH*100);
 
-    DISPLAYLEVEL(4, "test%3i : decompress %u zeroes : ", testNb++, ZEROESLENGTH);
+    DISPLAYLEVEL(3, "test%3i : decompress %u zeroes : ", testNb++, ZEROESLENGTH);
     { CHECK_V(r, ZSTD_decompress(decodedBuffer, ZEROESLENGTH, compressedBuffer, cSize) );
       if (r != ZEROESLENGTH) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
     /* nbSeq limit test */
     #define _3BYTESTESTLENGTH 131000
@@ -1142,18 +1141,18 @@ static int basicUnitTests(U32 seed, double compressibility)
                 ((BYTE*)CNBuffer)[i+1] = _3BytesSeqs[id][1];
                 ((BYTE*)CNBuffer)[i+2] = _3BytesSeqs[id][2];
     }   }   }
-    DISPLAYLEVEL(4, "test%3i : compress lots 3-bytes sequences : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : compress lots 3-bytes sequences : ", testNb++);
     { CHECK_V(r, ZSTD_compress(compressedBuffer, ZSTD_compressBound(_3BYTESTESTLENGTH),
                                  CNBuffer, _3BYTESTESTLENGTH, 19) );
       cSize = r; }
-    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/_3BYTESTESTLENGTH*100);
+    DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/_3BYTESTESTLENGTH*100);
 
-    DISPLAYLEVEL(4, "test%3i : decompress lots 3-bytes sequence : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress lots 3-bytes sequence : ", testNb++);
     { CHECK_V(r, ZSTD_decompress(decodedBuffer, _3BYTESTESTLENGTH, compressedBuffer, cSize) );
       if (r != _3BYTESTESTLENGTH) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
-    DISPLAYLEVEL(4, "test%3i : incompressible data and ill suited dictionary : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : incompressible data and ill suited dictionary : ", testNb++);
     RDG_genBuffer(CNBuffer, CNBuffSize, 0.0, 0.1, seed);
     {   /* Train a dictionary on low characters */
         size_t dictSize = 16 KB;
@@ -1186,25 +1185,25 @@ static int basicUnitTests(U32 seed, double compressibility)
         free(dictBuffer);
         free(samplesSizes);
     }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
 
     /* findFrameCompressedSize on skippable frames */
-    DISPLAYLEVEL(4, "test%3i : frame compressed size of skippable frame : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : frame compressed size of skippable frame : ", testNb++);
     {   const char* frame = "\x50\x2a\x4d\x18\x05\x0\x0\0abcde";
         size_t const frameSrcSize = 13;
         if (ZSTD_findFrameCompressedSize(frame, frameSrcSize) != frameSrcSize) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
     /* error string tests */
-    DISPLAYLEVEL(4, "test%3i : testing ZSTD error code strings : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : testing ZSTD error code strings : ", testNb++);
     if (strcmp("No error detected", ZSTD_getErrorName((ZSTD_ErrorCode)(0-ZSTD_error_no_error))) != 0) goto _output_error;
     if (strcmp("No error detected", ZSTD_getErrorString(ZSTD_error_no_error)) != 0) goto _output_error;
     if (strcmp("Unspecified error code", ZSTD_getErrorString((ZSTD_ErrorCode)(0-ZSTD_error_GENERIC))) != 0) goto _output_error;
     if (strcmp("Error (generic)", ZSTD_getErrorName((size_t)0-ZSTD_error_GENERIC)) != 0) goto _output_error;
     if (strcmp("Error (generic)", ZSTD_getErrorString(ZSTD_error_GENERIC)) != 0) goto _output_error;
     if (strcmp("No error detected", ZSTD_getErrorName(ZSTD_error_GENERIC)) != 0) goto _output_error;
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");
 
 _end:
     free(CNBuffer);
@@ -1356,10 +1355,11 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
         crcOrig = XXH64(sampleBuffer, sampleSize, 0);
 
         /* compression tests */
-        {   unsigned const cLevel =
+        {   int const cLevel =
                     ( FUZ_rand(&lseed) %
                      (ZSTD_maxCLevel() - (FUZ_highbit32((U32)sampleSize) / cLevelLimiter)) )
-                     + 1;
+                    + 1;
+            DISPLAYLEVEL(5, "fuzzer t%u: Simple compression test (level %i) \n", testNb, cLevel);
             cSize = ZSTD_compressCCtx(ctx, cBuffer, cBufferSize, sampleBuffer, sampleSize, cLevel);
             CHECK(ZSTD_isError(cSize), "ZSTD_compressCCtx failed : %s", ZSTD_getErrorName(cSize));
 
@@ -1387,6 +1387,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
         }
 
         /* successful decompression test */
+        DISPLAYLEVEL(5, "fuzzer t%u: simple decompression test \n", testNb);
         {   size_t const margin = (FUZ_rand(&lseed) & 1) ? 0 : (FUZ_rand(&lseed) & 31) + 1;
             size_t const dSize = ZSTD_decompress(dstBuffer, sampleSize + margin, cBuffer, cSize);
             CHECK(dSize != sampleSize, "ZSTD_decompress failed (%s) (srcSize : %u ; cSize : %u)", ZSTD_getErrorName(dSize), (U32)sampleSize, (U32)cSize);
@@ -1397,6 +1398,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
         free(sampleBuffer);   /* no longer useful after this point */
 
         /* truncated src decompression test */
+        DISPLAYLEVEL(5, "fuzzer t%u: decompression of truncated source \n", testNb);
         {   size_t const missing = (FUZ_rand(&lseed) % (cSize-2)) + 1;   /* no problem, as cSize > 4 (frameHeaderSizer) */
             size_t const tooSmallSize = cSize - missing;
             void* cBufferTooSmall = malloc(tooSmallSize);   /* valgrind will catch read overflows */
@@ -1408,6 +1410,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
         }
 
         /* too small dst decompression test */
+        DISPLAYLEVEL(5, "fuzzer t%u: decompress into too small dst buffer \n", testNb);
         if (sampleSize > 3) {
             size_t const missing = (FUZ_rand(&lseed) % (sampleSize-2)) + 1;   /* no problem, as cSize > 4 (frameHeaderSizer) */
             size_t const tooSmallSize = sampleSize - missing;
@@ -1443,6 +1446,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
             }   }   }
 
             /* decompress noisy source */
+            DISPLAYLEVEL(5, "fuzzer t%u: decompress noisy source \n", testNb);
             {   U32 const endMark = 0xA9B1C3D6;
                 memcpy(dstBuffer+sampleSize, &endMark, 4);
                 {   size_t const decompressResult = ZSTD_decompress(dstBuffer, sampleSize, cBuffer, cSize);
@@ -1454,8 +1458,8 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
                     CHECK(endMark!=endCheck, "ZSTD_decompress on noisy src : dst buffer overflow");
         }   }   }   /* noisy src decompression test */
 
-        /*=====   Streaming compression test, scattered segments and dictionary   =====*/
-
+        /*=====   Bufferless streaming compression test, scattered segments and dictionary   =====*/
+        DISPLAYLEVEL(5, "fuzzer t%u: Bufferless streaming compression test \n", testNb);
         {   U32 const testLog = FUZ_rand(&lseed) % maxSrcLog;
             U32 const dictLog = FUZ_rand(&lseed) % maxSrcLog;
             int const cLevel = (FUZ_rand(&lseed) %
@@ -1468,10 +1472,13 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
             dictSize = FUZ_rLogLength(&lseed, dictLog);   /* needed also for decompression */
             dict = srcBuffer + (FUZ_rand(&lseed) % (srcBufferSize - dictSize));
 
+            DISPLAYLEVEL(6, "fuzzer t%u: Compressing up to <=%u bytes at level %i with dictionary size %u \n",
+                            testNb, (U32)maxTestSize, cLevel, (U32)dictSize);
+
             if (FUZ_rand(&lseed) & 0xF) {
                 CHECK_Z ( ZSTD_compressBegin_usingDict(refCtx, dict, dictSize, cLevel) );
             } else {
-                ZSTD_compressionParameters const cPar = ZSTD_getCParams(cLevel, 0, dictSize);
+                ZSTD_compressionParameters const cPar = ZSTD_getCParams(cLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize);
                 ZSTD_frameParameters const fPar = { FUZ_rand(&lseed)&1 /* contentSizeFlag */,
                                                     !(FUZ_rand(&lseed)&3) /* contentChecksumFlag*/,
                                                     0 /*NodictID*/ };   /* note : since dictionary is fake, dictIDflag has no impact */
@@ -1509,6 +1516,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
         }
 
         /* streaming decompression test */
+        DISPLAYLEVEL(5, "fuzzer t%u: Bufferless streaming decompression test \n", testNb);
         /* ensure memory requirement is good enough (should always be true) */
         {   ZSTD_frameHeader zfh;
             CHECK( ZSTD_getFrameHeader(&zfh, cBuffer, ZSTD_frameHeaderSize_max),
@@ -1651,7 +1659,7 @@ int main(int argc, const char** argv)
 
                 case 'v':
                     argument++;
-                    g_displayLevel = 4;
+                    g_displayLevel++;
                     break;
 
                 case 'q':
diff --git a/tests/playTests.sh b/tests/playTests.sh
index b5ffadc23..1bd39545b 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -93,6 +93,7 @@ else
     hasMT="true"
 fi
 
+
 $ECHO "\n===>  simple tests "
 
 ./datagen > tmp
@@ -329,9 +330,14 @@ $ECHO "- Create first dictionary "
 TESTFILE=../programs/zstdcli.c
 $ZSTD --train *.c ../programs/*.c -o tmpDict
 cp $TESTFILE tmp
+$ECHO "- Dictionary compression roundtrip"
 $ZSTD -f tmp -D tmpDict
 $ZSTD -d tmp.zst -D tmpDict -fo result
 $DIFF $TESTFILE result
+$ECHO "- Dictionary compression with btlazy2 strategy"
+$ZSTD -f tmp -D tmpDict --zstd=strategy=6
+$ZSTD -d tmp.zst -D tmpDict -fo result
+$DIFF $TESTFILE result
 if [ -n "$hasMT" ]
 then
     $ECHO "- Test dictionary compression with multithreading "
@@ -719,6 +725,7 @@ roundTripTest -g18000018 -P94 18
 roundTripTest -g18000019 -P96 19
 
 roundTripTest -g5000000000 -P99 1
+roundTripTest -g1700000000 -P0 "1 --zstd=strategy=6"   # ensure btlazy2 can survive an overflow rescale
 
 fileRoundTripTest -g4193M -P99 1