diff --git a/lib/common/zstd_common.c b/lib/common/zstd_common.c
index 0d9c1154e..19e139a7d 100644
--- a/lib/common/zstd_common.c
+++ b/lib/common/zstd_common.c
@@ -75,17 +75,30 @@ const char* ZBUFF_getErrorName(size_t errorCode) { return ERR_getErrorName(error
 
 
 
+/*=**************************************************************
+*  Custom allocator
+****************************************************************/
+/* default uses stdlib */
 void* ZSTD_defaultAllocFunction(void* opaque, size_t size)
 {
     void* address = malloc(size);
     (void)opaque;
-    /* printf("alloc %p, %d opaque=%p \n", address, (int)size, opaque); */
     return address;
 }
 
 void ZSTD_defaultFreeFunction(void* opaque, void* address)
 {
     (void)opaque;
-    /* if (address) printf("free %p opaque=%p \n", address, opaque); */
     free(address);
 }
+
+void* ZSTD_malloc(size_t size, ZSTD_customMem customMem)
+{
+    return customMem.customAlloc(customMem.opaque, size);
+}
+
+void ZSTD_free(void* ptr, ZSTD_customMem customMem)
+{
+    if (ptr!=NULL)
+        customMem.customFree(customMem.opaque, ptr);
+}
diff --git a/lib/common/zstd_internal.h b/lib/common/zstd_internal.h
index 8b9b6290b..259dc04f0 100644
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@@ -220,6 +220,9 @@ int ZSTD_isSkipFrame(ZSTD_DCtx* dctx);
 void* ZSTD_defaultAllocFunction(void* opaque, size_t size);
 void ZSTD_defaultFreeFunction(void* opaque, void* address);
 static const ZSTD_customMem defaultCustomMem = { ZSTD_defaultAllocFunction, ZSTD_defaultFreeFunction, NULL };
+void* ZSTD_malloc(size_t size, ZSTD_customMem customMem);
+void ZSTD_free(void* ptr, ZSTD_customMem customMem);
+
 
 /*======  common function  ======*/
 
diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index 1761a448d..911dfeb0b 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -133,13 +133,10 @@ ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
 {
     ZSTD_CCtx* cctx;
 
-    if (!customMem.customAlloc && !customMem.customFree)
-        customMem = defaultCustomMem;
+    if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
+    if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    if (!customMem.customAlloc || !customMem.customFree)
-        return NULL;
-
-    cctx = (ZSTD_CCtx*) customMem.customAlloc(customMem.opaque, sizeof(ZSTD_CCtx));
+    cctx = (ZSTD_CCtx*) ZSTD_malloc(sizeof(ZSTD_CCtx), customMem);
     if (!cctx) return NULL;
     memset(cctx, 0, sizeof(ZSTD_CCtx));
     memcpy(&(cctx->customMem), &customMem, sizeof(ZSTD_customMem));
@@ -149,8 +146,8 @@ ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
 size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
 {
     if (cctx==NULL) return 0;   /* support free on NULL */
-    if (cctx->workSpace) cctx->customMem.customFree(cctx->customMem.opaque, cctx->workSpace);
-    cctx->customMem.customFree(cctx->customMem.opaque, cctx);
+    ZSTD_free(cctx->workSpace, cctx->customMem);
+    ZSTD_free(cctx, cctx->customMem);
     return 0;   /* reserved as a potential error code in the future */
 }
 
@@ -272,8 +269,8 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
         size_t const neededSpace = tableSpace + (256*sizeof(U32)) /* huffTable */ + tokenSpace
                               + ((params.cParams.strategy == ZSTD_btopt) ? optSpace : 0);
         if (zc->workSpaceSize < neededSpace) {
-            zc->customMem.customFree(zc->customMem.opaque, zc->workSpace);
-            zc->workSpace = zc->customMem.customAlloc(zc->customMem.opaque, neededSpace);
+            ZSTD_free(zc->workSpace, zc->customMem);
+            zc->workSpace = ZSTD_malloc(neededSpace, zc->customMem);
             if (zc->workSpace == NULL) return ERROR(memory_allocation);
             zc->workSpaceSize = neededSpace;
     }   }
@@ -2686,7 +2683,7 @@ size_t ZSTD_compress(void* dst, size_t dstCapacity, const void* src, size_t srcS
     memset(&ctxBody, 0, sizeof(ctxBody));
     memcpy(&ctxBody.customMem, &defaultCustomMem, sizeof(ZSTD_customMem));
     result = ZSTD_compressCCtx(&ctxBody, dst, dstCapacity, src, srcSize, compressionLevel);
-    ctxBody.customMem.customFree(ctxBody.customMem.opaque, ctxBody.workSpace);   /* can't free ctxBody, since it's on stack; just free heap content */
+    ZSTD_free(ctxBody.workSpace, defaultCustomMem);  /* can't free ctxBody itself, as it's on stack; free only heap content */
     return result;
 }
 
@@ -2701,29 +2698,26 @@ struct ZSTD_CDict_s {
 
 ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, ZSTD_parameters params, ZSTD_customMem customMem)
 {
-    if (!customMem.customAlloc && !customMem.customFree)
-        customMem = defaultCustomMem;
+    if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
+    if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    if (!customMem.customAlloc || !customMem.customFree)  /* can't have 1/2 custom alloc/free as NULL */
-        return NULL;
-
-    {   ZSTD_CDict* const cdict = (ZSTD_CDict*) customMem.customAlloc(customMem.opaque, sizeof(*cdict));
-        void* const dictContent = customMem.customAlloc(customMem.opaque, dictSize);
+    {   ZSTD_CDict* const cdict = (ZSTD_CDict*) ZSTD_malloc(sizeof(ZSTD_CDict), customMem);
+        void* const dictContent = ZSTD_malloc(dictSize, customMem);
         ZSTD_CCtx* const cctx = ZSTD_createCCtx_advanced(customMem);
 
         if (!dictContent || !cdict || !cctx) {
-            customMem.customFree(customMem.opaque, dictContent);
-            customMem.customFree(customMem.opaque, cdict);
-            customMem.customFree(customMem.opaque, cctx);
+            ZSTD_free(dictContent, customMem);
+            ZSTD_free(cdict, customMem);
+            ZSTD_free(cctx, customMem);
             return NULL;
         }
 
         memcpy(dictContent, dict, dictSize);
         {   size_t const errorCode = ZSTD_compressBegin_advanced(cctx, dictContent, dictSize, params, 0);
             if (ZSTD_isError(errorCode)) {
-                customMem.customFree(customMem.opaque, dictContent);
-                customMem.customFree(customMem.opaque, cdict);
-                customMem.customFree(customMem.opaque, cctx);
+                ZSTD_free(dictContent, customMem);
+                ZSTD_free(cdict, customMem);
+                ZSTD_free(cctx, customMem);
                 return NULL;
         }   }
 
@@ -2744,12 +2738,13 @@ ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionL
 
 size_t ZSTD_freeCDict(ZSTD_CDict* cdict)
 {
-    ZSTD_freeFunction const cFree = cdict->refContext->customMem.customFree;
-    void* const opaque = cdict->refContext->customMem.opaque;
-    ZSTD_freeCCtx(cdict->refContext);
-    cFree(opaque, cdict->dictContent);
-    cFree(opaque, cdict);
-    return 0;
+    if (cdict==NULL) return 0;   /* support free on NULL */
+    {   ZSTD_customMem cMem = cdict->refContext->customMem;
+        ZSTD_freeCCtx(cdict->refContext);
+        ZSTD_free(cdict->dictContent, cMem);
+        ZSTD_free(cdict, cMem);
+        return 0;
+    }
 }
 
 /*! ZSTD_compress_usingCDict() :
@@ -2807,13 +2802,10 @@ ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem)
 {
     ZSTD_CStream* zcs;
 
-    if (!customMem.customAlloc && !customMem.customFree)
-        customMem = defaultCustomMem;
+    if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
+    if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    if (!customMem.customAlloc || !customMem.customFree)
-        return NULL;
-
-    zcs = (ZSTD_CStream*)customMem.customAlloc(customMem.opaque, sizeof(ZSTD_CStream));
+    zcs = (ZSTD_CStream*)ZSTD_malloc(sizeof(ZSTD_CStream), customMem);
     if (zcs==NULL) return NULL;
     memset(zcs, 0, sizeof(ZSTD_CStream));
     memcpy(&zcs->customMem, &customMem, sizeof(ZSTD_customMem));
@@ -2825,11 +2817,13 @@ ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem)
 size_t ZSTD_freeCStream(ZSTD_CStream* zcs)
 {
     if (zcs==NULL) return 0;   /* support free on NULL */
-    ZSTD_freeCCtx(zcs->zc);
-    if (zcs->inBuff) zcs->customMem.customFree(zcs->customMem.opaque, zcs->inBuff);
-    if (zcs->outBuff) zcs->customMem.customFree(zcs->customMem.opaque, zcs->outBuff);
-    zcs->customMem.customFree(zcs->customMem.opaque, zcs);
-    return 0;
+    {   ZSTD_customMem const cMem = zcs->customMem;
+        ZSTD_freeCCtx(zcs->zc);
+        ZSTD_free(zcs->inBuff, cMem);
+        ZSTD_free(zcs->outBuff, cMem);
+        ZSTD_free(zcs, cMem);
+        return 0;
+    }
 }
 
 
@@ -2846,16 +2840,16 @@ size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
     {   size_t const neededInBuffSize = (size_t)1 << params.cParams.windowLog;
         if (zcs->inBuffSize < neededInBuffSize) {
             zcs->inBuffSize = neededInBuffSize;
-            zcs->customMem.customFree(zcs->customMem.opaque, zcs->inBuff);   /* should not be necessary */
-            zcs->inBuff = (char*)zcs->customMem.customAlloc(zcs->customMem.opaque, neededInBuffSize);
+            ZSTD_free(zcs->inBuff, zcs->customMem);  /* should not be necessary */
+            zcs->inBuff = (char*) ZSTD_malloc(neededInBuffSize, zcs->customMem);
             if (zcs->inBuff == NULL) return ERROR(memory_allocation);
         }
         zcs->blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, neededInBuffSize);
     }
     if (zcs->outBuffSize < ZSTD_compressBound(zcs->blockSize)+1) {
         zcs->outBuffSize = ZSTD_compressBound(zcs->blockSize)+1;
-        zcs->customMem.customFree(zcs->customMem.opaque, zcs->outBuff);   /* should not be necessary */
-        zcs->outBuff = (char*)zcs->customMem.customAlloc(zcs->customMem.opaque, zcs->outBuffSize);
+        ZSTD_free(zcs->outBuff, zcs->customMem);   /* should not be necessary */
+        zcs->outBuff = (char*) ZSTD_malloc(zcs->outBuffSize, zcs->customMem);
         if (zcs->outBuff == NULL) return ERROR(memory_allocation);
     }
 
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index e540e3fe9..329179857 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -174,7 +174,7 @@ ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
     if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
     if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    dctx = (ZSTD_DCtx*) customMem.customAlloc(customMem.opaque, sizeof(ZSTD_DCtx));
+    dctx = (ZSTD_DCtx*) ZSTD_malloc(sizeof(ZSTD_DCtx), customMem);
     if (!dctx) return NULL;
     memcpy(&dctx->customMem, &customMem, sizeof(customMem));
     ZSTD_decompressBegin(dctx);
@@ -189,7 +189,7 @@ ZSTD_DCtx* ZSTD_createDCtx(void)
 size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
 {
     if (dctx==NULL) return 0;   /* support free on NULL */
-    dctx->customMem.customFree(dctx->customMem.opaque, dctx);
+    ZSTD_free(dctx, dctx->customMem);
     return 0;   /* reserved as a potential error code in the future */
 }
 
@@ -1244,29 +1244,26 @@ struct ZSTD_DDict_s {
 
 ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, ZSTD_customMem customMem)
 {
-    if (!customMem.customAlloc && !customMem.customFree)
-        customMem = defaultCustomMem;
+    if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
+    if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    if (!customMem.customAlloc || !customMem.customFree)
-        return NULL;
-
-    {   ZSTD_DDict* const ddict = (ZSTD_DDict*) customMem.customAlloc(customMem.opaque, sizeof(*ddict));
-        void* const dictContent = customMem.customAlloc(customMem.opaque, dictSize);
+    {   ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
+        void* const dictContent = ZSTD_malloc(dictSize, customMem);
         ZSTD_DCtx* const dctx = ZSTD_createDCtx_advanced(customMem);
 
         if (!dictContent || !ddict || !dctx) {
-            customMem.customFree(customMem.opaque, dictContent);
-            customMem.customFree(customMem.opaque, ddict);
-            customMem.customFree(customMem.opaque, dctx);
+            ZSTD_free(dictContent, customMem);
+            ZSTD_free(ddict, customMem);
+            ZSTD_free(dctx, customMem);
             return NULL;
         }
 
         memcpy(dictContent, dict, dictSize);
         {   size_t const errorCode = ZSTD_decompressBegin_usingDict(dctx, dictContent, dictSize);
             if (ZSTD_isError(errorCode)) {
-                customMem.customFree(customMem.opaque, dictContent);
-                customMem.customFree(customMem.opaque, ddict);
-                customMem.customFree(customMem.opaque, dctx);
+                ZSTD_free(dictContent, customMem);
+                ZSTD_free(ddict, customMem);
+                ZSTD_free(dctx, customMem);
                 return NULL;
         }   }
 
@@ -1288,12 +1285,13 @@ ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
 
 size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
 {
-    ZSTD_freeFunction const cFree = ddict->refContext->customMem.customFree;
-    void* const opaque = ddict->refContext->customMem.opaque;
-    ZSTD_freeDCtx(ddict->refContext);
-    cFree(opaque, ddict->dict);
-    cFree(opaque, ddict);
-    return 0;
+    if (ddict==NULL) return 0;   /* support free on NULL */
+    {   ZSTD_customMem const cMem = ddict->refContext->customMem;
+        ZSTD_freeDCtx(ddict->refContext);
+        ZSTD_free(ddict->dict, cMem);
+        ZSTD_free(ddict, cMem);
+        return 0;
+    }
 }
 
 /*! ZSTD_decompress_usingDDict() :
@@ -1355,13 +1353,10 @@ ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
 {
     ZSTD_DStream* zds;
 
-    if (!customMem.customAlloc && !customMem.customFree)
-        customMem = defaultCustomMem;
+    if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
+    if (!customMem.customAlloc || !customMem.customFree) return NULL;
 
-    if (!customMem.customAlloc || !customMem.customFree)
-        return NULL;
-
-    zds = (ZSTD_DStream*)customMem.customAlloc(customMem.opaque, sizeof(ZSTD_DStream));
+    zds = (ZSTD_DStream*) ZSTD_malloc(sizeof(ZSTD_DStream), customMem);
     if (zds==NULL) return NULL;
     memset(zds, 0, sizeof(ZSTD_DStream));
     memcpy(&zds->customMem, &customMem, sizeof(ZSTD_customMem));
@@ -1375,18 +1370,18 @@ ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
 size_t ZSTD_freeDStream(ZSTD_DStream* zds)
 {
     if (zds==NULL) return 0;   /* support free on null */
-    ZSTD_freeDCtx(zds->zd);
-    if (zds->inBuff) zds->customMem.customFree(zds->customMem.opaque, zds->inBuff);
-    if (zds->outBuff) zds->customMem.customFree(zds->customMem.opaque, zds->outBuff);
-    if (zds->dictContent) zds->customMem.customFree(zds->customMem.opaque, zds->dictContent);
+    {   ZSTD_customMem const cMem = zds->customMem;
+        ZSTD_freeDCtx(zds->zd);
+        ZSTD_free(zds->inBuff, cMem);
+        ZSTD_free(zds->outBuff, cMem);
+        ZSTD_free(zds->dictContent, cMem);
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
-    if (zds->legacyContext) {
-        ZSTD_freeLegacyStreamContext(zds->legacyContext, zds->previousLegacyVersion);
-        zds->legacyContext = NULL;
-    }
+        if (zds->legacyContext)
+            ZSTD_freeLegacyStreamContext(zds->legacyContext, zds->previousLegacyVersion);
 #endif
-    zds->customMem.customFree(zds->customMem.opaque, zds);
-    return 0;
+        ZSTD_free(zds, cMem);
+        return 0;
+    }
 }
 
 
@@ -1401,8 +1396,8 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
     zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
     if ((dict != zds->dictSource) | (dictSize != zds->dictSize)) {   /* new dictionary */
         if (dictSize > zds->dictSize) {
-            if (zds->dictContent) zds->customMem.customFree(zds->customMem.opaque, zds->dictContent);
-            zds->dictContent = zds->customMem.customAlloc(zds->customMem.opaque, dictSize);
+            ZSTD_free(zds->dictContent, zds->customMem);
+            zds->dictContent = ZSTD_malloc(dictSize, zds->customMem);
             if (zds->dictContent == NULL) return ERROR(memory_allocation);
         }
         memcpy(zds->dictContent, dict, dictSize);
@@ -1515,15 +1510,15 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                 size_t const neededOutSize = zds->fParams.windowSize + blockSize;
                 zds->blockSize = blockSize;
                 if (zds->inBuffSize < blockSize) {
-                    zds->customMem.customFree(zds->customMem.opaque, zds->inBuff);
+                    ZSTD_free(zds->inBuff, zds->customMem);
                     zds->inBuffSize = blockSize;
-                    zds->inBuff = (char*)zds->customMem.customAlloc(zds->customMem.opaque, blockSize);
+                    zds->inBuff = (char*)ZSTD_malloc(blockSize, zds->customMem);
                     if (zds->inBuff == NULL) return ERROR(memory_allocation);
                 }
                 if (zds->outBuffSize < neededOutSize) {
-                    zds->customMem.customFree(zds->customMem.opaque, zds->outBuff);
+                    ZSTD_free(zds->outBuff, zds->customMem);
                     zds->outBuffSize = neededOutSize;
-                    zds->outBuff = (char*)zds->customMem.customAlloc(zds->customMem.opaque, neededOutSize);
+                    zds->outBuff = (char*)ZSTD_malloc(neededOutSize, zds->customMem);
                     if (zds->outBuff == NULL) return ERROR(memory_allocation);
             }   }
             zds->stage = zdss_read;