Enforce nbThreads<=1 for estimateCCtxSize

lib/compress/zstd_compress.c

@@ -678,7 +678,11 @@ ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, u
 
 size_t ZSTD_estimateCCtxSize_advanced_opaque(const ZSTD_CCtx_params* params)
 {
-    ZSTD_compressionParameters const cParams = params->cParams;
+    /* Estimate CCtx size is supported for single-threaded compression only. */
+    if (params->nbThreads > 1) {
+      return 0;
+    }
+    {   ZSTD_compressionParameters const cParams = params->cParams;
         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << cParams.windowLog);
         U32    const divider = (cParams.searchLength==3) ? 3 : 4;
         size_t const maxNbSeq = blockSize / divider;
@@ -701,6 +705,7 @@ size_t ZSTD_estimateCCtxSize_advanced_opaque(const ZSTD_CCtx_params* params)
         DEBUGLOG(5, "sizeof(ZSTD_CCtx) : %u", (U32)sizeof(ZSTD_CCtx));
         DEBUGLOG(5, "estimate workSpace : %u", (U32)neededSpace);
         return sizeof(ZSTD_CCtx) + neededSpace;
+    }
 }
 
 size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cParams)
@@ -717,13 +722,17 @@ size_t ZSTD_estimateCCtxSize(int compressionLevel)
 
 size_t ZSTD_estimateCStreamSize_advanced_opaque(const ZSTD_CCtx_params* params)
 {
-    size_t const CCtxSize = ZSTD_estimateCCtxSize_advanced_opaque(params);
+    if (params->nbThreads > 1) {
+        return 0;
+    }
+    {   size_t const CCtxSize = ZSTD_estimateCCtxSize_advanced_opaque(params);
         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_MAX, (size_t)1 << params->cParams.windowLog);
         size_t const inBuffSize = ((size_t)1 << params->cParams.windowLog) + blockSize;
         size_t const outBuffSize = ZSTD_compressBound(blockSize) + 1;
         size_t const streamingSize = inBuffSize + outBuffSize;
 
         return CCtxSize + streamingSize;
+    }
 }
 
 size_t ZSTD_estimateCStreamSize_advanced(ZSTD_compressionParameters cParams)

lib/zstd.h

@@ -498,7 +498,7 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
  *  It will also consider src size to be arbitrarily "large", which is worst case.
  *  If srcSize is known to always be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation.
  *  ZSTD_estimateCCtxSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
- *  ZSTD_estimateCCtxSize_advanced_opaque() can be used in tandem with ZSTD_CCtxParam_setParameter().
+ *  ZSTD_estimateCCtxSize_advanced_opaque() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return 0 if ZSTD_p_nbThreads is set to a value > 1.
  *  Note : CCtx estimation is only correct for single-threaded compression */
 ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
 ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cParams);
@@ -510,7 +510,7 @@ ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
  *  It will also consider src size to be arbitrarily "large", which is worst case.
  *  If srcSize is known to always be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation.
  *  ZSTD_estimateCStreamSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
- *  ZSTD_estimateCStreamSize_advanced_opaque() can be used in tandem with ZSTD_CCtxParam_setParameter().
+ *  ZSTD_estimateCStreamSize_advanced_opaque() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return 0 if ZSTD_p_nbThreads is set to a value > 1.
  *  Note : CStream estimation is only correct for single-threaded compression.
  *  ZSTD_DStream memory budget depends on window Size.
  *  This information can be passed manually, using ZSTD_estimateDStreamSize,
@@ -1113,7 +1113,8 @@ size_t ZSTD_compress_generic_simpleArgs (
  *  - ZSTD_compress_generic() : Do compression using the CCtx.
  *  - ZSTD_freeCCtxParams() : Free the memory.
  *
- *  This can be used with ZSTD_estimateCCtxSize_opaque() for static allocation. */
+ *  This can be used with ZSTD_estimateCCtxSize_opaque() for static allocation
+ *  for single-threaded compression. */
 
 ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
 

tests/Makefile

@@ -323,6 +323,7 @@ test-zstream: zstreamtest
 	$(QEMU_SYS) ./zstreamtest $(ZSTREAM_TESTTIME) $(FUZZER_FLAGS)
 	$(QEMU_SYS) ./zstreamtest --mt $(ZSTREAM_TESTTIME) $(FUZZER_FLAGS)
 	$(QEMU_SYS) ./zstreamtest --newapi $(ZSTREAM_TESTTIME) $(FUZZER_FLAGS)
+	$(QEMU_SYS) ./zstreamtest --opaqueapi $(ZSTREAM_TESTTIME) $(FUZZER_FLAGS)
 
 test-zstream32: zstreamtest32
 	$(QEMU_SYS) ./zstreamtest32 $(ZSTREAM_TESTTIME) $(FUZZER_FLAGS)