Expose frameSrcSize to experimental API

lib/decompress/zstd_decompress.c

@@ -306,8 +306,6 @@ size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t
     return 0;
 }
 
-static size_t ZSTD_frameSrcSize(const void* src, size_t srcSize);
-
 /** ZSTD_getFrameContentSize() :
 *   compatible with legacy mode
 *   @return : decompressed size of the single frame pointed to be `src` if known, otherwise
@@ -371,17 +369,7 @@ unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize)
                 totalDstSize += ret;
             }
             {
-                size_t frameSrcSize;
+                size_t const frameSrcSize = ZSTD_getFrameCompressedSize(src, srcSize);
-#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
-                if (ZSTD_isLegacy(src, srcSize))
-                {
-                    frameSrcSize = ZSTD_frameSrcSizeLegacy(src, srcSize);
-                }
-                else
-#endif
-                {
-                    frameSrcSize = ZSTD_frameSrcSize(src, srcSize);
-                }
                 if (ZSTD_isError(frameSrcSize)) {
                     return ZSTD_CONTENTSIZE_ERROR;
                 }
@@ -1449,47 +1437,57 @@ size_t ZSTD_generateNxBytes(void* dst, size_t dstCapacity, BYTE byte, size_t len
     return length;
 }
 
-static size_t ZSTD_frameSrcSize(const void *src, size_t srcSize)
+/** ZSTD_getFrameCompressedSize() :
+ *  compatible with legacy mode
+ *  `src` must point to the start of a ZSTD or ZSTD legacy frame
+ *  `srcSize` must be at least as large as the frame contained
+ *  @return : the compressed size of the frame starting at `src` */
+size_t ZSTD_getFrameCompressedSize(const void *src, size_t srcSize)
 {
-    const BYTE* ip = (const BYTE*)src;
+#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
-    const BYTE* const ipstart = ip;
+    if (ZSTD_isLegacy(src, srcSize)) return ZSTD_getFrameCompressedSizeLegacy(src, srcSize);
-    size_t remainingSize = srcSize;
+#endif
-    ZSTD_frameParams fParams;
-
-    size_t const headerSize = ZSTD_frameHeaderSize(ip, remainingSize);
-    if (ZSTD_isError(headerSize)) return headerSize;
-
-    /* Frame Header */
     {
-        size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
+        const BYTE* ip = (const BYTE*)src;
-        if (ZSTD_isError(ret)) return ret;
+        const BYTE* const ipstart = ip;
-        if (ret > 0) return ERROR(srcSize_wrong);
+        size_t remainingSize = srcSize;
+        ZSTD_frameParams fParams;
+
+        size_t const headerSize = ZSTD_frameHeaderSize(ip, remainingSize);
+        if (ZSTD_isError(headerSize)) return headerSize;
+
+        /* Frame Header */
+        {
+            size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
+            if (ZSTD_isError(ret)) return ret;
+            if (ret > 0) return ERROR(srcSize_wrong);
+        }
+
+        ip += headerSize;
+        remainingSize -= headerSize;
+
+        /* Loop on each block */
+        while (1) {
+            blockProperties_t blockProperties;
+            size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
+            if (ZSTD_isError(cBlockSize)) return cBlockSize;
+
+            if (ZSTD_blockHeaderSize + cBlockSize > remainingSize) return ERROR(srcSize_wrong);
+
+            ip += ZSTD_blockHeaderSize + cBlockSize;
+            remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
+
+            if (blockProperties.lastBlock) break;
+        }
+
+        if (fParams.checksumFlag) {   /* Frame content checksum */
+            if (remainingSize < 4) return ERROR(srcSize_wrong);
+            ip += 4;
+            remainingSize -= 4;
+        }
+
+        return ip - ipstart;
     }
-
-    ip += headerSize;
-    remainingSize -= headerSize;
-
-    /* Loop on each block */
-    while (1) {
-        blockProperties_t blockProperties;
-        size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
-        if (ZSTD_isError(cBlockSize)) return cBlockSize;
-
-        if (ZSTD_blockHeaderSize + cBlockSize > remainingSize) return ERROR(srcSize_wrong);
-
-        ip += ZSTD_blockHeaderSize + cBlockSize;
-        remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
-
-        if (blockProperties.lastBlock) break;
-    }
-
-    if (fParams.checksumFlag) {   /* Frame content checksum verification */
-        if (remainingSize < 4) return ERROR(srcSize_wrong);
-        ip += 4;
-        remainingSize -= 4;
-    }
-
-    return ip - ipstart;
 }
 
 /*! ZSTD_decompressFrame() :
@@ -1578,7 +1576,7 @@ static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
 
 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
         if (ZSTD_isLegacy(src, srcSize)) {
-            size_t const frameSize = ZSTD_frameSrcSizeLegacy(src, srcSize);
+            size_t const frameSize = ZSTD_getFrameCompressedSizeLegacy(src, srcSize);
             size_t decodedSize;
             if (ZSTD_isError(frameSize)) return frameSize;
 

lib/legacy/zstd_legacy.h

@@ -123,26 +123,26 @@ MEM_STATIC size_t ZSTD_decompressLegacy(
     }
 }
 
-MEM_STATIC size_t ZSTD_frameSrcSizeLegacy(const void *src,
+MEM_STATIC size_t ZSTD_getFrameCompressedSizeLegacy(const void *src,
                                              size_t compressedSize)
 {
     U32 const version = ZSTD_isLegacy(src, compressedSize);
     switch(version)
     {
         case 1 :
-            return ZSTDv01_frameSrcSize(src, compressedSize);
+            return ZSTDv01_getFrameCompressedSize(src, compressedSize);
         case 2 :
-            return ZSTDv02_frameSrcSize(src, compressedSize);
+            return ZSTDv02_getFrameCompressedSize(src, compressedSize);
         case 3 :
-            return ZSTDv03_frameSrcSize(src, compressedSize);
+            return ZSTDv03_getFrameCompressedSize(src, compressedSize);
         case 4 :
-            return ZSTDv04_frameSrcSize(src, compressedSize);
+            return ZSTDv04_getFrameCompressedSize(src, compressedSize);
         case 5 :
-            return ZSTDv05_frameSrcSize(src, compressedSize);
+            return ZSTDv05_getFrameCompressedSize(src, compressedSize);
         case 6 :
-            return ZSTDv06_frameSrcSize(src, compressedSize);
+            return ZSTDv06_getFrameCompressedSize(src, compressedSize);
         case 7 :
-            return ZSTDv07_frameSrcSize(src, compressedSize);
+            return ZSTDv07_getFrameCompressedSize(src, compressedSize);
         default :
             return ERROR(prefix_unknown);
     }

lib/legacy/zstd_v01.c

@@ -1992,7 +1992,7 @@ size_t ZSTDv01_decompress(void* dst, size_t maxDstSize, const void* src, size_t
     return ZSTDv01_decompressDCtx(&ctx, dst, maxDstSize, src, srcSize);
 }
 
-size_t ZSTDv01_frameSrcSize(const void* src, size_t srcSize)
+size_t ZSTDv01_getFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;

lib/legacy/zstd_v01.h

@@ -40,7 +40,7 @@ ZSTDv01_getFrameSrcSize() : get the source length of a ZSTD frame compliant with
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv01_isError())
 */
-size_t ZSTDv01_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv01_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /**
 ZSTDv01_isError() : tells if the result of ZSTDv01_decompress() is an error

lib/legacy/zstd_v02.c

@@ -3378,7 +3378,7 @@ static size_t ZSTD_decompress(void* dst, size_t maxDstSize, const void* src, siz
     return ZSTD_decompressDCtx(&ctx, dst, maxDstSize, src, srcSize);
 }
 
-static size_t ZSTD_frameSrcSize(const void *src, size_t srcSize)
+static size_t ZSTD_getFrameCompressedSize(const void *src, size_t srcSize)
 {
 
     const BYTE* ip = (const BYTE*)src;
@@ -3524,9 +3524,9 @@ size_t ZSTDv02_decompress( void* dst, size_t maxOriginalSize,
 	return ZSTD_decompress(dst, maxOriginalSize, src, compressedSize);
 }
 
-size_t ZSTDv02_frameSrcSize(const void *src, size_t compressedSize)
+size_t ZSTDv02_getFrameCompressedSize(const void *src, size_t compressedSize)
 {
-    return ZSTD_frameSrcSize(src, compressedSize);
+    return ZSTD_getFrameCompressedSize(src, compressedSize);
 }
 
 ZSTDv02_Dctx* ZSTDv02_createDCtx(void)

lib/legacy/zstd_v02.h

@@ -40,7 +40,7 @@ ZSTDv02_getFrameSrcSize() : get the source length of a ZSTD frame compliant with
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv02_isError())
 */
-size_t ZSTDv02_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv02_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /**
 ZSTDv02_isError() : tells if the result of ZSTDv02_decompress() is an error

lib/legacy/zstd_v03.c

@@ -3019,7 +3019,7 @@ static size_t ZSTD_decompress(void* dst, size_t maxDstSize, const void* src, siz
     return ZSTD_decompressDCtx(&ctx, dst, maxDstSize, src, srcSize);
 }
 
-static size_t ZSTD_frameSrcSize(const void* src, size_t srcSize)
+static size_t ZSTD_getFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;
@@ -3165,9 +3165,9 @@ size_t ZSTDv03_decompress( void* dst, size_t maxOriginalSize,
 	return ZSTD_decompress(dst, maxOriginalSize, src, compressedSize);
 }
 
-size_t ZSTDv03_frameSrcSize(const void* src, size_t srcSize)
+size_t ZSTDv03_getFrameCompressedSize(const void* src, size_t srcSize)
 {
-    return ZSTD_frameSrcSize(src, srcSize);
+    return ZSTD_getFrameCompressedSize(src, srcSize);
 }
 
 ZSTDv03_Dctx* ZSTDv03_createDCtx(void)

lib/legacy/zstd_v03.h

@@ -40,7 +40,7 @@ ZSTDv03_getFrameSrcSize() : get the source length of a ZSTD frame compliant with
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv03_isError())
 */
-size_t ZSTDv03_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv03_getFrameCompressedSize(const void* src, size_t compressedSize);
 
     /**
 ZSTDv03_isError() : tells if the result of ZSTDv03_decompress() is an error

lib/legacy/zstd_v04.c

@@ -3326,7 +3326,7 @@ static size_t ZSTD_decompress_usingDict(ZSTD_DCtx* ctx,
     return op-ostart;
 }
 
-static size_t ZSTD_frameSrcSize(const void* src, size_t srcSize)
+static size_t ZSTD_getFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;
@@ -3782,9 +3782,9 @@ size_t ZSTDv04_decompress(void* dst, size_t maxDstSize, const void* src, size_t
 #endif
 }
 
-size_t ZSTDv04_frameSrcSize(const void* src, size_t srcSize)
+size_t ZSTDv04_getFrameCompressedSize(const void* src, size_t srcSize)
 {
-    return ZSTD_frameSrcSize(src, srcSize);
+    return ZSTD_getFrameCompressedSize(src, srcSize);
 }
 
 size_t ZSTDv04_resetDCtx(ZSTDv04_Dctx* dctx) { return ZSTD_resetDCtx(dctx); }

lib/legacy/zstd_v04.h

@@ -40,7 +40,7 @@ ZSTDv04_getFrameSrcSize() : get the source length of a ZSTD frame compliant with
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv04_isError())
 */
-size_t ZSTDv04_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv04_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /**
 ZSTDv04_isError() : tells if the result of ZSTDv04_decompress() is an error

lib/legacy/zstd_v05.c

@@ -3583,7 +3583,7 @@ size_t ZSTDv05_decompress(void* dst, size_t maxDstSize, const void* src, size_t
 #endif
 }
 
-size_t ZSTDv05_frameSrcSize(const void *src, size_t srcSize)
+size_t ZSTDv05_getFrameCompressedSize(const void *src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;

lib/legacy/zstd_v05.h

@@ -38,7 +38,7 @@ ZSTDv05_getFrameSrcSize() : get the source length of a ZSTD frame
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv05_isError())
 */
-size_t ZSTDv05_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv05_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /* *************************************
 *  Helper functions

lib/legacy/zstd_v06.c

@@ -3729,7 +3729,7 @@ size_t ZSTDv06_decompress(void* dst, size_t dstCapacity, const void* src, size_t
 #endif
 }
 
-size_t ZSTDv06_frameSrcSize(const void* src, size_t srcSize)
+size_t ZSTDv06_getFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;

lib/legacy/zstd_v06.h

@@ -47,7 +47,7 @@ ZSTDv06_getFrameSrcSize() : get the source length of a ZSTD frame
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv06_isError())
 */
-size_t ZSTDv06_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv06_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /* *************************************
 *  Helper functions

lib/legacy/zstd_v07.c

@@ -3968,7 +3968,7 @@ size_t ZSTDv07_decompress(void* dst, size_t dstCapacity, const void* src, size_t
 #endif
 }
 
-size_t ZSTDv07_frameSrcSize(const void* src, size_t srcSize)
+size_t ZSTDv07_getFrameCompressedSize(const void* src, size_t srcSize)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;

lib/legacy/zstd_v07.h

@@ -54,7 +54,7 @@ ZSTDv07_getFrameSrcSize() : get the source length of a ZSTD frame
     return : the number of bytes that would be read to decompress this frame
              or an errorCode if it fails (which can be tested using ZSTDv07_isError())
 */
-size_t ZSTDv07_frameSrcSize(const void* src, size_t compressedSize);
+size_t ZSTDv07_getFrameCompressedSize(const void* src, size_t compressedSize);
 
 /*======  Helper functions  ======*/
 ZSTDLIBv07_API unsigned    ZSTDv07_isError(size_t code);          /*!< tells if a `size_t` function result is an error code */

lib/zstd.h

@@ -396,6 +396,17 @@ typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
 typedef void  (*ZSTD_freeFunction) (void* opaque, void* address);
 typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
 
+/***************************************
+*  Compressed size functions
+***************************************/
+
+/*! ZSTD_getFrameCompressedSize() :
+ *  `src` should point to the start of a ZSTD encoded frame
+ *  `srcSize` must be at least as large as the frame
+ *  @return : the compressed size of the frame pointed to by `src`, suitable to pass to
+ *      `ZSTD_decompress` or similar, or an error code if given invalid input. */
+ZSTDLIB_API size_t ZSTD_getFrameCompressedSize(const void* src, size_t srcSize);
+
 /***************************************
 *  Decompressed size functions
 ***************************************/