Add legacy support to decompressBound

lib/legacy/zstd_v05.c

@@ -491,6 +491,9 @@ static const size_t ZSTDv05_frameHeaderSize_min = 5;
 
 #define WILDCOPY_OVERLENGTH 8
 
+#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
+#define ZSTD_CONTENTSIZE_ERROR   (0ULL - 2)
+
 typedef enum { bt_compressed, bt_raw, bt_rle, bt_end } blockType_t;
 
 
@@ -3508,34 +3511,56 @@ size_t ZSTDv05_decompress(void* dst, size_t maxDstSize, const void* src, size_t
 #endif
 }
 
-size_t ZSTDv05_findFrameCompressedSize(const void *src, size_t srcSize)
+MEM_STATIC void ZSTD_errorFrameSizeInfoLegacy(size_t* cSize, unsigned long long* dBound, size_t ret)
+{
+    *cSize = ret;
+    *dBound = ZSTD_CONTENTSIZE_ERROR;
+}
+
+void ZSTDv05_findFrameSizeInfoLegacy(const void *src, size_t srcSize,
+                                     size_t* cSize, unsigned long long* dBound)
 {
     const BYTE* ip = (const BYTE*)src;
     size_t remainingSize = srcSize;
+    size_t nbBlocks = 0;
     blockProperties_t blockProperties;
 
     /* Frame Header */
-    if (srcSize < ZSTDv05_frameHeaderSize_min) return ERROR(srcSize_wrong);
-    if (MEM_readLE32(src) != ZSTDv05_MAGICNUMBER) return ERROR(prefix_unknown);
+    if (srcSize < ZSTDv05_frameHeaderSize_min) {
+        ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(srcSize_wrong));
+        return;
+    }
+    if (MEM_readLE32(src) != ZSTDv05_MAGICNUMBER) {
+        ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(prefix_unknown));
+        return;
+    }
     ip += ZSTDv05_frameHeaderSize_min; remainingSize -= ZSTDv05_frameHeaderSize_min;
 
     /* Loop on each block */
     while (1)
     {
         size_t cBlockSize = ZSTDv05_getcBlockSize(ip, remainingSize, &blockProperties);
-        if (ZSTDv05_isError(cBlockSize)) return cBlockSize;
+        if (ZSTDv05_isError(cBlockSize)) {
+            ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, cBlockSize);
+            return;
+        }
 
         ip += ZSTDv05_blockHeaderSize;
         remainingSize -= ZSTDv05_blockHeaderSize;
-        if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
+        if (cBlockSize > remainingSize) {
+            ZSTD_errorFrameSizeInfoLegacy(cSize, dBound, ERROR(srcSize_wrong));
+            return;
+        }
 
         if (cBlockSize == 0) break;   /* bt_end */
 
         ip += cBlockSize;
         remainingSize -= cBlockSize;
+        nbBlocks++;
     }
 
-    return ip - (const BYTE*)src;
+    *cSize = ip - (const BYTE*)src;
+    *dBound = nbBlocks * BLOCKSIZE;
 }
 
 /* ******************************