patch.diff

--- zstddeclib_1.5.5.c	2023-10-15 16:40:17.010929849 -0400
+++ zstddeclib_.c	2023-10-15 13:13:05.783926370 -0400
@@ -16,6 +16,13 @@
  * in the COPYING file in the root directory of this source tree).
  * You may select, at your option, one of the above-listed licenses.
  */
+
+/*
+ * findDecompressedSize interface changed from unsigned long long to U32 for wasm / browser compatibility (matthias.wirth@gmail.com)
+ * further info on the issue: https://github.com/WebAssembly/WASI/issues/54
+ * This is not necessary for browsers after 2020, but there are still plenty of older devices around
+ */
+
 /*
  * Settings to bake for the standalone decompressor.
  *
@@ -5479,7 +5486,7 @@
  *   note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
  *            read each contained frame header.  This is fast as most of the data is skipped,
  *            however it does mean that all frame data must be present and valid. */
-ZSTDLIB_STATIC_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);
+ZSTDLIB_STATIC_API U32 ZSTD_findDecompressedSize(const void* src, size_t srcSize);
 
 /*! ZSTD_decompressBound() :
  *  `src` should point to the start of a series of ZSTD encoded and/or skippable frames
@@ -17881,16 +17888,18 @@
  *      skippable frames
  *  note: compatible with legacy mode
  * @return : decompressed size of the frames contained */
-unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize)
+U32 ZSTD_findDecompressedSize(const void* src, size_t srcSize)
 {
     unsigned long long totalDstSize = 0;
 
+    U32 _error = 0xffffffff;
+
     while (srcSize >= ZSTD_startingInputLength(ZSTD_f_zstd1)) {
         U32 const magicNumber = MEM_readLE32(src);
 
         if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
             size_t const skippableSize = readSkippableFrameSize(src, srcSize);
-            if (ZSTD_isError(skippableSize)) return ZSTD_CONTENTSIZE_ERROR;
+            if (ZSTD_isError(skippableSize)) return _error;
             assert(skippableSize <= srcSize);
 
             src = (const BYTE *)src + skippableSize;
@@ -17899,15 +17908,15 @@
         }
 
         {   unsigned long long const fcs = ZSTD_getFrameContentSize(src, srcSize);
-            if (fcs >= ZSTD_CONTENTSIZE_ERROR) return fcs;
+            if (fcs >= ZSTD_CONTENTSIZE_ERROR) return _error;
 
             if (totalDstSize + fcs < totalDstSize)
-                return ZSTD_CONTENTSIZE_ERROR; /* check for overflow */
+                return _error; /* check for overflow */
             totalDstSize += fcs;
         }
         /* skip to next frame */
         {   size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
-            if (ZSTD_isError(frameSrcSize)) return ZSTD_CONTENTSIZE_ERROR;
+            if (ZSTD_isError(frameSrcSize)) return _error;
             assert(frameSrcSize <= srcSize);
 
             src = (const BYTE *)src + frameSrcSize;
@@ -17915,9 +17924,9 @@
         }
     }  /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */
 
-    if (srcSize) return ZSTD_CONTENTSIZE_ERROR;
+    if (totalDstSize >= UINT32_MAX || srcSize) return _error;
 
-    return totalDstSize;
+    return (U32) totalDstSize;
 }
 
 /** ZSTD_getDecompressedSize() :