From: Yann Collet <cyan@fb.com>
Date: Tue, 28 Feb 2017 09:15:28 +0000 (-0800)
Subject: fixed decoding skippable frames
X-Git-Tag: v1.1.4~1^2~31^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a33ae6420491e4aa6819041452a108df96977b02;p=thirdparty%2Fzstd.git

fixed decoding skippable frames
---

diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 305a9a876..1252b2c37 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -1469,8 +1469,7 @@ size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
         if (ZSTD_isError(headerSize)) return headerSize;
 
         /* Frame Header */
-        {
-            size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
+        {   size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
             if (ZSTD_isError(ret)) return ret;
             if (ret > 0) return ERROR(srcSize_wrong);
         }
@@ -1503,7 +1502,7 @@ size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
 }
 
 /*! ZSTD_decompressFrame() :
-*   `dctx` must be properly initialized */
+*   @dctx must be properly initialized */
 static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
                                  void* dst, size_t dstCapacity,
                                  const void** srcPtr, size_t *srcSizePtr)
@@ -1570,7 +1569,7 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
         remainingSize -= 4;
     }
 
-    // Allow caller to get size read
+    /* Allow caller to get size read */
     *srcPtr = ip;
     *srcSizePtr = remainingSize;
     return op-ostart;
@@ -2302,7 +2301,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
             }   }
 
             /* check for single-pass mode opportunity */
-            if (zds->fParams.frameContentSize
+            if (zds->fParams.frameContentSize && zds->fParams.windowSize /* skippable frame if == 0 */
                 && (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) {
                 size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend-istart);
                 if (cSize <= (size_t)(iend-istart)) {
diff --git a/tests/zstreamtest.c b/tests/zstreamtest.c
index c22a284c7..54b890266 100644
--- a/tests/zstreamtest.c
+++ b/tests/zstreamtest.c
@@ -218,7 +218,7 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
     outBuff.pos = 0;
     { size_t const r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
       if (r != 0) goto _output_error; }
-    if (outBuff.pos != 0) goto _output_error;   /* skippable frame len is 0 */
+    if (outBuff.pos != 0) goto _output_error;   /* skippable frame output len is 0 */
     DISPLAYLEVEL(3, "OK \n");
 
     /* Basic decompression test */