From: Nick Terrell <terrelln@fb.com>
Date: Fri, 13 Oct 2017 19:47:00 +0000 (-0700)
Subject: Fix invalid use of dictionary offcode table
X-Git-Tag: v1.3.3^2~56^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=24ac2dbd2a56dccbfe52293ac98c3cdd8eb0c0c0;p=thirdparty%2Fzstd.git

Fix invalid use of dictionary offcode table

Fixes #888.
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index e072fe30e..3f1a7cdba 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -1536,6 +1536,12 @@ MEM_STATIC size_t ZSTD_compressSequences(seqStore_t* seqStorePtr,
     int const uncompressibleError = (cSize == ERROR(dstSize_tooSmall)) && (srcSize <= dstCapacity);
     if (ZSTD_isError(cSize) && !uncompressibleError)
         return cSize;
+    /* We check that dictionaries have offset codes available for the first
+     * block. After the first block, the offcode table might not have large
+     * enough codes to represent the offsets in the data.
+     */
+    if (entropy->offcode_repeatMode == FSE_repeat_valid)
+        entropy->offcode_repeatMode = FSE_repeat_check;
 
     /* Check compressibility */
     {   size_t const minGain = ZSTD_minGain(srcSize);  /* note : fixed formula, maybe should depend on compression level, or strategy */