From: senhuang42 <senhuang96@fb.com>
Date: Tue, 10 Nov 2020 20:33:33 +0000 (-0500)
Subject: Fix srcSize=0 edge case
X-Git-Tag: v1.4.7~30^2~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=48405b46336007bcaa810e7a0f4af41d78ff9a2e;p=thirdparty%2Fzstd.git

Fix srcSize=0 edge case
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index c19b243c9..98890c4d0 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -4694,6 +4694,16 @@ static size_t ZSTD_compressSequences_internal(void* dst, size_t dstCapacity,
     BYTE* op = (BYTE*)dst;
 
     DEBUGLOG(4, "ZSTD_compressSequences_internal srcSize: %zu, inSeqsSize: %zu", srcSize, inSeqsSize);
+    /* Special case: empty frame */
+    if (remaining == 0) {
+        U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw)<<1);
+        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall, "No room for empty frame block header");
+        MEM_writeLE32(op, cBlockHeader24);
+        op += ZSTD_blockHeaderSize;
+        dstCapacity -= ZSTD_blockHeaderSize;
+        cSize += ZSTD_blockHeaderSize;
+    }
+
     while (remaining) {
         U32 cBlockSize;
         int additionalByteAdjustment;