[FFmpeg-devel] [PATCH 4/6] avutil/imgutils: Optimize writing 4 bytes in memset_bytes()

[Michael Niedermayer]

Fixes: Timeout
Fixes: 11502/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920
Before: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 11294 ms
After : Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 4249 ms

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavutil/imgutils.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c
index 4938a7ef67..6c0d3950de 100644
--- a/libavutil/imgutils.c
+++ b/libavutil/imgutils.c
@@ -529,6 +529,14 @@ static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear,
         }
     } else if (clear_size == 4) {
         uint32_t val = AV_RN32(clear);
+#if HAVE_FAST_64BIT
+        uint64_t val8 = val * 0x100000001ULL;
+        for (; dst_size >= 32; dst_size -= 32) {
+            AV_WN64(dst   , val8); AV_WN64(dst+ 8, val8);
+            AV_WN64(dst+16, val8); AV_WN64(dst+24, val8);
+            dst += 32;
+        }
+#endif
         for (; dst_size >= 4; dst_size -= 4) {
             AV_WN32(dst, val);
             dst += 4;
-- 
2.20.1