From f5c6d42124a4ef8c71b8bd5f9ce078384655daf6 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 25 Dec 2018 23:15:20 +0100 Subject: [PATCH] avutil/imgutils: Optimize memset_bytes() by using av_memcpy_backptr() This is strongly based on code by Marton Balint, and depends on the previous commit 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 11209 ms After: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 4104 ms Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Marton Balint Signed-off-by: Michael Niedermayer (cherry picked from commit f64c0dffa13e6263de3fdff0058ab2fdb03ac1d6) Signed-off-by: Michael Niedermayer --- libavutil/imgutils.c | 27 +++++---------------------- 1 file changed, 5 insertions(+), 22 deletions(-) diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c index 4938a7ef67..afc73e2def 100644 --- a/libavutil/imgutils.c +++ b/libavutil/imgutils.c @@ -501,7 +501,6 @@ int av_image_copy_to_buffer(uint8_t *dst, int dst_size, static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear, size_t clear_size) { - size_t pos = 0; int same = 1; int i; @@ -521,28 +520,12 @@ static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear, if (clear_size == 1) { memset(dst, clear[0], dst_size); dst_size = 0; - } else if (clear_size == 2) { - uint16_t val = AV_RN16(clear); - for (; dst_size >= 2; dst_size -= 2) { - AV_WN16(dst, val); - dst += 2; - } - } else if (clear_size == 4) { - uint32_t val = AV_RN32(clear); - for (; dst_size >= 4; dst_size -= 4) { - AV_WN32(dst, val); - dst += 4; - } - } else if (clear_size == 8) { - uint32_t val = AV_RN64(clear); - for (; dst_size >= 8; dst_size -= 8) { - AV_WN64(dst, val); - dst += 8; - } + } else { + if (clear_size > dst_size) + clear_size = dst_size; + memcpy(dst, clear, clear_size); + av_memcpy_backptr(dst + clear_size, clear_size, dst_size - clear_size); } - - for (; dst_size; dst_size--) - *dst++ = clear[pos++ % clear_size]; } // Maximum size in bytes of a plane element (usually a pixel, or multiple pixels