On Sun, Dec 30, 2018 at 07:15:49PM +0100, Marton Balint wrote: > > > On Fri, 28 Dec 2018, Michael Niedermayer wrote: > > >On Wed, Dec 26, 2018 at 10:16:47PM +0100, Marton Balint wrote: > >> > >> > >>On Wed, 26 Dec 2018, Paul B Mahol wrote: > >> > >>>On 12/26/18, Michael Niedermayer <mich...@niedermayer.cc> wrote: > >>>>On Wed, Dec 26, 2018 at 04:32:17PM +0100, Paul B Mahol wrote: > >>>>>On 12/25/18, Michael Niedermayer <mich...@niedermayer.cc> wrote: > >>>>>>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 <mich...@niedermayer.cc> > >>>>>>--- > >>>>>> libavutil/imgutils.c | 6 ++++++ > >>>>>> 1 file changed, 6 insertions(+) > >>>>>> > >>>>>>diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c > >>>>>>index 4938a7ef67..cc38f1e878 100644 > >>>>>>--- a/libavutil/imgutils.c > >>>>>>+++ b/libavutil/imgutils.c > >>>>>>@@ -529,6 +529,12 @@ 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); > >>>>>>+ 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; > >>>>>>+ } > >>>>>> for (; dst_size >= 4; dst_size -= 4) { > >>>>>> AV_WN32(dst, val); > >>>>>> dst += 4; > >>>>>>-- > >>>>>>2.20.1 > >>>>>> > >>>>> > >>>>>NAK, implement special memset function instead. > >>>> > >>>>I can move the added loop into a seperate function, if thats what you > >>>>suggest ? > >>> > >>>No, don't do that. > >>> > >>>>All the code is already in a "special" memset though, this is > >>>>memset_bytes() > >>>> > >>> > >>>I guess function is less useful if its static. So any duplicate should > >>>be avoided in codebase. > >> > >>Isn't av_memcpy_backptr does almost exactly what is needed here? That can > >>also be optimized further if needed. > > > >av_memcpy_backptr() copies data with overlap, its more like a recursive > >memmove(). > > So? As far as I see the memset_bytes function in imgutils.c can be replaced > with this: > > 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); > > I am not against an av_memset_bytes API addition, but I believe it should > share code with av_memcpy_backptr to avoid duplication.
Iam a bit concerned that combining them could result in lower speed but i can surely combine them if people prefer? thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB If you think the mosad wants you dead since a long time then you are either wrong or dead since a long time.
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