[FFmpeg-cvslog] avcodec/put_bits: Always check buffer end before writing
Michael Niedermayer
git at videolan.org
Sat Jan 2 19:36:09 CET 2016
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Jan 1 02:41:06 2016 +0100| [cccb0ffccc3723acc7aab3a859b24743596dd9c0] | committer: Michael Niedermayer
avcodec/put_bits: Always check buffer end before writing
This causes a overall slowdown of 0.1 % (tested with mpeg4 single thread encoding of matrixbench at QP=3)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cccb0ffccc3723acc7aab3a859b24743596dd9c0
---
libavcodec/put_bits.h | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/libavcodec/put_bits.h b/libavcodec/put_bits.h
index 5b1bc8b..0db8a03 100644
--- a/libavcodec/put_bits.h
+++ b/libavcodec/put_bits.h
@@ -163,9 +163,13 @@ static inline void put_bits(PutBitContext *s, int n, unsigned int value)
#ifdef BITSTREAM_WRITER_LE
bit_buf |= value << (32 - bit_left);
if (n >= bit_left) {
- av_assert2(s->buf_ptr+3<s->buf_end);
- AV_WL32(s->buf_ptr, bit_buf);
- s->buf_ptr += 4;
+ if (3 < s->buf_end - s->buf_ptr) {
+ AV_WL32(s->buf_ptr, bit_buf);
+ s->buf_ptr += 4;
+ } else {
+ av_log(NULL, AV_LOG_ERROR, "Internal error, put_bits buffer too small\n");
+ av_assert2(0);
+ }
bit_buf = value >> bit_left;
bit_left += 32;
}
@@ -177,9 +181,13 @@ static inline void put_bits(PutBitContext *s, int n, unsigned int value)
} else {
bit_buf <<= bit_left;
bit_buf |= value >> (n - bit_left);
- av_assert2(s->buf_ptr+3<s->buf_end);
- AV_WB32(s->buf_ptr, bit_buf);
- s->buf_ptr += 4;
+ if (3 < s->buf_end - s->buf_ptr) {
+ AV_WB32(s->buf_ptr, bit_buf);
+ s->buf_ptr += 4;
+ } else {
+ av_log(NULL, AV_LOG_ERROR, "Internal error, put_bits buffer too small\n");
+ av_assert2(0);
+ }
bit_left += 32 - n;
bit_buf = value;
}
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