diff options
| -rw-r--r-- | libavcodec/rangecoder.c | 19 | ||||
| -rw-r--r-- | libavcodec/rangecoder.h | 9 | ||||
| -rw-r--r-- | libavcodec/tests/rangecoder.c | 7 |
3 files changed, 33 insertions, 2 deletions
diff --git a/libavcodec/rangecoder.c b/libavcodec/rangecoder.c index fa7d5526d1..a6a3f082ef 100644 --- a/libavcodec/rangecoder.c +++ b/libavcodec/rangecoder.c @@ -121,3 +121,22 @@ int ff_rac_terminate(RangeCoder *c, int version) return c->bytestream - c->bytestream_start; } + +int ff_rac_check_termination(RangeCoder *c, int version) +{ + if (version == 1) { + RangeCoder tmp = *c; + get_rac(c, (uint8_t[]) { 129 }); + + if (c->bytestream == tmp.bytestream && c->bytestream > c->bytestream_start) + tmp.low -= *--tmp.bytestream; + tmp.bytestream_end = tmp.bytestream; + + if (get_rac(&tmp, (uint8_t[]) { 129 })) + return AVERROR_INVALIDDATA; + } else { + if (c->bytestream_end != c->bytestream) + return AVERROR_INVALIDDATA; + } + return 0; +} diff --git a/libavcodec/rangecoder.h b/libavcodec/rangecoder.h index 4495f6df1a..4d4ca4d526 100644 --- a/libavcodec/rangecoder.h +++ b/libavcodec/rangecoder.h @@ -57,6 +57,15 @@ void ff_init_range_decoder(RangeCoder *c, const uint8_t *buf, int buf_size); */ int ff_rac_terminate(RangeCoder *c, int version); +/** + * Check if at the current position there is a valid looking termination + * @param version version 0 requires the decoder to know the data size in bytes + * version 1 needs about 1 bit more space but does not need to + * carry the size from encoder to decoder + * @returns negative AVERROR code on error or non negative. + */ +int ff_rac_check_termination(RangeCoder *c, int version); + void ff_build_rac_states(RangeCoder *c, int factor, int max_p); static inline void renorm_encoder(RangeCoder *c) diff --git a/libavcodec/tests/rangecoder.c b/libavcodec/tests/rangecoder.c index 3fd07ed9a9..b6edc1493f 100644 --- a/libavcodec/tests/rangecoder.c +++ b/libavcodec/tests/rangecoder.c @@ -60,8 +60,11 @@ int main(void) av_log(NULL, AV_LOG_ERROR, "rac failure at %d pass %d version %d\n", i, p, version); return 1; } - if(version) - get_rac(&c, (uint8_t[]) { 129 }); + + if (ff_rac_check_termination(&c, version) < 0) { + av_log(NULL, AV_LOG_ERROR, "rac failure at termination pass %d version %d\n", p, version); + return 1; + } if (c.bytestream - c.bytestream_start - actual_length != version) { av_log(NULL, AV_LOG_ERROR, "rac failure at pass %d version %d\n", p, version); return 1; |