On Mon, May 22, 2017 at 05:36:10PM +0200, Michael Niedermayer wrote: > On Sun, May 21, 2017 at 01:42:18PM +0200, wm4 wrote: > > On Sat, 20 May 2017 23:01:04 +0200 > > Michael Niedermayer <mich...@niedermayer.cc> wrote: > > > > > This reorders the operations so as to avoid computations with the above > > > arguments > > > before they have been initialized. > > > Fixes part of 1708/clusterfuzz-testcase-minimized-5035111957397504 > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavcodec/mlpdec.c | 34 +++++++++++++++++++++++++--------- > > > 1 file changed, 25 insertions(+), 9 deletions(-) > > > > > > diff --git a/libavcodec/mlpdec.c b/libavcodec/mlpdec.c > > > index c0a23c5f0d..11be380d27 100644 > > > --- a/libavcodec/mlpdec.c > > > +++ b/libavcodec/mlpdec.c > > > @@ -825,8 +825,6 @@ static int read_channel_params(MLPDecodeContext *m, > > > unsigned int substr, > > > return AVERROR_INVALIDDATA; > > > } > > > > > > - cp->sign_huff_offset = calculate_sign_huff(m, substr, ch); > > > - > > > return 0; > > > } > > > > > > @@ -838,7 +836,8 @@ static int read_decoding_params(MLPDecodeContext *m, > > > GetBitContext *gbp, > > > { > > > SubStream *s = &m->substream[substr]; > > > unsigned int ch; > > > - int ret; > > > + int ret = 0; > > > + unsigned recompute_sho = 0; > > > > > > if (s->param_presence_flags & PARAM_PRESENCE) > > > if (get_bits1(gbp)) > > > @@ -878,19 +877,36 @@ static int read_decoding_params(MLPDecodeContext > > > *m, GetBitContext *gbp, > > > if (s->param_presence_flags & PARAM_QUANTSTEP) > > > if (get_bits1(gbp)) > > > for (ch = 0; ch <= s->max_channel; ch++) { > > > - ChannelParams *cp = &s->channel_params[ch]; > > > - > > > s->quant_step_size[ch] = get_bits(gbp, 4); > > > > > > - cp->sign_huff_offset = calculate_sign_huff(m, substr, > > > ch); > > > + recompute_sho |= 1<<ch; > > > } > > > > > > for (ch = s->min_channel; ch <= s->max_channel; ch++) > > > - if (get_bits1(gbp)) > > > + if (get_bits1(gbp)) { > > > + recompute_sho |= 1<<ch; > > > if ((ret = read_channel_params(m, substr, gbp, ch)) < 0) > > > - return ret; > > > + goto fail; > > > + } > > > > > > - return 0; > > > + > > > > > > > +fail: > > > + for (ch = 0; ch <= s->max_channel; ch++) { > > > + if (recompute_sho & (1<<ch)) { > > > + ChannelParams *cp = &s->channel_params[ch]; > > > + > > > + if (cp->codebook > 0 && cp->huff_lsbs < > > > s->quant_step_size[ch]) { > > > + if (ret >= 0) { > > > + av_log(m->avctx, AV_LOG_ERROR, "quant_step_size > > > larger than huff_lsbs\n"); > > > + ret = AVERROR_INVALIDDATA; > > > + } > > > + s->quant_step_size[ch] = 0; > > > + } > > > + > > > + cp->sign_huff_offset = calculate_sign_huff(m, substr, ch); > > > + } > > > + } > > > + return ret; > > > > What's all this stuff for? > > As described in the commit message it > "Check quant_step_size against huff_lsbs" > > both these are updated independant and conditionally, so the loop > checking them is seperate after both which is ugly. > If you have an idea how to do this cleaner ... > > as it is in git the case checked for results in negative shift > exponents
applied thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Its not that you shouldnt use gotos but rather that you should write readable code and code with gotos often but not always is less readable
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