[FFmpeg-devel] [PATCH] avcodec/mlz: simplify

[Paul B Mahol]

On 7/1/17, Thilo Borgmann <thilo.borgmann at mail.de> wrote:
> Am 01.07.17 um 14:42 schrieb Paul B Mahol:
>> On 7/1/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
>>> On Sat, Jul 01, 2017 at 02:18:17PM +0200, Paul B Mahol wrote:
>>>> On 7/1/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
>>>>> On Sat, Jul 01, 2017 at 12:05:52PM +0200, Paul B Mahol wrote:
>>>>>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>>>>>> ---
>>>>>>  libavcodec/mlz.c | 7 +------
>>>>>>  1 file changed, 1 insertion(+), 6 deletions(-)
>>>>>>
>>>>>> diff --git a/libavcodec/mlz.c b/libavcodec/mlz.c
>>>>>> index ebce796..715ea5c 100644
>>>>>> --- a/libavcodec/mlz.c
>>>>>> +++ b/libavcodec/mlz.c
>>>>>> @@ -112,12 +112,7 @@ static int decode_string(MLZ* mlz, unsigned char
>>>>>> *buff, int string_code, int *fi
>>>>>>  }
>>>>>>
>>>>>>  static int input_code(GetBitContext* gb, int len) {
>>>>>> -    int tmp_code = 0;
>>>>>> -    int i;
>>>>>> -    for (i = 0; i < len; ++i) {
>>>>>> -        tmp_code |= get_bits1(gb) << i;
>>>>>> -    }
>>>>>> -    return tmp_code;
>>>>>> +    return get_bitsz(gb, len);
>>>>>
>>>>> have you tested this ? (seems not triggered in fate, i ve only found
>>>>> fuzzed samples that trigger this with len >= 1 quickly)
>>>>> isnt this the opposite endianness ?
>>>>
>>>> I created file with 22rev2 als encoder and decoding produce same hash,
>>>> before and after this patch.
>>>>
>>>> ALS uses big endian bit reader.
>>>
>>> ok, but please change the commit message then as the code before and
>>> afterwards dont read in the same endianness so this is not a
>>> simplification but a bugfix then
>>
>> Hmm, on second look you are probably right.
>> They changed to this in R23 version and I failed to create file that
>> triggers this path.
>> So I will not apply this mostly because R23 support needs more work.
>
> Do I understand correctly, this patch works with RM22 only and fails on
> RM23?

Probably. I can not confirm because I failed to create sample with
path that triggers this code.