[FFmpeg-devel] [PATCH 1/7] avutil: add FF_BAIL_ON_OVERFLOW

[Andreas Cadhalpun]

On 20.12.2016 10:23, Muhammad Faiz wrote:
> On 12/20/16, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
>> On 16.12.2016 07:36, Muhammad Faiz wrote:
>>> On 12/16/16, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
>>>> Suggested-by: Rodger Combs <rodger.combs at gmail.com>
>>>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>>>> ---
>>>>  libavutil/common.h | 2 ++
>>>>  1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/libavutil/common.h b/libavutil/common.h
>>>> index 8142b31..00b7504 100644
>>>> --- a/libavutil/common.h
>>>> +++ b/libavutil/common.h
>>>> @@ -99,6 +99,8 @@
>>>>  #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a=
>>>> SWAP_tmp;}while(0)
>>>>  #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
>>>>
>>>> +#define FF_BAIL_ON_OVERFLOW(ctx, x) if (x) {av_log(ctx, AV_LOG_ERROR,
>>>> "Overflow check failed: " #x"\n"); return AVERROR_INVALIDDATA;}
>>>
>>> Where is the overflow check calculation?
>>
>> The parameter 'x' is the overflow check used in 'if (x)'.
> 
> Is it impossible to do something like
> int ff_mul_check_overflow(int *result, int a, int b)
> with AVERROR return code on overlow?

Not really, as the point of the macro is to do the error handling,
which would be needed for a function. Also the function is not
generic enough, as the type can be int64_t. And then using such
a function would make the code rather less readable.

> I suggest this is AVERROR(ERANGE)

This seems like a better fit for the error type, so I've locally
change the error in the macro to this.

Best regards,
Andreas