[FFmpeg-devel] [PATCH] RV30/40 decoder

[Måns Rullgård]

Ivan Kalvachev wrote:
> 2007/9/17, Michael Niedermayer <michaelni at gmx.at>:
>> Hi
>>
>> On Mon, Sep 17, 2007 at 01:16:06PM +0100, Steve Lhomme wrote:
>> > Kostya wrote:
>> >> On Mon, Sep 17, 2007 at 11:34:17AM +0200, Michael Niedermayer wrote:
>> >>> Hi
>> >>>
>> >>> On Mon, Sep 17, 2007 at 08:19:50AM +0300, Kostya wrote:
>> >>>>>> +    cw = av_mallocz(size * 2);
>> >>>>>> +    syms = av_malloc(size * 2);
>> >>>>>> +    bits = av_malloc(size);
>> >>>>> these could as well use use arrays on the stack, simplifying the source
>> >>>> Table sizes vary from 16 to 1296 elements. I suspect that it's easier to
>> >>>> allocate
>> >>>> memory instead of remembering where 1296 came from.
>> >>> then use
>> >>> int bits[size];
>> >> I did not know this was possible. I will give it a try.
>> >
>> > Not every compiler can handle this.
>>
>> true, only ANSI and ISO C compilers can compile ANSI and ISO C, ffmpeg is
>> written in ANSI/ISO C thus requires a ANSI/ISO C compiler
>> you cant compile it with a pascal, ada, fortran, basic, ... compiler
>
> Still I find the usage of variable size stack arrays as sign for bad coding.
> If you want to put assert or non-debug check of the size you are
> forced put the declaration after the code (or use new block{} that is
> even uglier) .

The same C standard (C99) that introduced variable-size arrays also
allows declarations after code.  If you don't like that, you can do
something like this:

int foo = (assert(size < X), 0);
char buf[size];

I'm not sure that qualifies as pretty either, though...

-- 
M?ns Rullg?rd
mans at mansr.com