[FFmpeg-devel] [PATCH] Add DPX decoder rev-9

[Jimmy Christensen]

On 2009-05-27 14:30, Michael Niedermayer wrote:
> On Tue, May 26, 2009 at 05:51:25AM +0200, Jimmy Christensen wrote:
>> On 2009-05-25 23:58, Michael Niedermayer wrote:
>>> On Mon, May 25, 2009 at 08:54:12AM +0200, Jimmy Christensen wrote:
>>>> On 2009-05-15 03:51, Michael Niedermayer wrote:
>>>>> On Mon, May 11, 2009 at 11:31:25AM +0200, Jimmy Christensen wrote:
>>> [...]
>>>>>
>>>>>
>>>>> [...]
>>>>>> +    for (x = 0; x<    s->height; x++) {
>>>>>> +        uint8_t *dst = ptr;
>>>>>> +        for (y = 0; y<    s->width; y++) {
>>>>>
>>>>>> +            rgbBuffer = AV_RB32(buf);
>>>>>> +            memcpy(&rgb10Field,&rgbBuffer, 4);
>>>>>> +            rgb16Field.R = rgb10Field.R * 64; // 10-bit>    16-bit
>>>>>> +            rgb16Field.G = rgb10Field.G * 64; // 10-bit>    16-bit
>>>>>> +            rgb16Field.B = rgb10Field.B * 64; // 10-bit>    16-bit
>>>>>> +            memcpy(dst,&rgb16Field, dstBpp);
>>>>>
>>>>> not portable
>>>>>
>>>>
>>>> I rewrote a little, but still uses memcpy from rgb16Field to dst, since
>>>> that should actually be portable.
>>>
>>> you will have to quote page and pararaph of the C standard that gurantees
>>> bitfields to work the way you seem to belive they do
>>>
>>
>> So the bit masking is fine (RED10, GREEN10 and BLUE10), but I need to
>> change the memcpy?
>
> we need C code that works, any construct that has undefined or implementation
> defined behavior is unacceptable. That is with a few exceptions that happen
> to be exceedingly inconvenient to avoid or would cause speedloss and happen
> to work on all for us relevant implementations, like
> signed>>  or CHAR_BIT == 8
>

I'm not familiar with coding on other platforms and what code is 
portable or not. I'm just seeing that it works here and try to get some 
input on how to fix the code to make it portable. So forgive my lack of 
knowledge. I was merely asking for a yes or no.