[Ffmpeg-devel] privatizing FifoBuffer into libavutil -- take II

[Michael Niedermayer]

Hi

On Mon, Sep 18, 2006 at 11:49:23PM -0700, Roman Shaposhnik wrote:
> Please review and comment.
> 
> Thanks,
> Roman.
> 
> P.S. Since patch was generated after 'svn cp' I'm attaching actual
> fifo.[ch] for the ease of review.

[...]


>  
> -int fifo_size(FifoBuffer *f, uint8_t *rptr)
> +int av_fifo_size(AVFifoBuffer *f)
>  {
>      int size;
>  
[...]
> +    if (f->wptr >= f->rptr) {
> +        size = f->wptr - f->rptr;
>      } else {
[...]
> +        size = (f->end - f->rptr) + (f->wptr - f->buffer);
>      }

int size = f->wptr - f->rptr;
if(size<0)
    size += f->end - f->buffer;

is simpler, same for the other such pieces of code


[...]
> -void fifo_write(FifoBuffer *f, const uint8_t *buf, int size, uint8_t **wptr_ptr)
> +void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size)
>  {
>      int len;
> -    uint8_t *wptr;
>  
> -    if(!wptr_ptr)
> -        wptr_ptr= &f->wptr;
> -    wptr = *wptr_ptr;
> -
>      while (size > 0) {
> -        len = f->end - wptr;
> +        len = f->end - f->wptr;
>          if (len > size)
>              len = size;

len= FFMIN(f->end - f->wptr, size)


[...] 
> +void av_fifo_drain(AVFifoBuffer *f, int size)
>  {
> -    char buf[1024];
> -    return filename && (av_get_frame_filename(buf, sizeof(buf), filename, 1)>=0);
> +    f->rptr += size;
> +    if (f->rptr >= f->end)
> +        f->rptr = f->buffer + (f->rptr - f->end);

f->rptr -= f->end - f->buffer;


[...]
> +static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
>  {
>      return f->buffer[(f->rptr - f->buffer + offs) % (f->end - f->buffer)];

i bet that the following is faster

ptr= f->rptr + offs;
if(ptr >= s->end)
    ptr -= f->end - f->buffer;
return *ptr;

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is