Re: [PATCH 05/23] sdlaudio: always clear the sample buffer

[Thomas Huth <thuth@redhat.com>]

On 10/01/2021 11.02, Volker Rümelin wrote:
> Always fill the remaining audio callback buffer with silence.
> SDL 2.0 doesn't initialize the audio callback buffer. This was
> an incompatible change compared to SDL 1.2. For reference read
> the SDL 1.2 to 2.0 migration guide.
> 
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> ---
>   audio/sdlaudio.c | 33 ++++++++++++++++-----------------
>   1 file changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/audio/sdlaudio.c b/audio/sdlaudio.c
> index 68126a99ab..79eed23849 100644
> --- a/audio/sdlaudio.c
> +++ b/audio/sdlaudio.c
> @@ -211,27 +211,26 @@ static void sdl_callback (void *opaque, Uint8 *buf, int len)
>       SDLAudioState *s = &glob_sdl;
>       HWVoiceOut *hw = &sdl->hw;
>   
> -    if (s->exit) {
> -        return;
> -    }
> +    if (!s->exit) {
>   
> -    /* dolog("callback: len=%d avail=%zu\n", len, hw->pending_emul); */
> +        /* dolog("callback: len=%d avail=%zu\n", len, hw->pending_emul); */
>   
> -    while (hw->pending_emul && len) {
> -        size_t write_len;
> -        ssize_t start = ((ssize_t) hw->pos_emul) - hw->pending_emul;
> -        if (start < 0) {
> -            start += hw->size_emul;
> -        }
> -        assert(start >= 0 && start < hw->size_emul);
> +        while (hw->pending_emul && len) {
> +            size_t write_len;
> +            ssize_t start = (ssize_t)hw->pos_emul - hw->pending_emul;
> +            if (start < 0) {
> +                start += hw->size_emul;
> +            }
> +            assert(start >= 0 && start < hw->size_emul);
>   
> -        write_len = MIN(MIN(hw->pending_emul, len),
> -                        hw->size_emul - start);
> +            write_len = MIN(MIN(hw->pending_emul, len),
> +                            hw->size_emul - start);
>   
> -        memcpy(buf, hw->buf_emul + start, write_len);
> -        hw->pending_emul -= write_len;
> -        len -= write_len;
> -        buf += write_len;
> +            memcpy(buf, hw->buf_emul + start, write_len);
> +            hw->pending_emul -= write_len;
> +            len -= write_len;
> +            buf += write_len;
> +        }
>       }
>   
>       /* clear remaining buffer that we couldn't fill with data */
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>