[PATCH v5] dsound: Commit next audio chunk between play cursor and write cursor to playing.

[Andrew Eikum]

This is looking pretty good. I'm going to run it through my set of
dsound test applications, and there's a little bit of feedback below.

On Fri, Sep 10, 2021 at 06:36:23PM +0300, Eduard Permyakov wrote:
> diff --git a/dlls/dsound/buffer.c b/dlls/dsound/buffer.c
> index dc3b54906ce..63468732e1d 100644
> --- a/dlls/dsound/buffer.c
> +++ b/dlls/dsound/buffer.c
> @@ -101,6 +101,24 @@ static int __cdecl notify_compar(const void *l, const void *r)
>      return 1;
>  }
>  
> +static void commit_next_chunk(IDirectSoundBufferImpl *dsb)
> +{
> +    void *dstbuff = dsb->committedbuff, *srcbuff = dsb->buffer->memory;
> +    DWORD srcoff = dsb->sec_mixpos, srcsize = dsb->buflen, cpysize = dsb->writelead;
> +
> +    if(cpysize > srcsize - srcoff) {
> +        DWORD overflow = cpysize - (srcsize - srcoff);
> +        memcpy(dstbuff, (BYTE*)srcbuff + srcoff, srcsize - srcoff);
> +        memcpy((BYTE*)dstbuff + (srcsize - srcoff), srcbuff, overflow);
> +    }else{
> +        memcpy(dstbuff, (BYTE*)srcbuff + srcoff, cpysize);
> +    }
> +
> +    dsb->use_committed = TRUE;
> +    dsb->committed_mixpos = 0;

Is it right to always reset this to zero? Is it possible an app could
write to the committed chunk while committed_mixpos is non-zero, and
so reset committed_mixpos when it shouldn't be?

> @@ -153,7 +153,12 @@ struct IDirectSoundBufferImpl
>      LONG64                      freqAccNum;
>      /* used for mixing */
>      DWORD                       sec_mixpos;
> -
> +    /* Holds a copy of the next 'writelead' bytes, to be used for mixing. This makes it
> +     * so that these bytes get played once even if this region of the buffer gets overwritten,
> +     * which is more in-line with native DirectSound behavior. */
> +    BOOL                        use_committed;
> +    LPVOID                      committedbuff;
> +    DWORD                       committed_mixpos;

I think use_committed (and committed_mixpos?) should be initialized in
Duplicate. What about SetCurrentPosition?

Andrew