C++ (Cpp) dmix_down_sem Examples

Example #1

File: pcm_dmix.c Project: xenyinzen/lx_toolset

/*
 *  synchronize shm ring buffer with hardware
 */
static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
{
	snd_pcm_direct_t *dmix = pcm->private_data;
	snd_pcm_uframes_t appl_ptr, slave_appl_ptr, slave_bsize;
	snd_pcm_uframes_t size, slave_hw_ptr;
	const snd_pcm_channel_area_t *src_areas, *dst_areas;
	
	/* calculate the size to transfer */
	size = dmix->appl_ptr - dmix->last_appl_ptr;
	if (! size)
		return;
	slave_bsize = dmix->shmptr->s.buffer_size;
	slave_hw_ptr = dmix->slave_hw_ptr;
	/* don't write on the last active period - this area may be cleared
	 * by the driver during mix operation...
	 */
	slave_hw_ptr -= slave_hw_ptr % dmix->shmptr->s.period_size;
	slave_hw_ptr += slave_bsize;
	if (dmix->slave_hw_ptr > dmix->slave_appl_ptr)
		slave_hw_ptr -= dmix->shmptr->s.boundary;
	if (dmix->slave_appl_ptr + size >= slave_hw_ptr)
		size = slave_hw_ptr - dmix->slave_appl_ptr;
	if (! size)
		return;
	/* add sample areas here */
	src_areas = snd_pcm_mmap_areas(pcm);
	dst_areas = snd_pcm_mmap_areas(dmix->spcm);
	appl_ptr = dmix->last_appl_ptr % pcm->buffer_size;
	dmix->last_appl_ptr += size;
	dmix->last_appl_ptr %= pcm->boundary;
	slave_appl_ptr = dmix->slave_appl_ptr % slave_bsize;
	dmix->slave_appl_ptr += size;
	dmix->slave_appl_ptr %= dmix->shmptr->s.boundary;
	dmix_down_sem(dmix);
	for (;;) {
		snd_pcm_uframes_t transfer = size;
		if (appl_ptr + transfer > pcm->buffer_size)
			transfer = pcm->buffer_size - appl_ptr;
		if (slave_appl_ptr + transfer > slave_bsize)
			transfer = slave_bsize - slave_appl_ptr;
		mix_areas(dmix, src_areas, dst_areas, appl_ptr, slave_appl_ptr, transfer);
		size -= transfer;
		if (! size)
			break;
		slave_appl_ptr += transfer;
		slave_appl_ptr %= slave_bsize;
		appl_ptr += transfer;
		appl_ptr %= pcm->buffer_size;
	}
	dmix_up_sem(dmix);
}

Example #2

File: pcm_dmix.c Project: ProfessorKaos64/steamlink-sdk

/*
 *  synchronize shm ring buffer with hardware
 */
static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
{
	snd_pcm_direct_t *dmix = pcm->private_data;
	snd_pcm_uframes_t slave_hw_ptr, slave_appl_ptr, slave_size;
	snd_pcm_uframes_t appl_ptr, size, transfer;
	const snd_pcm_channel_area_t *src_areas, *dst_areas;
	
	/* calculate the size to transfer */
	/* check the available size in the local buffer
	 * last_appl_ptr keeps the last updated position
	 */
	size = dmix->appl_ptr - dmix->last_appl_ptr;
	if (! size)
		return;
	if (size >= pcm->boundary / 2)
		size = pcm->boundary - size;

	/* the slave_app_ptr can be far behind the slave_hw_ptr */
	/* reduce mixing and errors here - just skip not catched writes */
	if (dmix->slave_hw_ptr <= dmix->slave_appl_ptr)
		slave_size = dmix->slave_appl_ptr - dmix->slave_hw_ptr;
	else
		slave_size = dmix->slave_appl_ptr + (dmix->slave_boundary - dmix->slave_hw_ptr);
	if (slave_size > dmix->slave_buffer_size) {
		transfer = dmix->slave_buffer_size - slave_size;
		if (transfer > size)
			transfer = size;
		dmix->last_appl_ptr += transfer;
		dmix->last_appl_ptr %= pcm->boundary;
		dmix->slave_appl_ptr += transfer;
		dmix->slave_appl_ptr %= dmix->slave_boundary;
		size = dmix->appl_ptr - dmix->last_appl_ptr;
		if (! size)
			return;
		if (size >= pcm->boundary / 2)
			size = pcm->boundary - size;
	}

	/* check the available size in the slave PCM buffer */
	slave_hw_ptr = dmix->slave_hw_ptr;
	/* don't write on the last active period - this area may be cleared
	 * by the driver during mix operation...
	 */
	slave_hw_ptr -= slave_hw_ptr % dmix->slave_period_size;
	slave_hw_ptr += dmix->slave_buffer_size;
	if (slave_hw_ptr >= dmix->slave_boundary)
		slave_hw_ptr -= dmix->slave_boundary;
	if (slave_hw_ptr < dmix->slave_appl_ptr)
		slave_size = slave_hw_ptr + (dmix->slave_boundary - dmix->slave_appl_ptr);
	else
		slave_size = slave_hw_ptr - dmix->slave_appl_ptr;
	if (slave_size < size)
		size = slave_size;
	if (! size)
		return;

	/* add sample areas here */
	src_areas = snd_pcm_mmap_areas(pcm);
	dst_areas = snd_pcm_mmap_areas(dmix->spcm);
	appl_ptr = dmix->last_appl_ptr % pcm->buffer_size;
	dmix->last_appl_ptr += size;
	dmix->last_appl_ptr %= pcm->boundary;
	slave_appl_ptr = dmix->slave_appl_ptr % dmix->slave_buffer_size;
	dmix->slave_appl_ptr += size;
	dmix->slave_appl_ptr %= dmix->slave_boundary;
	dmix_down_sem(dmix);
	for (;;) {
		transfer = size;
		if (appl_ptr + transfer > pcm->buffer_size)
			transfer = pcm->buffer_size - appl_ptr;
		if (slave_appl_ptr + transfer > dmix->slave_buffer_size)
			transfer = dmix->slave_buffer_size - slave_appl_ptr;
		mix_areas(dmix, src_areas, dst_areas, appl_ptr, slave_appl_ptr, transfer);
		size -= transfer;
		if (! size)
			break;
		slave_appl_ptr += transfer;
		slave_appl_ptr %= dmix->slave_buffer_size;
		appl_ptr += transfer;
		appl_ptr %= pcm->buffer_size;
	}
	dmix_up_sem(dmix);
}