size_t write(void const *src, size_t len)
{
size_t const avail = write_avail();
if (avail == 0) return 0;
size_t const limit_len = len > avail ? avail : len;
size_t const total = wpos + len;
size_t first, rest;
if (total > CAPACITY) {
first = CAPACITY - wpos;
rest = total % CAPACITY;
} else {
first = limit_len;
rest = 0;
}
Genode::memcpy(&_data[wpos], src, first);
wpos = (wpos + first) % CAPACITY;
if (rest) {
Genode::memcpy(&_data[wpos], ((char const*)src) + first, rest);
wpos = (wpos + rest) % CAPACITY;
}
return limit_len;
}
static void dsound_thread(void *data)
{
DWORD write_ptr;
dsound_t *ds = (dsound_t*)data;
SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);
get_positions(ds, NULL, &write_ptr);
write_ptr = (write_ptr + ds->buffer_size / 2) % ds->buffer_size;
while (ds->thread_alive)
{
struct audio_lock region;
DWORD read_ptr, avail, fifo_avail;
get_positions(ds, &read_ptr, NULL);
avail = write_avail(read_ptr, write_ptr, ds->buffer_size);
EnterCriticalSection(&ds->crit);
fifo_avail = fifo_read_avail(ds->buffer);
LeaveCriticalSection(&ds->crit);
if (avail < CHUNK_SIZE || ((fifo_avail < CHUNK_SIZE) && (avail < ds->buffer_size / 2)))
{
/* No space to write, or we don't have data in our fifo,
* but we can wait some time before it underruns ... */
/* We could opt for using the notification interface,
* but it is not guaranteed to work, so use high
* priority sleeping patterns.
*/
retro_sleep(1);
continue;
}
if (!grab_region(ds, write_ptr, ®ion))
{
ds->thread_alive = false;
SetEvent(ds->event);
break;
}
if (fifo_avail < CHUNK_SIZE)
{
/* Got space to write, but nothing in FIFO (underrun),
* fill block with silence. */
memset(region.chunk1, 0, region.size1);
memset(region.chunk2, 0, region.size2);
release_region(ds, ®ion);
write_ptr = (write_ptr + region.size1 + region.size2) % ds->buffer_size;
}
else
{
/* All is good. Pull from it and notify FIFO. */
EnterCriticalSection(&ds->crit);
if (region.chunk1)
fifo_read(ds->buffer, region.chunk1, region.size1);
if (region.chunk2)
fifo_read(ds->buffer, region.chunk2, region.size2);
LeaveCriticalSection(&ds->crit);
release_region(ds, ®ion);
write_ptr = (write_ptr + region.size1 + region.size2) % ds->buffer_size;
SetEvent(ds->event);
}
}
ExitThread(0);
}
size_t FifoBuffer<T, Container>::write(const T* in, size_t num_elems)
{
size_t write_amount = num_elems > write_avail() ? write_avail() : num_elems;
m_container.insert(m_container.end(), in, in + write_amount);
return write_amount;
}