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#include <AK/BufferStream.h>
#include <LibCore/CThread.h>
#include <limits>
#include "ASMixer.h"
ASMixer::ASMixer()
: m_device("/dev/audio")
{
if (!m_device.open(CIODevice::WriteOnly)) {
dbgprintf("Can't open audio device: %s\n", m_device.error_string());
return;
}
CThread sound_thread([](void* context) -> int {
ASMixer* mixer = (ASMixer*)context;
mixer->mix();
return 0;
}, this);
}
void ASMixer::queue(ASClientConnection&, const ABuffer& buffer)
{
ASSERT(buffer.size_in_bytes());
CLocker lock(m_lock);
m_pending_mixing.append(ASMixerBuffer(buffer));
}
void ASMixer::mix()
{
Vector<ASMixerBuffer> active_mix_buffers;
for (;;) {
{
CLocker lock(m_lock);
for (const auto& buf : m_pending_mixing)
active_mix_buffers.append(buf);
m_pending_mixing.clear();
}
// ### use a wakeup of some kind rather than this garbage
if (active_mix_buffers.size() == 0) {
// nothing to mix yet
usleep(10000);
continue;
}
int max_size = 0;
for (auto& buffer : active_mix_buffers) {
if (buffer.done)
continue;
ASSERT(buffer.buffer->size_in_bytes()); // zero sized buffer? how?
max_size = max(max_size, buffer.buffer->size_in_bytes() - buffer.pos);
}
// ### clear up 'done' buffers more aggressively
if (max_size == 0) {
active_mix_buffers.clear();
continue;
}
max_size = min(1023, max_size);
Vector<ASample> mixed_buffer;
mixed_buffer.resize(max_size);
// Mix the buffers together into the output
for (auto& buffer : active_mix_buffers) {
if (buffer.done)
continue;
auto& samples = buffer.buffer->samples();
for (int i = 0; i < max_size && buffer.pos < samples.size(); ++buffer.pos, ++i) {
auto& mixed_sample = mixed_buffer[i];
mixed_sample += samples[buffer.pos];
}
// clear it later
if (buffer.pos == samples.size())
buffer.done = true;
}
// output the mixed stuff to the device
// max_size is 0 indexed, so add 1.
const int output_buffer_byte_size = (max_size + 1) * 2 * 2;
ASSERT(output_buffer_byte_size == 4096);
ByteBuffer buffer(ByteBuffer::create_uninitialized(output_buffer_byte_size));
BufferStream stream(buffer);
for (int i = 0; i < mixed_buffer.size(); ++i) {
auto& mixed_sample = mixed_buffer[i];
mixed_sample.clamp();
i16 out_sample;
out_sample = mixed_sample.left * std::numeric_limits<i16>::max();
stream << out_sample;
ASSERT(!stream.at_end()); // we should have enough space for both channels in one buffer!
out_sample = mixed_sample.right * std::numeric_limits<i16>::max();
stream << out_sample;
ASSERT(!stream.at_end());
}
if (stream.offset() != 0) {
buffer.trim(stream.offset());
m_device.write(buffer);
mixed_buffer.resize(0);
}
}
}
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