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/* ------------------------------------------------------------------
* Copyright (C) 2011 Martin Storsjo
* Copyright (C) 2017 Matthias P. Braendli
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
/*! \file AlsaInput.h
*
* This input uses libasound to get audio data.
*/
#pragma once
#include "config.h"
#if HAVE_ALSA
#include <cstdio>
#include <string>
#include <thread>
#include <atomic>
#include <alsa/asoundlib.h>
#include "SampleQueue.h"
#include "common.h"
#include "InputInterface.h"
/*! Common functionality for the direct alsa input and the
* threaded alsa input. The threaded one is used for
* drift compensation.
*/
class AlsaInput : public InputInterface
{
public:
AlsaInput(const std::string& alsa_dev,
unsigned int channels,
unsigned int rate,
SampleQueue<uint8_t>& queue) :
m_alsa_dev(alsa_dev),
m_channels(channels),
m_rate(rate),
m_queue(queue) { }
AlsaInput(const AlsaInput& other) = delete;
AlsaInput& operator=(const AlsaInput& other) = delete;
virtual ~AlsaInput();
protected:
/* Read from the ALSA device. Returns number of samples,
* or -1 in case of error
*/
ssize_t m_read(uint8_t* buf, snd_pcm_uframes_t length);
/* Open the ALSA device and set it up */
void m_init_alsa(void);
std::string m_alsa_dev;
unsigned int m_channels;
unsigned int m_rate;
SampleQueue<uint8_t>& m_queue;
snd_pcm_t *m_alsa_handle = nullptr;
};
class AlsaInputDirect : public AlsaInput
{
public:
AlsaInputDirect(const std::string& alsa_dev,
unsigned int channels,
unsigned int rate,
SampleQueue<uint8_t>& queue) :
AlsaInput(alsa_dev, channels, rate, queue) { }
virtual void prepare(void) override;
virtual bool fault_detected(void) const override { return false; };
virtual bool read_source(size_t num_bytes) override;
/*! Read length Bytes from from the alsa device.
* length must be a multiple of channels * bytes_per_sample.
*
* \return the number of bytes read.
*/
ssize_t read(uint8_t* buf, size_t length);
};
class AlsaInputThreaded : public AlsaInput
{
public:
AlsaInputThreaded(const std::string& alsa_dev,
unsigned int channels,
unsigned int rate,
SampleQueue<uint8_t>& queue) :
AlsaInput(alsa_dev, channels, rate, queue),
m_fault(false),
m_running(false) { }
virtual ~AlsaInputThreaded()
{
if (m_running) {
m_running = false;
m_thread.join();
}
}
/*! Start the ALSA thread that fills the queue */
virtual void prepare(void) override;
virtual bool fault_detected(void) const override { return m_fault; };
virtual bool read_source(size_t num_bytes) override;
private:
void process();
std::atomic<bool> m_fault;
std::atomic<bool> m_running;
std::thread m_thread;
};
#endif // HAVE_ALSA
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