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/* ------------------------------------------------------------------
* Copyright (C) 2011 Martin Storsjo
* Copyright (C) 2013,2014 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.
* -------------------------------------------------------------------
*/
#ifndef __ALSA_H_
#define __ALSA_H_
#include <cstdio>
#include <stdint.h>
#include <string>
#include <alsa/asoundlib.h>
#include <boost/thread/thread.hpp>
#include "SampleQueue.h"
using namespace std;
// 16 bits per sample is fine for now
#define BYTES_PER_SAMPLE 2
// How many samples we insert into the queue each call
#define NUM_SAMPLES_PER_CALL 10 // 10 samples @ 32kHz = 3.125ms
class AlsaInput
{
public:
AlsaInput(const string& alsa_dev,
unsigned int channels,
unsigned int rate,
SampleQueue<uint8_t>& queue) :
m_running(false),
m_alsa_dev(alsa_dev),
m_channels(channels),
m_rate(rate),
m_queue(queue),
m_alsa_handle(NULL) { }
~AlsaInput()
{
if (m_running) {
m_running = false;
m_thread.interrupt();
m_thread.join();
}
if (m_alsa_handle) {
snd_pcm_abort(m_alsa_handle);
m_alsa_handle = NULL;
}
}
int prepare();
int start();
private:
AlsaInput(const AlsaInput& other) : m_queue(other.m_queue) {}
size_t read(uint8_t* buf, snd_pcm_uframes_t length);
void process();
bool m_running;
boost::thread m_thread;
string m_alsa_dev;
unsigned int m_channels;
unsigned int m_rate;
SampleQueue<uint8_t>& m_queue;
snd_pcm_t *m_alsa_handle;
};
#endif
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