overte-HifiExperiments/libraries/shared/src/AudioInjector.cpp

//
//  AudioInjector.cpp
//  hifi
//
//  Created by Stephen Birarda on 4/23/13.
//
//

#include <sys/time.h>
#include <fstream>

#include "SharedUtil.h"
#include "PacketHeaders.h"

#include "AudioInjector.h"

const int BUFFER_LENGTH_BYTES = 512;
const int BUFFER_LENGTH_SAMPLES = BUFFER_LENGTH_BYTES / sizeof(int16_t);
const float SAMPLE_RATE = 22050.0f;
const float BUFFER_SEND_INTERVAL_USECS = (BUFFER_LENGTH_SAMPLES / SAMPLE_RATE) * 1000000;

AudioInjector::AudioInjector(const char* filename) :
    _numTotalBytesAudio(0),
    _bearing(0),
    _attenuationModifier(255)
{
    _position[0] = 0.0f;
    _position[1] = 0.0f;
    _position[2] = 0.0f;
    
    std::fstream sourceFile;
    
    sourceFile.open(filename, std::ios::in | std::ios::binary);
    sourceFile.seekg(0, std::ios::end);
    
    _numTotalBytesAudio = sourceFile.tellg();
    if (_numTotalBytesAudio == -1) {
        printf("Error reading audio data from file %s\n", filename);
        _audioSampleArray = NULL;
    } else {
        printf("Read %d bytes from audio file\n", _numTotalBytesAudio);
        sourceFile.seekg(0, std::ios::beg);
        long sizeOfShortArray = _numTotalBytesAudio / 2;
        _audioSampleArray = new int16_t[sizeOfShortArray];
        
        sourceFile.read((char *)_audioSampleArray, _numTotalBytesAudio);
    }
}

AudioInjector::~AudioInjector() {
    delete[] _audioSampleArray;
}

void AudioInjector::setPosition(float* position) {
    _position[0] = position[0];
    _position[1] = position[1];
    _position[2] = position[2];
}

void AudioInjector::injectAudio(UDPSocket* injectorSocket, sockaddr* destinationSocket) const {
    if (_audioSampleArray != NULL) {
        timeval startTime;
        
        // one byte for header, 3 positional floats, 1 bearing float, 1 attenuation modifier byte
        int leadingBytes = 1 + (sizeof(float) * 4) + 1;
        unsigned char dataPacket[BUFFER_LENGTH_BYTES + leadingBytes];
        
        dataPacket[0] = PACKET_HEADER_INJECT_AUDIO;
        unsigned char *currentPacketPtr = dataPacket + 1;
        
        for (int i = 0; i < 3; i++) {
            memcpy(currentPacketPtr, &_position[i], sizeof(float));
            currentPacketPtr += sizeof(float);
        }
        
        *currentPacketPtr = _attenuationModifier;
        currentPacketPtr++;
        
        memcpy(currentPacketPtr, &_bearing, sizeof(float));
        currentPacketPtr += sizeof(float);
        
        for (int i = 0; i < _numTotalBytesAudio; i += BUFFER_LENGTH_BYTES) {
            gettimeofday(&startTime, NULL);
            
            int numBytesToCopy = BUFFER_LENGTH_BYTES;
            
            if (_numTotalBytesAudio - i < BUFFER_LENGTH_BYTES) {
                numBytesToCopy = _numTotalBytesAudio - i;
                memset(currentPacketPtr + numBytesToCopy, 0, BUFFER_LENGTH_BYTES - numBytesToCopy);
            }
            
            memcpy(currentPacketPtr, _audioSampleArray + (i / 2), numBytesToCopy);
            
            injectorSocket->send(destinationSocket, dataPacket, sizeof(dataPacket));
            
            double usecToSleep = BUFFER_SEND_INTERVAL_USECS - (usecTimestampNow() - usecTimestamp(&startTime));
            if (usecToSleep > 0) {
                usleep(usecToSleep);
            }
        }
    }
}