gistfile1.c

#include <stdio.h>
#include <stdio.h>
#include <soundio/soundio.h>
#include <stdlib.h>
#include <string.h>
#include <portaudio.h>

#define NUM_SECONDS   (5)
#define SAMPLE_RATE   (44100)
#define FRAMES_PER_BUFFER  (64)

#ifndef M_PI
#define M_PI  (3.14159265)
#endif

#define TABLE_SIZE   (200)

typedef struct {
    int left_phase;
    int right_phase;
    char message[20];
    float *sine;
}
        paTestData;

static int patestCallback(const void *inputBuffer, void *outputBuffer,
                          unsigned long framesPerBuffer,
                          const PaStreamCallbackTimeInfo *timeInfo,
                          PaStreamCallbackFlags statusFlags,
                          void *userData) {
    paTestData *data = (paTestData *) userData;
    float *out = (float *) outputBuffer;
    unsigned long i;

    (void) timeInfo; /* Prevent unused variable warnings. */
    (void) statusFlags;
    (void) inputBuffer;
    for (i = 0; i < framesPerBuffer; i++) {
        *out++ = data->sine[data->left_phase];  /* left */
        *out++ = data->sine[data->right_phase];  /* right */
        data->left_phase += 1;
        if (data->left_phase >= TABLE_SIZE) data->left_phase -= TABLE_SIZE;
        data->right_phase += 3; /* higher pitch so we can distinguish left and right. */
        if (data->right_phase >= TABLE_SIZE) data->right_phase -= TABLE_SIZE;
    }

    return paContinue;
}

/*
 * This routine is called by portaudio when playback is done.
 */
static void StreamFinished(void *userData) {
    paTestData *data = (paTestData *) userData;
    printf("Stream Completed: %s\n", data->message);
}

/*******************************************************************/
int main(void);

PaError play(int tableSize) {
    PaStreamParameters outputParameters;
    PaStream *stream;
    PaError err;
    paTestData data;
    int i;

    printf("PortAudio Test: output sine wave. SR = %d, BufSize = %d\n", SAMPLE_RATE, FRAMES_PER_BUFFER);

    data.sine = malloc(sizeof(float) * tableSize);

    for (i = 0; i < tableSize; i++) {
        data.sine[i] = (float) sin(((double) i / (double) tableSize) * M_PI * 3.);
    }
    data.left_phase = data.right_phase = 0;

    err = Pa_Initialize();
    if (err != paNoError) goto error;

    outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
    if (outputParameters.device == paNoDevice) {
        fprintf(stderr, "Error: No default output device.\n");
        goto error;
    }
    outputParameters.channelCount = 2;       /* stereo output */
    outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output */
    outputParameters.suggestedLatency = Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;
    outputParameters.hostApiSpecificStreamInfo = NULL;

    err = Pa_OpenStream(
            &stream,
            NULL, /* no input */
            &outputParameters,
            SAMPLE_RATE,
            FRAMES_PER_BUFFER,
            paClipOff,      /* we won't output out of range samples so don't bother clipping them */
            patestCallback,
            &data);
    if (err != paNoError) goto error;

    sprintf(data.message, "No Message");
    err = Pa_SetStreamFinishedCallback(stream, &StreamFinished);
    if (err != paNoError) goto error;

    err = Pa_StartStream(stream);
    if (err != paNoError) goto error;

    printf("Play for %d seconds.\n", NUM_SECONDS);
    Pa_Sleep(NUM_SECONDS * 1000);

    err = Pa_StopStream(stream);
    if (err != paNoError) goto error;

    err = Pa_CloseStream(stream);
    if (err != paNoError) goto error;

    Pa_Terminate();
    printf("Test finished.\n");
    free(data.sine);
    return err;
    error:
    Pa_Terminate();
    fprintf(stderr, "An error occured while using the portaudio stream\n");
    fprintf(stderr, "Error number: %d\n", err);
    fprintf(stderr, "Error message: %s\n", Pa_GetErrorText(err));
    return err;
}

int main(void) {
    play(200);
}