parec_muilti_str.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <pthread.h>

#include <pulse/error.h>
#include <pulse/channelmap.h>
#include <pulse/stream.h>
#include <pulse/context.h>
#include <pulse/mainloop.h>

// thank you https://gist.github.com/toroidal-code/8798775

static char * argv0;
static pa_context * pa_ctx;
static pthread_t p1;
static pthread_t p2;

static int fd1 = -1;
static int fd2 = -1;

/* A simple routine calling UNIX write() in a loop */
static ssize_t loop_write(int fd, const void*data, size_t size) {
    ssize_t ret = 0;

    while (size > 0) {
        ssize_t r;

        if ((r = write(fd, data, size)) < 0)
            return r;

        if (r == 0)
            break;

        ret += r;
        data = (const uint8_t*) data + r;
        size -= (size_t) r;
    }

    return ret;
}

static void pa_die(char const * nam, int e) {
    if (e) {
        fprintf(stderr,"%s() failed: %s\n", nam, pa_strerror(e));
        _exit(1);
    }
}

static void on_read(pa_stream *p, size_t len, void *user_data) {

    int fd = *(int*)user_data;
    void const * buf;
    // it seems that incoming len is pointless.
    pa_die("pa_stream_peek", pa_stream_peek(p, &buf, &len));
    if (len) {
        if (buf) {
            loop_write(fd, buf, len);
        } else {
            // hole
            unsigned char buf2[len];
            memset(buf2, 0, len);
            loop_write(fd, buf2, len);
        }
        pa_die("pa_stream_drop", pa_stream_drop(p));
    }

}

static void start_stream(char const * file, int * fd) {

    static const pa_sample_spec ss = {
            .format = PA_SAMPLE_S16LE,
            .rate = 44100,
            .channels = 2
    };
    pa_stream * s;

    pa_channel_map cm;

    pa_channel_map_init_stereo(&cm);

    if (!pa_channel_map_valid(&cm)) {
        printf("channel map not valid\n");
        _exit(1);
    }

    if (!(s = pa_stream_new(pa_ctx, file, &ss, &cm))) {
        printf("no new stream\n");
        _exit(1);
    }

    *fd = open(file, O_WRONLY|O_TRUNC|O_CREAT, 0644);
    if (*fd < 0) {
        perror("create");
        _exit(1);
    }

    pa_stream_set_read_callback(s, on_read, fd);
    pa_die("pa_stream_connect_record", pa_stream_connect_record(s, NULL, NULL, PA_STREAM_NOFLAGS));

}

static void on_state(pa_context *c, void *userdata) {

    pa_context_state_t st = pa_context_get_state(c);

    printf("context state %d\n", (int)st);

    if (st == PA_CONTEXT_READY) {
        start_stream("1", &fd1);
        start_stream("2", &fd2);
    }

}

int main(int argc, char*argv[]) {
    /* The sample type to use */

    pa_mainloop * pa_lp = pa_mainloop_new();
    if (!pa_lp) {
        printf("no main loop\n");
        return 1;
    }

    pa_mainloop_api * pa_lp_api = pa_mainloop_get_api(pa_lp);

    pa_ctx = pa_context_new(pa_lp_api, "two");
    if (!pa_ctx) {
        printf("no context\n");
        return 1;
    }

    pa_context_set_state_callback(pa_ctx, on_state, NULL);
    pa_die("pa_context_connect", pa_context_connect(pa_ctx, NULL, PA_CONTEXT_NOFLAGS, NULL));

    int dummy;
    pa_mainloop_run(pa_lp, &dummy);

    return 0;
}