Add preliminary JACK support

Add preliminary support for the JACK Audio Connection Kit.
Code needs to be heavily cleaned up and checked, this is just to establish
a first working configuration.

glava/jack_input.c

@@ -0,0 +1,201 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <math.h>
+#include <time.h>
+#include <string.h>
+#include <errno.h>
+#include <poll.h>
+
+#include <jack/jack.h>
+
+#include "fifo.h"
+
+
+/* glava backend */
+struct audio_data* audio;
+int buffer_steps;
+int buffer_offset;
+
+
+/* Resampling buffer */
+//When enough JACK samples to fill another glava buffer frame are summed,
+//the current sample_sum_* is appended to frames_*[frame_index]
+double sample_sum_1, sample_sum_2;
+float sample_counter;
+
+float sample_sz_ratio = 93.75f;
+
+int frame_index;
+int LIMIT;
+
+
+/* JACK backend */
+const int glava_sample_rate = 22050;
+const int JACK_sample_rate = 96000;
+jack_port_t *input_port1, *input_port2;
+jack_client_t* client;
+
+void updateBuffer(float frames_l[], float frames_r[]) {
+    float* bl = (float*) audio->audio_out_l;
+    float* br = (float*) audio->audio_out_r;
+
+    pthread_mutex_lock(&audio->mutex);
+
+    //Shift buffers:
+    memmove(bl, &bl[buffer_steps], buffer_offset * sizeof(float));
+    memmove(br, &br[buffer_steps], buffer_offset * sizeof(float));
+
+    //Append samples from frames_l and frames_r:
+    float blockSum = 0.0f;
+    for (int i = 0; i < buffer_steps; i++) {
+        blockSum += frames_l[i];
+    }
+
+    for (int frame = 0; frame < buffer_steps; frame++) {
+        bl[buffer_offset + frame] = frames_l[frame];
+        br[buffer_offset + frame] = frames_r[frame];
+    }
+
+    float checkSum = 0.0f;
+    for (int i = 0; i < buffer_steps; i++) {
+        checkSum += bl[buffer_offset + i];
+    }
+    //fprintf(stdout, "[DEBUG] Copied data from frames_l to glava buffers; block sum: %f, check sum: %f.\n", blockSum, checkSum);
+
+
+    frame_index = 0;
+
+    audio->modified = true;
+    pthread_mutex_unlock(&audio->mutex);
+}
+
+int process (jack_nframes_t nframes, void *arg) {
+    double *frames_l = (double*)arg;
+    //TODO: double *frames_r = frames_l;
+
+    float* samples1 = (jack_default_audio_sample_t*)jack_port_get_buffer (input_port1, nframes);
+	float* samples2 = (jack_default_audio_sample_t*)jack_port_get_buffer (input_port2, nframes);
+
+    //Try to resample from JACK sample rate to glava sample rate
+    //TODO: find a proper resampling algorithm
+
+    /*for (int frame = 0; frame < nframes; frame++) {
+        sample_sum_1 += *samples1;
+        sample_sum_2 += *samples2;
+        sample_counter++;
+
+        if (sample_counter >= sample_sz_ratio) {
+            if (frame_index >= LIMIT) {
+                frame_index = LIMIT - 1;
+                fprintf(stderr, "Dear god, frame_index was %d while limit is %d!\n", frame_index, LIMIT);
+            }
+            frames_l[frame_index] = sample_sum_1 / sample_counter;
+            //TODO: frames_r[frame_index] = sample_sum_2 / sample_counter;
+
+            sample_sum_1 = 0.0;
+            sample_sum_2 = 0.0;
+
+            if(++frame_index >= buffer_steps) {
+                //TODO: Swap frames_l for frames_r
+                updateBuffer(frames_l, frames_l);
+            }
+
+            sample_counter -= sample_sz_ratio;
+        }
+    }*/
+
+    updateBuffer(samples1, samples2);
+
+    return 0;
+}
+
+void jack_shutdown (void *arg) {
+    //DO SOMETHING HERE?
+    printf ("jack_shutdown() called.\n");
+}
+
+static void init(struct audio_data* audio) {
+    printf ("[DEBUG] init() called.\n");
+    if (!audio->source) {
+        audio->source = strdup("/tmp/mpd.fifo");
+    }
+
+    const char *client_name = "glava";
+    const char *server_name = NULL;
+    jack_options_t options = JackNullOption;
+    jack_status_t status;
+    client = jack_client_open (client_name, options, &status, server_name);
+
+    if (client == NULL) {
+		fprintf (stderr, "jack_client_open() failed, status = 0x%2.0x\n", status);
+		if (status & JackServerFailed) {
+			printf ("Unable to connect to JACK server!\n");
+		}
+		exit (1);
+	}
+	if (status & JackServerStarted) {
+		fprintf (stdout, "JACK server started\n");
+	}
+	if (status & JackNameNotUnique) {
+		client_name = jack_get_client_name(client);
+		fprintf (stderr, "Unique name '%s' assigned!\n", client_name);
+	}
+
+    jack_on_shutdown (client, jack_shutdown, 0);
+
+    input_port1 = jack_port_register (client, "input1", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
+    input_port2 = jack_port_register (client, "input2", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0);
+    
+    if ((input_port1 == NULL) || (input_port2 == NULL)) {
+        fprintf (stderr, "No more JACK ports available!\n");
+        exit (1);
+    }
+    printf ("[DEBUG] init() finished.\n");
+}
+
+static void* entry(void* data) {
+    printf ("[DEBUG] entry() called.\n");
+    audio = (struct audio_data *) data;
+
+    size_t buffer_sz = audio->audio_buf_sz;
+    size_t glava_sample_sz = audio->sample_sz;
+    sample_sz_ratio = ((float)JACK_sample_rate) / glava_sample_rate;
+
+    //How many samples the buffer will shift each update:
+    //TODO: buffer_steps = glava_sample_sz / 4;
+    buffer_steps = 64;
+    buffer_offset = buffer_sz - buffer_steps;
+
+    fprintf(stdout, "Buffer size: '%d', Sample size: '%d'\n", buffer_sz, glava_sample_sz);
+ 
+    double frames_l[buffer_steps];
+    //TODO: Clean all of this up...
+    double *frames_r = frames_l;
+    LIMIT = buffer_steps;
+
+    jack_set_process_callback (client, process, frames_l);
+    printf ("[DEBUG] trying to activate client...\n");
+    if (jack_activate (client)) {
+        fprintf (stderr, "Cannot activate client!\n");
+        exit (1);
+    }
+    
+    while (true) {
+        sleep(1);
+
+        if (audio->terminate == 1) {
+            break;
+        }
+    }
+
+    jack_client_close (client);
+    printf ("[DEBUG] entry() finished.\n");
+    return 0;
+}
+
+AUDIO_ATTACH(jack);

glava/jack_input.h

@@ -0,0 +1,7 @@
+
+#ifndef JACK_INPUT_H
+#define JACK_INPUT_H
+
+#include "fifo.h"
+
+#endif

meson.build

@@ -25,7 +25,8 @@ glava_dependencies = [
   cc.find_library('dl'),
   cc.find_library('m'),
   cc.find_library('X11'),
-  cc.find_library('Xext')
+  cc.find_library('Xext'),
+  cc.find_library('jack')
 ]
 
 if cc.get_id() == 'clang'