ao: add option parsing

audio_ao.c

@@ -16,8 +16,42 @@ static void help(void) {
 }
 
 static int init(int argc, char **argv) {
-    printf("ao: init\n");
     ao_initialize();
+    int driver = ao_default_driver_id();
+    ao_option *ao_opts = NULL;
+
+    optind = 0;
+    // some platforms apparently require optreset = 1; - which?
+    char opt, *mid;
+    while ((opt = getopt(argc, argv, "d:i:n:o:")) > 0) {
+        switch (opt) {
+            case 'd':
+                driver = ao_driver_id(optarg);
+                if (!driver)
+                    die("could not find ao driver %s\n", optarg);
+                break;
+            case 'i':
+                ao_append_option(&ao_opts, "id", optarg);
+                break;
+            case 'n':
+                ao_append_option(&ao_opts, "dev", optarg);
+                // Old libao versions (for example, 0.8.8) only support
+                // "dsp" instead of "dev".
+                ao_append_option(&ao_opts, "dsp", optarg);
+                break;
+            case 'o':
+                mid = strchr(optarg, '=');
+                if (!mid)
+                    die("Expected an = in audio option %s\n", optarg);
+                *mid = 0;
+                ao_append_option(&ao_opts, optarg, mid+1);
+                break;
+            default:
+                help();
+                die("Invalid audio option -%c specified\n", opt);
+        }
+    }
+
     ao_sample_format fmt;
     memset(&fmt, 0, sizeof(fmt));
 
@@ -26,8 +60,6 @@ static int init(int argc, char **argv) {
     fmt.channels = 2;
     fmt.byte_format = AO_FMT_NATIVE;
 
-    int driver = ao_default_driver_id();
-
     dev = ao_open_live(driver, &fmt, NULL);
 
     return dev ? 0 : 1;
@@ -39,9 +71,8 @@ static void deinit(void) {
 }
 
 static void start(int sample_rate) {
-    printf("ao: start\n");
     if (sample_rate != 44100)
-        die("unexpceted sample rate!\n");
+        die("unexpected sample rate!\n");
 }
 
 static void play(short buf[], int samples) {