Implement xas_object

Changes:

    * Implement xas_object as a base "class" for all playback state
      objects; allow implementation of start() and stop() methods to
      control playback

    * Move code for setting gain, bank slot to a new method,
      xas_bank_player_select()

    * Remove code from xas_bank_player_start() setting gain, bank slot

    * Add xas_object header to each monaural playable object

9 files changed, 86 insertions, 19 deletions

diff --git a/examples/say.c b/examples/say.c
index fa16242..c89a245 100644
--- a/examples/say.c
+++ b/examples/say.c
@@ -154,12 +154,14 @@ int main(int argc, char **argv) {
         goto error_bank_record;
     }
 
+    xas_bank_player_select(player, 0, 1.0);
+
     for (i=0; i<duration_frames; i++) {
         void *buf;
         ssize_t readlen;
 
         if (i >= 300 && !xas_bank_player_playing(player)) {
-            xas_bank_player_start(player, 0, 1.0);
+            xas_bank_player_start(player);
         }
 
         if ((readlen = xas_audio_stream_read(mixer->output,
diff --git a/include/xas/bank.h b/include/xas/bank.h
index 33be492..cd1511e 100644
--- a/include/xas/bank.h
+++ b/include/xas/bank.h
@@ -3,6 +3,7 @@
 
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 enum xas_bank_player_status {
@@ -22,6 +23,8 @@ typedef struct _xas_bank {
 } xas_bank;
 
 typedef struct _xas_bank_player {
+    xas_object obj;
+
     xas_bank *bank;
     enum xas_bank_player_status status;
 
@@ -50,9 +53,11 @@ xas_bank_player *xas_bank_player_new(xas_bank *bank);
 
 void xas_bank_player_destroy(xas_bank_player *player);
 
-int xas_bank_player_start(xas_bank_player *player,
-                            size_t entry,
-                            float gain);
+int xas_bank_player_select(xas_bank_player *player,
+                             size_t entry,
+                             float gain);
+
+int xas_bank_player_start(xas_bank_player *player);
 
 int xas_bank_player_stop(xas_bank_player *player);
 
diff --git a/include/xas/object.h b/include/xas/object.h
new file mode 100644
index 0000000..b8b713b
--- /dev/null
+++ b/include/xas/object.h
@@ -0,0 +1,19 @@
+#ifndef _XAS_OBJECT_H
+#define _XAS_OBJECT_H
+
+typedef struct _xas_object xas_object;
+
+typedef int (*xas_object_start_callback)(xas_object *object);
+
+typedef int (*xas_object_stop_callback)(xas_object *object);
+
+struct _xas_object {
+    xas_object_start_callback start;
+    xas_object_stop_callback  stop;
+};
+
+int xas_object_start(xas_object *object);
+
+int xas_object_stop(xas_object *object);
+
+#endif /* _XAS_OBJECT_H */
diff --git a/include/xas/synth.h b/include/xas/synth.h
index 53f3343..61f50bc 100644
--- a/include/xas/synth.h
+++ b/include/xas/synth.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 #define XAS_SYNTH_DEFAULT_FREQUENCY 2600 /* Hz */
@@ -25,6 +26,8 @@ typedef struct _xas_synth xas_synth;
 typedef int16_t (*xas_synth_sample_callback)(xas_synth *synth);
 
 struct _xas_synth {
+    xas_object obj;
+
     enum xas_synth_type  type;
     enum xas_synth_state state;
 
diff --git a/include/xas/vox.h b/include/xas/vox.h
index 5a1cacf..9d63bba 100644
--- a/include/xas/vox.h
+++ b/include/xas/vox.h
@@ -5,6 +5,7 @@
 #include <stdarg.h>
 #include <sys/types.h>
 
+#include <xas/object.h>
 #include <xas/audio.h>
 
 #define XAS_VOX_SETTINGS_TMP_PATH    "/tmp/xas-vox.XXXXXX"
@@ -16,6 +17,8 @@ enum xas_vox_state {
 };
 
 typedef struct _xas_vox {
+    xas_object obj;
+
     xas_audio_format format;
     size_t buffer_size;
 
@@ -66,12 +69,12 @@ int xas_vox_set_parameter_int(xas_vox *vox,
                                 const char *name,
                                 int value);
 
+int xas_vox_generate(xas_vox *vox);
+
 int xas_vox_stop(xas_vox *vox);
 
 int xas_vox_active(xas_vox *vox);
 
-int xas_vox_generate(xas_vox *vox);
-
 int xas_vox_vsayf(xas_vox *vox, const char *message, va_list args);
 
 int xas_vox_sayf(xas_vox *vox, const char *message, ...);
diff --git a/src/bank.c b/src/bank.c
index 1623834..1d1dc3a 100644
--- a/src/bank.c
+++ b/src/bank.c
@@ -125,6 +125,9 @@ xas_bank_player *xas_bank_player_new(xas_bank *bank) {
         goto error_malloc_player;
     }
 
+    player->obj.start = (xas_object_start_callback)xas_bank_player_start;
+    player->obj.stop  = (xas_object_stop_callback)xas_bank_player_stop;
+
     player->bank   = bank;
     player->status = XAS_BANK_PLAYER_STOPPED;
     player->gain   = 0.0f;
@@ -141,16 +144,21 @@ void xas_bank_player_destroy(xas_bank_player *player) {
     free(player);
 }
 
-int xas_bank_player_start(xas_bank_player *player,
-                            size_t entry,
-                            float gain) {
+int xas_bank_player_select(xas_bank_player *player,
+                             size_t entry,
+                             float gain) {
+    player->entry = entry;
+    player->gain  = gain;
+
+    return 0;
+}
+
+int xas_bank_player_start(xas_bank_player *player) {
     if (player->status == XAS_BANK_PLAYER_PLAYING) {
         return 0;
     }
 
     player->status = XAS_BANK_PLAYER_PLAYING;
-    player->gain   = gain;
-    player->entry  = entry;
     player->index  = 0;
 
     return 0;
diff --git a/src/object.c b/src/object.c
new file mode 100644
index 0000000..55ea4af
--- /dev/null
+++ b/src/object.c
@@ -0,0 +1,9 @@
+#include <xas/object.h>
+
+int xas_object_start(xas_object *object) {
+    object->start(object);
+}
+
+int xas_object_stop(xas_object *object) {
+    object->stop(object);
+}
diff --git a/src/synth.c b/src/synth.c
index 86990e8..fddd2a0 100644
--- a/src/synth.c
+++ b/src/synth.c
@@ -99,6 +99,18 @@ static ssize_t synth_fill(xas_synth *synth,
     return count;
 }
 
+static int synth_start(xas_synth *synth) {
+    xas_synth_start(synth);
+
+    return 0;
+}
+
+static int synth_stop(xas_synth *synth) {
+    xas_synth_stop(synth);
+
+    return 0;
+}
+
 xas_synth *xas_synth_new(xas_audio_format format,
                              size_t buffer_size,
                              enum xas_synth_type type) {
@@ -108,6 +120,9 @@ xas_synth *xas_synth_new(xas_audio_format format,
         goto error_malloc_synth;
     }
 
+    synth->obj.start = (xas_object_start_callback)synth_start;
+    synth->obj.stop  = (xas_object_stop_callback)synth_stop;
+
     synth->type      = type;
     synth->state     = XAS_SYNTH_IDLE;
     synth->phase     = 0.0f;
diff --git a/src/vox.c b/src/vox.c
index 6f71e5f..cd31aa0 100644
--- a/src/vox.c
+++ b/src/vox.c
@@ -275,6 +275,9 @@ xas_vox *xas_vox_new_args(xas_audio_format format,
         goto error_malloc_vox;
     }
 
+    vox->obj.start = (xas_object_start_callback)xas_vox_generate;
+    vox->obj.stop  = (xas_object_stop_callback)xas_vox_stop;
+
     vox->text2wave_path = text2wave_path;
 
     vox->format.channels    = XAS_AUDIO_MONO;
@@ -394,14 +397,6 @@ int xas_vox_set_parameter_int(xas_vox *vox,
     return set_parameter_va(vox, name, "%d", value);
 }
 
-int xas_vox_stop(xas_vox *vox) {
-    if (vox->state == XAS_VOX_ACTIVE) {
-        return vox_stop(vox);
-    }
-
-    return 0;
-}
-
 int xas_vox_active(xas_vox *vox) {
     return vox->state == XAS_VOX_ACTIVE;
 }
@@ -435,6 +430,14 @@ error_riff_open_fd:
     return -1;
 }
 
+int xas_vox_stop(xas_vox *vox) {
+    if (vox->state == XAS_VOX_ACTIVE) {
+        return vox_stop(vox);
+    }
+
+    return 0;
+}
+
 int xas_vox_vsayf(xas_vox *vox, const char *format, va_list args) {
     if (vox->state == XAS_VOX_IDLE && vox_start(vox) < 0) {
         goto error_vox_start;