Refactor src/synth.c

Changes:

    * Implement xas_synth type to consolidate synthesiser
      implementation and different tone generator types

    * Refactor examples/ code to remove duplicate synthesiser code

1 files changed, 37 insertions, 11 deletions

diff --git a/include/xas/synth.h b/include/xas/synth.h
index 20446cd..53f3343 100644
--- a/include/xas/synth.h
+++ b/include/xas/synth.h
@@ -6,23 +6,49 @@
 
 #include <xas/audio.h>
 
-typedef struct _xas_synth xas_synth;
+#define XAS_SYNTH_DEFAULT_FREQUENCY 2600 /* Hz */
 
-typedef int16_t (*xas_synth_callback_sample)(xas_synth *synth, void *ctx);
+enum xas_synth_type {
+    XAS_SYNTH_SINE,
+    XAS_SYNTH_SQUARE,
+    XAS_SYNTH_TRIANGLE,
+    XAS_SYNTH_SAWTOOTH
+};
 
-typedef void (*xas_synth_callback_cleanup)(xas_synth *synth, void *ctx);
+enum xas_synth_state {
+    XAS_SYNTH_IDLE,
+    XAS_SYNTH_ACTIVE
+};
+
+typedef struct _xas_synth xas_synth;
+
+typedef int16_t (*xas_synth_sample_callback)(xas_synth *synth);
 
 struct _xas_synth {
+    enum xas_synth_type  type;
+    enum xas_synth_state state;
+
     xas_audio_format format;
-    xas_synth_callback_sample  sample;
-    xas_synth_callback_cleanup cleanup;
-    void *ctx;
+    size_t buffer_size;
+
+    xas_synth_sample_callback sample;
+
+    float phase;
+    size_t frequency;
 };
 
-xas_audio_stream *xas_synth_new(xas_synth_callback_sample  sample,
-                                    xas_synth_callback_cleanup cleanup,
-                                    xas_audio_format format,
-                                    size_t buffer_size,
-                                    void *ctx);
+xas_synth *xas_synth_new(xas_audio_format format,
+                             size_t buffer_size,
+                             enum xas_synth_type type);
+
+void xas_synth_destroy(xas_synth *synth);
+
+void xas_synth_set_frequency(xas_synth *synth, size_t frequency);
+
+void xas_synth_start(xas_synth *synth);
+
+void xas_synth_stop(xas_synth *synth);
+
+xas_audio_stream *xas_synth_new_stream(xas_synth *synth);
 
 #endif /* _XAS_SYNTH_H */