til: add preliminary audio backend

This is an early implementation of something resembling an audio
backend for rototiller/libtil.

The assumption for now is that everything will use signed 16-bit
native-endian stereo output @ 44.1khz.

1 files changed, 39 insertions, 0 deletions

diff --git a/src/til_audio.h b/src/til_audio.h
new file mode 100644
index 0000000..f5640b6
--- /dev/null
+++ b/src/til_audio.h
@@ -0,0 +1,39 @@
+#ifndef _TIL_AUDIO_H
+#define _TIL_AUDIO_H
+
+#include <stdint.h>
+
+typedef struct til_settings_t til_settings_t;
+typedef struct til_setting_t til_setting_t;
+typedef struct til_setting_desc_t til_setting_desc_t;
+typedef struct til_setup_t til_setup_t;
+typedef struct til_audio_context_t til_audio_context_t;
+
+typedef struct til_audio_ops_t {
+	int		(*setup)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
+	int		(*init)(til_setup_t *setup, til_audio_context_t **res_audio_context);
+	void		(*shutdown)(til_audio_context_t *audio_context);
+	void		(*drop)(til_audio_context_t *audio_context);
+	void		(*pause)(til_audio_context_t *audio_context);
+	void		(*unpause)(til_audio_context_t *audio_context);
+	int		(*queue)(til_audio_context_t *audio_context, int16_t *frames, int n_frames);
+	unsigned	(*n_queued)(til_audio_context_t *audio_context);
+} til_audio_ops_t;
+
+typedef struct til_audio_hooks_t {
+	void	(*seeked)(void *hooks_context, const til_audio_context_t *audio_context, unsigned ticks);
+	void	(*paused)(void *hooks_context, const til_audio_context_t *audio_context);
+	void	(*unpaused)(void *hooks_context, const til_audio_context_t *audio_context);
+} til_audio_hooks_t;
+
+int til_audio_open(const til_audio_ops_t *ops, til_setup_t *setup, til_audio_context_t **res_audio_context);
+void til_audio_shutdown(til_audio_context_t *audio_context);
+int til_audio_set_hooks(til_audio_context_t *audio_context, til_audio_hooks_t *hooks, void *hooks_context);
+int til_audio_unset_hooks(til_audio_context_t *audio_context, til_audio_hooks_t *hooks, void *hooks_context);
+int til_audio_queue(til_audio_context_t *audio_context, int16_t *frames, int n_frames);
+unsigned til_audio_n_queued(til_audio_context_t *audio_context);
+void til_audio_seek(til_audio_context_t *audio_context, unsigned ticks);
+void til_audio_pause(til_audio_context_t *audio_context);
+void til_audio_unpause(til_audio_context_t *audio_context);
+
+#endif