Add psgplay_digital_to_stereo_callback

frno7 · Sep 11, 2022 · 5aee9e3 · 5aee9e3
1 parent 4b81c6a
commit 5aee9e3
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Showing 3 changed files with 52 additions and 2 deletions.
diff --git a/include/psgplay/stereo.h b/include/psgplay/stereo.h
@@ -34,4 +34,36 @@ struct psgplay_stereo {
 ssize_t psgplay_read_stereo(struct psgplay *pp,
 	struct psgplay_stereo *buffer, size_t count);
 
+/**
+ * psgplay_digital_to_stereo_cb - callback type to transform digital samples
+ * 	into stereo samples
+ * @stereo: stereo samples
+ * @digital: digital samples
+ * @count: number of stereo samples to transform into digital samples
+ * @arg: argument supplied to psgplay_digital_to_stereo_callback()
+ */
+typedef void (*psgplay_digital_to_stereo_cb)(
+	struct psgplay_stereo *stereo, const struct psgplay_digital *digital,
+	size_t count, void *arg);
+
+/**
+ * psgplay_digital_to_stereo_linear - linear stereo mix of digital samples
+ * @stereo: stereo samples
+ * @digital: digital samples
+ * @count: number of stereo samples to transform into digital samples
+ * @arg: ignored, can be %NULL
+ */
+void psgplay_digital_to_stereo_linear(struct psgplay_stereo *stereo,
+	const struct psgplay_digital *digital, size_t count, void *arg);
+
+/**
+ * psgplay_digital_to_stereo_callback - invoke callback to transform digital
+ * 	samples into stereo samples
+ * @pp: PSG play object
+ * @cb: callback
+ * @arg: optional argument supplied to @cb, can be %NULL
+ */
+void psgplay_digital_to_stereo_callback(struct psgplay *pp,
+	const psgplay_digital_to_stereo_cb cb, void *arg);
+
 #endif /* PSGPLAY_STEREO_H */
diff --git a/lib/psgplay/Makefile b/lib/psgplay/Makefile
@@ -58,6 +58,8 @@ LIBPSGPLAY_WEB_FUNCTIONS =						\
 	_psgplay_init							\
 	_psgplay_read_stereo						\
 	_psgplay_read_digital						\
+	_psgplay_digital_to_stereo_callback				\
+	_psgplay_digital_to_stereo_linear				\
 	_psgplay_free							\
 	_ice_identify							\
 	_ice_crunched_size						\

diff --git a/lib/psgplay/psgplay.c b/lib/psgplay/psgplay.c
@@ -55,6 +55,11 @@ struct psgplay {
 		} lowpass;
 	} downsample;
 
+	struct {
+		psgplay_digital_to_stereo_cb cb;
+		void *arg;
+	} digital_to_stereo_callback;
+
 	const struct machine *machine;
 
 	struct {
@@ -207,7 +212,7 @@ static s16 psg_dac(const u8 level)
 	return (level < 16 ? dac[level] : 0xffff) - 0x8000;
 }
 
-static void digital_to_stereo(struct psgplay_stereo *stereo,
+void psgplay_digital_to_stereo_linear(struct psgplay_stereo *stereo,
 	const struct psgplay_digital *digital, size_t count, void *arg)
 {
 	for (size_t i = 0; i < count; i++) {
@@ -226,6 +231,13 @@ static void digital_to_stereo(struct psgplay_stereo *stereo,
 	}
 }
 
+void psgplay_digital_to_stereo_callback(struct psgplay *pp,
+	const psgplay_digital_to_stereo_cb cb, void *arg)
+{
+	pp->digital_to_stereo_callback.cb = cb;
+	pp->digital_to_stereo_callback.arg = arg;
+}
+
 static size_t stereo_downsample(struct psgplay_stereo *resample,
 	const struct psgplay_stereo *stereo, size_t count, void *arg)
 {
@@ -258,7 +270,8 @@ static void digital_to_stereo_downsample(struct psgplay *pp,
 	while (i < count && !pp->errno_) {
 		const size_t n = min(count - i, ARRAY_SIZE(stereo));
 
-		digital_to_stereo(stereo, &digital[i], n, NULL);
+		pp->digital_to_stereo_callback.cb(stereo, &digital[i], n,
+			pp->digital_to_stereo_callback.arg);
 
 		const size_t r = stereo_downsample(
 			resample, stereo, n, &pp->downsample);
@@ -340,6 +353,9 @@ struct psgplay *psgplay_init(const void *data, size_t size,
 	pp->machine = &atari_st;
 	pp->machine->init(data, size, offset, &regs, &ports);
 
+	psgplay_digital_to_stereo_callback(pp,
+		psgplay_digital_to_stereo_linear, NULL);
+
 	return pp;
 }