From bef7ae60a51a6b3841032a4cd74d603c0c6dff43 Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phcoder@google.com>
Date: Fri, 1 Nov 2019 17:06:08 +0100
Subject: [PATCH] Encapsulate SDL-sound code into separate file

---
 Makefile   |   4 +-
 sdlsound.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++
 sound.c    | 117 ++++++++---------------------------------------------
 3 files changed, 127 insertions(+), 103 deletions(-)
 create mode 100644 sdlsound.c

diff --git a/Makefile b/Makefile
index c498c71..0f501c5 100644
--- a/Makefile
+++ b/Makefile
@@ -49,11 +49,11 @@ UTILS = maketape readtape
 SRCS =	access.c boot.c branch.c conf.c covox.c double.c ea.c itab.c \
 	main.c service.c ui.c scr-sdl.c scr.c timer.c tape.c disk.c mouse.c printer.c \
 	single.c weird.c tty.c io.c timing.c sound.c disas.c serial.c bkplip.c \
-	terakdisk.c synth.c emu2149.c sdltty.c
+	terakdisk.c synth.c emu2149.c sdlsound.c sdltty.c
 OBJS =	access.o boot.o branch.o conf.o covox.o double.o ea.o itab.o icon.o \
 	main.o service.o ui.o scr-sdl.o scr.o timer.o tape.o disk.o mouse.o printer.o \
 	single.o weird.o tty.o io.o timing.o sound.o disas.o serial.o bkplip.o \
-	terakdisk.o synth.o emu2149.o sdltty.o
+	terakdisk.o synth.o emu2149.o sdlsound.o sdltty.o
 INCS =	defines.h scr.h conf.h emu2149.h emutypes.h
 USRCS = readtape.c maketape.c pngtorgba.c
 TEXTS =	README.html configure.in icon.c
diff --git a/sdlsound.c b/sdlsound.c
new file mode 100644
index 0000000..0f8b683
--- /dev/null
+++ b/sdlsound.c
@@ -0,0 +1,109 @@
+#include "defines.h"
+#include "conf.h"
+#include <SDL/SDL.h>
+#include <SDL/SDL_thread.h>
+#include <SDL/SDL_mutex.h>
+#include <libintl.h>
+#define _(String) gettext (String)
+
+//#define SOUND_EXPONENT	(8+io_sound_freq/20000)
+//#define SOUND_BUFSIZE   (1<<SOUND_EXPONENT)		/* about 1/43 sec */
+#define SOUND_BUFSIZE 512
+
+#define NUMBUF 2
+
+typedef struct {
+	short * buf;
+	unsigned int ptr;
+} sound_buf_t;
+
+sound_buf_t sound_buf[NUMBUF];
+unsigned io_sound_bufsize;
+
+int cur_buf;
+
+static SDL_sem * sem;
+
+static void callback(void * dummy, Uint8 * outbuf, int len)
+{
+	int i;
+	static int cur_out_buf;
+	if (SDL_SemValue(sem) == NUMBUF) {
+		// Underflow: TODO fill the buffer with silence
+		// fprintf(stderr, "!");
+		return;
+	}
+	memcpy(outbuf, sound_buf[cur_out_buf].buf, len);
+	cur_out_buf = (cur_out_buf + 1) % NUMBUF;
+	SDL_SemPost(sem);
+}
+
+static void sound_finish() {
+	/* release the write thread so it can terminate */
+	SDL_PauseAudio(1); 
+	SDL_DestroySemaphore(sem);
+}
+
+static SDL_AudioSpec desired;
+
+void platform_sound_flush() {
+	if (sound_buf[cur_buf].ptr != 0) {
+		SDL_SemWait(sem);
+		sound_buf[cur_buf].ptr = 0;
+		cur_buf = (cur_buf + 1) % NUMBUF;
+	}
+}
+
+void sound_write_sample(short val) {
+	short * p = &sound_buf[cur_buf].buf[sound_buf[cur_buf].ptr++];
+	if (sound_buf[cur_buf].buf == NULL)
+	  return;
+	*p = val;
+	if (io_sound_bufsize == sound_buf[cur_buf].ptr) {
+		platform_sound_flush();
+	}
+}
+
+void sound_discard() {
+	sound_buf[cur_buf].ptr = 0;
+}
+
+void platform_sound_init() {
+	int iarg, i;
+
+	if (fullspeed) {
+		io_max_sound_age = 2 * SOUND_BUFSIZE;
+		/* otherwise UINT_MAX */
+	}
+
+	fprintf(stderr, _("sound_init called\n"));
+
+	if (-1 == SDL_InitSubSystem(SDL_INIT_AUDIO)) {
+		fprintf(stderr, _("Failed to initialize audio subsystem\n"));
+	}
+
+	desired.format = 16;
+	desired.channels = 1;
+	desired.freq = io_sound_freq;
+	desired.samples = io_sound_bufsize = SOUND_BUFSIZE;
+	desired.callback = callback;
+	if (-1 == SDL_OpenAudio(&desired, 0)) {
+		fprintf(stderr, _("Failed to initialize sound, freq %d, %d samples\n"), io_sound_freq, SOUND_BUFSIZE);
+		nflag = 0;
+		return;
+	}
+
+	sem = SDL_CreateSemaphore(NUMBUF);
+
+	for (i = 0; i < NUMBUF; i++) {
+		sound_buf[i].ptr = 0;
+		sound_buf[i].buf = malloc(io_sound_bufsize * sizeof(short));
+	}
+	if (!sound_buf[NUMBUF-1].buf) {
+		fprintf(stderr, _("Failed to allocate sound buffers\n"));
+		exit(1);
+	}
+
+	atexit(sound_finish);
+	SDL_PauseAudio(0);
+}
diff --git a/sound.c b/sound.c
index 564b1e4..a2e36f0 100644
--- a/sound.c
+++ b/sound.c
@@ -1,131 +1,46 @@
 #include "defines.h"
+#include "conf.h"
 #include <stdio.h>
-#include <SDL/SDL.h>
-#include <SDL/SDL_thread.h>
-#include <SDL/SDL_mutex.h>
-#include <libintl.h>
-#define _(String) gettext (String)
+#include "intl.h"
 
-#define SOUND_EXPONENT	(8+io_sound_freq/20000)
-//#define SOUND_BUFSIZE   (1<<SOUND_EXPONENT)		/* about 1/43 sec */
-#define SOUND_BUFSIZE 512
 #define MAX_SOUND_AGE	~0	/* always play */ 
 
-unsigned io_sound_bufsize,
-	io_sound_freq = 11025;
-
-typedef struct {
-	short * buf;
-	unsigned int ptr;
-} sound_buf_t;
-
-#define NUMBUF 2
-
-sound_buf_t sound_buf[NUMBUF];
-
-SDL_sem * sem;
- 
-int cur_buf;
-
-void callback(void * dummy, Uint8 * outbuf, int len)
-{
-	int i;
-	static int cur_out_buf;
-	if (SDL_SemValue(sem) == NUMBUF) {
-		// Underflow: TODO fill the buffer with silence
-		// fprintf(stderr, "!");
-		return;
-	}
-	memcpy(outbuf, sound_buf[cur_out_buf].buf, len);
-	cur_out_buf = (cur_out_buf + 1) % NUMBUF;
-	SDL_SemPost(sem);
-}
+unsigned io_sound_freq = 44100;
 
 /* Called after every instruction */
 void sound_flush() {
-	int i;
 	if (fullspeed && io_sound_age >= io_max_sound_age && covox_age >= io_max_sound_age) {
-		if (sound_buf[cur_buf].ptr != 0) 
-		{
-			SDL_SemWait(sem);
-			sound_buf[cur_buf].ptr = 0;
-			cur_buf = (cur_buf + 1) % NUMBUF;
-		}
+		platform_sound_flush();
 		return;
 	}
 	while (ticks >= io_sound_count) {
-		short * p = &sound_buf[cur_buf].buf[sound_buf[cur_buf].ptr++];
 		if (io_sound_age < 1000)
-			*p = io_sound_val + covox_val << 4;
+			sound_write_sample (io_sound_val + covox_val << 4);
 		else
-			*p = (covox_val << 4) + synth_next();
-		io_sound_count += io_sound_pace;
+			sound_write_sample ((covox_val << 4) + synth_next());
 		io_sound_age++;
-		covox_age++;
-		if (io_sound_bufsize == sound_buf[cur_buf].ptr ||
-			io_sound_age == io_max_sound_age) {
-			SDL_SemWait(sem);
-			sound_buf[cur_buf].ptr = 0;
-			cur_buf = (cur_buf + 1) % NUMBUF;
-			
+		if (io_sound_age == io_max_sound_age) {
+			platform_sound_flush();
 		}
+		covox_age++;
+		io_sound_count += io_sound_pace;
 	}
 }
 
-void sound_finish() {
-	/* release the write thread so it can terminate */
-	SDL_PauseAudio(1); 
-	SDL_DestroySemaphore(sem);
-}
-
-SDL_AudioSpec desired;
-
 void sound_init() {
-	static init_done = 0;
-	int iarg, i;
-        io_max_sound_age = MAX_SOUND_AGE;
-        io_sound_age = MAX_SOUND_AGE;
-
+	static int init_done = 0;
 	if (!nflag)
 		return;
-	if (fullspeed) {
-		io_max_sound_age = 2 * SOUND_BUFSIZE;
-		/* otherwise UINT_MAX */
-	}
 	if (init_done) {
-		sound_buf[cur_buf].ptr = 0;
 		io_sound_age = io_max_sound_age;
-		return;
-	}
-	fprintf(stderr, _("sound_init called\n"));
-
-	if (-1 == SDL_InitSubSystem(SDL_INIT_AUDIO)) {
-		fprintf(stderr, _("Failed to initialize audio subsystem\n"));
-	}
-
-	desired.format = 16;
-	desired.channels = 1;
-	desired.freq = io_sound_freq;
-	desired.samples = io_sound_bufsize = SOUND_BUFSIZE;
-	desired.callback = callback;
-	if (-1 == SDL_OpenAudio(&desired, 0)) {
-		fprintf(stderr, _("Failed to initialize sound, freq %d, %d samples\n"), io_sound_freq, SOUND_BUFSIZE);
-		nflag = 0;
+		sound_discard();
 		return;
 	}
 
-	io_sound_pace = TICK_RATE/io_sound_freq;
-	sem = SDL_CreateSemaphore(NUMBUF);
+	platform_sound_init();
 
-	for (i = 0; i < NUMBUF; i++) {
-		sound_buf[i].ptr = 0;
-		sound_buf[i].buf = malloc(io_sound_bufsize * sizeof(short));
-	}
-	if (!sound_buf[NUMBUF-1].buf) {
-		fprintf(stderr, _("Failed to allocate sound buffers\n"));
-		exit(1);
-	}
-	atexit(sound_finish);
-	SDL_PauseAudio(0);
+	io_sound_pace = TICK_RATE/(io_sound_freq + 0.0);
+	io_max_sound_age = MAX_SOUND_AGE;
+	io_sound_age = MAX_SOUND_AGE;	/* in io_sound_pace's since last change */
 	init_done = 1;
 }