Add cdrom.bgm.c and use it when DRIFILE_BGM exists

This enables BGM playback in the download edition of Daiakuji, where S*
commands are plumbed to the music system (*BA.ald).

CMakeLists.txt

@@ -110,6 +110,7 @@ endif()
 
 # CDROM
 
+list(APPEND SRC_CDROM cdrom.bgm.c)
 if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
   list(APPEND SRC_CDROM cdrom.Linux.c)
   list(APPEND SUMMARY_CDROM "Linux ioctl")

src/ald_manager.c

@@ -36,11 +36,6 @@ static drifiles *dri[DRIFILETYPEMAX];
 /* cache handler for dri file */
 static cacher *cacheid;
 
-/*
- * static maethods
-*/
-static void ald_free(dridata *dfile);
-
 /*
  * free dridata 
  *   dfile: dridata to be free
@@ -109,3 +104,9 @@ void ald_init(int type, const char **file, int cnt, boolean use_mmap) {
 		cacheid = cache_new(ald_free);
 	}
 }
+
+int ald_get_maxno(DRIFILETYPE type) {
+	if (type >= DRIFILETYPEMAX || !dri[type])
+		return 0;
+	return dri[type]->nr_files;
+}

src/ald_manager.h

@@ -38,9 +38,10 @@ typedef enum {
 	DRIFILE_BGM =6   /* stream music data */
 } DRIFILETYPE;
 
-extern void     ald_init(int type, const char **file, int cnt, boolean use_mmap);
-extern dridata *ald_getdata(DRIFILETYPE type, int no);
-extern void     ald_freedata(dridata *data);
+void ald_init(int type, const char **file, int cnt, boolean use_mmap);
+dridata *ald_getdata(DRIFILETYPE type, int no);
+void ald_freedata(dridata *data);
+int ald_get_maxno(DRIFILETYPE type);
 
 #endif /* !__ALD_MANAGER__ */
 

src/cdrom.bgm.c

@@ -0,0 +1,72 @@
+/*
+ * cdrom.bgm.c  CD->bgm bridge
+ *
+ * Copyright (C) 2023 <KichikuouChrome@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <stdio.h>
+
+#include "cdrom.h"
+#include "music.h"
+
+static int current_track;
+
+static int cdrom_bgm_init(char *dev) {
+	return OK;
+}
+
+static int cdrom_bgm_exit(void) {
+	return OK;
+}
+
+static int cdrom_bgm_reset(void) {
+	return OK;
+}
+
+static int cdrom_bgm_start(int trk, int loop) {
+	if (musbgm_play(trk, 0, 100) != OK)
+		return NG;
+	current_track = trk;
+	return OK;
+}
+
+static int cdrom_bgm_stop(void) {
+	return musbgm_stop(current_track, 0);
+}
+
+static int cdrom_bgm_getPlayingInfo(cd_time *info) {
+	int t = musbgm_getpos(current_track);  // in 10ms
+	if (!t)
+		return NG;
+	info->t = current_track;
+	info->m = t / (60*100); t %= (60*100);
+	info->s = t / 100;      t %= 100;
+	info->f = t * CD_FPS / 100;
+	return OK;
+}
+
+cdromdevice_t cdrom_bgm = {
+	cdrom_bgm_init,
+	cdrom_bgm_exit,
+	cdrom_bgm_reset,
+	cdrom_bgm_start,
+	cdrom_bgm_stop,
+	cdrom_bgm_getPlayingInfo,
+	NULL,
+	NULL
+};

src/cdrom.h

@@ -49,6 +49,8 @@ struct _cdromdevice {
 };
 typedef struct _cdromdevice cdromdevice_t;
 
+extern cdromdevice_t cdrom_bgm;
+
 extern cdromdevice_t *cd_init(const char *dev);
 
 #define CD_FPS 75

src/music_cdrom.c

@@ -25,6 +25,7 @@
 #include <string.h>
 
 #include "portab.h"
+#include "ald_manager.h"
 #include "music_private.h"
 #include "music_cdrom.h"
 #include "cdrom.h"
@@ -37,9 +38,14 @@ void muscd_set_devicename(char *name) {
 }
 
 int muscd_init(void) {
-	prv.cddev = cd_init(dev);
-	if (!prv.cddev) {
-		return NG;
+	// In the download edition of Daiakuji, SS command plays music from *BA.ald.
+	if (ald_get_maxno(DRIFILE_BGM) > 0) {
+		prv.cddev = &cdrom_bgm;
+	} else {
+		prv.cddev = cd_init(dev);
+		if (!prv.cddev) {
+			return NG;
+		}
 	}
 	prv.cddev->init(dev);
 	prv.cd_current_track = 0;