Fix cdGetMaxTrack for download edition of Daiakuji

It should return the maximum index of the BGM archive.

Fixes #43.

src/ald_manager.c

@@ -108,5 +108,5 @@ void ald_init(int type, const char **file, int cnt, boolean use_mmap) {
 int ald_get_maxno(DRIFILETYPE type) {
 	if (type >= DRIFILETYPEMAX || !dri[type])
 		return 0;
-	return dri[type]->nr_files;
+	return dri[type]->maxno;
 }

src/cdrom.bgm.c

@@ -22,11 +22,14 @@
 #include <stdio.h>
 
 #include "cdrom.h"
+#include "ald_manager.h"
 #include "music.h"
+#include "music_private.h"
 
 static int current_track;
 
 static int cdrom_bgm_init(char *dev) {
+	prv.cd_maxtrk = ald_get_maxno(DRIFILE_BGM) + 1;
 	return OK;
 }
 

src/dri.c

@@ -67,6 +67,8 @@ static bool read_index(int disk, drifiles *d, FILE *fp) {
 	for (int i = 0; i < nr_files; i++) {
 		if (disk != ltbl[i * 3] - 1)
 			continue;
+		if (d->maxno < i)
+			d->maxno = i;
 		d->disk[i] = ltbl[i * 3];
 		int ptr = LittleEndian_getW(ltbl, i * 3 + 1);
 		d->offset[i] = LittleEndian_get3B(ptbl, ptr * 3) << 8;

src/dri.h

@@ -34,6 +34,7 @@ struct _drifiles {
 	mmap_t   *mmap[DRIFILEMAX];
 	char     *fnames[DRIFILEMAX];
 	int      nr_files; // upper limit on how many files could be referenced by this archive
+	int      maxno;
 	uint8_t  *disk;    // file numbers
 	uint32_t *offset;  // offsets in file
 };