Container support for gme decoder.

src/decoder/gme_decoder_plugin.c

 #include "config.h"
 #include "../decoder_api.h"
 #include "audio_check.h"
+#include "uri.h"
+
 #include <glib.h>
 #include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
 #include <gme/gme.h>
 
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "gme"
 
+#define SUBTUNE_PREFIX "tune_"
+
 enum {
 	GME_SAMPLE_RATE = 44100,
 	GME_CHANNELS = 2,
@@ -15,10 +23,91 @@ enum {
 	GME_BUFFER_SAMPLES = GME_BUFFER_FRAMES * GME_CHANNELS,
 };
 
+/**
+ * returns the file path stripped of any /tune_xxx.* subtune
+ * suffix
+ */
+static char *
+get_container_name(const char *path_fs)
+{
+	const char *subtune_suffix = uri_get_suffix(path_fs);
+	char *path_container = g_strdup(path_fs);
+	char *pat = g_strconcat("*/" SUBTUNE_PREFIX "???.", subtune_suffix, NULL);
+	GPatternSpec *path_with_subtune = g_pattern_spec_new(pat);
+	g_free(pat);
+	if (!g_pattern_match(path_with_subtune,
+			     strlen(path_container), path_container, NULL)) {
+		g_pattern_spec_free(path_with_subtune);
+		return path_container;
+	}
+
+	char *ptr = g_strrstr(path_container, "/" SUBTUNE_PREFIX);
+	if (ptr != NULL)
+		*ptr='\0';
+
+	g_pattern_spec_free(path_with_subtune);
+	return path_container;
+}
+
+/**
+ * returns tune number from file.nsf/tune_xxx.* style path or 0 if no subtune
+ * is appended.
+ */
+static int
+get_song_num(const char *path_fs)
+{
+	const char *subtune_suffix = uri_get_suffix(path_fs);
+	char *pat = g_strconcat("*/" SUBTUNE_PREFIX "???.", subtune_suffix, NULL);
+	GPatternSpec *path_with_subtune = g_pattern_spec_new(pat);
+	g_free(pat);
+
+	if (g_pattern_match(path_with_subtune,
+			    strlen(path_fs), path_fs, NULL)) {
+		char *sub = g_strrstr(path_fs, "/" SUBTUNE_PREFIX);
+		g_pattern_spec_free(path_with_subtune);
+		if(!sub)
+			return 0;
+
+		sub += strlen("/" SUBTUNE_PREFIX);
+		int song_num = strtol(sub, NULL, 10);
+
+		return song_num - 1;
+	} else {
+		g_pattern_spec_free(path_with_subtune);
+		return 0;
+	}
+}
+
+static char *
+gme_container_scan(const char *path_fs, const unsigned int tnum)
+{
+	Music_Emu *emu;
+	const char* gme_err;
+	unsigned int num_songs;
+
+	gme_err = gme_open_file(path_fs, &emu, GME_SAMPLE_RATE);
+	if (gme_err != NULL) {
+		g_warning("%s", gme_err);
+		return NULL;
+	}
+
+	num_songs = gme_track_count(emu);
+	/* if it only contains a single tune, don't treat as container */
+	if (num_songs < 2)
+		return NULL;
+
+	const char *subtune_suffix = uri_get_suffix(path_fs);
+	if (tnum <= num_songs){
+		char *subtune = g_strdup_printf(
+			SUBTUNE_PREFIX "%03u.%s", tnum, subtune_suffix);
+		return subtune;
+	} else
+		return NULL;
+}
+
 static void
 gme_file_decode(struct decoder *decoder, const char *path_fs)
 {
-	int track = 0; /* index of track to play */
 	float song_len;
 	Music_Emu *emu;
 	gme_info_t *ti;
@@ -26,13 +115,17 @@ gme_file_decode(struct decoder *decoder, const char *path_fs)
 	enum decoder_command cmd;
 	short buf[GME_BUFFER_SAMPLES];
 	const char* gme_err;
+	char *path_container = get_container_name(path_fs);
+	int song_num = get_song_num(path_fs);
 
-	gme_err = gme_open_file(path_fs, &emu, GME_SAMPLE_RATE);
+	gme_err = gme_open_file(path_container, &emu, GME_SAMPLE_RATE);
+	g_free(path_container);
 	if (gme_err != NULL) {
 		g_warning("%s", gme_err);
 		return;
 	}
-	if((gme_err = gme_track_info(emu, &ti, 0)) != NULL){
+
+	if((gme_err = gme_track_info(emu, &ti, song_num)) != NULL){
 		g_warning("%s", gme_err);
 		gme_delete(emu);
 		return;
@@ -57,7 +150,7 @@ gme_file_decode(struct decoder *decoder, const char *path_fs)
 
 	decoder_initialized(decoder, &audio_format, true, song_len);
 
-	if((gme_err = gme_start_track(emu, track)) != NULL)
+	if((gme_err = gme_start_track(emu, song_num)) != NULL)
 		g_warning("%s", gme_err);
 
 	/* play */
@@ -90,13 +183,17 @@ gme_tag_dup(const char *path_fs)
 	Music_Emu *emu;
 	gme_info_t *ti;
 	const char* gme_err;
+	char *path_container=get_container_name(path_fs);
+	int song_num;
+	song_num=get_song_num(path_fs);
 
-	gme_err = gme_open_file(path_fs, &emu, GME_SAMPLE_RATE);
+	gme_err = gme_open_file(path_container, &emu, GME_SAMPLE_RATE);
+	g_free(path_container);
 	if (gme_err != NULL) {
 		g_warning("%s", gme_err);
 		return NULL;
 	}
-	if((gme_err = gme_track_info(emu, &ti, 0)) != NULL){
+	if((gme_err = gme_track_info(emu, &ti, song_num)) != NULL){
 		g_warning("%s", gme_err);
 		gme_delete(emu);
 		return NULL;
@@ -106,8 +203,16 @@ gme_tag_dup(const char *path_fs)
 	if(ti != NULL){
 		if(ti->length > 0)
 			tag->time = ti->length / 1000;
-		if(ti->song != NULL)
-			tag_add_item(tag, TAG_TITLE, ti->song);
+		if(ti->song != NULL){
+			if(gme_track_count(emu) > 1){
+				/* start numbering subtunes from 1 */
+				char *tag_title=g_strdup_printf("%s (%d/%d)",
+					ti->song, song_num+1, gme_track_count(emu));
+				tag_add_item(tag, TAG_TITLE, tag_title);
+				g_free(tag_title);
+			}else
+				tag_add_item(tag, TAG_TITLE, ti->song);
+		}
 		if(ti->author != NULL)
 			tag_add_item(tag, TAG_ARTIST, ti->author);
 		if(ti->game != NULL)
@@ -135,4 +240,5 @@ const struct decoder_plugin gme_decoder_plugin = {
 	.file_decode = gme_file_decode,
 	.tag_dup = gme_tag_dup,
 	.suffixes = gme_suffixes,
+	.container_scan = gme_container_scan,
 };