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-rw-r--r--ext/spc/tag.c353
1 files changed, 353 insertions, 0 deletions
diff --git a/ext/spc/tag.c b/ext/spc/tag.c
new file mode 100644
index 000000000..41ce812fc
--- /dev/null
+++ b/ext/spc/tag.c
@@ -0,0 +1,353 @@
+/* Copyright (C) 2007 Brian Koropoff <bkoropoff at gmail com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <glib/gstring.h>
+#include <glib/gtypes.h>
+#include <glib/gmem.h>
+#include <glib/gprintf.h>
+
+#include <tag.h>
+#include <string.h>
+#include <stdlib.h>
+
+
+#define EXTENDED_OFFSET 0x10200
+#define EXTENDED_MAGIC ((guint32) ('x' << 0 | 'i' << 8 | 'd' << 16 | '6' << 24))
+
+#define TYPE_LENGTH 0x0
+#define TYPE_STRING 0x1
+#define TYPE_INTEGER 0x4
+
+#define TAG_TITLE 0x01
+#define TAG_GAME 0x02
+#define TAG_ARTIST 0x03
+#define TAG_DUMPER 0x04
+#define TAG_DUMP_DATE 0x05
+#define TAG_EMULATOR 0x06
+#define TAG_COMMENT 0x07
+#define TAG_ALBUM 0x10
+#define TAG_DISC 0x11
+#define TAG_TRACK 0x12
+#define TAG_PUBLISHER 0x13
+#define TAG_YEAR 0x14
+#define TAG_INTRO 0x30
+#define TAG_LOOP 0x31
+#define TAG_END 0x32
+#define TAG_FADE 0x33
+#define TAG_MUTED 0x34
+#define TAG_COUNT 0x35
+#define TAG_AMP 0x36
+
+#define READ_INT8(data, offset) (data[offset])
+#define READ_INT16(data, offset) ((data[offset] << 0) + (data[offset+1] << 8))
+#define READ_INT24(data, offset) ((data[offset] << 0) + (data[offset+1] << 8) + (data[offset+2] << 16))
+#define READ_INT32(data, offset) ((data[offset] << 0) + (data[offset+1] << 8) + (data[offset+2] << 16) + (data[offset+3] << 24))
+
+static inline gboolean
+spc_tag_is_extended (guchar * data, guint length)
+{
+ // Extended tags come at the end of the file (at a known offset)
+ // and start with "xid6"
+ return (length > EXTENDED_OFFSET + 4
+ && READ_INT32 (data, EXTENDED_OFFSET) == EXTENDED_MAGIC);
+}
+
+static inline gboolean
+spc_tag_is_text_format (guchar * data, guint length)
+{
+ // Because the id666 format is brain dead, there's
+ // no definite way to decide if it is in text
+ // format. This function implements a set of
+ // heuristics to make a best-effort guess.
+
+ // If the date field contains separators, it is probably text
+ if (data[0xA0] == '/' || data[0xA0] == '.')
+ return TRUE;
+ // If the first byte of the date field is small (but not 0,
+ // which could indicate an empty string), it's probably binary
+ if (data[0x9E] >= 1 && data[0x9E] <= 31)
+ return FALSE;
+
+ // If all previous tests turned up nothing, assume it's text
+ return TRUE;
+}
+
+static inline gboolean
+spc_tag_is_present (guchar * data, guint length)
+{
+ return data[0x23] == 26;
+}
+
+static inline GDate *
+spc_tag_unpack_date (guint32 packed)
+{
+ guint dump_year = packed / 10000;
+ guint dump_month = (packed % 10000) / 100;
+ guint dump_day = packed % 100;
+
+ if (dump_month == 0)
+ dump_month = 1;
+ if (dump_day == 0)
+ dump_day = 1;
+
+ if (dump_year != 0)
+ return g_date_new_dmy (dump_day, dump_month, dump_year);
+ else
+ return NULL;
+}
+
+void
+spc_tag_clear (spc_tag_info * info)
+{
+ info->title = info->game = info->publisher = info->artist = info->album =
+ info->comment = info->dumper = NULL;
+ info->dump_date = NULL;
+ info->time_seconds = 0;
+ info->time_fade_milliseconds = 0;
+ info->time_intro = 0;
+ info->time_end = 0;
+ info->time_loop = 0;
+ info->time_fade = 0;
+ info->loop_count = 0;
+ info->muted = 0;
+ info->disc = 0;
+ info->amplification = 0;
+}
+
+void
+spc_tag_get_info (guchar * data, guint length, spc_tag_info * info)
+{
+ spc_tag_clear (info);
+
+ if (spc_tag_is_present (data, length)) {
+ gboolean text_format = spc_tag_is_text_format (data, length);
+
+ info->title = g_new0 (gchar, 0x21);
+ info->game = g_new0 (gchar, 0x21);
+ info->artist = g_new0 (gchar, 0x21);
+ info->dumper = g_new0 (gchar, 0x10);
+ info->comment = g_new0 (gchar, 0x32);
+
+ strncpy (info->title, (gchar *) & data[0x2E], 32);
+ strncpy (info->artist, (gchar *) & data[(text_format ? 0xB1 : 0xB0)], 32);
+ strncpy (info->game, (gchar *) & data[0x4E], 32);
+ strncpy (info->dumper, (gchar *) & data[0x6E], 16);
+ strncpy (info->comment, (gchar *) & data[0x7E], 32);
+
+ if (text_format) {
+ gchar time[4];
+ gchar fade[6];
+ guint dump_year, dump_month, dump_day;
+
+ strncpy (time, (gchar *) data + 0xA9, 3);
+ strncpy (fade, (gchar *) data + 0xAC, 5);
+
+ time[3] = fade[5] = 0;
+
+ info->time_seconds = atoi (time);
+ info->time_fade_milliseconds = atoi (fade);
+
+ dump_year = (guint) atoi ((gchar *) data + 0x9E);
+ dump_month = (guint) atoi ((gchar *) data + 0x9E + 3);
+ dump_day = (guint) atoi ((gchar *) data + 0x9E + 3 + 3);
+
+ if (dump_month == 0)
+ dump_month = 1;
+ if (dump_day == 0)
+ dump_day = 1;
+ if (dump_year != 0)
+ info->dump_date = g_date_new_dmy (dump_day, dump_month, dump_year);
+
+ info->muted = READ_INT8 (data, 0xD1);
+ info->emulator = READ_INT8 (data, 0xD2);
+ } else {
+ info->time_seconds = READ_INT24 (data, 0xA9);
+ info->time_fade_milliseconds = READ_INT32 (data, 0xAC);
+ info->dump_date = spc_tag_unpack_date (READ_INT32 (data, 0x9E));
+ info->muted = READ_INT8 (data, 0xD0);
+ info->emulator = READ_INT8 (data, 0xD1);
+ }
+ }
+
+ if (spc_tag_is_extended (data, length)) {
+ guchar *chunk = data + EXTENDED_OFFSET + 8;
+ guint32 chunk_size = *((guint32 *) (data + EXTENDED_OFFSET + 4));
+
+ guchar *subchunk, *subchunk_next;
+
+ for (subchunk = chunk; subchunk < chunk + chunk_size;
+ subchunk = subchunk_next) {
+ guint8 tag = READ_INT8 (subchunk, 0);
+ guint8 type = READ_INT8 (subchunk, 1);
+ guint16 length = READ_INT16 (subchunk, 2);
+ guchar *value = subchunk + 4;
+
+ switch (type) {
+ case TYPE_LENGTH:
+ {
+ switch (tag) {
+ case TAG_TRACK:
+ info->track = READ_INT8 (subchunk, 2 + 1);
+ break;
+ case TAG_YEAR:
+ info->year = READ_INT16 (subchunk, 2);
+ break;
+ case TAG_COUNT:
+ info->loop_count = READ_INT8 (subchunk, 2);
+ break;
+ case TAG_EMULATOR:
+ info->emulator = READ_INT8 (subchunk, 2);
+ break;
+ case TAG_DISC:
+ info->disc = READ_INT8 (subchunk, 2);
+ break;
+ case TAG_MUTED:
+ info->muted = READ_INT8 (subchunk, 2);
+ break;
+ default:
+ break;
+ }
+
+ subchunk_next = subchunk + 4;
+ break;
+ }
+ case TYPE_STRING:
+ {
+ gchar *dest;
+
+ if (length <= 1)
+ dest = NULL;
+ else
+ switch (tag) {
+ case TAG_TITLE:
+ dest = info->title = g_renew (gchar, info->title, length);
+ break;
+ case TAG_GAME:
+ dest = info->game = g_renew (gchar, info->game, length);
+ break;
+ case TAG_ARTIST:
+ dest = info->artist = g_renew (gchar, info->artist, length);
+ break;
+ case TAG_ALBUM:
+ dest = info->album = g_renew (gchar, info->album, length);
+ break;
+ case TAG_DUMPER:
+ dest = info->dumper = g_renew (gchar, info->dumper, length);
+ break;
+ case TAG_COMMENT:
+ dest = info->comment = g_renew (gchar, info->comment, length);
+ break;
+ case TAG_PUBLISHER:
+ dest = info->publisher =
+ g_renew (gchar, info->publisher, length);
+ break;
+ default:
+ dest = NULL;
+ break;
+ }
+
+ if (dest)
+ strncpy (dest, (gchar *) value, length);
+
+ subchunk_next = value + length;
+ break;
+ }
+ case TYPE_INTEGER:
+ {
+ switch (tag) {
+ case TAG_INTRO:
+ info->time_intro = READ_INT32 (value, 0);
+ break;
+ case TAG_END:
+ info->time_end = READ_INT32 (value, 0);
+ break;
+ case TAG_FADE:
+ info->time_fade = READ_INT32 (value, 0);
+ break;
+ case TAG_LOOP:
+ info->time_loop = READ_INT32 (value, 0);
+ break;
+ case TAG_DUMP_DATE:
+ info->dump_date = spc_tag_unpack_date (READ_INT32 (value, 0));
+ break;
+ case TAG_AMP:
+ info->amplification = READ_INT32 (value, 0);
+ break;
+ default:
+ break;
+ }
+ subchunk_next = value + length;
+ break;
+ }
+ default:
+ subchunk_next = value + length;
+ break;
+ }
+ }
+ }
+
+ if (info->title && !*info->title) {
+ g_free (info->title);
+ info->title = NULL;
+ }
+ if (info->game && !*info->game) {
+ g_free (info->game);
+ info->game = NULL;
+ }
+ if (info->artist && !*info->artist) {
+ g_free (info->artist);
+ info->artist = NULL;
+ }
+ if (info->album && !*info->album) {
+ g_free (info->album);
+ info->album = NULL;
+ }
+ if (info->publisher && !*info->publisher) {
+ g_free (info->publisher);
+ info->publisher = NULL;
+ }
+ if (info->comment && !*info->comment) {
+ g_free (info->comment);
+ info->comment = NULL;
+ }
+ if (info->dumper && !*info->dumper) {
+ g_free (info->dumper);
+ info->dumper = NULL;
+ }
+}
+
+void
+spc_tag_free (spc_tag_info * info)
+{
+ if (info->title)
+ g_free (info->title);
+ if (info->game)
+ g_free (info->game);
+ if (info->artist)
+ g_free (info->artist);
+ if (info->album)
+ g_free (info->album);
+ if (info->publisher)
+ g_free (info->publisher);
+ if (info->comment)
+ g_free (info->comment);
+ if (info->dumper)
+ g_free (info->dumper);
+ if (info->dump_date)
+ g_date_free (info->dump_date);
+}
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