beginnings of cuesheet file parser

src/share/grabbag/cuesheet.c

@@ -35,3 +35,156 @@ GRABBAG_API void grabbag__cuesheet_frame_to_msf(unsigned frame, unsigned *minute
 	frame /= 60;
 	*minutes = frame;
 }
+
+/* since we only care about values >= 0 or error, returns < 0 for any illegal int, else value */
+static int local__parse_int_(const char *s)
+{
+	int ret = 0;
+	char c;
+
+	if(*s == '\0')
+		return -1;
+
+	while('\0' != (c = *s++))
+		if(c >= '0' && c <= '9')
+			ret = ret * 10 + (c - '0');
+		else
+			return -1;
+
+	return ret;
+}
+
+static char *local__get_field_(char **s)
+{
+	char *p;
+
+	FLAC__ASSERT(0 != s);
+
+	if(0 == *s)
+		return 0;
+
+	/* skip leading whitespace */
+	while(**s && 0 != strchr(" \t\r\n", **s))
+		(*s)++;
+
+	if(**s == 0)
+		*s = 0;
+
+	p = *s;
+
+	if(p) {
+		while(**s && 0 == strchr(" \t\r\n", **s))
+			(*s)++;
+		if(**s)
+			**s = '\0';
+		else
+			*s = 0;
+	}
+
+	return p;
+}
+
+static FLAC__bool local__cuesheet_parse_(FILE *file, const char **error_message, unsigned *last_line_read, FLAC__StreamMetadata *cuesheet, FLAC__bool check_cd_da_subset)
+{
+#if defined _MSC_VER || defined __MINGW32__
+#define FLAC__STRCASECMP stricmp
+#else
+#define FLAC__STRCASECMP strcasecmp
+#endif
+	char buffer[4096], *line, *field;
+	unsigned linelen;
+	int in_track = -1, in_index = -1;
+
+	while(0 != fgets(buffer, sizeof(buffer), file)) {
+		*last_line_read++;
+		line = buffer;
+
+		linelen = strlen(line);
+		if(line[linelen-1] != '\n') {
+			*error_message = "line too long";
+			return false;
+		}
+
+		if(0 != (field = local__get_field_(&line))) {
+			if(0 == FLAC__STRCASECMP(field, "CATALOG")) {
+				/*@@@@ error if already encountered CATALOG */
+				/*@@@@ check_cd_da_subset: 13 digits ['0'..'9'] */
+			}
+			else if(0 == FLAC__STRCASECMP(field, "FLAGS")) {
+				/*@@@@ error if already encountered FLAGS in this track */
+				if(in_track < 0) {
+					/*@@@@*/
+				}
+				if(in_index >= 0) {
+					/*@@@@*/
+				}
+				/*@@@@ search for PRE flag only */
+			}
+			else if(0 == FLAC__STRCASECMP(field, "INDEX")) {
+				if(in_track < 0) {
+					*error_message = "found INDEX before any TRACK";
+					return false;
+				}
+				/*@@@@ check_cd_da_subset: 0..99 */
+				/*@@@@ check_cd_da_subset: first index of first track is 00:00:00 */
+				/*@@@@ check first is 0 or 1 */
+				/*@@@@ check sequential */
+				/*@@@@ parse msf (or sample offset if !check_cd_da_subset)
+			}
+			else if(0 == FLAC__STRCASECMP(field, "ISRC")) {
+				/*@@@@ error if already encountered ISRC in this track */
+				if(in_track < 0) {
+					/*@@@@*/
+				}
+				if(in_index >= 0) {
+					/*@@@@*/
+				}
+			}
+			else if(0 == FLAC__STRCASECMP(field, "TRACK")) {
+				if(0 == (field = local__get_field_(&line))) {
+					*error_message = "TRACK is missing track number";
+					return false;
+				}
+				in_track = local__parse_int_(field);
+				in_index = -1;
+				if(in_track <= 0) {
+					*error_message = "TRACK has invalid track number";
+					return false;
+				}
+				/*@@@@ check_cd_da_subset: 1..99 */
+				/*@@@@ check_cd_da_subset: sequential */
+			}
+		}
+	}
+
+	if(!feof(file)) {
+		*error_message = "read error";
+		return false;
+	}
+	return true;
+#undef FLAC__STRCASECMP
+}
+
+GRABBAG_API FLAC__StreamMetadata *grabbag__cuesheet_parse(FILE *file, const char **error_message, unsigned *last_line_read, FLAC__bool check_cd_da_subset)
+{
+	FLAC__StreamMetadata *cuesheet;
+
+	FLAC__ASSERT(0 != file);
+	FLAC__ASSERT(0 != error_message);
+	FLAC__ASSERT(0 != last_line_read);
+
+	*last_line_read = 0;
+	cuesheet = FLAC__metadata_object_new(FLAC__METADATA_TYPE_CUESHEET);
+
+	if(0 == cuesheet) {
+		*error_message = "memory allocation error";
+		return 0;
+	}
+
+	if(!local__cuesheet_parse_(file, error_message, last_line_read, cuesheet, check_cd_da_subset)) {
+		FLAC__metadata_object_delete(cuesheet);
+		return 0;
+	}
+
+	return cuesheet;
+}