part: Add functions to iterate through partition list

These functions will come in handy once we support more partition types.

part.c

@@ -70,7 +70,26 @@ static struct partition_def partitions[] = {
 };
 
 
-struct part *part_init(struct disk *disk, int part_id) {
+
+
+/* Returns the number of partitions available */
+uint32_t part_disk_count(struct disk *disk) {
+    return sizeof(partitions)/sizeof(*partitions);
+}
+
+/* Returns the name of the specified partition */
+char *part_disk_name(struct disk *disk, uint8_t part_id) {
+    return part_id<part_disk_count(disk)?partitions[part_id].name:NULL;
+}
+
+/* Returns the format of the specified partition */
+enum part_format part_disk_format(struct disk *disk, uint8_t part_id) {
+    return part_id<part_disk_count(disk)?partitions[part_id].format:0;
+}
+
+
+
+struct part *part_init(struct disk *disk, uint8_t part_id) {
     struct part *part;
 
     part = malloc(sizeof(struct part));

part.h

@@ -9,12 +9,32 @@ enum part_format {
 struct disk;
 struct part;
 
-struct part *part_init(struct disk *disk, int part_id);
+
+/* Returns the number of partitions available */
+uint32_t part_disk_count(struct disk *disk);
+
+/* Returns the name of the specified partition */
+char *part_disk_name(struct disk *disk, uint8_t part_id);
+
+/* Returns the format of the specified partition */
+enum part_format part_disk_format(struct disk *disk, uint8_t part_id);
+
+
+
+
+struct part *part_init(struct disk *disk, uint8_t part_id);
 void part_free(struct part **part);
 
+/* Returns the length of the selected partition */
 uint64_t part_length(struct part *part);
+
+/* Returns a pointer to the partition's data */
 const uint8_t *part_data(struct part *part);
+
+/* Returns a byte from the specified offset */
 uint8_t part_byte(struct part *part, uint64_t offset);
+
+/* Returns the format of the selected partition */
 enum part_format part_format(struct part *part);
 
 #endif //__PART_H__