/* fat12 */

#ifndef _FAT12_H
#define _FAT12_H

struct __attribute__((__packed__)) bpb {
    uint8_t  jmp[3];                /* presumably some machine code */
    char     oem_id[8];
    uint16_t sect_size;
    uint8_t  sect_per_cluster;
    uint16_t resv_sect;
    uint8_t  fat_ct;
    uint16_t dirent_ct;
    uint16_t sect_ct;
    uint8_t  media_type;
    uint16_t fat_size;
    uint16_t track_size;
    uint16_t heads;
    uint32_t hidden_sect;
    uint32_t larg_sect_ct;
    /*
     * XXX: Most PC98 disks don't seem to have the extended
     * BPB. Should we even care about these?
     */
    uint8_t  drive_num;
    uint8_t  _reserved;
    uint8_t  signature;
    uint32_t serial_num;
    char     label[11];
    char     sys_id[8];
};

struct __attribute__((__packed__)) dos_dirent {
    char     filename[11];
    uint8_t  attributes;
#define ATTR_READONLY   0x01
#define ATTR_HIDDEN     0x02
#define ATTR_SYSTEM     0x04
#define ATTR_VOLID      0x08
#define ATTR_ISDIR      0x10
#define ATTR_ARCHIVE    0x20
#define ATTR_LFN        (ATTR_READONLY|ATTR_HIDDEN|ATTR_SYSTEM|ATTR_VOLID)
    uint8_t  _reserved;
    uint8_t  creation_time_tenths;
    uint16_t creation_time;
    uint16_t creation_date;
    uint16_t access_date;
    uint16_t high_loc;              /* only used with FAT32 */
    uint16_t mod_time;
    uint16_t mod_date;
    uint16_t low_loc;               /* entry cluster location */
    uint32_t size;
};

#define FAT12_MAX_CLUSTERS  4085
#define FAT16_MAX_CLUSTERS  65525

typedef struct dosfs_t {
    struct bpb ib;
    unsigned int fs_ver;
    int ifd;
    unsigned int root_loc;
    unsigned int root_size;
    unsigned int data_loc;
    unsigned int data_size;
} dosfs_t;

typedef struct dosfile_t {
    struct dos_dirent ent;
    char   fname[9];
    char   fext[4];
    unsigned int *fat_chain;
    int fc_len;
    struct dosfile_t  *next;
} dosfile_t;

int open_image(const char *, int, dosfs_t *);
void close_image(dosfs_t *);

dosfile_t *dos_listdir(dosfs_t *, unsigned int);
void dos_freedir(dosfile_t *);

int get_byte_offset(dosfs_t *, dosfile_t *, int);

#endif /* !_FAT12_H */