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#include <stdint.h>
#include <stdbool.h>
#include <string.h>
// various errors with fat32
enum
{
FAT_ERR_NONE = 0,
FAT_ERR_NOFAT = -1,
FAT_ERR_BROKEN = -2,
FAT_ERR_IO = -3,
FAT_ERR_PARAM = -4,
FAT_ERR_PATH = -5,
// also can tell if files don't exist.
FAT_ERR_EOF = -6,
//
FAT_ERR_DENIED = -7,
FAT_ERR_FULL = -8,
};
enum
{
FAT_ATTR_NONE = 0x00,
FAT_ATTR_RO = 0x01,
FAT_ATTR_HIDDEN = 0x02,
FAT_ATTR_SYS = 0x04,
FAT_ATTR_LABEL = 0x08,
FAT_ATTR_DIR = 0x10,
FAT_ATTR_ARCHIVE = 0x20,
FAT_ATTR_LFN = 0x0f,
};
enum
{
FAT_WRITE = 0x01, // Open file for writing
FAT_READ = 0x02, // Open file for reading
FAT_APPEND = 0x04, // Set file offset to the end of the file
FAT_TRUNC = 0x08, // Truncate the file after opening
FAT_CREATE = 0x10, // Create the file if it do not exist
FAT_ACCESSED = 0x20, // do not use (internal)
FAT_MODIFIED = 0x40, // do not use (internal)
FAT_FILE_DIRTY = 0x80, // do not use (internal)
};
enum
{
FAT_SEEK_START,
FAT_SEEK_CURR,
FAT_SEEK_END,
};
typedef struct
{
bool (*read)(uint8_t* buf, uint32_t sect);
bool (*write)(const uint8_t* buf, uint32_t sect);
} DiskOps;
// time checker if I can be bothered to implement it.
typedef struct
{
uint8_t hour;
uint8_t min;
uint8_t sec;
uint8_t day;
uint8_t month;
uint16_t year;
} Timestamp;
typedef struct Fat
{
struct Fat* next;
DiskOps ops;
uint32_t clust_msk;
uint32_t clust_cnt;
uint32_t info_sect;
uint32_t fat_sect[2];
uint32_t data_sect;
uint32_t root_clust;
uint32_t last_used;
uint32_t free_cnt;
uint32_t sect;
uint8_t buf[512];
uint8_t flags;
uint8_t clust_shift;
uint8_t name_len;
char name[32];
} Fat;
typedef struct
{
//Timestamp created;
//Timestamp modified;
uint32_t size;
uint8_t attr;
char name[255];
uint8_t name_len;
} DirInfo;
typedef struct
{
Fat* fat;
uint32_t sclust;
uint32_t clust;
uint32_t sect;
uint16_t idx;
} Dir;
// file structure
typedef struct
{
Fat* fat;
uint32_t dir_sect;
uint32_t sclust;
uint32_t clust;
uint32_t sect;
uint32_t size;
uint32_t offset;
uint16_t dir_idx;
uint8_t attr;
uint8_t flags;
uint8_t buf[512];
} File;
typedef struct __attribute__((packed))
{
uint8_t jump[3];
char name[8];
uint16_t bytes_per_sect;
uint8_t sect_per_clust;
uint16_t res_sect_cnt;
uint8_t fat_cnt;
uint16_t root_ent_cnt;
uint16_t sect_cnt_16;
uint8_t media;
uint16_t sect_per_fat_16;
uint16_t sect_per_track;
uint16_t head_cnt;
uint32_t hidden_sect_cnt;
uint32_t sect_cnt_32;
uint32_t sect_per_fat_32;
uint16_t ext_flags;
uint8_t minor;
uint8_t major;
uint32_t root_cluster;
uint16_t info_sect;
uint16_t copy_bpb_sector;
uint8_t reserved_0[12];
uint8_t drive_num;
uint8_t reserved_1;
uint8_t boot_sig;
uint32_t volume_id;
char volume_label[11];
char fs_type[8];
uint8_t reserved_2[420];
uint8_t sign[2];
} Bpb;
typedef struct __attribute__((packed))
{
uint32_t head_sig;
uint8_t reserved_0[480];
uint32_t struct_sig;
uint32_t free_cnt;
uint32_t next_free;
uint8_t reserved_1[12];
uint32_t tail_sig;
} FsInfo;
typedef struct __attribute__((packed))
{
uint8_t name[11];
uint8_t attr;
uint8_t reserved;
uint8_t tenth;
uint16_t cre_time;
uint16_t cre_date;
uint16_t acc_date;
uint16_t clust_hi;
uint16_t mod_time;
uint16_t mod_date;
uint16_t clust_lo;
uint32_t size;
} Sfn;
typedef union __attribute__((packed))
{
uint8_t raw[32];
struct
{
uint8_t seq;
uint8_t name0[10];
uint8_t attr;
uint8_t type;
uint8_t crc;
uint8_t name1[12];
uint16_t clust;
uint8_t name2[4];
};
} Lfn;
typedef struct
{
uint32_t sect;
uint16_t idx;
} Loc;
static Fat* g_fat_list;
static uint8_t g_buf[512];
static uint16_t g_len;
static uint8_t g_crc;
static int sync_buf(Fat* fat) {
// checks whether the flag is active. If not, we
if(fat->flags & 0x01) {
// if write fails for whatever reason
if(!fat->ops.write(fat->buf, fat->sect)) {
return FAT_ERR_IO;
}
}
}
static int update_buf(Fat* fat, uint32_t sect) {
// if fat->sect already is sect, we are good
if(fat->sect != sect) {
}
}
// attempts to sync the filesystem to fat32. Returns error code assuming one happens.
static int sync_fs(Fat* fat)
{
int error = sync_buf(fat);
if (error) {
return error;
}
FsInfo* info = (FsInfo*)fat->buf;
fat->flags |=
}
static int get_fat(Fat* fat, uint32_t clust, uint32_t* out_val, uint8_t* out_flags) {
}
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