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#include <string.h>
//#include "fat.h"
#include <stdint.h>
#include <stdbool.h>
#include "comus/fs.h"
// Note that the structures came from strawberryhacker
#define FLAG_MIRROR (1 << 7)
#define FLAG_SECOND (0x01)
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];
} fat_header;
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;
} file_system_info;
struct fat
{
//uint32_t placeholder;
uint32_t fat_sect[2];
uint8_t clust_shift;
uint8_t data_sect;
};
static uint32_t sect_to_clust(struct fat* fat, uint32_t sect)
{
return ((sect - fat->data_sect) >> fat->clust_shift) + 2;
}
//------------------------------------------------------------------------------
static uint32_t clust_to_sect(struct fat* fat, uint32_t clust)
{
return ((clust - 2) << fat->clust_shift) + fat->data_sect;
}
int fat32_init(struct disk* disk, struct fat* fat) {
fat_header hdr;
file_system_info info;
disk_read(disk, 0, sizeof(fat_header), &hdr);
disk_read(disk, hdr.info_sect * 512, sizeof(file_system_info), &info);
bool mirror = (hdr.ext_flags & FLAG_MIRROR) != 0;
bool use_first = (hdr.ext_flags & FLAG_MIRROR) == 0;
uint32_t fat0 = hdr.res_sect_cnt;
uint32_t fat1 = hdr.res_sect_cnt + hdr.sect_per_fat_32;
fat->fat_sect[0] = use_first ? fat0 : fat1;
fat->fat_sect[1] = mirror ? (use_first ? fat1: fat0) : 0;
fat->clust_shift = __builtin_ctz(hdr.sect_per_clust);
fat->data_sect = hdr.res_sect_cnt + hdr.fat_cnt * hdr.sect_per_fat_32;
// TODO: Read info into fat
}
int create_directory() {
return;
}
int create_file() {
return;
}
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