uhfs.h

#define UHFS_DEBUG  1

#define UHFS_FIXDBLK        0xfffffffc      /* fixed / not allocatable */
#define UHFS_DEADBLK        0xfffffffd      /* invalid (dead block) */
#define UHFS_EOCHBLK        0xfffffffe      /* last block in the chain (end of file or end of chain of cluster map blocks) */
#define UHFS_FREEBLK        0xffffffff      /* unused (free) block */

#define UHFS_ATTRDIR        0x01            /* directory */
#define UHFS_ATTRHIDDEN     0x02            /* hidden */
#define UHFS_ATTRARCHIVE    0x04            /* file needs archiving */
#define UHFS_ATTRSYSTEM     0x08            /* system */
#define UHFS_ATTREXEC       0x10            /* execute */
#define UHFS_ATTRWRITE      0x20            /* write */
#define UHFS_ATTRREAD       0x40            /* read */
#define UHFS_ATTRFREE       0x80            /* deleted / free directory entry */

#define UHFS_RDONLY     0x0001
#define UHFS_WRONLY     0x0002
#define UHFS_RDWR       0x0003
#define UHFS_CREAT      0x0004
#define UHFS_APPEND     0x0008
#define UHFS_SYNC       0x0010
#define UHFS_NONBLOCK       0x0020
#define UHFS_EOF        0x4000
#define UHFS_OPENFILE       0x8000

enum {
    UHFS_EOK        = 0,
    UHFS_EERROR     = -1000,
    UHFS_ENOTMOUNTED    = -1001,
    UHFS_EALREADYMOUNTED    = -1002,
    UHFS_EINVSECTORSIZE = -1003,
    UHFS_EINVBLOCKSIZE  = -1004,
    UHFS_ESTORAGEFULL   = -1005,
    UHFS_EPATHNOTFOUND  = -1006,
    UHFS_ENOTADIR       = -1007,
    UHFS_ENOTAFILE      = -1008,
    UHFS_EFILEEXISTS    = -1009,
    UHFS_EFILENOTOPEN   = -1010,
    UHFS_EDIRNOTEMPTY   = -1011
};

struct fs_date {
    uint32_t day : 5;           /* range 1 - 31 */
    uint32_t month : 4;         /* range 1 - 12 */
    uint32_t year : 15;         /* range 0 - 32767 */
    uint32_t reserved : 8;
};

struct fs_time {
    uint32_t millisecond : 7;       /* precision is 0.0078125 seconds */
    uint32_t second : 6;            /* range 0 - 59 */
    uint32_t minute : 6;            /* range 0 - 59 */
    uint32_t hour : 5;          /* range 0 - 23 */
    uint32_t reserved : 8;
};

struct fs_superblock {
    uint32_t signature;
    int8_t oem_id[16];
    uint32_t block_size;
    uint32_t n_blocks;
    int8_t volume_label[16];
    struct fs_date vdate;
    struct fs_time vtime;
    uint32_t first_cmb;
    uint32_t root_dir_block;
    uint32_t metadata_block;
};

struct fs_direntry {
    int8_t      filename[39];       /* all bytes except / and NULL */
    uint8_t     attributes;
    struct fs_date  date;
    struct fs_time  time;
    uint32_t    metadata_block;     /* block containing metadata for this file (future use) */
    uint32_t    first_block;        /* the number of the first data block */
    uint64_t    size;
};

union fs_datablock {
    uint32_t *cmb_data;
    int8_t *data;
    struct fs_direntry *dir_data;
};

struct fs_blkdevice {
    /* these structures remain fixed after the filesystem is initialized */
    struct blk_info fsblk_info;
    uint64_t vsize;
    struct fs_superblock fssblock;
    /* these structures change during filesystem usage */
    struct fs_direntry fsdirentry;
    union fs_datablock datablock;
};

struct file {
    struct device *dev;
    uint32_t first_block;
    int8_t mode;
    int32_t flags;
    uint32_t block;
    int64_t offset;
};

/* volume management */
int32_t hf_mkfs(struct device *dev, uint32_t blk_size);
int32_t hf_mount(struct device *dev);
int32_t hf_umount(struct device *dev);
int32_t hf_getfree(struct device *dev);
int32_t hf_getlabel(struct device *dev, int8_t *label);
int32_t hf_setlabel(struct device *dev, int8_t *label);

/* directory management / operations */
int32_t hf_mkdir(struct device *dev, int8_t *path);
struct file * hf_opendir(struct device *dev, int8_t *path);
int32_t hf_closedir(struct file *desc);
int32_t hf_readdir(struct file *desc, struct fs_direntry *entry);
int32_t hf_rmdir(struct device *dev, int8_t *path);

/* file management */
int32_t hf_create(struct device *dev, int8_t *path);
int32_t hf_unlink(struct device *dev, int8_t *path);
int64_t hf_size(struct device *dev, int8_t *path);
int32_t hf_rename(struct device *dev, int8_t *path, int8_t *newname);
int32_t hf_chmod(struct device *dev, int8_t *path, int8_t mode);
int32_t hf_touch(struct device *dev, int8_t *path, struct fs_date *ndate, struct fs_time *ntime);

/* file operations */
struct file * hf_fopen(struct device *dev, int8_t *path, int8_t *mode);
int32_t hf_fclose(struct file *desc);
int64_t hf_fread(void *buf, int32_t isize, int32_t items, struct file *desc);
int64_t hf_fwrite(void *buf, int32_t isize, int32_t items, struct file *desc);
int32_t hf_fseek(struct file *desc, int64_t offset, int32_t whence);
int64_t hf_ftell(struct file *desc);
int32_t hf_feof(struct file *desc);