FAT16 library written for an ATmega project with SD card
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#pragma once
//
// Simple FAT16 library.
//
// To use it, implement BLOCKDEV functions
// and attach them to it's instance.
//
#include <stdint.h>
#include <stdbool.h>
#include "blockdev.h"
// -------------------------------
/**
* File types (values can be used for debug printing).
* Accessible using file->type
*/
typedef enum
{
FT_NONE = '-',
FT_DELETED = 'x',
FT_SUBDIR = 'D',
FT_PARENT = 'P',
FT_LABEL = 'L',
FT_LFN = '~',
FT_INVALID = '?', // not recognized weird file
FT_SELF = '.',
FT_FILE = 'F'
} FAT16_FT;
/** "File address" for saving and restoring file */
typedef struct
{
uint16_t clu;
uint16_t num;
uint32_t cur_rel;
} FSAVEPOS;
// Include definitions of fully internal structs
#include "fat16_internal.h"
/**
* File handle struct.
*
* File handle contains cursor, file name, type, size etc.
* Everything (files, dirs) is accessed using this.
*/
typedef struct __attribute__((packed))
{
/**
* Raw file name. Starting 0x05 was converted to 0xE5.
* To get PRINTABLE file name, use fat16_dispname()
*/
uint8_t name[11];
/**
* File attributes - bit field composed of FA_* flags
* (internal)
*/
uint8_t attribs;
// 14 bytes skipped (10 reserved, date, time)
/** First cluster of the file. (internal) */
uint16_t clu_start;
/**
* File size in bytes.
* This is the current allocated and readable file size.
*/
uint32_t size;
// --- the following fields are added when reading ---
/** File type. */
FAT16_FT type;
// --- INTERNAL FIELDS ---
// Cursor variables. (internal)
uint32_t cur_abs; // absolute position in device
uint32_t cur_rel; // relative position in file
uint16_t cur_clu; // cluster where the cursor is
uint16_t cur_ofs; // offset within the active cluster
// File position in the directory. (internal)
uint16_t clu; // first cluster of directory
uint16_t num; // file entry number
// Pointer to the FAT16 handle. (internal)
const FAT16* fat;
}
FFILE;
/**
* Store modified file metadata and flush it to disk.
*/
void ff_flush_file(FFILE* file);
/**
* Save a file "position" into a struct, for later restoration.
* Cursor is also saved.
*/
FSAVEPOS ff_savepos(const FFILE* file);
/**
* Restore a file from a saved position.
*/
void ff_reopen(FFILE* file, const FSAVEPOS* pos);
/**
* Initialize the file system - store into "fat"
*/
bool ff_init(const BLOCKDEV* dev, FAT16* fat);
/**
* Open the first file of the root directory.
* The file may be invalid (eg. a volume label, deleted etc),
* or blank (type FT_NONE) if the filesystem is empty.
*/
void ff_root(const FAT16* fat, FFILE* file);
/**
* Resolve the disk label.
* That can be in the Boot Sector, or in the first root directory entry.
*
* @param fat the FAT handle
* @param label_out string to store the label in. Should have at least 12 bytes.
*/
char* ff_disk_label(const FAT16* fat, char* label_out);
// ----------- FILE I/O -------------
/**
* Move file cursor to a position relative to file start
* Returns false on I/O error (bad file, out of range...)
*/
bool ff_seek(FFILE* file, uint32_t addr);
/**
* Read bytes from file into memory
* Returns number of bytes read, 0 on error.
*/
uint16_t ff_read(FFILE* file, void* target, uint16_t len);
/**
* Write into file at a "seek" position.
*/
bool ff_write(FFILE* file, const void* source, uint32_t len);
/**
* Store a 0-terminated string at cursor.
*/
bool ff_write_str(FFILE* file, const char* source);
/**
* Create a new file in given folder
*
* file ... open directory; new file is opened into this handle.
* name ... name of the new file, including extension
*/
bool ff_newfile(FFILE* file, const char* name);
/**
* Create a sub-directory of given name.
* Directory is allocated and populated with entries "." and ".."
*/
bool ff_mkdir(FFILE* file, const char* name);
/**
* Set new file size.
* Allocates / frees needed clusters, does NOT erase them.
*
* Useful mainly for shrinking.
*/
void set_file_size(FFILE* file, uint32_t size);
/**
* Delete a *FILE* and free it's clusters.
*/
bool ff_rmfile(FFILE* file);
/**
* Delete an empty *DIRECTORY* and free it's clusters.
*/
bool ff_rmdir(FFILE* file);
/**
* Delete a file or directory, even FT_LFN and FT_INVALID.
* Directories are deleted recursively (!)
*/
bool ff_delete(FFILE* file);
// --------- NAVIGATION ------------
/** Go to previous file in the directory (false = no prev file) */
bool ff_prev(FFILE* file);
/** Go to next file in directory (false = no next file) */
bool ff_next(FFILE* file);
/**
* Open a subdirectory denoted by the file.
* Provided handle changes to the first entry of the directory.
*/
bool ff_opendir(FFILE* dir);
/**
* Open a parent directory. Fails in root.
* Provided handle changes to the first entry of the parent directory.
*/
bool ff_parent(FFILE* file);
/** Jump to first file in this directory */
void ff_first(FFILE* file);
/**
* Find a file with given "display name" in this directory, and open it.
* If file is found, "file" will contain it's handle.
* Otherwise, the handle is unchanged.
*/
bool ff_find(FFILE* file, const char* name);
// -------- FILE INSPECTION -----------
/** Check if file is a valid entry, or long-name/label/deleted */
bool ff_is_regular(const FFILE* file);
/**
* Resolve a file name, trim spaces and add null terminator.
* Returns the passed char*, or NULL on error.
*/
char* ff_dispname(const FFILE* file, char* disp_out);
/**
* Convert filename to zero-padded fixed length one
* Returns the passed char*.
*/
char* ff_rawname(const char* disp_in, char* raw_out);