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avr-lib/lib/fat16.h

258 lines
5.5 KiB

#pragma once
//
// Simple FAT16 library.
//
// To use it, implement BLOCKDEV functions
// and attach them to it's instance.
//
#include <stdint.h>
#include <stdbool.h>
/**
* Abstract block device interface
*
* Populate this with pointers to your I/O functions.
*/
typedef struct
{
// Sequential read
void (*load)(void* dest, const uint16_t len);
// Sequential write
void (*store)(const void* src, const uint16_t len);
// Sequential byte write
void (*write)(const uint8_t b);
// Sequential byte read
uint8_t (*read)(void);
// Absolute seek
void (*seek)(const uint32_t);
// Relative seek
void (*rseek)(const int16_t);
} BLOCKDEV;
// -------------------------------
/**
* 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;
// 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;
}
FAT16_FILE;
/** Initialize the file system - store into "fat" */
void fat16_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 fat16_root(const FAT16* fat, FAT16_FILE* file);
/**
* Resolve the disk label.
* That can be in the Boot Sector, or in the first root directory entry.
*/
char* fat16_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 fat16_seek(FAT16_FILE* file, uint32_t addr);
/**
* Read bytes from file into memory
* Returns false on I/O error (bad file, out of range...)
*/
bool fat16_read(FAT16_FILE* file, void* target, uint32_t len);
/**
* Write into file at a "seek" position.
* "seek" cursor must be within (0..filesize)
*/
bool fat16_write(FAT16_FILE* file, void* source, uint32_t len);
/**
* 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 fat16_mkfile(FAT16_FILE* file, const char* name);
/**
* Create a sub-directory of given name.
* Directory is allocated and populated with entries "." and ".."
*/
bool fat16_mkdir(FAT16_FILE* file, const char* name);
/**
* Set new file size.
* Allocates / frees needed clusters, does NOT erase them.
*
* Useful mainly for shrinking.
*/
void fat16_resize(FAT16_FILE* file, uint32_t size);
/**
* Delete a *FILE* and free it's clusters.
*/
bool fat16_rmfile(FAT16_FILE* file);
/**
* Delete an empty *DIRECTORY* and free it's clusters.
*/
bool fat16_rmdir(FAT16_FILE* file);
/**
* Delete a file or directory, even FT_LFN and FT_INVALID.
* Directories are deleted recursively (!)
*/
bool fat16_delete(FAT16_FILE* file);
// --------- NAVIGATION ------------
/** Go to previous file in the directory (false = no prev file) */
bool fat16_prev(FAT16_FILE* file);
/** Go to next file in directory (false = no next file) */
bool fat16_next(FAT16_FILE* file);
/**
* Open a subdirectory denoted by the file.
* Provided handle changes to the first entry of the directory.
*/
bool fat16_opendir(FAT16_FILE* dir);
/**
* Open a parent directory. Fails in root.
* Provided handle changes to the first entry of the parent directory.
*/
bool fat16_parent(FAT16_FILE* file);
/** Jump to first file in this directory */
void fat16_first(FAT16_FILE* file);
/**
* Find a file with given "display name" in this directory.
* If file is found, "dir" will contain it's handle.
* If file is NOT found, the handle points to the last entry of the directory.
*/
bool fat16_find(FAT16_FILE* dir, const char* name);
// -------- FILE INSPECTION -----------
/** Check if file is a valid entry, or long-name/label/deleted */
bool fat16_is_regular(const FAT16_FILE* file);
/**
* Resolve a file name, trim spaces and add null terminator.
* Returns the passed char*, or NULL on error.
*/
char* fat16_dispname(const FAT16_FILE* file, char* disp_out);
/**
* Convert filename to zero-padded fixed length one
* Returns the passed char*.
*/
char* fat16_rawname(const char* disp_in, char* raw_out);