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Improved comments and moved internal stuff to special header file

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master
Ondřej Hruška 10 years ago
parent a2e837a92a
commit 70bb4237f1
3 changed files with 124 additions and 83 deletions
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  1. 6
      fat16.c
  2. 139
      fat16.h
  3. 62
      fat16_internal.h

6
fat16.c
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@ -706,13 +706,13 @@ void fat16_first(FAT16_FILE* file)
/** Open a directory denoted by the file. */
bool fat16_opendir(FAT16_FILE* file)
bool fat16_opendir(FAT16_FILE* dir)
{
// Don't open non-dirs and "." directory.
if (!(file->attribs & FA_DIR) || file->type == FT_SELF)
if (!(dir->attribs & FA_DIR) || dir->type == FT_SELF)
return false;
open_file(file->fat, file, file->clu_start, 0);
open_file(dir->fat, dir, dir->clu_start, 0);
return true;
}

139
fat16.h
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@ -1,6 +1,10 @@
#pragma once
/** Abstract block device interface */
/**
* Abstract block device interface
*
* Populate this with pointers to your I/O functions.
*/
typedef struct
{
// Sequential read
@ -20,7 +24,10 @@ typedef struct
// -------------------------------
/** file types (values don't matter) */
/**
* File types (values can be used for debug printing).
* Accessible using file->type
*/
typedef enum
{
FT_NONE = '-',
@ -29,102 +36,73 @@ typedef enum
FT_PARENT = 'P',
FT_LABEL = 'L',
FT_LFN = '~',
FT_INVALID = 'i', // not recognized weird file
FT_INVALID = '?', // not recognized weird file
FT_SELF = '.',
FT_FILE = 'F'
} FAT16_FT;
// File Attributes (bit flags)
#define FA_READONLY 0x01 // read only file
#define FA_HIDDEN 0x02 // hidden file
#define FA_SYSTEM 0x04 // system file
#define FA_LABEL 0x08 // volume label entry, found only in root directory.
#define FA_DIR 0x10 // subdirectory
#define FA_ARCHIVE 0x20 // archive flag
/** Boot Sector structure - INTERNAL! */
typedef struct __attribute__((packed))
{
// Include definitions of fully internal structs
#include "fat16_internal.h"
// Fields loaded directly from disk:
// 13 bytes skipped
uint8_t sectors_per_cluster;
uint16_t reserved_sectors;
uint8_t num_fats;
uint16_t root_entries;
// 3 bytes skipped
uint16_t fat_size_sectors;
// 8 bytes skipped
uint32_t total_sectors; // if "short size sectors" is used, it's copied here too
// 7 bytes skipped
char volume_label[11]; // space padded, no terminator
// Added fields:
uint32_t bytes_per_cluster;
}
Fat16BootSector;
/** FAT filesystem handle - private fields! */
/**
* File handle struct.
*
* File handle contains cursor, file name, type, size etc.
* Everything (files, dirs) is accessed using this.
*/
typedef struct __attribute__((packed))
{
// Backing block device
const BLOCKDEV* dev;
// Root directory sector start
uint32_t rd_addr;
// Start of first cluster (number "2")
uint32_t data_addr;
// Start of fat table
uint32_t fat_addr;
/**
* Raw file name. Starting 0x05 was converted to 0xE5.
* To get PRINTABLE file name, use fat16_dispname()
*/
uint8_t name[11];
// Boot sector data struct
Fat16BootSector bs;
}
FAT16;
/**
* File attributes - bit field composed of FA_* flags
* (internal)
*/
uint8_t attribs;
// 14 bytes skipped (10 reserved, date, time)
/** File handle struct */
typedef struct __attribute__((packed))
{
// Fields loaded directly from disk:
uint8_t name[11]; // Starting 0x05 converted to 0xE5, other "magic chars" left intact
uint8_t attribs; // composed of FA_* constants
// 14 bytes skipped
/** 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;
// Added fields:
// --- the following fields are added when reading ---
/** File type. */
FAT16_FT type;
// --- Private fields ---
// Cursor
// --- 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
// File position in the directory. (internal)
uint16_t clu; // first cluster of directory
uint16_t num; // fiel entry number
uint16_t num; // file entry number
// pointer to FAT
// Pointer to the FAT16 handle. (internal)
const FAT16* fat;
}
FAT16_FILE;
/** Initialize a filesystem */
/** Initialize the file system - store into "fat" */
void fat16_init(const BLOCKDEV* dev, FAT16* fat);
@ -132,14 +110,13 @@ 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.
*
* Either way, the prev and next functions will work as expected.
*/
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);
@ -185,29 +162,29 @@ bool fat16_mkdir(FAT16_FILE* file, const char* name);
/**
* Write new file size (also to the disk).
* Allocates / frees needed clusters, does not erase them.
* 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 entry and free clusters.
* Does NOT work on folders.
* Delete a *FILE* and free it's clusters.
*/
bool fat16_rmfile(FAT16_FILE* file);
/**
* Delete an empty directory.
* Calling with non-subfolder entry or non-empty directory will cause error.
* Delete an empty *DIRECTORY* and free it's clusters.
*/
bool fat16_rmdir(FAT16_FILE* file);
/**
* Delete a file or directory, regardless of type.
* Directories are deleted recursively.
* Delete a file or directory, even FT_LFN and FT_INVALID.
* Directories are deleted recursively (!)
*/
bool fat16_delete(FAT16_FILE* file);
@ -226,17 +203,19 @@ bool fat16_next(FAT16_FILE* file);
/**
* Open a subdirectory denoted by the file.
* Provided handle changes to first entry of the directory.
* Provided handle changes to the first entry of the directory.
*/
bool fat16_opendir(FAT16_FILE* file);
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);
/** Rewind to first file in directory */
/** Jump to first file in this directory */
void fat16_first(FAT16_FILE* file);

62
fat16_internal.h
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@ -0,0 +1,62 @@
#pragma once
// Internal types and stuff that is needed in the header for declarations,
// but is not a part of the public API.
/** Boot Sector structure */
typedef struct __attribute__((packed))
{
// Fields loaded directly from disk:
// 13 bytes skipped
uint8_t sectors_per_cluster;
uint16_t reserved_sectors;
uint8_t num_fats;
uint16_t root_entries;
// 3 bytes skipped
uint16_t fat_size_sectors;
// 8 bytes skipped
uint32_t total_sectors; // if "short size sectors" is used, it's copied here too
// 7 bytes skipped
char volume_label[11]; // space padded, no terminator
// Added fields:
uint32_t bytes_per_cluster;
}
Fat16BootSector;
/** FAT filesystem handle */
typedef struct __attribute__((packed))
{
// Backing block device
const BLOCKDEV* dev;
// Root directory sector start
uint32_t rd_addr;
// Start of first cluster (number "2")
uint32_t data_addr;
// Start of fat table
uint32_t fat_addr;
// Boot sector data struct
Fat16BootSector bs;
}
FAT16;
/**
* File Attributes (bit flags)
* Accessible using file->attribs
*/
#define FA_READONLY 0x01 // read only file
#define FA_HIDDEN 0x02 // hidden file
#define FA_SYSTEM 0x04 // system file
#define FA_LABEL 0x08 // volume label entry, found only in root directory.
#define FA_DIR 0x10 // subdirectory
#define FA_ARCHIVE 0x20 // archive flag
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