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/*++
Copyright (c) 2005, Intel Corporation
All rights reserved. This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:
FatFileSystem.h
Abstract:
Definitions for on-disk FAT structures
Revision History
--*/
#ifndef _FATFILESYSTEM_H_
#define _FATFILESYSTEM_H_
#pragma pack(1)
//
// FAT info signature
//
#define FAT_INFO_SIGNATURE 0x41615252
#define FAT_INFO_BEGIN_SIGNATURE 0x61417272
#define FAT_INFO_END_SIGNATURE 0xAA550000
//
// FAT entry values
//
#define FAT_CLUSTER_SPECIAL_EXT (-1 & (~0xF))
#define FAT_CLUSTER_SPECIAL ((FAT_CLUSTER_SPECIAL_EXT) | 0x07)
#define FAT_CLUSTER_FREE 0
#define FAT_CLUSTER_RESERVED (FAT_CLUSTER_SPECIAL)
#define FAT_CLUSTER_BAD (FAT_CLUSTER_SPECIAL)
#define FAT_CLUSTER_LAST (-1)
#define FAT_END_OF_FAT_CHAIN(Cluster) ((Cluster) > (FAT_CLUSTER_SPECIAL))
#define FAT_MIN_CLUSTER 2
#define FAT_MAX_FAT12_CLUSTER 0xFF5
#define FAT_MAX_FAT16_CLUSTER 0xFFF5
#define FAT_CLUSTER_SPECIAL_FAT12 0xFF7
#define FAT_CLUSTER_SPECIAL_FAT16 0xFFF7
#define FAT_CLUSTER_SPECIAL_FAT32 0x0FFFFFF7
#define FAT_CLUSTER_MASK_FAT12 0xFFF
#define FAT_CLUSTER_UNMASK_FAT12 0xF000
#define FAT_CLUSTER_MASK_FAT32 0x0FFFFFFF
#define FAT_CLUSTER_UNMASK_FAT32 0xF0000000
#define FAT_POS_FAT12(a) ((a) * 3 / 2)
#define FAT_POS_FAT16(a) ((a) * 2)
#define FAT_POS_FAT32(a) ((a) * 4)
#define FAT_ODD_CLUSTER_FAT12(a) (((a) & 1) != 0)
//
// FAT attribute define
//
#define FAT_ATTRIBUTE_READ_ONLY 0x01
#define FAT_ATTRIBUTE_HIDDEN 0x02
#define FAT_ATTRIBUTE_SYSTEM 0x04
#define FAT_ATTRIBUTE_VOLUME_ID 0x08
#define FAT_ATTRIBUTE_DIRECTORY 0x10
#define FAT_ATTRIBUTE_ARCHIVE 0x20
#define FAT_ATTRIBUTE_DEVICE 0x40
#define FAT_ATTRIBUTE_LFN 0x0F
//
// Some Long File Name definitions
//
#define FAT_LFN_LAST 0x40 // Ordinal field
#define MAX_LFN_ENTRIES 20
#define LFN_CHAR1_LEN 5
#define LFN_CHAR2_LEN 6
#define LFN_CHAR3_LEN 2
#define LFN_CHAR_TOTAL (LFN_CHAR1_LEN + LFN_CHAR2_LEN + LFN_CHAR3_LEN)
#define LFN_ENTRY_NUMBER(a) (((a) + LFN_CHAR_TOTAL - 1) / LFN_CHAR_TOTAL)
//
// Some 8.3 File Name definitions
//
#define FAT_MAIN_NAME_LEN 8
#define FAT_EXTEND_NAME_LEN 3
#define FAT_NAME_LEN (FAT_MAIN_NAME_LEN + FAT_EXTEND_NAME_LEN)
//
// Some directory entry information
//
#define FAT_ENTRY_INFO_OFFSET 13
#define DELETE_ENTRY_MARK 0xE5
#define EMPTY_ENTRY_MARK 0x00
//
// Volume dirty Mask
//
#define FAT16_DIRTY_MASK 0x7fff
#define FAT32_DIRTY_MASK 0xf7ffffff
//
// internal flag
//
#define FAT_CASE_MIXED 0x01
#define FAT_CASE_NAME_LOWER 0x08
#define FAT_CASE_EXT_LOWER 0x10
typedef struct {
UINT8 Ia32Jump[3];
CHAR8 OemId[8];
UINT16 SectorSize;
UINT8 SectorsPerCluster;
UINT16 ReservedSectors;
UINT8 NumFats;
UINT16 RootEntries; // < FAT32, root dir is fixed size
UINT16 Sectors;
UINT8 Media;
UINT16 SectorsPerFat; // < FAT32
UINT16 SectorsPerTrack; // (ignored)
UINT16 Heads; // (ignored)
UINT32 HiddenSectors; // (ignored)
UINT32 LargeSectors; // Used if Sectors==0
} FAT_BOOT_SECTOR_BASIC;
typedef struct {
UINT8 PhysicalDriveNumber; // (ignored)
UINT8 CurrentHead; // holds boot_sector_dirty bit
UINT8 Signature; // (ignored)
CHAR8 Id[4];
CHAR8 FatLabel[11];
CHAR8 SystemId[8];
} FAT_BOOT_SECTOR_EXT;
typedef struct {
UINT32 LargeSectorsPerFat; // FAT32
UINT16 ExtendedFlags; // FAT32 (ignored)
UINT16 FsVersion; // FAT32 (ignored)
UINT32 RootDirFirstCluster; // FAT32
UINT16 FsInfoSector; // FAT32
UINT16 BackupBootSector; // FAT32
UINT8 Reserved[12]; // FAT32 (ignored)
UINT8 PhysicalDriveNumber; // (ignored)
UINT8 CurrentHead; // holds boot_sector_dirty bit
UINT8 Signature; // (ignored)
CHAR8 Id[4];
CHAR8 FatLabel[11];
CHAR8 SystemId[8];
} FAT32_BOOT_SECTOR_EXT;
typedef struct {
FAT_BOOT_SECTOR_BASIC FatBsb;
union {
FAT_BOOT_SECTOR_EXT FatBse;
FAT32_BOOT_SECTOR_EXT Fat32Bse;
} FatBse;
} FAT_BOOT_SECTOR;
//
// FAT Info Structure
//
typedef struct {
UINT32 ClusterCount;
UINT32 NextCluster;
} FAT_FREE_INFO;
typedef struct {
UINT32 Signature;
UINT8 ExtraBootCode[480];
UINT32 InfoBeginSignature;
FAT_FREE_INFO FreeInfo;
UINT8 Reserved[12];
UINT32 InfoEndSignature;
} FAT_INFO_SECTOR;
//
// Directory Entry
//
#define FAT_MAX_YEAR_FROM_1980 0x7f
typedef struct {
UINT16 Day : 5;
UINT16 Month : 4;
UINT16 Year : 7; // From 1980
} FAT_DATE;
typedef struct {
UINT16 DoubleSecond : 5;
UINT16 Minute : 6;
UINT16 Hour : 5;
} FAT_TIME;
typedef struct {
FAT_TIME Time;
FAT_DATE Date;
} FAT_DATE_TIME;
typedef struct {
CHAR8 FileName[11]; // 8.3 filename
UINT8 Attributes;
UINT8 CaseFlag;
UINT8 CreateMillisecond; // (creation milliseconds - ignored)
FAT_DATE_TIME FileCreateTime;
FAT_DATE FileLastAccess;
UINT16 FileClusterHigh; // >= FAT32
FAT_DATE_TIME FileModificationTime;
UINT16 FileCluster;
UINT32 FileSize;
} FAT_DIRECTORY_ENTRY;
typedef struct {
UINT8 Ordinal;
CHAR8 Name1[10]; // (Really 5 chars, but not WCHAR aligned)
UINT8 Attributes;
UINT8 Type;
UINT8 Checksum;
CHAR16 Name2[6];
UINT16 MustBeZero;
CHAR16 Name3[2];
} FAT_DIRECTORY_LFN;
#pragma pack()
#endif
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