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Arduino/libraries/SD/utility/FatStructs.h
2014-12-02 22:15:57 +01:00

419 lines
17 KiB
C

/* Arduino SdFat Library
* Copyright (C) 2009 by William Greiman
*
* This file is part of the Arduino SdFat Library
*
* This Library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This Library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Arduino SdFat Library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#ifndef FatStructs_h
#define FatStructs_h
/**
* \file
* FAT file structures
*/
/*
* mostly from Microsoft document fatgen103.doc
* http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
*/
//------------------------------------------------------------------------------
/** Value for byte 510 of boot block or MBR */
uint8_t const BOOTSIG0 = 0X55;
/** Value for byte 511 of boot block or MBR */
uint8_t const BOOTSIG1 = 0XAA;
//------------------------------------------------------------------------------
/**
* \struct partitionTable
* \brief MBR partition table entry
*
* A partition table entry for a MBR formatted storage device.
* The MBR partition table has four entries.
*/
struct partitionTable {
/**
* Boot Indicator . Indicates whether the volume is the active
* partition. Legal values include: 0X00. Do not use for booting.
* 0X80 Active partition.
*/
uint8_t boot;
/**
* Head part of Cylinder-head-sector address of the first block in
* the partition. Legal values are 0-255. Only used in old PC BIOS.
*/
uint8_t beginHead;
/**
* Sector part of Cylinder-head-sector address of the first block in
* the partition. Legal values are 1-63. Only used in old PC BIOS.
*/
unsigned beginSector : 6;
/** High bits cylinder for first block in partition. */
unsigned beginCylinderHigh : 2;
/**
* Combine beginCylinderLow with beginCylinderHigh. Legal values
* are 0-1023. Only used in old PC BIOS.
*/
uint8_t beginCylinderLow;
/**
* Partition type. See defines that begin with PART_TYPE_ for
* some Microsoft partition types.
*/
uint8_t type;
/**
* head part of cylinder-head-sector address of the last sector in the
* partition. Legal values are 0-255. Only used in old PC BIOS.
*/
uint8_t endHead;
/**
* Sector part of cylinder-head-sector address of the last sector in
* the partition. Legal values are 1-63. Only used in old PC BIOS.
*/
unsigned endSector : 6;
/** High bits of end cylinder */
unsigned endCylinderHigh : 2;
/**
* Combine endCylinderLow with endCylinderHigh. Legal values
* are 0-1023. Only used in old PC BIOS.
*/
uint8_t endCylinderLow;
/** Logical block address of the first block in the partition. */
uint32_t firstSector;
/** Length of the partition, in blocks. */
uint32_t totalSectors;
} __attribute__((packed));
/** Type name for partitionTable */
typedef struct partitionTable part_t;
//------------------------------------------------------------------------------
/**
* \struct masterBootRecord
*
* \brief Master Boot Record
*
* The first block of a storage device that is formatted with a MBR.
*/
struct masterBootRecord {
/** Code Area for master boot program. */
uint8_t codeArea[440];
/** Optional WindowsNT disk signature. May contain more boot code. */
uint32_t diskSignature;
/** Usually zero but may be more boot code. */
uint16_t usuallyZero;
/** Partition tables. */
part_t part[4];
/** First MBR signature byte. Must be 0X55 */
uint8_t mbrSig0;
/** Second MBR signature byte. Must be 0XAA */
uint8_t mbrSig1;
} __attribute__((packed));
/** Type name for masterBootRecord */
typedef struct masterBootRecord mbr_t;
//------------------------------------------------------------------------------
/**
* \struct biosParmBlock
*
* \brief BIOS parameter block
*
* The BIOS parameter block describes the physical layout of a FAT volume.
*/
struct biosParmBlock {
/**
* Count of bytes per sector. This value may take on only the
* following values: 512, 1024, 2048 or 4096
*/
uint16_t bytesPerSector;
/**
* Number of sectors per allocation unit. This value must be a
* power of 2 that is greater than 0. The legal values are
* 1, 2, 4, 8, 16, 32, 64, and 128.
*/
uint8_t sectorsPerCluster;
/**
* Number of sectors before the first FAT.
* This value must not be zero.
*/
uint16_t reservedSectorCount;
/** The count of FAT data structures on the volume. This field should
* always contain the value 2 for any FAT volume of any type.
*/
uint8_t fatCount;
/**
* For FAT12 and FAT16 volumes, this field contains the count of
* 32-byte directory entries in the root directory. For FAT32 volumes,
* this field must be set to 0. For FAT12 and FAT16 volumes, this
* value should always specify a count that when multiplied by 32
* results in a multiple of bytesPerSector. FAT16 volumes should
* use the value 512.
*/
uint16_t rootDirEntryCount;
/**
* This field is the old 16-bit total count of sectors on the volume.
* This count includes the count of all sectors in all four regions
* of the volume. This field can be 0; if it is 0, then totalSectors32
* must be non-zero. For FAT32 volumes, this field must be 0. For
* FAT12 and FAT16 volumes, this field contains the sector count, and
* totalSectors32 is 0 if the total sector count fits
* (is less than 0x10000).
*/
uint16_t totalSectors16;
/**
* This dates back to the old MS-DOS 1.x media determination and is
* no longer usually used for anything. 0xF8 is the standard value
* for fixed (non-removable) media. For removable media, 0xF0 is
* frequently used. Legal values are 0xF0 or 0xF8-0xFF.
*/
uint8_t mediaType;
/**
* Count of sectors occupied by one FAT on FAT12/FAT16 volumes.
* On FAT32 volumes this field must be 0, and sectorsPerFat32
* contains the FAT size count.
*/
uint16_t sectorsPerFat16;
/** Sectors per track for interrupt 0x13. Not used otherwise. */
uint16_t sectorsPerTrtack;
/** Number of heads for interrupt 0x13. Not used otherwise. */
uint16_t headCount;
/**
* Count of hidden sectors preceding the partition that contains this
* FAT volume. This field is generally only relevant for media
* visible on interrupt 0x13.
*/
uint32_t hidddenSectors;
/**
* This field is the new 32-bit total count of sectors on the volume.
* This count includes the count of all sectors in all four regions
* of the volume. This field can be 0; if it is 0, then
* totalSectors16 must be non-zero.
*/
uint32_t totalSectors32;
/**
* Count of sectors occupied by one FAT on FAT32 volumes.
*/
uint32_t sectorsPerFat32;
/**
* This field is only defined for FAT32 media and does not exist on
* FAT12 and FAT16 media.
* Bits 0-3 -- Zero-based number of active FAT.
* Only valid if mirroring is disabled.
* Bits 4-6 -- Reserved.
* Bit 7 -- 0 means the FAT is mirrored at runtime into all FATs.
* -- 1 means only one FAT is active; it is the one referenced in bits 0-3.
* Bits 8-15 -- Reserved.
*/
uint16_t fat32Flags;
/**
* FAT32 version. High byte is major revision number.
* Low byte is minor revision number. Only 0.0 define.
*/
uint16_t fat32Version;
/**
* Cluster number of the first cluster of the root directory for FAT32.
* This usually 2 but not required to be 2.
*/
uint32_t fat32RootCluster;
/**
* Sector number of FSINFO structure in the reserved area of the
* FAT32 volume. Usually 1.
*/
uint16_t fat32FSInfo;
/**
* If non-zero, indicates the sector number in the reserved area
* of the volume of a copy of the boot record. Usually 6.
* No value other than 6 is recommended.
*/
uint16_t fat32BackBootBlock;
/**
* Reserved for future expansion. Code that formats FAT32 volumes
* should always set all of the bytes of this field to 0.
*/
uint8_t fat32Reserved[12];
} __attribute__((packed));
/** Type name for biosParmBlock */
typedef struct biosParmBlock bpb_t;
//------------------------------------------------------------------------------
/**
* \struct fat32BootSector
*
* \brief Boot sector for a FAT16 or FAT32 volume.
*
*/
struct fat32BootSector {
/** X86 jmp to boot program */
uint8_t jmpToBootCode[3];
/** informational only - don't depend on it */
char oemName[8];
/** BIOS Parameter Block */
bpb_t bpb;
/** for int0x13 use value 0X80 for hard drive */
uint8_t driveNumber;
/** used by Windows NT - should be zero for FAT */
uint8_t reserved1;
/** 0X29 if next three fields are valid */
uint8_t bootSignature;
/** usually generated by combining date and time */
uint32_t volumeSerialNumber;
/** should match volume label in root dir */
char volumeLabel[11];
/** informational only - don't depend on it */
char fileSystemType[8];
/** X86 boot code */
uint8_t bootCode[420];
/** must be 0X55 */
uint8_t bootSectorSig0;
/** must be 0XAA */
uint8_t bootSectorSig1;
} __attribute__((packed));
//------------------------------------------------------------------------------
// End Of Chain values for FAT entries
/** FAT16 end of chain value used by Microsoft. */
uint16_t const FAT16EOC = 0XFFFF;
/** Minimum value for FAT16 EOC. Use to test for EOC. */
uint16_t const FAT16EOC_MIN = 0XFFF8;
/** FAT32 end of chain value used by Microsoft. */
uint32_t const FAT32EOC = 0X0FFFFFFF;
/** Minimum value for FAT32 EOC. Use to test for EOC. */
uint32_t const FAT32EOC_MIN = 0X0FFFFFF8;
/** Mask a for FAT32 entry. Entries are 28 bits. */
uint32_t const FAT32MASK = 0X0FFFFFFF;
/** Type name for fat32BootSector */
typedef struct fat32BootSector fbs_t;
//------------------------------------------------------------------------------
/**
* \struct directoryEntry
* \brief FAT short directory entry
*
* Short means short 8.3 name, not the entry size.
*
* Date Format. A FAT directory entry date stamp is a 16-bit field that is
* basically a date relative to the MS-DOS epoch of 01/01/1980. Here is the
* format (bit 0 is the LSB of the 16-bit word, bit 15 is the MSB of the
* 16-bit word):
*
* Bits 9-15: Count of years from 1980, valid value range 0-127
* inclusive (1980-2107).
*
* Bits 5-8: Month of year, 1 = January, valid value range 1-12 inclusive.
*
* Bits 0-4: Day of month, valid value range 1-31 inclusive.
*
* Time Format. A FAT directory entry time stamp is a 16-bit field that has
* a granularity of 2 seconds. Here is the format (bit 0 is the LSB of the
* 16-bit word, bit 15 is the MSB of the 16-bit word).
*
* Bits 11-15: Hours, valid value range 0-23 inclusive.
*
* Bits 5-10: Minutes, valid value range 0-59 inclusive.
*
* Bits 0-4: 2-second count, valid value range 0-29 inclusive (0 - 58 seconds).
*
* The valid time range is from Midnight 00:00:00 to 23:59:58.
*/
struct directoryEntry {
/**
* Short 8.3 name.
* The first eight bytes contain the file name with blank fill.
* The last three bytes contain the file extension with blank fill.
*/
uint8_t name[11];
/** Entry attributes.
*
* The upper two bits of the attribute byte are reserved and should
* always be set to 0 when a file is created and never modified or
* looked at after that. See defines that begin with DIR_ATT_.
*/
uint8_t attributes;
/**
* Reserved for use by Windows NT. Set value to 0 when a file is
* created and never modify or look at it after that.
*/
uint8_t reservedNT;
/**
* The granularity of the seconds part of creationTime is 2 seconds
* so this field is a count of tenths of a second and its valid
* value range is 0-199 inclusive. (WHG note - seems to be hundredths)
*/
uint8_t creationTimeTenths;
/** Time file was created. */
uint16_t creationTime;
/** Date file was created. */
uint16_t creationDate;
/**
* Last access date. Note that there is no last access time, only
* a date. This is the date of last read or write. In the case of
* a write, this should be set to the same date as lastWriteDate.
*/
uint16_t lastAccessDate;
/**
* High word of this entry's first cluster number (always 0 for a
* FAT12 or FAT16 volume).
*/
uint16_t firstClusterHigh;
/** Time of last write. File creation is considered a write. */
uint16_t lastWriteTime;
/** Date of last write. File creation is considered a write. */
uint16_t lastWriteDate;
/** Low word of this entry's first cluster number. */
uint16_t firstClusterLow;
/** 32-bit unsigned holding this file's size in bytes. */
uint32_t fileSize;
} __attribute__((packed));
//------------------------------------------------------------------------------
// Definitions for directory entries
//
/** Type name for directoryEntry */
typedef struct directoryEntry dir_t;
/** escape for name[0] = 0XE5 */
uint8_t const DIR_NAME_0XE5 = 0X05;
/** name[0] value for entry that is free after being "deleted" */
uint8_t const DIR_NAME_DELETED = 0XE5;
/** name[0] value for entry that is free and no allocated entries follow */
uint8_t const DIR_NAME_FREE = 0X00;
/** file is read-only */
uint8_t const DIR_ATT_READ_ONLY = 0X01;
/** File should hidden in directory listings */
uint8_t const DIR_ATT_HIDDEN = 0X02;
/** Entry is for a system file */
uint8_t const DIR_ATT_SYSTEM = 0X04;
/** Directory entry contains the volume label */
uint8_t const DIR_ATT_VOLUME_ID = 0X08;
/** Entry is for a directory */
uint8_t const DIR_ATT_DIRECTORY = 0X10;
/** Old DOS archive bit for backup support */
uint8_t const DIR_ATT_ARCHIVE = 0X20;
/** Test value for long name entry. Test is
(d->attributes & DIR_ATT_LONG_NAME_MASK) == DIR_ATT_LONG_NAME. */
uint8_t const DIR_ATT_LONG_NAME = 0X0F;
/** Test mask for long name entry */
uint8_t const DIR_ATT_LONG_NAME_MASK = 0X3F;
/** defined attribute bits */
uint8_t const DIR_ATT_DEFINED_BITS = 0X3F;
/** Directory entry is part of a long name */
static inline uint8_t DIR_IS_LONG_NAME(const dir_t* dir) {
return (dir->attributes & DIR_ATT_LONG_NAME_MASK) == DIR_ATT_LONG_NAME;
}
/** Mask for file/subdirectory tests */
uint8_t const DIR_ATT_FILE_TYPE_MASK = (DIR_ATT_VOLUME_ID | DIR_ATT_DIRECTORY);
/** Directory entry is for a file */
static inline uint8_t DIR_IS_FILE(const dir_t* dir) {
return (dir->attributes & DIR_ATT_FILE_TYPE_MASK) == 0;
}
/** Directory entry is for a subdirectory */
static inline uint8_t DIR_IS_SUBDIR(const dir_t* dir) {
return (dir->attributes & DIR_ATT_FILE_TYPE_MASK) == DIR_ATT_DIRECTORY;
}
/** Directory entry is for a file or subdirectory */
static inline uint8_t DIR_IS_FILE_OR_SUBDIR(const dir_t* dir) {
return (dir->attributes & DIR_ATT_VOLUME_ID) == 0;
}
#endif // FatStructs_h