| /* 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/>. | |
| */ | |
| /** | |
| \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; | |
| } | |