/* 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 . */ #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