FatStructs.h

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#ifndef FatStructs_h
#define FatStructs_h

/*
 * mostly from Microsoft document fatgen103.doc
 * http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
 */
//------------------------------------------------------------------------------
#define BOOTSIG0 0X55

#define BOOTSIG1 0XAA
//------------------------------------------------------------------------------
struct partitionTable {
  uint8_t boot;
  uint8_t beginHead;
  unsigned beginSector : 6;
  unsigned beginCylinderHigh : 2;
  uint8_t beginCylinderLow;
  uint8_t type;
  uint8_t endHead;
  unsigned endSector : 6;
  unsigned endCylinderHigh : 2;
  uint8_t endCylinderLow;
  uint32_t firstSector;
  uint32_t totalSectors;
};
typedef struct partitionTable part_t;
//------------------------------------------------------------------------------
struct masterBootRecord {
  uint8_t codeArea[440];
  uint32_t diskSignature;
  uint16_t usuallyZero;
  part_t part[4];
  uint8_t mbrSig0;
  uint8_t mbrSig1;
};
typedef struct masterBootRecord mbr_t;
//------------------------------------------------------------------------------
struct biosParmBlock {
  uint16_t bytesPerSector;
  uint8_t sectorsPerCluster;
  uint16_t reservedSectorCount;
  uint8_t fatCount;
  uint16_t rootDirEntryCount;
  uint16_t totalSectors16;
  uint8_t mediaType;
  uint16_t sectorsPerFat16;
  uint16_t sectorsPerTrtack;
  uint16_t headCount;
  uint32_t hidddenSectors;
  uint32_t totalSectors32;
  uint32_t sectorsPerFat32;
  uint16_t fat32Flags;
  uint16_t fat32Version;
  uint32_t fat32RootCluster;
  uint16_t fat32FSInfo;
  uint16_t fat32BackBootBlock;
  uint8_t fat32Reserved[12];
};
typedef struct biosParmBlock bpb_t;
//------------------------------------------------------------------------------
struct fat32BootSector {
  uint8_t jmpToBootCode[3];
  char oemName[8];
  bpb_t bpb;
  uint8_t driveNumber;
  uint8_t reserved1;
  uint8_t bootSignature;
  uint32_t volumeSerialNumber;
  char volumeLabel[11];
  char fileSystemType[8];
  uint8_t bootCode[420];
  uint8_t bootSectorSig0;
  uint8_t bootSectorSig1;
};
//------------------------------------------------------------------------------
// End Of Chain values for FAT entries
#define FAT16EOC_MIN 0XFFF8

#define FAT32EOC_MIN 0X0FFFFFF8

#define FAT16EOC 0XFFFF

#define FAT32EOC 0X0FFFFFFF

#define FAT32MASK 0X0FFFFFFF

typedef struct fat32BootSector fbs_t;
//------------------------------------------------------------------------------
struct directoryEntry {
  uint8_t name[11];
  uint8_t attributes;
  uint8_t reservedNT;
  uint8_t creationTimeTenths;
  uint16_t creationTime;
  uint16_t creationDate;
  uint16_t lastAccessDate;
  uint16_t firstClusterHigh;
  uint16_t lastWriteTime;
  uint16_t lastWriteDate;
  uint16_t firstClusterLow;
  uint32_t fileSize;
};
//------------------------------------------------------------------------------
// Macros for directory entries
//
typedef struct directoryEntry dir_t;
#define DIR_NAME_0XE5 0X05

#define DIR_NAME_DELETED 0XE5

#define DIR_NAME_FREE 0X00

#define DIR_ATT_READ_ONLY 0X01

#define DIR_ATT_HIDDEN 0X02

#define DIR_ATT_SYSTEM 0X04

#define DIR_ATT_VOLUME_ID 0X08

#define DIR_ATT_DIRECTORY 0X10

#define DIR_ATT_ARCHIVE 0X20

#define DIR_ATT_LONG_NAME 0X0F

#define DIR_ATT_LONG_NAME_MASK 0X3F

#define DIR_ATT_DEFINED_BITS 0X3F

#define DIR_IS_LONG_NAME(dir)                                                  \
  (((dir).attributes & DIR_ATT_LONG_NAME_MASK) == DIR_ATT_LONG_NAME)

#define DIR_ATT_FILE_TYPE_MASK (DIR_ATT_VOLUME_ID | DIR_ATT_DIRECTORY)

#define DIR_IS_FILE(dir) (((dir).attributes & DIR_ATT_FILE_TYPE_MASK) == 0)

#define DIR_IS_SUBDIR(dir)                                                     \
  (((dir).attributes & DIR_ATT_FILE_TYPE_MASK) == DIR_ATT_DIRECTORY)

#define DIR_IS_FILE_OR_SUBDIR(dir) (((dir).attributes & DIR_ATT_VOLUME_ID) == 0)
#endif // FatStructs_h