This page hosts a formal specification of vfat using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Java generated by Kaitai Struct depends on the Java runtime library. You have to install it before you can parse data.
The Java runtime library is published in the Maven Central Repository. Refer to the artifact page for instructions how to add it into your project with the build tool that you use.
Parse a local file and get structure in memory:
Vfat data = Vfat.fromFile("path/to/local/file.bin");
Or parse structure from a byte array:
byte[] someArray = new byte[] { ... };
Vfat data = new Vfat(new ByteBufferKaitaiStream(someArray));
After that, one can get various attributes from the structure by invoking getter methods like:
data.bootSector() // => get boot sector
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import io.kaitai.struct.ByteBufferKaitaiStream;
import io.kaitai.struct.KaitaiStruct;
import io.kaitai.struct.KaitaiStream;
import java.io.IOException;
import java.util.Arrays;
import java.nio.charset.Charset;
import java.util.ArrayList;
/**
* @see <a href="https://download.microsoft.com/download/0/8/4/084c452b-b772-4fe5-89bb-a0cbf082286a/fatgen103.doc">Source</a>
*/
public class Vfat extends KaitaiStruct {
public static Vfat fromFile(String fileName) throws IOException {
return new Vfat(new ByteBufferKaitaiStream(fileName));
}
public Vfat(KaitaiStream _io) {
this(_io, null, null);
}
public Vfat(KaitaiStream _io, KaitaiStruct _parent) {
this(_io, _parent, null);
}
public Vfat(KaitaiStream _io, KaitaiStruct _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root == null ? this : _root;
_read();
}
private void _read() {
this.bootSector = new BootSector(this._io, this, _root);
}
/**
* Extended BIOS Parameter Block for FAT32
*/
public static class ExtBiosParamBlockFat32 extends KaitaiStruct {
public static ExtBiosParamBlockFat32 fromFile(String fileName) throws IOException {
return new ExtBiosParamBlockFat32(new ByteBufferKaitaiStream(fileName));
}
public ExtBiosParamBlockFat32(KaitaiStream _io) {
this(_io, null, null);
}
public ExtBiosParamBlockFat32(KaitaiStream _io, Vfat.BootSector _parent) {
this(_io, _parent, null);
}
public ExtBiosParamBlockFat32(KaitaiStream _io, Vfat.BootSector _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.lsPerFat = this._io.readU4le();
this.hasActiveFat = this._io.readBitsIntLe(1) != 0;
this.reserved1 = this._io.readBitsIntLe(3);
this.activeFatId = this._io.readBitsIntLe(4);
this._io.alignToByte();
this.reserved2 = this._io.readBytes(1);
if (!(Arrays.equals(reserved2(), new byte[] { 0 }))) {
throw new KaitaiStream.ValidationNotEqualError(new byte[] { 0 }, reserved2(), _io(), "/types/ext_bios_param_block_fat32/seq/4");
}
this.fatVersion = this._io.readU2le();
this.rootDirStartClus = this._io.readU4le();
this.lsFsInfo = this._io.readU2le();
this.bootSectorsCopyStartLs = this._io.readU2le();
this.reserved3 = this._io.readBytes(12);
this.physDriveNum = this._io.readU1();
this.reserved4 = this._io.readU1();
this.extBootSign = this._io.readU1();
this.volumeId = this._io.readBytes(4);
this.partitionVolumeLabel = new String(KaitaiStream.bytesStripRight(this._io.readBytes(11), (byte) 32), Charset.forName("ASCII"));
this.fsTypeStr = new String(KaitaiStream.bytesStripRight(this._io.readBytes(8), (byte) 32), Charset.forName("ASCII"));
}
private long lsPerFat;
private boolean hasActiveFat;
private long reserved1;
private long activeFatId;
private byte[] reserved2;
private int fatVersion;
private long rootDirStartClus;
private int lsFsInfo;
private int bootSectorsCopyStartLs;
private byte[] reserved3;
private int physDriveNum;
private int reserved4;
private int extBootSign;
private byte[] volumeId;
private String partitionVolumeLabel;
private String fsTypeStr;
private Vfat _root;
private Vfat.BootSector _parent;
/**
* Logical sectors per file allocation table (corresponds with
* the old entry `ls_per_fat` in the DOS 2.0 BPB).
*/
public long lsPerFat() { return lsPerFat; }
/**
* If true, then there is "active" FAT, which is designated in
* `active_fat` attribute. If false, all FATs are mirrored as
* usual.
*/
public boolean hasActiveFat() { return hasActiveFat; }
public long reserved1() { return reserved1; }
/**
* Zero-based number of active FAT, if `has_active_fat`
* attribute is true.
*/
public long activeFatId() { return activeFatId; }
public byte[] reserved2() { return reserved2; }
public int fatVersion() { return fatVersion; }
/**
* Cluster number of root directory start, typically 2 if it
* contains no bad sector. (Microsoft's FAT32 implementation
* imposes an artificial limit of 65,535 entries per directory,
* whilst many third-party implementations do not.)
*/
public long rootDirStartClus() { return rootDirStartClus; }
/**
* Logical sector number of FS Information Sector, typically 1,
* i.e., the second of the three FAT32 boot sectors. Values
* like 0 and 0xFFFF are used by some FAT32 implementations to
* designate abscence of FS Information Sector.
*/
public int lsFsInfo() { return lsFsInfo; }
/**
* First logical sector number of a copy of the three FAT32
* boot sectors, typically 6.
*/
public int bootSectorsCopyStartLs() { return bootSectorsCopyStartLs; }
public byte[] reserved3() { return reserved3; }
/**
* Physical drive number (0x00 for (first) removable media,
* 0x80 for (first) fixed disk as per INT 13h).
*/
public int physDriveNum() { return physDriveNum; }
public int reserved4() { return reserved4; }
/**
* Should be 0x29 to indicate that an EBPB with the following 3
* entries exists.
*/
public int extBootSign() { return extBootSign; }
/**
* Volume ID (serial number).
*
* Typically the serial number "xxxx-xxxx" is created by a
* 16-bit addition of both DX values returned by INT 21h/AH=2Ah
* (get system date) and INT 21h/AH=2Ch (get system time) for
* the high word and another 16-bit addition of both CX values
* for the low word of the serial number. Alternatively, some
* DR-DOS disk utilities provide a /# option to generate a
* human-readable time stamp "mmdd-hhmm" build from BCD-encoded
* 8-bit values for the month, day, hour and minute instead of
* a serial number.
*/
public byte[] volumeId() { return volumeId; }
public String partitionVolumeLabel() { return partitionVolumeLabel; }
public String fsTypeStr() { return fsTypeStr; }
public Vfat _root() { return _root; }
public Vfat.BootSector _parent() { return _parent; }
}
public static class BootSector extends KaitaiStruct {
public static BootSector fromFile(String fileName) throws IOException {
return new BootSector(new ByteBufferKaitaiStream(fileName));
}
public BootSector(KaitaiStream _io) {
this(_io, null, null);
}
public BootSector(KaitaiStream _io, Vfat _parent) {
this(_io, _parent, null);
}
public BootSector(KaitaiStream _io, Vfat _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.jmpInstruction = this._io.readBytes(3);
this.oemName = new String(KaitaiStream.bytesStripRight(this._io.readBytes(8), (byte) 32), Charset.forName("ASCII"));
this.bpb = new BiosParamBlock(this._io, this, _root);
if (!(isFat32())) {
this.ebpbFat16 = new ExtBiosParamBlockFat16(this._io, this, _root);
}
if (isFat32()) {
this.ebpbFat32 = new ExtBiosParamBlockFat32(this._io, this, _root);
}
}
private Integer posFats;
/**
* Offset of FATs in bytes from start of filesystem
*/
public Integer posFats() {
if (this.posFats != null)
return this.posFats;
int _tmp = (int) ((bpb().bytesPerLs() * bpb().numReservedLs()));
this.posFats = _tmp;
return this.posFats;
}
private Long lsPerFat;
public Long lsPerFat() {
if (this.lsPerFat != null)
return this.lsPerFat;
long _tmp = (long) ((isFat32() ? ebpbFat32().lsPerFat() : bpb().lsPerFat()));
this.lsPerFat = _tmp;
return this.lsPerFat;
}
private Integer lsPerRootDir;
/**
* Size of root directory in logical sectors
* @see "FAT: General Overview of On-Disk Format, section "FAT Data Structure""
*/
public Integer lsPerRootDir() {
if (this.lsPerRootDir != null)
return this.lsPerRootDir;
int _tmp = (int) (((((bpb().maxRootDirRec() * 32) + bpb().bytesPerLs()) - 1) / bpb().bytesPerLs()));
this.lsPerRootDir = _tmp;
return this.lsPerRootDir;
}
private Boolean isFat32;
/**
* Determines if filesystem is FAT32 (true) or FAT12/16 (false)
* by analyzing some preliminary conditions in BPB. Used to
* determine whether we should parse post-BPB data as
* `ext_bios_param_block_fat16` or `ext_bios_param_block_fat32`.
*/
public Boolean isFat32() {
if (this.isFat32 != null)
return this.isFat32;
boolean _tmp = (boolean) (bpb().maxRootDirRec() == 0);
this.isFat32 = _tmp;
return this.isFat32;
}
private Integer sizeFat;
/**
* Size of one FAT in bytes
*/
public Integer sizeFat() {
if (this.sizeFat != null)
return this.sizeFat;
int _tmp = (int) ((bpb().bytesPerLs() * lsPerFat()));
this.sizeFat = _tmp;
return this.sizeFat;
}
private Integer posRootDir;
/**
* Offset of root directory in bytes from start of filesystem
*/
public Integer posRootDir() {
if (this.posRootDir != null)
return this.posRootDir;
int _tmp = (int) ((bpb().bytesPerLs() * (bpb().numReservedLs() + (lsPerFat() * bpb().numFats()))));
this.posRootDir = _tmp;
return this.posRootDir;
}
private Integer sizeRootDir;
/**
* Size of root directory in bytes
*/
public Integer sizeRootDir() {
if (this.sizeRootDir != null)
return this.sizeRootDir;
int _tmp = (int) ((lsPerRootDir() * bpb().bytesPerLs()));
this.sizeRootDir = _tmp;
return this.sizeRootDir;
}
private byte[] jmpInstruction;
private String oemName;
private BiosParamBlock bpb;
private ExtBiosParamBlockFat16 ebpbFat16;
private ExtBiosParamBlockFat32 ebpbFat32;
private Vfat _root;
private Vfat _parent;
public byte[] jmpInstruction() { return jmpInstruction; }
public String oemName() { return oemName; }
/**
* Basic BIOS parameter block, present in all versions of FAT
*/
public BiosParamBlock bpb() { return bpb; }
/**
* FAT12/16-specific extended BIOS parameter block
*/
public ExtBiosParamBlockFat16 ebpbFat16() { return ebpbFat16; }
/**
* FAT32-specific extended BIOS parameter block
*/
public ExtBiosParamBlockFat32 ebpbFat32() { return ebpbFat32; }
public Vfat _root() { return _root; }
public Vfat _parent() { return _parent; }
}
public static class BiosParamBlock extends KaitaiStruct {
public static BiosParamBlock fromFile(String fileName) throws IOException {
return new BiosParamBlock(new ByteBufferKaitaiStream(fileName));
}
public BiosParamBlock(KaitaiStream _io) {
this(_io, null, null);
}
public BiosParamBlock(KaitaiStream _io, Vfat.BootSector _parent) {
this(_io, _parent, null);
}
public BiosParamBlock(KaitaiStream _io, Vfat.BootSector _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.bytesPerLs = this._io.readU2le();
this.lsPerClus = this._io.readU1();
this.numReservedLs = this._io.readU2le();
this.numFats = this._io.readU1();
this.maxRootDirRec = this._io.readU2le();
this.totalLs2 = this._io.readU2le();
this.mediaCode = this._io.readU1();
this.lsPerFat = this._io.readU2le();
this.psPerTrack = this._io.readU2le();
this.numHeads = this._io.readU2le();
this.numHiddenSectors = this._io.readU4le();
this.totalLs4 = this._io.readU4le();
}
private int bytesPerLs;
private int lsPerClus;
private int numReservedLs;
private int numFats;
private int maxRootDirRec;
private int totalLs2;
private int mediaCode;
private int lsPerFat;
private int psPerTrack;
private int numHeads;
private long numHiddenSectors;
private long totalLs4;
private Vfat _root;
private Vfat.BootSector _parent;
/**
* Bytes per logical sector
*/
public int bytesPerLs() { return bytesPerLs; }
/**
* Logical sectors per cluster
*/
public int lsPerClus() { return lsPerClus; }
/**
* Count of reserved logical sectors. The number of logical
* sectors before the first FAT in the file system image.
*/
public int numReservedLs() { return numReservedLs; }
/**
* Number of File Allocation Tables
*/
public int numFats() { return numFats; }
/**
* Maximum number of FAT12 or FAT16 root directory entries. 0
* for FAT32, where the root directory is stored in ordinary
* data clusters.
*/
public int maxRootDirRec() { return maxRootDirRec; }
/**
* Total logical sectors (if zero, use total_ls_4)
*/
public int totalLs2() { return totalLs2; }
/**
* Media descriptor
*/
public int mediaCode() { return mediaCode; }
/**
* Logical sectors per File Allocation Table for
* FAT12/FAT16. FAT32 sets this to 0 and uses the 32-bit value
* at offset 0x024 instead.
*/
public int lsPerFat() { return lsPerFat; }
/**
* Physical sectors per track for disks with INT 13h CHS
* geometry, e.g., 15 for a "1.20 MB" (1200 KB) floppy. A zero
* entry indicates that this entry is reserved, but not used.
*/
public int psPerTrack() { return psPerTrack; }
/**
* Number of heads for disks with INT 13h CHS geometry,[9]
* e.g., 2 for a double sided floppy.
*/
public int numHeads() { return numHeads; }
/**
* Number of hidden sectors preceding the partition that
* contains this FAT volume. This field should always be zero
* on media that are not partitioned. This DOS 3.0 entry is
* incompatible with a similar entry at offset 0x01C in BPBs
* since DOS 3.31. It must not be used if the logical sectors
* entry at offset 0x013 is zero.
*/
public long numHiddenSectors() { return numHiddenSectors; }
/**
* Total logical sectors including hidden sectors. This DOS 3.2
* entry is incompatible with a similar entry at offset 0x020
* in BPBs since DOS 3.31. It must not be used if the logical
* sectors entry at offset 0x013 is zero.
*/
public long totalLs4() { return totalLs4; }
public Vfat _root() { return _root; }
public Vfat.BootSector _parent() { return _parent; }
}
public static class RootDirectoryRec extends KaitaiStruct {
public static RootDirectoryRec fromFile(String fileName) throws IOException {
return new RootDirectoryRec(new ByteBufferKaitaiStream(fileName));
}
public RootDirectoryRec(KaitaiStream _io) {
this(_io, null, null);
}
public RootDirectoryRec(KaitaiStream _io, Vfat.RootDirectory _parent) {
this(_io, _parent, null);
}
public RootDirectoryRec(KaitaiStream _io, Vfat.RootDirectory _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.fileName = this._io.readBytes(11);
this._raw_attrs = this._io.readBytes(1);
KaitaiStream _io__raw_attrs = new ByteBufferKaitaiStream(_raw_attrs);
this.attrs = new AttrFlags(_io__raw_attrs, this, _root);
this.reserved = this._io.readBytes(10);
this._raw_lastWriteTime = this._io.readBytes(4);
KaitaiStream _io__raw_lastWriteTime = new ByteBufferKaitaiStream(_raw_lastWriteTime);
this.lastWriteTime = new DosDatetime(_io__raw_lastWriteTime);
this.startClus = this._io.readU2le();
this.fileSize = this._io.readU4le();
}
public static class AttrFlags extends KaitaiStruct {
public static AttrFlags fromFile(String fileName) throws IOException {
return new AttrFlags(new ByteBufferKaitaiStream(fileName));
}
public AttrFlags(KaitaiStream _io) {
this(_io, null, null);
}
public AttrFlags(KaitaiStream _io, Vfat.RootDirectoryRec _parent) {
this(_io, _parent, null);
}
public AttrFlags(KaitaiStream _io, Vfat.RootDirectoryRec _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.readOnly = this._io.readBitsIntLe(1) != 0;
this.hidden = this._io.readBitsIntLe(1) != 0;
this.system = this._io.readBitsIntLe(1) != 0;
this.volumeId = this._io.readBitsIntLe(1) != 0;
this.isDirectory = this._io.readBitsIntLe(1) != 0;
this.archive = this._io.readBitsIntLe(1) != 0;
this.reserved = this._io.readBitsIntLe(2);
}
private Boolean longName;
public Boolean longName() {
if (this.longName != null)
return this.longName;
boolean _tmp = (boolean) ( ((readOnly()) && (hidden()) && (system()) && (volumeId())) );
this.longName = _tmp;
return this.longName;
}
private boolean readOnly;
private boolean hidden;
private boolean system;
private boolean volumeId;
private boolean isDirectory;
private boolean archive;
private long reserved;
private Vfat _root;
private Vfat.RootDirectoryRec _parent;
public boolean readOnly() { return readOnly; }
public boolean hidden() { return hidden; }
public boolean system() { return system; }
public boolean volumeId() { return volumeId; }
public boolean isDirectory() { return isDirectory; }
public boolean archive() { return archive; }
public long reserved() { return reserved; }
public Vfat _root() { return _root; }
public Vfat.RootDirectoryRec _parent() { return _parent; }
}
private byte[] fileName;
private AttrFlags attrs;
private byte[] reserved;
private DosDatetime lastWriteTime;
private int startClus;
private long fileSize;
private Vfat _root;
private Vfat.RootDirectory _parent;
private byte[] _raw_attrs;
private byte[] _raw_lastWriteTime;
public byte[] fileName() { return fileName; }
public AttrFlags attrs() { return attrs; }
public byte[] reserved() { return reserved; }
public DosDatetime lastWriteTime() { return lastWriteTime; }
public int startClus() { return startClus; }
public long fileSize() { return fileSize; }
public Vfat _root() { return _root; }
public Vfat.RootDirectory _parent() { return _parent; }
public byte[] _raw_attrs() { return _raw_attrs; }
public byte[] _raw_lastWriteTime() { return _raw_lastWriteTime; }
}
public static class RootDirectory extends KaitaiStruct {
public static RootDirectory fromFile(String fileName) throws IOException {
return new RootDirectory(new ByteBufferKaitaiStream(fileName));
}
public RootDirectory(KaitaiStream _io) {
this(_io, null, null);
}
public RootDirectory(KaitaiStream _io, Vfat _parent) {
this(_io, _parent, null);
}
public RootDirectory(KaitaiStream _io, Vfat _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.records = new ArrayList<RootDirectoryRec>();
for (int i = 0; i < _root().bootSector().bpb().maxRootDirRec(); i++) {
this.records.add(new RootDirectoryRec(this._io, this, _root));
}
}
private ArrayList<RootDirectoryRec> records;
private Vfat _root;
private Vfat _parent;
public ArrayList<RootDirectoryRec> records() { return records; }
public Vfat _root() { return _root; }
public Vfat _parent() { return _parent; }
}
/**
* Extended BIOS Parameter Block (DOS 4.0+, OS/2 1.0+). Used only
* for FAT12 and FAT16.
*/
public static class ExtBiosParamBlockFat16 extends KaitaiStruct {
public static ExtBiosParamBlockFat16 fromFile(String fileName) throws IOException {
return new ExtBiosParamBlockFat16(new ByteBufferKaitaiStream(fileName));
}
public ExtBiosParamBlockFat16(KaitaiStream _io) {
this(_io, null, null);
}
public ExtBiosParamBlockFat16(KaitaiStream _io, Vfat.BootSector _parent) {
this(_io, _parent, null);
}
public ExtBiosParamBlockFat16(KaitaiStream _io, Vfat.BootSector _parent, Vfat _root) {
super(_io);
this._parent = _parent;
this._root = _root;
_read();
}
private void _read() {
this.physDriveNum = this._io.readU1();
this.reserved1 = this._io.readU1();
this.extBootSign = this._io.readU1();
this.volumeId = this._io.readBytes(4);
this.partitionVolumeLabel = new String(KaitaiStream.bytesStripRight(this._io.readBytes(11), (byte) 32), Charset.forName("ASCII"));
this.fsTypeStr = new String(KaitaiStream.bytesStripRight(this._io.readBytes(8), (byte) 32), Charset.forName("ASCII"));
}
private int physDriveNum;
private int reserved1;
private int extBootSign;
private byte[] volumeId;
private String partitionVolumeLabel;
private String fsTypeStr;
private Vfat _root;
private Vfat.BootSector _parent;
/**
* Physical drive number (0x00 for (first) removable media,
* 0x80 for (first) fixed disk as per INT 13h).
*/
public int physDriveNum() { return physDriveNum; }
public int reserved1() { return reserved1; }
/**
* Should be 0x29 to indicate that an EBPB with the following 3
* entries exists.
*/
public int extBootSign() { return extBootSign; }
/**
* Volume ID (serial number).
*
* Typically the serial number "xxxx-xxxx" is created by a
* 16-bit addition of both DX values returned by INT 21h/AH=2Ah
* (get system date) and INT 21h/AH=2Ch (get system time) for
* the high word and another 16-bit addition of both CX values
* for the low word of the serial number. Alternatively, some
* DR-DOS disk utilities provide a /# option to generate a
* human-readable time stamp "mmdd-hhmm" build from BCD-encoded
* 8-bit values for the month, day, hour and minute instead of
* a serial number.
*/
public byte[] volumeId() { return volumeId; }
public String partitionVolumeLabel() { return partitionVolumeLabel; }
public String fsTypeStr() { return fsTypeStr; }
public Vfat _root() { return _root; }
public Vfat.BootSector _parent() { return _parent; }
}
private ArrayList<byte[]> fats;
public ArrayList<byte[]> fats() {
if (this.fats != null)
return this.fats;
long _pos = this._io.pos();
this._io.seek(bootSector().posFats());
this.fats = new ArrayList<byte[]>();
for (int i = 0; i < bootSector().bpb().numFats(); i++) {
this.fats.add(this._io.readBytes(bootSector().sizeFat()));
}
this._io.seek(_pos);
return this.fats;
}
private RootDirectory rootDir;
public RootDirectory rootDir() {
if (this.rootDir != null)
return this.rootDir;
long _pos = this._io.pos();
this._io.seek(bootSector().posRootDir());
this._raw_rootDir = this._io.readBytes(bootSector().sizeRootDir());
KaitaiStream _io__raw_rootDir = new ByteBufferKaitaiStream(_raw_rootDir);
this.rootDir = new RootDirectory(_io__raw_rootDir, this, _root);
this._io.seek(_pos);
return this.rootDir;
}
private BootSector bootSector;
private Vfat _root;
private KaitaiStruct _parent;
private byte[] _raw_rootDir;
public BootSector bootSector() { return bootSector; }
public Vfat _root() { return _root; }
public KaitaiStruct _parent() { return _parent; }
public byte[] _raw_rootDir() { return _raw_rootDir; }
}