GPT (GUID) partition table: JavaScript parsing library

This page hosts a formal specification of GPT (GUID) partition table using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for JavaScript generated by Kaitai Struct depends on the JavaScript runtime library. You have to install it before you can parse data.

The JavaScript runtime library is available at npm:

npm install kaitai-struct

Code

See the usage examples in the JavaScript notes.

Parse structure from an ArrayBuffer:

var arrayBuffer = ...;
var data = new GptPartitionTable(new KaitaiStream(arrayBuffer));

After that, one can get various attributes from the structure by accessing fields or properties like:

data.sectorSize // => get sector size

JavaScript source code to parse GPT (GUID) partition table

GptPartitionTable.js

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['kaitai-struct/KaitaiStream'], factory);
  } else if (typeof module === 'object' && module.exports) {
    module.exports = factory(require('kaitai-struct/KaitaiStream'));
  } else {
    root.GptPartitionTable = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
/**
 * @see {@link https://en.wikipedia.org/wiki/GUID_Partition_Table|Source}
 */

var GptPartitionTable = (function() {
  function GptPartitionTable(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  GptPartitionTable.prototype._read = function() {
  }

  var PartitionEntry = GptPartitionTable.PartitionEntry = (function() {
    function PartitionEntry(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PartitionEntry.prototype._read = function() {
      this.typeGuid = this._io.readBytes(16);
      this.guid = this._io.readBytes(16);
      this.firstLba = this._io.readU8le();
      this.lastLba = this._io.readU8le();
      this.attributes = this._io.readU8le();
      this.name = KaitaiStream.bytesToStr(this._io.readBytes(72), "UTF-16LE");
    }

    return PartitionEntry;
  })();

  var PartitionHeader = GptPartitionTable.PartitionHeader = (function() {
    function PartitionHeader(_io, _parent, _root) {
      this._io = _io;
      this._parent = _parent;
      this._root = _root || this;

      this._read();
    }
    PartitionHeader.prototype._read = function() {
      this.signature = this._io.readBytes(8);
      if (!((KaitaiStream.byteArrayCompare(this.signature, [69, 70, 73, 32, 80, 65, 82, 84]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([69, 70, 73, 32, 80, 65, 82, 84], this.signature, this._io, "/types/partition_header/seq/0");
      }
      this.revision = this._io.readU4le();
      this.headerSize = this._io.readU4le();
      this.crc32Header = this._io.readU4le();
      this.reserved = this._io.readU4le();
      this.currentLba = this._io.readU8le();
      this.backupLba = this._io.readU8le();
      this.firstUsableLba = this._io.readU8le();
      this.lastUsableLba = this._io.readU8le();
      this.diskGuid = this._io.readBytes(16);
      this.entriesStart = this._io.readU8le();
      this.entriesCount = this._io.readU4le();
      this.entriesSize = this._io.readU4le();
      this.crc32Array = this._io.readU4le();
    }
    Object.defineProperty(PartitionHeader.prototype, 'entries', {
      get: function() {
        if (this._m_entries !== undefined)
          return this._m_entries;
        var io = this._root._io;
        var _pos = io.pos;
        io.seek((this.entriesStart * this._root.sectorSize));
        this._raw__m_entries = new Array(this.entriesCount);
        this._m_entries = new Array(this.entriesCount);
        for (var i = 0; i < this.entriesCount; i++) {
          this._raw__m_entries[i] = io.readBytes(this.entriesSize);
          var _io__raw__m_entries = new KaitaiStream(this._raw__m_entries[i]);
          this._m_entries[i] = new PartitionEntry(_io__raw__m_entries, this, this._root);
        }
        io.seek(_pos);
        return this._m_entries;
      }
    });

    return PartitionHeader;
  })();
  Object.defineProperty(GptPartitionTable.prototype, 'sectorSize', {
    get: function() {
      if (this._m_sectorSize !== undefined)
        return this._m_sectorSize;
      this._m_sectorSize = 512;
      return this._m_sectorSize;
    }
  });
  Object.defineProperty(GptPartitionTable.prototype, 'primary', {
    get: function() {
      if (this._m_primary !== undefined)
        return this._m_primary;
      var io = this._root._io;
      var _pos = io.pos;
      io.seek(this._root.sectorSize);
      this._m_primary = new PartitionHeader(io, this, this._root);
      io.seek(_pos);
      return this._m_primary;
    }
  });
  Object.defineProperty(GptPartitionTable.prototype, 'backup', {
    get: function() {
      if (this._m_backup !== undefined)
        return this._m_backup;
      var io = this._root._io;
      var _pos = io.pos;
      io.seek((this._io.size - this._root.sectorSize));
      this._m_backup = new PartitionHeader(io, this, this._root);
      io.seek(_pos);
      return this._m_backup;
    }
  });

  return GptPartitionTable;
})();
return GptPartitionTable;
}));