Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format: JavaScript parsing library

This page hosts a formal specification of Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format 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 MicrosoftCfb(new KaitaiStream(arrayBuffer));

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

data.header // => get header

JavaScript source code to parse Microsoft Compound File Binary (CFB), AKA OLE (Object Linking and Embedding) file format

MicrosoftCfb.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.MicrosoftCfb = factory(root.KaitaiStream);
  }
}(this, function (KaitaiStream) {
var MicrosoftCfb = (function() {
  function MicrosoftCfb(_io, _parent, _root) {
    this._io = _io;
    this._parent = _parent;
    this._root = _root || this;

    this._read();
  }
  MicrosoftCfb.prototype._read = function() {
    this.header = new CfbHeader(this._io, this, this._root);
  }

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

      this._read();
    }
    CfbHeader.prototype._read = function() {
      this.signature = this._io.readBytes(8);
      if (!((KaitaiStream.byteArrayCompare(this.signature, [208, 207, 17, 224, 161, 177, 26, 225]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([208, 207, 17, 224, 161, 177, 26, 225], this.signature, this._io, "/types/cfb_header/seq/0");
      }
      this.clsid = this._io.readBytes(16);
      if (!((KaitaiStream.byteArrayCompare(this.clsid, [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], this.clsid, this._io, "/types/cfb_header/seq/1");
      }
      this.versionMinor = this._io.readU2le();
      this.versionMajor = this._io.readU2le();
      this.byteOrder = this._io.readBytes(2);
      if (!((KaitaiStream.byteArrayCompare(this.byteOrder, [254, 255]) == 0))) {
        throw new KaitaiStream.ValidationNotEqualError([254, 255], this.byteOrder, this._io, "/types/cfb_header/seq/4");
      }
      this.sectorShift = this._io.readU2le();
      this.miniSectorShift = this._io.readU2le();
      this.reserved1 = this._io.readBytes(6);
      this.sizeDir = this._io.readS4le();
      this.sizeFat = this._io.readS4le();
      this.ofsDir = this._io.readS4le();
      this.transactionSeq = this._io.readS4le();
      this.miniStreamCutoffSize = this._io.readS4le();
      this.ofsMiniFat = this._io.readS4le();
      this.sizeMiniFat = this._io.readS4le();
      this.ofsDifat = this._io.readS4le();
      this.sizeDifat = this._io.readS4le();
      this.difat = new Array(109);
      for (var i = 0; i < 109; i++) {
        this.difat[i] = this._io.readS4le();
      }
    }

    /**
     * Magic bytes that confirm that this is a CFB file
     */

    /**
     * Reserved class ID field, must be all 0
     */

    /**
     * In theory, specifies a byte order. In practice, no other values besides FE FF (which imply little endian order) are used.
     */

    /**
     * For major version 3, must be 0x9 (sector size = 512 bytes). For major version 4, must be 0xc (sector size = 4096 bytes).
     */

    /**
     * Number of directory sectors in this file. For major version 3, must be 0.
     */

    /**
     * Number of FAT sectors in this file.
     */

    /**
     * Starting sector number for directory stream.
     */

    /**
     * A transaction sequence number, which is incremented each time the file is saved if transactions are implemented, 0 otherwise.
     */

    /**
     * Starting sector number for mini FAT.
     */

    /**
     * Number of mini FAT sectors in this file.
     */

    /**
     * Starting sector number for DIFAT.
     */

    /**
     * Number of DIFAT sectors in this file.
     */

    return CfbHeader;
  })();

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

      this._read();
    }
    FatEntries.prototype._read = function() {
      this.entries = [];
      var i = 0;
      while (!this._io.isEof()) {
        this.entries.push(this._io.readS4le());
        i++;
      }
    }

    return FatEntries;
  })();

  var DirEntry = MicrosoftCfb.DirEntry = (function() {
    DirEntry.ObjType = Object.freeze({
      UNKNOWN: 0,
      STORAGE: 1,
      STREAM: 2,
      ROOT_STORAGE: 5,

      0: "UNKNOWN",
      1: "STORAGE",
      2: "STREAM",
      5: "ROOT_STORAGE",
    });

    DirEntry.RbColor = Object.freeze({
      RED: 0,
      BLACK: 1,

      0: "RED",
      1: "BLACK",
    });

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

      this._read();
    }
    DirEntry.prototype._read = function() {
      this.name = KaitaiStream.bytesToStr(this._io.readBytes(64), "UTF-16LE");
      this.nameLen = this._io.readU2le();
      this.objectType = this._io.readU1();
      this.colorFlag = this._io.readU1();
      this.leftSiblingId = this._io.readS4le();
      this.rightSiblingId = this._io.readS4le();
      this.childId = this._io.readS4le();
      this.clsid = this._io.readBytes(16);
      this.state = this._io.readU4le();
      this.timeCreate = this._io.readU8le();
      this.timeMod = this._io.readU8le();
      this.ofs = this._io.readS4le();
      this.size = this._io.readU8le();
    }
    Object.defineProperty(DirEntry.prototype, 'miniStream', {
      get: function() {
        if (this._m_miniStream !== undefined)
          return this._m_miniStream;
        if (this.objectType == MicrosoftCfb.DirEntry.ObjType.ROOT_STORAGE) {
          var io = this._root._io;
          var _pos = io.pos;
          io.seek(((this.ofs + 1) * this._root.sectorSize));
          this._m_miniStream = io.readBytes(this.size);
          io.seek(_pos);
        }
        return this._m_miniStream;
      }
    });
    Object.defineProperty(DirEntry.prototype, 'child', {
      get: function() {
        if (this._m_child !== undefined)
          return this._m_child;
        if (this.childId != -1) {
          var io = this._root._io;
          var _pos = io.pos;
          io.seek((((this._root.header.ofsDir + 1) * this._root.sectorSize) + (this.childId * 128)));
          this._m_child = new DirEntry(io, this, this._root);
          io.seek(_pos);
        }
        return this._m_child;
      }
    });
    Object.defineProperty(DirEntry.prototype, 'leftSibling', {
      get: function() {
        if (this._m_leftSibling !== undefined)
          return this._m_leftSibling;
        if (this.leftSiblingId != -1) {
          var io = this._root._io;
          var _pos = io.pos;
          io.seek((((this._root.header.ofsDir + 1) * this._root.sectorSize) + (this.leftSiblingId * 128)));
          this._m_leftSibling = new DirEntry(io, this, this._root);
          io.seek(_pos);
        }
        return this._m_leftSibling;
      }
    });
    Object.defineProperty(DirEntry.prototype, 'rightSibling', {
      get: function() {
        if (this._m_rightSibling !== undefined)
          return this._m_rightSibling;
        if (this.rightSiblingId != -1) {
          var io = this._root._io;
          var _pos = io.pos;
          io.seek((((this._root.header.ofsDir + 1) * this._root.sectorSize) + (this.rightSiblingId * 128)));
          this._m_rightSibling = new DirEntry(io, this, this._root);
          io.seek(_pos);
        }
        return this._m_rightSibling;
      }
    });

    /**
     * User-defined flags for storage or root storage objects
     */

    /**
     * Creation time, in Windows FILETIME format (number of 100-nanosecond intervals since January 1, 1601, UTC)
     */

    /**
     * Modification time, in Windows FILETIME format (number of 100-nanosecond intervals since January 1, 1601, UTC).
     */

    /**
     * For stream object, number of starting sector. For a root storage object, first sector of the mini stream, if the mini stream exists.
     */

    /**
     * For stream object, size of user-defined data in bytes. For a root storage object, size of the mini stream.
     */

    return DirEntry;
  })();
  Object.defineProperty(MicrosoftCfb.prototype, 'sectorSize', {
    get: function() {
      if (this._m_sectorSize !== undefined)
        return this._m_sectorSize;
      this._m_sectorSize = (1 << this.header.sectorShift);
      return this._m_sectorSize;
    }
  });
  Object.defineProperty(MicrosoftCfb.prototype, 'fat', {
    get: function() {
      if (this._m_fat !== undefined)
        return this._m_fat;
      var _pos = this._io.pos;
      this._io.seek(this.sectorSize);
      this._raw__m_fat = this._io.readBytes((this.header.sizeFat * this.sectorSize));
      var _io__raw__m_fat = new KaitaiStream(this._raw__m_fat);
      this._m_fat = new FatEntries(_io__raw__m_fat, this, this._root);
      this._io.seek(_pos);
      return this._m_fat;
    }
  });
  Object.defineProperty(MicrosoftCfb.prototype, 'dir', {
    get: function() {
      if (this._m_dir !== undefined)
        return this._m_dir;
      var _pos = this._io.pos;
      this._io.seek(((this.header.ofsDir + 1) * this.sectorSize));
      this._m_dir = new DirEntry(this._io, this, this._root);
      this._io.seek(_pos);
      return this._m_dir;
    }
  });

  return MicrosoftCfb;
})();
return MicrosoftCfb;
}));