pdf.js/src/core/cmap.js

/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define('pdfjs/core/cmap', ['exports', 'pdfjs/shared/util',
      'pdfjs/core/primitives', 'pdfjs/core/stream', 'pdfjs/core/parser'],
      factory);
  } else if (typeof exports !== 'undefined') {
    factory(exports, require('../shared/util.js'), require('./primitives.js'),
      require('./stream.js'), require('./parser.js'));
  } else {
    factory((root.pdfjsCoreCMap = {}), root.pdfjsSharedUtil,
      root.pdfjsCorePrimitives, root.pdfjsCoreStream, root.pdfjsCoreParser);
  }
}(this, function (exports, sharedUtil, corePrimitives, coreStream, coreParser) {

var Util = sharedUtil.Util;
var assert = sharedUtil.assert;
var warn = sharedUtil.warn;
var error = sharedUtil.error;
var isInt = sharedUtil.isInt;
var isString = sharedUtil.isString;
var MissingDataException = sharedUtil.MissingDataException;
var CMapCompressionType = sharedUtil.CMapCompressionType;
var isEOF = corePrimitives.isEOF;
var isName = corePrimitives.isName;
var isCmd = corePrimitives.isCmd;
var isStream = corePrimitives.isStream;
var Stream = coreStream.Stream;
var Lexer = coreParser.Lexer;

var BUILT_IN_CMAPS = [
// << Start unicode maps.
'Adobe-GB1-UCS2',
'Adobe-CNS1-UCS2',
'Adobe-Japan1-UCS2',
'Adobe-Korea1-UCS2',
// >> End unicode maps.
'78-EUC-H',
'78-EUC-V',
'78-H',
'78-RKSJ-H',
'78-RKSJ-V',
'78-V',
'78ms-RKSJ-H',
'78ms-RKSJ-V',
'83pv-RKSJ-H',
'90ms-RKSJ-H',
'90ms-RKSJ-V',
'90msp-RKSJ-H',
'90msp-RKSJ-V',
'90pv-RKSJ-H',
'90pv-RKSJ-V',
'Add-H',
'Add-RKSJ-H',
'Add-RKSJ-V',
'Add-V',
'Adobe-CNS1-0',
'Adobe-CNS1-1',
'Adobe-CNS1-2',
'Adobe-CNS1-3',
'Adobe-CNS1-4',
'Adobe-CNS1-5',
'Adobe-CNS1-6',
'Adobe-GB1-0',
'Adobe-GB1-1',
'Adobe-GB1-2',
'Adobe-GB1-3',
'Adobe-GB1-4',
'Adobe-GB1-5',
'Adobe-Japan1-0',
'Adobe-Japan1-1',
'Adobe-Japan1-2',
'Adobe-Japan1-3',
'Adobe-Japan1-4',
'Adobe-Japan1-5',
'Adobe-Japan1-6',
'Adobe-Korea1-0',
'Adobe-Korea1-1',
'Adobe-Korea1-2',
'B5-H',
'B5-V',
'B5pc-H',
'B5pc-V',
'CNS-EUC-H',
'CNS-EUC-V',
'CNS1-H',
'CNS1-V',
'CNS2-H',
'CNS2-V',
'ETHK-B5-H',
'ETHK-B5-V',
'ETen-B5-H',
'ETen-B5-V',
'ETenms-B5-H',
'ETenms-B5-V',
'EUC-H',
'EUC-V',
'Ext-H',
'Ext-RKSJ-H',
'Ext-RKSJ-V',
'Ext-V',
'GB-EUC-H',
'GB-EUC-V',
'GB-H',
'GB-V',
'GBK-EUC-H',
'GBK-EUC-V',
'GBK2K-H',
'GBK2K-V',
'GBKp-EUC-H',
'GBKp-EUC-V',
'GBT-EUC-H',
'GBT-EUC-V',
'GBT-H',
'GBT-V',
'GBTpc-EUC-H',
'GBTpc-EUC-V',
'GBpc-EUC-H',
'GBpc-EUC-V',
'H',
'HKdla-B5-H',
'HKdla-B5-V',
'HKdlb-B5-H',
'HKdlb-B5-V',
'HKgccs-B5-H',
'HKgccs-B5-V',
'HKm314-B5-H',
'HKm314-B5-V',
'HKm471-B5-H',
'HKm471-B5-V',
'HKscs-B5-H',
'HKscs-B5-V',
'Hankaku',
'Hiragana',
'KSC-EUC-H',
'KSC-EUC-V',
'KSC-H',
'KSC-Johab-H',
'KSC-Johab-V',
'KSC-V',
'KSCms-UHC-H',
'KSCms-UHC-HW-H',
'KSCms-UHC-HW-V',
'KSCms-UHC-V',
'KSCpc-EUC-H',
'KSCpc-EUC-V',
'Katakana',
'NWP-H',
'NWP-V',
'RKSJ-H',
'RKSJ-V',
'Roman',
'UniCNS-UCS2-H',
'UniCNS-UCS2-V',
'UniCNS-UTF16-H',
'UniCNS-UTF16-V',
'UniCNS-UTF32-H',
'UniCNS-UTF32-V',
'UniCNS-UTF8-H',
'UniCNS-UTF8-V',
'UniGB-UCS2-H',
'UniGB-UCS2-V',
'UniGB-UTF16-H',
'UniGB-UTF16-V',
'UniGB-UTF32-H',
'UniGB-UTF32-V',
'UniGB-UTF8-H',
'UniGB-UTF8-V',
'UniJIS-UCS2-H',
'UniJIS-UCS2-HW-H',
'UniJIS-UCS2-HW-V',
'UniJIS-UCS2-V',
'UniJIS-UTF16-H',
'UniJIS-UTF16-V',
'UniJIS-UTF32-H',
'UniJIS-UTF32-V',
'UniJIS-UTF8-H',
'UniJIS-UTF8-V',
'UniJIS2004-UTF16-H',
'UniJIS2004-UTF16-V',
'UniJIS2004-UTF32-H',
'UniJIS2004-UTF32-V',
'UniJIS2004-UTF8-H',
'UniJIS2004-UTF8-V',
'UniJISPro-UCS2-HW-V',
'UniJISPro-UCS2-V',
'UniJISPro-UTF8-V',
'UniJISX0213-UTF32-H',
'UniJISX0213-UTF32-V',
'UniJISX02132004-UTF32-H',
'UniJISX02132004-UTF32-V',
'UniKS-UCS2-H',
'UniKS-UCS2-V',
'UniKS-UTF16-H',
'UniKS-UTF16-V',
'UniKS-UTF32-H',
'UniKS-UTF32-V',
'UniKS-UTF8-H',
'UniKS-UTF8-V',
'V',
'WP-Symbol'];

// CMap, not to be confused with TrueType's cmap.
var CMap = (function CMapClosure() {
  function CMap(builtInCMap) {
    // Codespace ranges are stored as follows:
    // [[1BytePairs], [2BytePairs], [3BytePairs], [4BytePairs]]
    // where nBytePairs are ranges e.g. [low1, high1, low2, high2, ...]
    this.codespaceRanges = [[], [], [], []];
    this.numCodespaceRanges = 0;
    // Map entries have one of two forms.
    // - cid chars are 16-bit unsigned integers, stored as integers.
    // - bf chars are variable-length byte sequences, stored as strings, with
    //   one byte per character.
    this._map = [];
    this.name = '';
    this.vertical = false;
    this.useCMap = null;
    this.builtInCMap = builtInCMap;
  }
  CMap.prototype = {
    addCodespaceRange(n, low, high) {
      this.codespaceRanges[n - 1].push(low, high);
      this.numCodespaceRanges++;
    },

    mapCidRange(low, high, dstLow) {
      while (low <= high) {
        this._map[low++] = dstLow++;
      }
    },

    mapBfRange(low, high, dstLow) {
      var lastByte = dstLow.length - 1;
      while (low <= high) {
        this._map[low++] = dstLow;
        // Only the last byte has to be incremented.
        dstLow = dstLow.substr(0, lastByte) +
                 String.fromCharCode(dstLow.charCodeAt(lastByte) + 1);
      }
    },

    mapBfRangeToArray(low, high, array) {
      var i = 0, ii = array.length;
      while (low <= high && i < ii) {
        this._map[low] = array[i++];
        ++low;
      }
    },

    // This is used for both bf and cid chars.
    mapOne(src, dst) {
      this._map[src] = dst;
    },

    lookup(code) {
      return this._map[code];
    },

    contains(code) {
      return this._map[code] !== undefined;
    },

    forEach(callback) {
      // Most maps have fewer than 65536 entries, and for those we use normal
      // array iteration. But really sparse tables are possible -- e.g. with
      // indices in the *billions*. For such tables we use for..in, which isn't
      // ideal because it stringifies the indices for all present elements, but
      // it does avoid iterating over every undefined entry.
      let map = this._map;
      let length = map.length;
      if (length <= 0x10000) {
        for (let i = 0; i < length; i++) {
          if (map[i] !== undefined) {
            callback(i, map[i]);
          }
        }
      } else {
        for (let i in map) {
          callback(i, map[i]);
        }
      }
    },

    charCodeOf(value) {
      // `Array.prototype.indexOf` is *extremely* inefficient for arrays which
      // are both very sparse and very large (see issue8372.pdf).
      let map = this._map;
      if (map.length <= 0x10000) {
        return map.indexOf(value);
      }
      for (let charCode in map) {
        if (map[charCode] === value) {
          return (charCode | 0);
        }
      }
      return -1;
    },

    getMap() {
      return this._map;
    },

    readCharCode(str, offset, out) {
      var c = 0;
      var codespaceRanges = this.codespaceRanges;
      var codespaceRangesLen = this.codespaceRanges.length;
      // 9.7.6.2 CMap Mapping
      // The code length is at most 4.
      for (var n = 0; n < codespaceRangesLen; n++) {
        c = ((c << 8) | str.charCodeAt(offset + n)) >>> 0;
        // Check each codespace range to see if it falls within.
        var codespaceRange = codespaceRanges[n];
        for (var k = 0, kk = codespaceRange.length; k < kk;) {
          var low = codespaceRange[k++];
          var high = codespaceRange[k++];
          if (c >= low && c <= high) {
            out.charcode = c;
            out.length = n + 1;
            return;
          }
        }
      }
      out.charcode = 0;
      out.length = 1;
    },

    get length() {
      return this._map.length;
    },

    get isIdentityCMap() {
      if (!(this.name === 'Identity-H' || this.name === 'Identity-V')) {
        return false;
      }
      if (this._map.length !== 0x10000) {
        return false;
      }
      for (var i = 0; i < 0x10000; i++) {
        if (this._map[i] !== i) {
          return false;
        }
      }
      return true;
    }
  };
  return CMap;
})();

// A special case of CMap, where the _map array implicitly has a length of
// 65536 and each element is equal to its index.
var IdentityCMap = (function IdentityCMapClosure() {
  function IdentityCMap(vertical, n) {
    CMap.call(this);
    this.vertical = vertical;
    this.addCodespaceRange(n, 0, 0xffff);
  }
  Util.inherit(IdentityCMap, CMap, {});

  IdentityCMap.prototype = {
    addCodespaceRange: CMap.prototype.addCodespaceRange,

    mapCidRange(low, high, dstLow) {
      error('should not call mapCidRange');
    },

    mapBfRange(low, high, dstLow) {
      error('should not call mapBfRange');
    },

    mapBfRangeToArray(low, high, array) {
      error('should not call mapBfRangeToArray');
    },

    mapOne(src, dst) {
      error('should not call mapCidOne');
    },

    lookup(code) {
      return (isInt(code) && code <= 0xffff) ? code : undefined;
    },

    contains(code) {
      return isInt(code) && code <= 0xffff;
    },

    forEach(callback) {
      for (var i = 0; i <= 0xffff; i++) {
        callback(i, i);
      }
    },

    charCodeOf(value) {
      return (isInt(value) && value <= 0xffff) ? value : -1;
    },

    getMap() {
      // Sometimes identity maps must be instantiated, but it's rare.
      var map = new Array(0x10000);
      for (var i = 0; i <= 0xffff; i++) {
        map[i] = i;
      }
      return map;
    },

    readCharCode: CMap.prototype.readCharCode,

    get length() {
      return 0x10000;
    },

    get isIdentityCMap() {
      error('should not access .isIdentityCMap');
    }
  };

  return IdentityCMap;
})();

var BinaryCMapReader = (function BinaryCMapReaderClosure() {
  function hexToInt(a, size) {
    var n = 0;
    for (var i = 0; i <= size; i++) {
      n = (n << 8) | a[i];
    }
    return n >>> 0;
  }

  function hexToStr(a, size) {
    // This code is hot. Special-case some common values to avoid creating an
    // object with subarray().
    if (size === 1) {
      return String.fromCharCode(a[0], a[1]);
    }
    if (size === 3) {
      return String.fromCharCode(a[0], a[1], a[2], a[3]);
    }
    return String.fromCharCode.apply(null, a.subarray(0, size + 1));
  }

  function addHex(a, b, size) {
    var c = 0;
    for (var i = size; i >= 0; i--) {
      c += a[i] + b[i];
      a[i] = c & 255;
      c >>= 8;
    }
  }

  function incHex(a, size) {
    var c = 1;
    for (var i = size; i >= 0 && c > 0; i--) {
      c += a[i];
      a[i] = c & 255;
      c >>= 8;
    }
  }

  var MAX_NUM_SIZE = 16;
  var MAX_ENCODED_NUM_SIZE = 19; // ceil(MAX_NUM_SIZE * 7 / 8)

  function BinaryCMapStream(data) {
    this.buffer = data;
    this.pos = 0;
    this.end = data.length;
    this.tmpBuf = new Uint8Array(MAX_ENCODED_NUM_SIZE);
  }

  BinaryCMapStream.prototype = {
    readByte() {
      if (this.pos >= this.end) {
        return -1;
      }
      return this.buffer[this.pos++];
    },
    readNumber() {
      var n = 0;
      var last;
      do {
        var b = this.readByte();
        if (b < 0) {
          error('unexpected EOF in bcmap');
        }
        last = !(b & 0x80);
        n = (n << 7) | (b & 0x7F);
      } while (!last);
      return n;
    },
    readSigned() {
      var n = this.readNumber();
      return (n & 1) ? ~(n >>> 1) : n >>> 1;
    },
    readHex(num, size) {
      num.set(this.buffer.subarray(this.pos,
        this.pos + size + 1));
      this.pos += size + 1;
    },
    readHexNumber(num, size) {
      var last;
      var stack = this.tmpBuf, sp = 0;
      do {
        var b = this.readByte();
        if (b < 0) {
          error('unexpected EOF in bcmap');
        }
        last = !(b & 0x80);
        stack[sp++] = b & 0x7F;
      } while (!last);
      var i = size, buffer = 0, bufferSize = 0;
      while (i >= 0) {
        while (bufferSize < 8 && stack.length > 0) {
          buffer = (stack[--sp] << bufferSize) | buffer;
          bufferSize += 7;
        }
        num[i] = buffer & 255;
        i--;
        buffer >>= 8;
        bufferSize -= 8;
      }
    },
    readHexSigned(num, size) {
      this.readHexNumber(num, size);
      var sign = num[size] & 1 ? 255 : 0;
      var c = 0;
      for (var i = 0; i <= size; i++) {
        c = ((c & 1) << 8) | num[i];
        num[i] = (c >> 1) ^ sign;
      }
    },
    readString() {
      var len = this.readNumber();
      var s = '';
      for (var i = 0; i < len; i++) {
        s += String.fromCharCode(this.readNumber());
      }
      return s;
    }
  };

  function processBinaryCMap(data, cMap, extend) {
    return new Promise(function (resolve, reject) {
      var stream = new BinaryCMapStream(data);
      var header = stream.readByte();
      cMap.vertical = !!(header & 1);

      var useCMap = null;
      var start = new Uint8Array(MAX_NUM_SIZE);
      var end = new Uint8Array(MAX_NUM_SIZE);
      var char = new Uint8Array(MAX_NUM_SIZE);
      var charCode = new Uint8Array(MAX_NUM_SIZE);
      var tmp = new Uint8Array(MAX_NUM_SIZE);
      var code;

      var b;
      while ((b = stream.readByte()) >= 0) {
        var type = b >> 5;
        if (type === 7) { // metadata, e.g. comment or usecmap
          switch (b & 0x1F) {
            case 0:
              stream.readString(); // skipping comment
              break;
            case 1:
              useCMap = stream.readString();
              break;
          }
          continue;
        }
        var sequence = !!(b & 0x10);
        var dataSize = b & 15;

        assert(dataSize + 1 <= MAX_NUM_SIZE);

        var ucs2DataSize = 1;
        var subitemsCount = stream.readNumber();
        var i;
        switch (type) {
          case 0: // codespacerange
            stream.readHex(start, dataSize);
            stream.readHexNumber(end, dataSize);
            addHex(end, start, dataSize);
            cMap.addCodespaceRange(dataSize + 1, hexToInt(start, dataSize),
                                   hexToInt(end, dataSize));
            for (i = 1; i < subitemsCount; i++) {
              incHex(end, dataSize);
              stream.readHexNumber(start, dataSize);
              addHex(start, end, dataSize);
              stream.readHexNumber(end, dataSize);
              addHex(end, start, dataSize);
              cMap.addCodespaceRange(dataSize + 1, hexToInt(start, dataSize),
                                     hexToInt(end, dataSize));
            }
            break;
          case 1: // notdefrange
            stream.readHex(start, dataSize);
            stream.readHexNumber(end, dataSize);
            addHex(end, start, dataSize);
            code = stream.readNumber();
            // undefined range, skipping
            for (i = 1; i < subitemsCount; i++) {
              incHex(end, dataSize);
              stream.readHexNumber(start, dataSize);
              addHex(start, end, dataSize);
              stream.readHexNumber(end, dataSize);
              addHex(end, start, dataSize);
              code = stream.readNumber();
              // nop
            }
            break;
          case 2: // cidchar
            stream.readHex(char, dataSize);
            code = stream.readNumber();
            cMap.mapOne(hexToInt(char, dataSize), code);
            for (i = 1; i < subitemsCount; i++) {
              incHex(char, dataSize);
              if (!sequence) {
                stream.readHexNumber(tmp, dataSize);
                addHex(char, tmp, dataSize);
              }
              code = stream.readSigned() + (code + 1);
              cMap.mapOne(hexToInt(char, dataSize), code);
            }
            break;
          case 3: // cidrange
            stream.readHex(start, dataSize);
            stream.readHexNumber(end, dataSize);
            addHex(end, start, dataSize);
            code = stream.readNumber();
            cMap.mapCidRange(hexToInt(start, dataSize), hexToInt(end, dataSize),
                             code);
            for (i = 1; i < subitemsCount; i++) {
              incHex(end, dataSize);
              if (!sequence) {
                stream.readHexNumber(start, dataSize);
                addHex(start, end, dataSize);
              } else {
                start.set(end);
              }
              stream.readHexNumber(end, dataSize);
              addHex(end, start, dataSize);
              code = stream.readNumber();
              cMap.mapCidRange(hexToInt(start, dataSize),
                               hexToInt(end, dataSize), code);
            }
            break;
          case 4: // bfchar
            stream.readHex(char, ucs2DataSize);
            stream.readHex(charCode, dataSize);
            cMap.mapOne(hexToInt(char, ucs2DataSize),
                        hexToStr(charCode, dataSize));
            for (i = 1; i < subitemsCount; i++) {
              incHex(char, ucs2DataSize);
              if (!sequence) {
                stream.readHexNumber(tmp, ucs2DataSize);
                addHex(char, tmp, ucs2DataSize);
              }
              incHex(charCode, dataSize);
              stream.readHexSigned(tmp, dataSize);
              addHex(charCode, tmp, dataSize);
              cMap.mapOne(hexToInt(char, ucs2DataSize),
                          hexToStr(charCode, dataSize));
            }
            break;
          case 5: // bfrange
            stream.readHex(start, ucs2DataSize);
            stream.readHexNumber(end, ucs2DataSize);
            addHex(end, start, ucs2DataSize);
            stream.readHex(charCode, dataSize);
            cMap.mapBfRange(hexToInt(start, ucs2DataSize),
                            hexToInt(end, ucs2DataSize),
                            hexToStr(charCode, dataSize));
            for (i = 1; i < subitemsCount; i++) {
              incHex(end, ucs2DataSize);
              if (!sequence) {
                stream.readHexNumber(start, ucs2DataSize);
                addHex(start, end, ucs2DataSize);
              } else {
                start.set(end);
              }
              stream.readHexNumber(end, ucs2DataSize);
              addHex(end, start, ucs2DataSize);
              stream.readHex(charCode, dataSize);
              cMap.mapBfRange(hexToInt(start, ucs2DataSize),
                              hexToInt(end, ucs2DataSize),
                              hexToStr(charCode, dataSize));
            }
            break;
          default:
            reject(new Error('processBinaryCMap: Unknown type: ' + type));
            return;
        }
      }

      if (useCMap) {
        resolve(extend(useCMap));
        return;
      }
      resolve(cMap);
    });
  }

  function BinaryCMapReader() {}

  BinaryCMapReader.prototype = {
    process: processBinaryCMap,
  };

  return BinaryCMapReader;
})();

var CMapFactory = (function CMapFactoryClosure() {
  function strToInt(str) {
    var a = 0;
    for (var i = 0; i < str.length; i++) {
      a = (a << 8) | str.charCodeAt(i);
    }
    return a >>> 0;
  }

  function expectString(obj) {
    if (!isString(obj)) {
      error('Malformed CMap: expected string.');
    }
  }

  function expectInt(obj) {
    if (!isInt(obj)) {
      error('Malformed CMap: expected int.');
    }
  }

  function parseBfChar(cMap, lexer) {
    while (true) {
      var obj = lexer.getObj();
      if (isEOF(obj)) {
        break;
      }
      if (isCmd(obj, 'endbfchar')) {
        return;
      }
      expectString(obj);
      var src = strToInt(obj);
      obj = lexer.getObj();
      // TODO are /dstName used?
      expectString(obj);
      var dst = obj;
      cMap.mapOne(src, dst);
    }
  }

  function parseBfRange(cMap, lexer) {
    while (true) {
      var obj = lexer.getObj();
      if (isEOF(obj)) {
        break;
      }
      if (isCmd(obj, 'endbfrange')) {
        return;
      }
      expectString(obj);
      var low = strToInt(obj);
      obj = lexer.getObj();
      expectString(obj);
      var high = strToInt(obj);
      obj = lexer.getObj();
      if (isInt(obj) || isString(obj)) {
        var dstLow = isInt(obj) ? String.fromCharCode(obj) : obj;
        cMap.mapBfRange(low, high, dstLow);
      } else if (isCmd(obj, '[')) {
        obj = lexer.getObj();
        var array = [];
        while (!isCmd(obj, ']') && !isEOF(obj)) {
          array.push(obj);
          obj = lexer.getObj();
        }
        cMap.mapBfRangeToArray(low, high, array);
      } else {
        break;
      }
    }
    error('Invalid bf range.');
  }

  function parseCidChar(cMap, lexer) {
    while (true) {
      var obj = lexer.getObj();
      if (isEOF(obj)) {
        break;
      }
      if (isCmd(obj, 'endcidchar')) {
        return;
      }
      expectString(obj);
      var src = strToInt(obj);
      obj = lexer.getObj();
      expectInt(obj);
      var dst = obj;
      cMap.mapOne(src, dst);
    }
  }

  function parseCidRange(cMap, lexer) {
    while (true) {
      var obj = lexer.getObj();
      if (isEOF(obj)) {
        break;
      }
      if (isCmd(obj, 'endcidrange')) {
        return;
      }
      expectString(obj);
      var low = strToInt(obj);
      obj = lexer.getObj();
      expectString(obj);
      var high = strToInt(obj);
      obj = lexer.getObj();
      expectInt(obj);
      var dstLow = obj;
      cMap.mapCidRange(low, high, dstLow);
    }
  }

  function parseCodespaceRange(cMap, lexer) {
    while (true) {
      var obj = lexer.getObj();
      if (isEOF(obj)) {
        break;
      }
      if (isCmd(obj, 'endcodespacerange')) {
        return;
      }
      if (!isString(obj)) {
        break;
      }
      var low = strToInt(obj);
      obj = lexer.getObj();
      if (!isString(obj)) {
        break;
      }
      var high = strToInt(obj);
      cMap.addCodespaceRange(obj.length, low, high);
    }
    error('Invalid codespace range.');
  }

  function parseWMode(cMap, lexer) {
    var obj = lexer.getObj();
    if (isInt(obj)) {
      cMap.vertical = !!obj;
    }
  }

  function parseCMapName(cMap, lexer) {
    var obj = lexer.getObj();
    if (isName(obj) && isString(obj.name)) {
      cMap.name = obj.name;
    }
  }

  function parseCMap(cMap, lexer, fetchBuiltInCMap, useCMap) {
    var previous;
    var embededUseCMap;
    objLoop: while (true) {
      try {
        var obj = lexer.getObj();
        if (isEOF(obj)) {
          break;
        } else if (isName(obj)) {
          if (obj.name === 'WMode') {
            parseWMode(cMap, lexer);
          } else if (obj.name === 'CMapName') {
            parseCMapName(cMap, lexer);
          }
          previous = obj;
        } else if (isCmd(obj)) {
          switch (obj.cmd) {
            case 'endcmap':
              break objLoop;
            case 'usecmap':
              if (isName(previous)) {
                embededUseCMap = previous.name;
              }
              break;
            case 'begincodespacerange':
              parseCodespaceRange(cMap, lexer);
              break;
            case 'beginbfchar':
              parseBfChar(cMap, lexer);
              break;
            case 'begincidchar':
              parseCidChar(cMap, lexer);
              break;
            case 'beginbfrange':
              parseBfRange(cMap, lexer);
              break;
            case 'begincidrange':
              parseCidRange(cMap, lexer);
              break;
          }
        }
      } catch (ex) {
        if (ex instanceof MissingDataException) {
          throw ex;
        }
        warn('Invalid cMap data: ' + ex);
        continue;
      }
    }

    if (!useCMap && embededUseCMap) {
      // Load the usecmap definition from the file only if there wasn't one
      // specified.
      useCMap = embededUseCMap;
    }
    if (useCMap) {
      return extendCMap(cMap, fetchBuiltInCMap, useCMap);
    }
    return Promise.resolve(cMap);
  }

  function extendCMap(cMap, fetchBuiltInCMap, useCMap) {
    return createBuiltInCMap(useCMap, fetchBuiltInCMap).then(function(newCMap) {
      cMap.useCMap = newCMap;
      // If there aren't any code space ranges defined clone all the parent ones
      // into this cMap.
      if (cMap.numCodespaceRanges === 0) {
        var useCodespaceRanges = cMap.useCMap.codespaceRanges;
        for (var i = 0; i < useCodespaceRanges.length; i++) {
          cMap.codespaceRanges[i] = useCodespaceRanges[i].slice();
        }
        cMap.numCodespaceRanges = cMap.useCMap.numCodespaceRanges;
      }
      // Merge the map into the current one, making sure not to override
      // any previously defined entries.
      cMap.useCMap.forEach(function(key, value) {
        if (!cMap.contains(key)) {
          cMap.mapOne(key, cMap.useCMap.lookup(key));
        }
      });

      return cMap;
    });
  }

  function createBuiltInCMap(name, fetchBuiltInCMap) {
    if (name === 'Identity-H') {
      return Promise.resolve(new IdentityCMap(false, 2));
    } else if (name === 'Identity-V') {
      return Promise.resolve(new IdentityCMap(true, 2));
    }
    if (BUILT_IN_CMAPS.indexOf(name) === -1) {
      return Promise.reject(new Error('Unknown CMap name: ' + name));
    }
    assert(fetchBuiltInCMap, 'Built-in CMap parameters are not provided.');

    return fetchBuiltInCMap(name).then(function (data) {
      var cMapData = data.cMapData, compressionType = data.compressionType;
      var cMap = new CMap(true);

      if (compressionType === CMapCompressionType.BINARY) {
        return new BinaryCMapReader().process(cMapData, cMap,
            function (useCMap) {
          return extendCMap(cMap, fetchBuiltInCMap, useCMap);
        });
      }
      assert(compressionType === CMapCompressionType.NONE,
        'TODO: Only BINARY/NONE CMap compression is currently supported.');
      // Uncompressed CMap.
      var lexer = new Lexer(new Stream(cMapData));
      return parseCMap(cMap, lexer, fetchBuiltInCMap, null);
    });
  }

  return {
    create(params) {
      var encoding = params.encoding;
      var fetchBuiltInCMap = params.fetchBuiltInCMap;
      var useCMap = params.useCMap;

      if (isName(encoding)) {
        return createBuiltInCMap(encoding.name, fetchBuiltInCMap);
      } else if (isStream(encoding)) {
        var cMap = new CMap();
        var lexer = new Lexer(encoding);
        return parseCMap(cMap, lexer, fetchBuiltInCMap, useCMap).then(
            function (parsedCMap) {
          if (parsedCMap.isIdentityCMap) {
            return createBuiltInCMap(parsedCMap.name, fetchBuiltInCMap);
          }
          return parsedCMap;
        });
      }
      return Promise.reject(new Error('Encoding required.'));
    }
  };
})();

exports.CMap = CMap;
exports.CMapFactory = CMapFactory;
exports.IdentityCMap = IdentityCMap;
}));