pdf.js/src/core/to_unicode_map.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.
 */

import { unreachable } from "../shared/util.js";

const ToUnicodeMap = (function ToUnicodeMapClosure() {
  // eslint-disable-next-line no-shadow
  function ToUnicodeMap(cmap = []) {
    // The elements of this._map can be integers or strings, depending on how
    // `cmap` was created.
    this._map = cmap;
  }

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

    forEach(callback) {
      for (const charCode in this._map) {
        callback(charCode, this._map[charCode].charCodeAt(0));
      }
    },

    has(i) {
      return this._map[i] !== undefined;
    },

    get(i) {
      return this._map[i];
    },

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

    amend(map) {
      for (const charCode in map) {
        this._map[charCode] = map[charCode];
      }
    },
  };

  return ToUnicodeMap;
})();

const IdentityToUnicodeMap = (function IdentityToUnicodeMapClosure() {
  // eslint-disable-next-line no-shadow
  function IdentityToUnicodeMap(firstChar, lastChar) {
    this.firstChar = firstChar;
    this.lastChar = lastChar;
  }

  IdentityToUnicodeMap.prototype = {
    get length() {
      return this.lastChar + 1 - this.firstChar;
    },

    forEach(callback) {
      for (let i = this.firstChar, ii = this.lastChar; i <= ii; i++) {
        callback(i, i);
      }
    },

    has(i) {
      return this.firstChar <= i && i <= this.lastChar;
    },

    get(i) {
      if (this.firstChar <= i && i <= this.lastChar) {
        return String.fromCharCode(i);
      }
      return undefined;
    },

    charCodeOf(v) {
      return Number.isInteger(v) && v >= this.firstChar && v <= this.lastChar
        ? v
        : -1;
    },

    amend(map) {
      unreachable("Should not call amend()");
    },
  };

  return IdentityToUnicodeMap;
})();

export { IdentityToUnicodeMap, ToUnicodeMap };