lib/core/core_utils.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 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.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.getLookupTableFactory = getLookupTableFactory;
exports.getInheritableProperty = getInheritableProperty;
exports.toRomanNumerals = toRomanNumerals;
exports.log2 = log2;
exports.readInt8 = readInt8;
exports.readUint16 = readUint16;
exports.readUint32 = readUint32;
exports.isWhiteSpace = isWhiteSpace;
exports.XRefParseException = exports.XRefEntryException = exports.MissingDataException = void 0;

var _util = require("../shared/util.js");

function getLookupTableFactory(initializer) {
  let lookup;
  return function () {
    if (initializer) {
      lookup = Object.create(null);
      initializer(lookup);
      initializer = null;
    }

    return lookup;
  };
}

class MissingDataException extends _util.BaseException {
  constructor(begin, end) {
    super(`Missing data [${begin}, ${end})`);
    this.begin = begin;
    this.end = end;
  }

}

exports.MissingDataException = MissingDataException;

class XRefEntryException extends _util.BaseException {}

exports.XRefEntryException = XRefEntryException;

class XRefParseException extends _util.BaseException {}

exports.XRefParseException = XRefParseException;

function getInheritableProperty({
  dict,
  key,
  getArray = false,
  stopWhenFound = true
}) {
  const LOOP_LIMIT = 100;
  let loopCount = 0;
  let values;

  while (dict) {
    const value = getArray ? dict.getArray(key) : dict.get(key);

    if (value !== undefined) {
      if (stopWhenFound) {
        return value;
      }

      if (!values) {
        values = [];
      }

      values.push(value);
    }

    if (++loopCount > LOOP_LIMIT) {
      (0, _util.warn)(`getInheritableProperty: maximum loop count exceeded for "${key}"`);
      break;
    }

    dict = dict.get("Parent");
  }

  return values;
}

const ROMAN_NUMBER_MAP = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM", "", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC", "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"];

function toRomanNumerals(number, lowerCase = false) {
  (0, _util.assert)(Number.isInteger(number) && number > 0, "The number should be a positive integer.");
  const romanBuf = [];
  let pos;

  while (number >= 1000) {
    number -= 1000;
    romanBuf.push("M");
  }

  pos = number / 100 | 0;
  number %= 100;
  romanBuf.push(ROMAN_NUMBER_MAP[pos]);
  pos = number / 10 | 0;
  number %= 10;
  romanBuf.push(ROMAN_NUMBER_MAP[10 + pos]);
  romanBuf.push(ROMAN_NUMBER_MAP[20 + number]);
  const romanStr = romanBuf.join("");
  return lowerCase ? romanStr.toLowerCase() : romanStr;
}

function log2(x) {
  if (x <= 0) {
    return 0;
  }

  return Math.ceil(Math.log2(x));
}

function readInt8(data, offset) {
  return data[offset] << 24 >> 24;
}

function readUint16(data, offset) {
  return data[offset] << 8 | data[offset + 1];
}

function readUint32(data, offset) {
  return (data[offset] << 24 | data[offset + 1] << 16 | data[offset + 2] << 8 | data[offset + 3]) >>> 0;
}

function isWhiteSpace(ch) {
  return ch === 0x20 || ch === 0x09 || ch === 0x0d || ch === 0x0a;
}