parse-base64vlq-mappings/base64.js

Parses out base64 VLQ encoded mappings.

/*
 * Copyright 2011 Mozilla Foundation and contributors
 * Licensed under the New BSD license. See LICENSE or:
 * http://opensource.org/licenses/BSD-3-Clause
 */

var charToIntMap = {};
var intToCharMap = {};

'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
  .split('')
  .forEach(function (ch, index) {
    charToIntMap[ch] = index;
    intToCharMap[index] = ch;
  });

/**
  * Encode an integer in the range of 0 to 63 to a single base 64 digit.
  */
exports.encode = function base64_encode(aNumber) {
  if (aNumber in intToCharMap) {
    return intToCharMap[aNumber];
  }
  throw new TypeError("Must be between 0 and 63: " + aNumber);
};

/**
  * Decode a single base 64 digit to an integer.
  */
exports.decode = function base64_decode(aChar) {
  if (aChar in charToIntMap) {
    return charToIntMap[aChar];
  }
  throw new TypeError("Not a valid base 64 digit: " + aChar);
};