chrome/browser/resources/cryptotoken/b64.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // WebSafeBase64Escape and Unescape.
   6 function B64_encode(bytes, opt_length) {
   7   if (!opt_length) opt_length = bytes.length;
   8   var b64out =
   9       'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';
  10   var result = '';
  11   var shift = 0;
  12   var accu = 0;
  13   var inputIndex = 0;
  14   while (opt_length--) {
  15     accu <<= 8;
  16     accu |= bytes[inputIndex++];
  17     shift += 8;
  18     while (shift >= 6) {
  19       var i = (accu >> (shift - 6)) & 63;
  20       result += b64out.charAt(i);
  21       shift -= 6;
  22     }
  23   }
  24   if (shift) {
  25     accu <<= 8;
  26     shift += 8;
  27     var i = (accu >> (shift - 6)) & 63;
  28     result += b64out.charAt(i);
  29   }
  30   return result;
  31 }
  32
  33 // Normal base64 encode; not websafe, including padding.
  34 function base64_encode(bytes, opt_length) {
  35   if (!opt_length) opt_length = bytes.length;
  36   var b64out =
  37       'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
  38   var result = '';
  39   var shift = 0;
  40   var accu = 0;
  41   var inputIndex = 0;
  42   while (opt_length--) {
  43     accu <<= 8;
  44     accu |= bytes[inputIndex++];
  45     shift += 8;
  46     while (shift >= 6) {
  47       var i = (accu >> (shift - 6)) & 63;
  48       result += b64out.charAt(i);
  49       shift -= 6;
  50     }
  51   }
  52   if (shift) {
  53     accu <<= 8;
  54     shift += 8;
  55     var i = (accu >> (shift - 6)) & 63;
  56     result += b64out.charAt(i);
  57   }
  58   while (result.length % 4) result += '=';
  59   return result;
  60 }
  61
  62 var B64_inmap =
  63 [
  64   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 63, 0, 0,
  65  53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 0, 0, 0, 0, 0, 0,
  66   0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
  67  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 0, 0, 0, 0, 64,
  68   0, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41,
  69  42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 0, 0, 0, 0, 0
  70 ];
  71
  72 function B64_decode(string) {
  73   var bytes = [];
  74   var accu = 0;
  75   var shift = 0;
  76   for (var i = 0; i < string.length; ++i) {
  77     var c = string.charCodeAt(i);
  78     if (c < 32 || c > 127 || !B64_inmap[c - 32]) return [];
  79     accu <<= 6;
  80     accu |= (B64_inmap[c - 32] - 1);
  81     shift += 6;
  82     if (shift >= 8) {
  83       bytes.push((accu >> (shift - 8)) & 255);
  84       shift -= 8;
  85     }
  86   }
  87   return bytes;
  88 }