Base64.js 4.5 KB

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  1. /**
  2. *
  3. * Base64 encode / decode
  4. *
  5. * @author haitao.tu
  6. * @date 2010-04-26
  7. * @email tuhaitao@foxmail.com
  8. *
  9. */
  10. function Base64() {
  11. // private property
  12. _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  13. // public method for encoding
  14. this.encode = function (input) {
  15. var output = "";
  16. var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
  17. var i = 0;
  18. input = _utf8_encode(input);
  19. while (i < input.length) {
  20. chr1 = input.charCodeAt(i++);
  21. chr2 = input.charCodeAt(i++);
  22. chr3 = input.charCodeAt(i++);
  23. enc1 = chr1 >> 2;
  24. enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
  25. enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
  26. enc4 = chr3 & 63;
  27. if (isNaN(chr2)) {
  28. enc3 = enc4 = 64;
  29. } else if (isNaN(chr3)) {
  30. enc4 = 64;
  31. }
  32. output = output +
  33. _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
  34. _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
  35. }
  36. return output;
  37. }
  38. // public method for decoding
  39. this.decode = function (input) {
  40. var output = "";
  41. var chr1, chr2, chr3;
  42. var enc1, enc2, enc3, enc4;
  43. var i = 0;
  44. input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
  45. while (i < input.length) {
  46. enc1 = _keyStr.indexOf(input.charAt(i++));
  47. enc2 = _keyStr.indexOf(input.charAt(i++));
  48. enc3 = _keyStr.indexOf(input.charAt(i++));
  49. enc4 = _keyStr.indexOf(input.charAt(i++));
  50. chr1 = (enc1 << 2) | (enc2 >> 4);
  51. chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
  52. chr3 = ((enc3 & 3) << 6) | enc4;
  53. output = output + String.fromCharCode(chr1);
  54. if (enc3 != 64) {
  55. output = output + String.fromCharCode(chr2);
  56. }
  57. if (enc4 != 64) {
  58. output = output + String.fromCharCode(chr3);
  59. }
  60. }
  61. output = _utf8_decode(output);
  62. return output;
  63. }
  64. // private method for UTF-8 encoding
  65. _utf8_encode = function (string) {
  66. string = string.replace(/\r\n/g,"\n");
  67. var utftext = "";
  68. for (var n = 0; n < string.length; n++) {
  69. var c = string.charCodeAt(n);
  70. if (c < 128) {
  71. utftext += String.fromCharCode(c);
  72. } else if((c > 127) && (c < 2048)) {
  73. utftext += String.fromCharCode((c >> 6) | 192);
  74. utftext += String.fromCharCode((c & 63) | 128);
  75. } else {
  76. utftext += String.fromCharCode((c >> 12) | 224);
  77. utftext += String.fromCharCode(((c >> 6) & 63) | 128);
  78. utftext += String.fromCharCode((c & 63) | 128);
  79. }
  80. }
  81. return utftext;
  82. }
  83. // private method for UTF-8 decoding
  84. _utf8_decode = function (utftext) {
  85. var string = "";
  86. var i = 0;
  87. var c = c1 = c2 = 0;
  88. while ( i < utftext.length ) {
  89. c = utftext.charCodeAt(i);
  90. if (c < 128) {
  91. string += String.fromCharCode(c);
  92. i++;
  93. } else if((c > 191) && (c < 224)) {
  94. c2 = utftext.charCodeAt(i+1);
  95. string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
  96. i += 2;
  97. } else {
  98. c2 = utftext.charCodeAt(i+1);
  99. c3 = utftext.charCodeAt(i+2);
  100. string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
  101. i += 3;
  102. }
  103. }
  104. return string;
  105. }
  106. }