base.js 3.5 KB

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