base64.js 1.8 KB

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  1. // base64 加密方法
  2. var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  3. // public method for encoding
  4. const encode = function(input){
  5. var output = "";
  6. var chr1=null, chr2=null, chr3=null, enc1=null, enc2=null, enc3=null, enc4=null;
  7. var i = 0;
  8. input = _utf8_encode(input);
  9. while (i < input.length) {
  10. chr1 = input.charCodeAt(i++);
  11. chr2 = input.charCodeAt(i++);
  12. chr3 = input.charCodeAt(i++);
  13. enc1 = chr1 >> 2;
  14. enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
  15. enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
  16. enc4 = chr3 & 63;
  17. if (isNaN(chr2)) {
  18. enc3 = enc4 = 64;
  19. } else if (isNaN(chr3)) {
  20. enc4 = 64;
  21. }
  22. output = output +
  23. _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
  24. _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
  25. }
  26. return output;
  27. }
  28. // private method for UTF-8 encoding
  29. const _utf8_encode = function(string) {
  30. string = string.replace(/\r\n/g,"\n");
  31. var utftext = "";
  32. for (var n = 0; n < string.length; n++) {
  33. var c = string.charCodeAt(n);
  34. if (c < 128) {
  35. utftext += String.fromCharCode(c);
  36. } else if((c > 127) && (c < 2048)) {
  37. utftext += String.fromCharCode((c >> 6) | 192);
  38. utftext += String.fromCharCode((c & 63) | 128);
  39. } else {
  40. utftext += String.fromCharCode((c >> 12) | 224);
  41. utftext += String.fromCharCode(((c >> 6) & 63) | 128);
  42. utftext += String.fromCharCode((c & 63) | 128);
  43. }
  44. }
  45. return utftext;
  46. }
  47. export default encode;