fork download
copy 
  1. class MyBase64 { 
  2.  
  3. private final static char[] ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray(); 
  4.  
  5. private static int[] toInt = new int[128]; 
  6.  
  7. static { 
  8. for(int i=0; i< ALPHABET.length; i++){ 
  9. toInt[ALPHABET[i]]= i; 
  10. } 
  11. } 
  12.  
  13. /** 
  14. * Translates the specified byte array into Base64 string. 
  15. * 
  16. * @param buf the byte array (not null) 
  17. * @return the translated Base64 string (not null) 
  18. */ 
  19. public static String encode(byte[] buf){ 
  20. int size = buf.length; 
  21. char[] ar = new char[((size + 2) / 3) * 4]; 
  22. int a = 0; 
  23. int i=0; 
  24. while(i < size){ 
  25. byte b0 = buf[i++]; 
  26. byte b1 = (i < size) ? buf[i++] : 0; 
  27. byte b2 = (i < size) ? buf[i++] : 0; 
  28.  
  29. int mask = 0x3F; 
  30. ar[a++] = ALPHABET[(b0 >> 2) & mask]; 
  31. ar[a++] = ALPHABET[((b0 << 4) | ((b1 & 0xFF) >> 4)) & mask]; 
  32. ar[a++] = ALPHABET[((b1 << 2) | ((b2 & 0xFF) >> 6)) & mask]; 
  33. ar[a++] = ALPHABET[b2 & mask]; 
  34. } 
  35. switch(size % 3){ 
  36. case 1: ar[--a] = '='; 
  37. case 2: ar[--a] = '='; 
  38. } 
  39. return new String(ar); 
  40. } 
  41.  
  42. /** 
  43. * Translates the specified Base64 string into a byte array. 
  44. * 
  45. * @param s the Base64 string (not null) 
  46. * @return the byte array (not null) 
  47. */ 
  48. public static byte[] decode(String s){ 
  49. int delta = s.endsWith( "==" ) ? 2 : s.endsWith( "=" ) ? 1 : 0; 
  50. byte[] buffer = new byte[s.length()*3/4 - delta]; 
  51. int mask = 0xFF; 
  52. int index = 0; 
  53. for(int i=0; i< s.length(); i+=4){ 
  54. int c0 = toInt[s.charAt( i )]; 
  55. int c1 = toInt[s.charAt( i + 1)]; 
  56. buffer[index++]= (byte)(((c0 << 2) | (c1 >> 4)) & mask); 
  57. if(index >= buffer.length){ 
  58. return buffer; 
  59. } 
  60. int c2 = toInt[s.charAt( i + 2)]; 
  61. buffer[index++]= (byte)(((c1 << 4) | (c2 >> 2)) & mask); 
  62. if(index >= buffer.length){ 
  63. return buffer; 
  64. } 
  65. int c3 = toInt[s.charAt( i + 3 )]; 
  66. buffer[index++]= (byte)(((c2 << 6) | c3) & mask); 
  67. } 
  68. return buffer; 
  69. } 
  70.  
  71. } 
  72.  
Runtime error #stdin #stdout 0.09s 212736KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Standard output is empty
https://ideone.com/9lYxY
language:
Java (HotSpot 12)
created:
14 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!