A tweet-sized 64bit decoder inspired by this base64 encoder: https://gist.github.com/999166
It will fail on older IEs (Version 7 or older) unless the input String is converted to an Array using .split('').
Thanks to @jed for this great idea of 140byt.es and thanks to him and Kambfhase for help; thanks to @nikola for a hint saving 2 brackets! Thanks to LeverOne for his support fixing the last bugs regarding RFC2045 conformity and golfing the last bytes.
| function( | |
| d, // base64 data (in IE7 or older, use .split('') to get this working | |
| b, // replacement map ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/") | |
| c, // character and - ascii value buffer | |
| u, // bit storage | |
| r, // result | |
| q, // bit counter | |
| x // char counter | |
| ){ | |
| for ( | |
| // initialize result and counters | |
| r = q = x = ''; | |
| // get next character | |
| c = d[x++]; | |
| // character found in table? initialize bit storage and add its ascii value; | |
| ~c && (u = q%4 ? u*64+c : c, | |
| // and if not first of each 4 characters, convert the first 8bits to one ascii character | |
| q++ % 4) ? r += String.fromCharCode(255&u>>(-2*q&6)) : 0 | |
| ) | |
| // try to find character in table (0-63, not found => -1) | |
| c = b.indexOf(c); | |
| // return result | |
| return r | |
| } |
| function(d,b,c,u,r,q,x){for(r=q=x='';c=d[x++];~c&&(u=q%4?u*64+c:c,q++%4)?r+=String.fromCharCode(255&u>>(-2*q&6)):0)c=b.indexOf(c);return r} |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright* (C) 2011 Alex Kloss <[email protected]> | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. | |
| * As far as something complicated as Copyright applies to such an | |
| simple code... |
| { | |
| "name": "Base64Decoder", | |
| "description": "Fully working Base64 decoder in 139bytes", | |
| "keywords": [ | |
| "base64", | |
| "decode", | |
| "padding", | |
| "rfc2045" | |
| ] | |
| } |
| <!DOCTYPE html> | |
| <title>Base64 decoder</title> | |
| <script type="text/javascript"> | |
| (function(){ | |
| var f = function(d,b,c,u,r,q,x){for(r=q=x='';c=d[x++];~c&&(u=q%4?u*64+c:c,q++%4)?r+=String.fromCharCode(255&u>>(-2*q&6)):0)c=b.indexOf(c);return r} | |
| , test = { | |
| "Zg==" : "f" | |
| ,"Zm8=" : "fo" | |
| ,"Zm9v" : "foo" | |
| ,"Zm9vYg==" : "foob" | |
| ,"Zm9vYmE=" : "fooba" | |
| ,"Zm9vYmFy" : "foobar" | |
| ,"MTQwYnl0ZX\n MgcnVsZXMh" : "140bytes rules!" | |
| } | |
| , error = 0; | |
| ; | |
| for( i in test ) { | |
| var r = f(i, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"); | |
| if( r != test[i] ) { | |
| error++; | |
| document.writeln( 'Expected "'+test[i]+'" for "'+i+'" but got "'+ r + ""<br>" ); | |
| } | |
| } | |
| if( error > 0) { | |
| document.writeln( "<br>"+error+ " tests failed!<br>" ); | |
| } else { | |
| document.writeln( "<br>Everything is fine!<br>" ); | |
| } | |
| })(); | |
| </script> | |
| </body> | |
| </html> |