mirror of
https://github.com/whscullin/apple2js.git
synced 2024-01-12 14:14:38 +00:00
113 lines
3.4 KiB
JavaScript
113 lines
3.4 KiB
JavaScript
/*exported base64_encode, base64_decode */
|
|
|
|
export function base64_encode (data) {
|
|
// Twacked by Will Scullin to handle arrays of "bytes"
|
|
|
|
// http://kevin.vanzonneveld.net
|
|
// + original by: Tyler Akins (http://rumkin.com)
|
|
// + improved by: Bayron Guevara
|
|
// + improved by: Thunder.m
|
|
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
|
|
// + bugfixed by: Pellentesque Malesuada
|
|
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
|
|
// - depends on: utf8_encode
|
|
// * example 1: base64_encode('Kevin van Zonneveld');
|
|
// * returns 1: 'S2V2aW4gdmFuIFpvbm5ldmVsZA=='
|
|
|
|
// mozilla has this native
|
|
// - but breaks in 2.0.0.12!
|
|
//if (typeof this.window['atob'] == 'function') {
|
|
// return atob(data);
|
|
//}
|
|
|
|
var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
|
|
var o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, enc='', tmp_arr = [];
|
|
|
|
if (!data) {
|
|
return data;
|
|
}
|
|
|
|
do { // pack three octets into four hexets
|
|
o1 = data[i++];
|
|
o2 = data[i++];
|
|
o3 = data[i++];
|
|
|
|
bits = o1<<16 | o2<<8 | o3;
|
|
|
|
h1 = bits>>18 & 0x3f;
|
|
h2 = bits>>12 & 0x3f;
|
|
h3 = bits>>6 & 0x3f;
|
|
h4 = bits & 0x3f;
|
|
|
|
// use hexets to index into b64, and append result to encoded string
|
|
tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
|
|
} while (i < data.length);
|
|
|
|
enc = tmp_arr.join('');
|
|
|
|
switch (data.length % 3) {
|
|
case 1:
|
|
enc = enc.slice(0, -2) + '==';
|
|
break;
|
|
case 2:
|
|
enc = enc.slice(0, -1) + '=';
|
|
break;
|
|
}
|
|
|
|
return enc;
|
|
}
|
|
|
|
export function base64_decode(data) {
|
|
// Twacked by Will Scullin to handle arrays of "bytes"
|
|
|
|
// http://kevin.vanzonneveld.net
|
|
// + original by: Tyler Akins (http://rumkin.com)
|
|
// + improved by: Thunder.m
|
|
// + input by: Aman Gupta
|
|
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
|
|
// + bugfixed by: Onno Marsman
|
|
// + bugfixed by: Pellentesque Malesuada
|
|
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
|
|
// + input by: Brett Zamir (http://brett-zamir.me)
|
|
// + bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
|
|
// - depends on: utf8_decode
|
|
// * example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==');
|
|
// * returns 1: 'Kevin van Zonneveld'
|
|
|
|
// mozilla has this native
|
|
// - but breaks in 2.0.0.12!
|
|
//if (typeof this.window['btoa'] == 'function') {
|
|
// return btoa(data);
|
|
//}
|
|
|
|
var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
|
|
var o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, tmp_arr = [];
|
|
|
|
if (!data) {
|
|
return data;
|
|
}
|
|
|
|
do { // unpack four hexets into three octets using index points in b64
|
|
h1 = b64.indexOf(data.charAt(i++));
|
|
h2 = b64.indexOf(data.charAt(i++));
|
|
h3 = b64.indexOf(data.charAt(i++));
|
|
h4 = b64.indexOf(data.charAt(i++));
|
|
|
|
bits = h1<<18 | h2<<12 | h3<<6 | h4;
|
|
|
|
o1 = bits>>16 & 0xff;
|
|
o2 = bits>>8 & 0xff;
|
|
o3 = bits & 0xff;
|
|
|
|
tmp_arr[ac++] = o1;
|
|
if (h3 != 64) {
|
|
tmp_arr[ac++] = o2;
|
|
}
|
|
if (h4 != 64) {
|
|
tmp_arr[ac++] = o3;
|
|
}
|
|
} while (i < data.length);
|
|
|
|
return tmp_arr;
|
|
}
|