sheetjs-clone/modules/04_base64.ts

41 lines
1.2 KiB
TypeScript
Raw Normal View History

var Base64_map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
function Base64_encode(input: string): string {
var o = "";
var c1=0, c2=0, c3=0, e1=0, e2=0, e3=0, e4=0;
for(var i = 0; i < input.length; ) {
c1 = input.charCodeAt(i++);
e1 = (c1 >> 2);
2022-02-04 20:57:47 +00:00
c2 = input.charCodeAt(i++);
e2 = ((c1 & 3) << 4) | (c2 >> 4);
2022-02-04 20:57:47 +00:00
c3 = input.charCodeAt(i++);
e3 = ((c2 & 15) << 2) | (c3 >> 6);
e4 = (c3 & 63);
if (isNaN(c2)) { e3 = e4 = 64; }
else if (isNaN(c3)) { e4 = 64; }
o += Base64_map.charAt(e1) + Base64_map.charAt(e2) + Base64_map.charAt(e3) + Base64_map.charAt(e4);
}
return o;
}
function Base64_decode(input: string): string {
var o = "";
var c1=0, c2=0, c3=0, e1=0, e2=0, e3=0, e4=0;
input = input.replace(/[^\w\+\/\=]/g, "");
for(var i = 0; i < input.length;) {
e1 = Base64_map.indexOf(input.charAt(i++));
e2 = Base64_map.indexOf(input.charAt(i++));
c1 = (e1 << 2) | (e2 >> 4);
o += String.fromCharCode(c1);
2022-02-04 20:57:47 +00:00
e3 = Base64_map.indexOf(input.charAt(i++));
c2 = ((e2 & 15) << 4) | (e3 >> 2);
if (e3 !== 64) { o += String.fromCharCode(c2); }
2022-02-04 20:57:47 +00:00
e4 = Base64_map.indexOf(input.charAt(i++));
c3 = ((e3 & 3) << 6) | e4;
if (e4 !== 64) { o += String.fromCharCode(c3); }
}
return o;
}