Function: base64_decode version 459

Function:
Description: Decodes string using MIME base64 algorithm.
Version:
Status: release
Date: 2011-12-27 16:38
Summary: Actually removed UTF-* decoding. :P
Programmer: jj5
Code
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
function base64_decode (data) {
    // http://jsphp.co/jsphp/fn/view/base64_decode
    // +   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,
        dec = "",
        tmp_arr = [];

    if (!data) {
        return data;
    }

    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;

        if (h3 == 64) {
            tmp_arr[ac++] = String.fromCharCode(o1);
        } else if (h4 == 64) {
            tmp_arr[ac++] = String.fromCharCode(o1, o2);
        } else {
            tmp_arr[ac++] = String.fromCharCode(o1, o2, o3);
        }
    } while (i < data.length);

    dec = tmp_arr.join('');
    // removed UTF-8 decoding, this should be done after base64_decode if necessary.
    //dec = this.utf8_decode(dec);

    return dec;
}
[top]

Comments

There are no comments yet, be the first!

Please Login or Register to post comments.