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June 11, 2021 20:26
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Manual b64 encoder/decoder
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| // encode | |
| var s = '' | |
| var c, d, e, f, g, h, i, j, o, b = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=", k = 0, l = 0, m = "", n = []; | |
| do c = s.charCodeAt(k++), d = s.charCodeAt(k++), e = s.charCodeAt(k++), j = c << 16 | d << 8 | e, f = 63 & j >> 18, g = 63 & j >> 12, h = 63 & j >> 6, i = 63 & j, n[l++] = b.charAt(f) + b.charAt(g) + b.charAt(h) + b.charAt(i); while (k < s.length); | |
| m = n.join(""), o = s.length % 3; | |
| s = (o ? m.slice(0, o - 3) :m) + "===".slice(o || 3); | |
| // decode | |
| var s = '' | |
| var b, c, d, e = {}, f = 0, g = 0, h = "", i = String.fromCharCode, j = s.length; | |
| for (b = 0; 64 > b; b++) e["ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".charAt(b)] = b; | |
| for (c = 0; j > c; c++) for (b = e[s.charAt(c)], f = (f << 6) + b, g += 6; g >= 8; ) ((d = 255 & f >>> (g -= 8)) || j - 2 > c) && (h += i(d)); | |
| s = h; | |
| function b2a(s) { | |
| var c, d, e, f, g, h, i, j, o; | |
| var b = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; | |
| var k = 0, l = 0; | |
| var m = ""; | |
| var n = []; | |
| do { | |
| c = s.charCodeAt(k++), d = s.charCodeAt(k++), e = s.charCodeAt(k++); | |
| j = c << 16 | d << 8 | e; | |
| f = 63 & j >> 18; | |
| g = 63 & j >> 12; | |
| h = 63 & j >> 6; | |
| i = 63 & j; | |
| n[l++] = b.charAt(f) + b.charAt(g) + b.charAt(h) + b.charAt(i); | |
| } while (k < s.length); | |
| m = n.join(""); | |
| o = s.length % 3; | |
| return (o ? m.slice(0, o - 3) :m) + "===".slice(o || 3); | |
| } | |
| function a2b(s) { | |
| var b, c, d; | |
| var e = {}; | |
| var f = 0, g = 0; | |
| var h = ""; | |
| var i = String.fromCharCode, j = s.length; | |
| for (b = 0; 64 > b; b++) { | |
| e["ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".charAt(b)] = b; | |
| } | |
| for (c = 0; j > c; c++) { | |
| for (b = e[s.charAt(c)], f = (f << 6) + b, g += 6; g >= 8;) { | |
| ((d = 255 & f >>> (g -= 8)) || j - 2 > c) && (h += i(d)); | |
| } | |
| } | |
| return h; | |
| } |
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