Cable-Desktop/js/stringview.js
Daniel Reichert db5683a69d Move Base64 functions to their own file
Remove Base64 string functions from helpers.js

Rename Base64 string functions

Removed unused functions from stringview.js
2014-12-03 00:42:55 -08:00

79 lines
2.3 KiB
JavaScript

"use strict";
/*
* These functions are from the Mozilla Developer Network
* https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
*
*/
var StringView = {
b64ToUint6: function(nChr) {
return nChr > 64 && nChr < 91 ?
nChr - 65
: nChr > 96 && nChr < 123 ?
nChr - 71
: nChr > 47 && nChr < 58 ?
nChr + 4
: nChr === 43 ?
62
: nChr === 47 ?
63
:
0;
},
base64ToBytes: function(sBase64, nBlocksSize) {
var
sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2;
var aBBytes = new ArrayBuffer(nOutLen);
var taBytes = new Uint8Array(aBBytes);
for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
nMod4 = nInIdx & 3;
nUint24 |= StringView.b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
if (nMod4 === 3 || nInLen - nInIdx === 1) {
for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
}
nUint24 = 0;
}
}
return aBBytes;
},
uint6ToB64: function(nUint6) {
return nUint6 < 26 ?
nUint6 + 65
: nUint6 < 52 ?
nUint6 + 71
: nUint6 < 62 ?
nUint6 - 4
: nUint6 === 62 ?
43
: nUint6 === 63 ?
47
:
65;
},
bytesToBase64: function(aBytes) {
var nMod3, sB64Enc = "";
for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
nMod3 = nIdx % 3;
if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
if (nMod3 === 2 || aBytes.length - nIdx === 1) {
sB64Enc += String.fromCharCode(
StringView.uint6ToB64(nUint24 >>> 18 & 63),
StringView.uint6ToB64(nUint24 >>> 12 & 63),
StringView.uint6ToB64(nUint24 >>> 6 & 63),
StringView.uint6ToB64(nUint24 & 63)
);
nUint24 = 0;
}
}
return sB64Enc.replace(/A(?=A$|$)/g, "=");
}
};