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// Array of bytes to Base64 string decoding
function b64ToUint6(nChr: number) {
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;
}
export function decode(sBase64: string, nBlocksSize?: number) {
const sB64Enc = sBase64.replace(/[^A-Za-z0-9+/]/g, "");
const nInLen = sB64Enc.length;
const nOutLen = nBlocksSize
? Math.ceil(((nInLen * 3 + 1) >> 2) / nBlocksSize) * nBlocksSize
: (nInLen * 3 + 1) >> 2;
const taBytes = new Uint8Array(nOutLen);
let nMod3;
let nMod4;
let nUint24 = 0;
let nOutIdx = 0;
for (let nInIdx = 0; nInIdx < nInLen; nInIdx++) {
nMod4 = nInIdx & 3;
nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << (6 * (3 - nMod4));
if (nMod4 === 3 || nInLen - nInIdx === 1) {
nMod3 = 0;
while (nMod3 < 3 && nOutIdx < nOutLen) {
taBytes[nOutIdx] = (nUint24 >>> ((16 >>> nMod3) & 24)) & 255;
nMod3++;
nOutIdx++;
}
nUint24 = 0;
}
}
return taBytes;
}
/* Base64 string to array encoding */
function uint6ToB64(nUint6: number) {
return nUint6 < 26
? nUint6 + 65
: nUint6 < 52
? nUint6 + 71
: nUint6 < 62
? nUint6 - 4
: nUint6 === 62
? 43
: nUint6 === 63
? 47
: 65;
}
export function encode(aBytes: Uint8Array) {
let nMod3 = 2;
let sB64Enc = "";
const nLen = aBytes.length;
let nUint24 = 0;
for (let 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.fromCodePoint(
uint6ToB64((nUint24 >>> 18) & 63),
uint6ToB64((nUint24 >>> 12) & 63),
uint6ToB64((nUint24 >>> 6) & 63),
uint6ToB64(nUint24 & 63)
);
nUint24 = 0;
}
}
return (
sB64Enc.substr(0, sB64Enc.length - 2 + nMod3) +
(nMod3 === 2 ? "" : nMod3 === 1 ? "=" : "==")
);
}
export default { encode, decode }
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