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function getValue(chr: string): number {
let a = chr;
switch (chr) {
case "O":
case "o":
a = "0;";
break;
case "i":
case "I":
case "l":
case "L":
a = "1";
break;
case "u":
case "U":
a = "V";
}
if (a >= "0" && a <= "9") {
return a.charCodeAt(0) - "0".charCodeAt(0);
}
if (a >= "a" && a <= "z") a = a.toUpperCase();
let dec = 0;
if (a >= "A" && a <= "Z") {
if ("I" < a) dec++;
if ("L" < a) dec++;
if ("O" < a) dec++;
if ("U" < a) dec++;
return a.charCodeAt(0) - "A".charCodeAt(0) + 10 - dec;
}
throw new Error('encoding');
}
const encTable = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
export function encodeCrock(data: ArrayBuffer): string {
const dataBytes = new Uint8Array(data);
let sb = "";
const size = data.byteLength;
let bitBuf = 0;
let numBits = 0;
let pos = 0;
while (pos < size || numBits > 0) {
if (pos < size && numBits < 5) {
const d = dataBytes[pos++];
bitBuf = (bitBuf << 8) | d;
numBits += 8;
}
if (numBits < 5) {
// zero-padding
bitBuf = bitBuf << (5 - numBits);
numBits = 5;
}
const v = (bitBuf >>> (numBits - 5)) & 31;
sb += encTable[v];
numBits -= 5;
}
return sb;
}
export function decodeCrock(encoded: string): Uint8Array {
const size = encoded.length;
let bitpos = 0;
let bitbuf = 0;
let readPosition = 0;
const outLen = Math.floor((size * 5) / 8);
const out = new Uint8Array(outLen);
let outPos = 0;
while (readPosition < size || bitpos > 0) {
if (readPosition < size) {
const v = getValue(encoded[readPosition++]);
bitbuf = (bitbuf << 5) | v;
bitpos += 5;
}
while (bitpos >= 8) {
const d = (bitbuf >>> (bitpos - 8)) & 0xff;
out[outPos++] = d;
bitpos -= 8;
}
if (readPosition == size && bitpos > 0) {
bitbuf = (bitbuf << (8 - bitpos)) & 0xff;
bitpos = bitbuf == 0 ? 0 : 8;
}
}
return out;
}
const bin = decodeCrock("PV2D1G85528VDSZGED8KE98FEXT3PWQ99WV590TNVKJKM3GM3GRG")
const base64String = Buffer
.from(String.fromCharCode.apply(null, bin))
.toString('base64');
console.log(base64String)
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