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/*
Fosscord: A FOSS re-implementation and extension of the Discord.com backend.
Copyright (C) 2023 Fosscord and Fosscord Contributors
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
const alphabet =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+";
// binary to string lookup table
const b2s = alphabet.split("");
// string to binary lookup table
// 123 == 'z'.charCodeAt(0) + 1
const s2b = new Array(123);
for (let i = 0; i < alphabet.length; i++) {
s2b[alphabet.charCodeAt(i)] = i;
}
// number to base64
export const ntob = (n: number): string => {
if (n < 0) return `-${ntob(-n)}`;
let lo = n >>> 0;
let hi = (n / 4294967296) >>> 0;
let right = "";
while (hi > 0) {
right = b2s[0x3f & lo] + right;
lo >>>= 6;
lo |= (0x3f & hi) << 26;
hi >>>= 6;
}
let left = "";
do {
left = b2s[0x3f & lo] + left;
lo >>>= 6;
} while (lo > 0);
return left + right;
};
// base64 to number
export const bton = (base64: string) => {
let number = 0;
const sign = base64.charAt(0) === "-" ? 1 : 0;
for (let i = sign; i < base64.length; i++) {
number = number * 64 + s2b[base64.charCodeAt(i)];
}
return sign ? -number : number;
};
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