80 lines
1.8 KiB
JavaScript
80 lines
1.8 KiB
JavaScript
export function decode(base32) {
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for (
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var base32chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567",
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bits = "",
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hex = "",
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i = 0;
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i < base32.length;
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i++
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) {
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var val = base32chars.indexOf(base32.charAt(i).toUpperCase());
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bits += leftpad(val.toString(2), 5, "0");
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}
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for (i = 0; i + 4 <= bits.length; i += 4) {
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var chunk = bits.substr(i, 4);
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hex += parseInt(chunk, 2).toString(16);
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}
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return hex;
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}
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function leftpad(str, len, pad) {
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return (
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len + 1 >= str.length &&
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(str = new Array(len + 1 - str.length).join(pad) + str),
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str
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);
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}
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export function encode(bytes) {
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const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
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let bits = 0;
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let value = 0;
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let output = '';
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for (let i = 0; i < bytes.length; i++) {
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value = (value << 8) | bytes[i];
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bits += 8;
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while (bits >= 5) {
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output += alphabet[(value >>> (bits - 5)) & 0x1F];
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bits -= 5;
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}
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}
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if (bits > 0) {
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output += alphabet[(value << (5 - bits)) & 0x1F];
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}
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const paddingLength = (8 - (output.length % 8)) % 8;
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output += '='.repeat(paddingLength);
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return output;
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}
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export function base64decode(base64) {
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const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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let result = [];
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let i = 0, j = 0;
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let b1, b2, b3, b4;
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while (i < base64.length) {
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b1 = chars.indexOf(base64.charAt(i++));
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b2 = chars.indexOf(base64.charAt(i++));
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b3 = chars.indexOf(base64.charAt(i++));
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b4 = chars.indexOf(base64.charAt(i++));
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if (b1 === -1 || b2 === -1) break;
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result[j++] = (b1 << 2) | (b2 >> 4);
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if (b3 !== -1) {
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result[j++] = ((b2 & 15) << 4) | (b3 >> 2);
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}
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if (b4 !== -1) {
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result[j++] = ((b3 & 3) << 6) | b4;
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}
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}
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return result.slice(0, j);
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} |