34 lines
1.0 KiB
JavaScript
34 lines
1.0 KiB
JavaScript
const SHORT_TO_HEX = {};
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const HEX_TO_SHORT = {};
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for (let i = 0; i < 256; i++) {
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let encodedByte = i.toString(16).toLowerCase();
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if (encodedByte.length === 1) {
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encodedByte = `0${encodedByte}`;
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}
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SHORT_TO_HEX[i] = encodedByte;
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HEX_TO_SHORT[encodedByte] = i;
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}
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export function fromHex(encoded) {
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if (encoded.length % 2 !== 0) {
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throw new Error("Hex encoded strings must have an even number length");
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}
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const out = new Uint8Array(encoded.length / 2);
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for (let i = 0; i < encoded.length; i += 2) {
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const encodedByte = encoded.slice(i, i + 2).toLowerCase();
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if (encodedByte in HEX_TO_SHORT) {
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out[i / 2] = HEX_TO_SHORT[encodedByte];
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}
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else {
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throw new Error(`Cannot decode unrecognized sequence ${encodedByte} as hexadecimal`);
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}
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}
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return out;
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}
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export function toHex(bytes) {
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let out = "";
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for (let i = 0; i < bytes.byteLength; i++) {
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out += SHORT_TO_HEX[bytes[i]];
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}
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return out;
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}
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