26 lines
1.1 KiB
TypeScript
26 lines
1.1 KiB
TypeScript
const obfuscatedStartOffset = 0;
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const obfuscatedEndOffset = 32;
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const guidSize = 32;
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export const obfuscate = (buf: Uint8Array, fontKey: string): Uint8Array => {
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const guid = fontKey.replace(/-/g, "");
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if (guid.length !== guidSize) {
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throw new Error(`Error: Cannot extract GUID from font filename: ${fontKey}`);
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}
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const hexStrings = guid.replace(/(..)/g, "$1 ").trim().split(" ");
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const hexNumbers = hexStrings.map((hexString) => parseInt(hexString, 16));
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// eslint-disable-next-line functional/immutable-data
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hexNumbers.reverse();
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const bytesToObfuscate = buf.slice(obfuscatedStartOffset, obfuscatedEndOffset);
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// eslint-disable-next-line no-bitwise
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const obfuscatedBytes = bytesToObfuscate.map((byte, i) => byte ^ hexNumbers[i % hexNumbers.length]);
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const out = new Uint8Array(obfuscatedStartOffset + obfuscatedBytes.length + Math.max(0, buf.length - obfuscatedEndOffset));
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out.set(buf.slice(0, obfuscatedStartOffset));
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out.set(obfuscatedBytes, obfuscatedStartOffset);
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out.set(buf.slice(obfuscatedEndOffset), obfuscatedStartOffset + obfuscatedBytes.length);
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return out;
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};
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