111 lines
2.6 KiB
TypeScript
111 lines
2.6 KiB
TypeScript
/**
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* Bytes to exclude from hashing.
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*
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* Why? I dunno.
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*/
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const MURMUR_SKIP_BYTES: { [key: number]: boolean } = {
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9: true,
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10: true,
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13: true,
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32: true,
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};
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import _sha1 from "sha1";
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/**
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* JS Implementation of MurmurHash2
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*
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* @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
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* @see http://github.com/garycourt/murmurhash-js
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* @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
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* @see http://sites.google.com/site/murmurhash/
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*/
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function murmurhash2_32_gc(arr, seed, len = arr.length) {
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let l = len,
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h = seed ^ l,
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i = 0,
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k;
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while (l >= 4) {
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k = (arr[i] & 0xff) | ((arr[++i] & 0xff) << 8) | ((arr[++i] & 0xff) << 16) | ((arr[++i] & 0xff) << 24);
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k = (k & 0xffff) * 0x5bd1e995 + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16);
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k ^= k >>> 24;
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k = (k & 0xffff) * 0x5bd1e995 + ((((k >>> 16) * 0x5bd1e995) & 0xffff) << 16);
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h = ((h & 0xffff) * 0x5bd1e995 + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16)) ^ k;
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l -= 4;
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++i;
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}
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switch (l) {
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case 3:
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h ^= (arr[i + 2] & 0xff) << 16;
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case 2:
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h ^= (arr[i + 1] & 0xff) << 8;
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case 1:
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h ^= arr[i] & 0xff;
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h = (h & 0xffff) * 0x5bd1e995 + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16);
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}
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h ^= h >>> 13;
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h = (h & 0xffff) * 0x5bd1e995 + ((((h >>> 16) * 0x5bd1e995) & 0xffff) << 16);
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h ^= h >>> 15;
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return h >>> 0;
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}
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/**
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* Returns the hash sum of bytes of given bytes using MurmurHash v2.
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*
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* This is what Twitch is using to fingerprint mod files.
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*/
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export const murmurhash = (inputBuffer: Buffer, seed = 1): string => {
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const output = new Uint8Array(inputBuffer.length);
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let pos = 0;
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for (let i = 0; i < inputBuffer.length; i++) {
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const byte = inputBuffer.readUInt8(i);
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if (!MURMUR_SKIP_BYTES[byte]) {
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output[pos++] = byte;
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}
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}
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return String(murmurhash2_32_gc(output, seed, pos));
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};
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import { HashDef } from "../types/hashDef";
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/**
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* Returns the hash sum of bytes of given bytes using SHA1.
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*
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* This is what Forge is using to check files.
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*/
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export const sha1 = (inputBuffer: Buffer): string => {
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return _sha1(inputBuffer);
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};
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const hashFuncs: { [key: string]: (buffer: Buffer) => string } = {
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murmurhash: murmurhash,
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sha1: sha1,
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};
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/**
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* Compare buffer to the given HashDef.
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*
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* @param {Buffer} buffer
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* @param {HashDef} hashDef
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*
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* @throws {Error} Throws a generic error if hashes don't match.
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*/
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export const compareBufferToHashDef = (buffer: Buffer, hashDef: HashDef): boolean => {
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if (!hashFuncs[hashDef.id]) {
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throw new Error(`No hash function found for ${hashDef.id}.`);
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}
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const sum = hashFuncs[hashDef.id](buffer);
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return (Array.isArray(hashDef.hashes) && hashDef.hashes.includes(sum)) || hashDef.hashes == sum;
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};
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