EmulatorJS/data/src/utils.js at main · allancoding/EmulatorJS · GitHub

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/**

* EJS Utility Functions

/**

* Computes a simple hash of the given data array.

* @param {Uint8Array} dataArray

* @returns {number} The computed hash.

export function simpleHash(dataArray) {

let hash = 0;

for (let i = 0; i < dataArray.length; i++) {

hash = ((hash << 5) - hash + dataArray[i]) & 0xffffffff;

}

return hash;

}

/**

* Cyrb53 hash function adapted for buffers.

* @param {*} charBuffer

* @param {*} seed

* @returns {string} Hexadecimal representation of the hash.

export async function cyrb53(charBuffer, seed = 0) {

// https://stackoverflow.com/questions/7616461

// Modified to accept a buffer instead of a string and return hex instead of an int

let h1 = 0xdeadbeef ^ seed, h2 = 0x41c6ce57 ^ seed;

for(let i = 0, ch; i < charBuffer.length; i++) {

ch = charBuffer[i];

h1 = Math.imul(h1 ^ ch, 2654435761);

h2 = Math.imul(h2 ^ ch, 1597334677);

}

h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507);

h1 ^= Math.imul(h2 ^ (h2 >>> 13), 3266489909);

h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507);

h2 ^= Math.imul(h1 ^ (h1 >>> 13), 3266489909);

// Cyrb53 is a 53-bit hash; we need 14 hex characters to represent it, and the first char will

// always be 0 or 1 (since it is only 1 bit)

return (4294967296 * (2097151 & h2) + (h1 >>> 0)).toString(16).padStart(14, "0");

}

/**

* Generate a random GUID string.

* @returns {string} A GUID in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

export function guid() {

const s4 = () => (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1);

return s4() + s4() + "-" + s4() + "-" + s4() + "-" + s4() + "-" + s4() + s4() + s4();

}

EmulatorJS/data/src/utils.js at main · allancoding/EmulatorJS · GitHub

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