@splitsoftware/splitio-commons/src/utils/murmur3/legacy.ts

Split JavaScript SDK common components

// Deprecated hashing function, used for split bucketing. Replaced by murmur3

//
// JAVA reference implementation for the hashing function.
//
// int h = 0;
// for (int i = 0; i < key.length(); i++) {
//     h = 31 * h + key.charAt(i);
// }
// return h ^ seed; // XOR the hash and seed
//

function ToInteger(x: number) {
  x = Number(x);
  return x < 0 ? Math.ceil(x) : Math.floor(x);
}

function modulo(a: number, b: number) {
  return a - Math.floor(a / b) * b;
}

function ToUint32(x: number) {
  return modulo(ToInteger(x), Math.pow(2, 32));
}

function ToInt32(x: number) {
  let uint32 = ToUint32(x);

  if (uint32 >= Math.pow(2, 31)) {
    return uint32 - Math.pow(2, 32);
  } else {
    return uint32;
  }
}

export function hash(str: string, seed: number): number {
  let h = 0;

  for (let i = 0; i < str.length; i++) {
    h = ToInt32(ToInt32(31 * h) + str.charCodeAt(i));
  }

  return ToInt32(h ^ seed);
}

export function bucket(str: string, seed: number): number {
  return Math.abs(hash(str, seed) % 100) + 1;
}