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- /*
- MIT License http://www.opensource.org/licenses/mit-license.php
- Author Tobias Koppers @sokra
- */
- "use strict";
- const SAFE_LIMIT = 0x80000000;
- const SAFE_PART = SAFE_LIMIT - 1;
- const COUNT = 4;
- const arr = [0, 0, 0, 0, 0];
- const primes = [3, 7, 17, 19];
- module.exports = (str, range) => {
- arr.fill(0);
- for (let i = 0; i < str.length; i++) {
- const c = str.charCodeAt(i);
- for (let j = 0; j < COUNT; j++) {
- const p = (j + COUNT - 1) % COUNT;
- arr[j] = (arr[j] + c * primes[j] + arr[p]) & SAFE_PART;
- }
- for (let j = 0; j < COUNT; j++) {
- const q = arr[j] % COUNT;
- arr[j] = arr[j] ^ (arr[q] >> 1);
- }
- }
- if (range <= SAFE_PART) {
- let sum = 0;
- for (let j = 0; j < COUNT; j++) {
- sum = (sum + arr[j]) % range;
- }
- return sum;
- } else {
- let sum1 = 0;
- let sum2 = 0;
- const rangeExt = Math.floor(range / SAFE_LIMIT);
- for (let j = 0; j < COUNT; j += 2) {
- sum1 = (sum1 + arr[j]) & SAFE_PART;
- }
- for (let j = 1; j < COUNT; j += 2) {
- sum2 = (sum2 + arr[j]) % rangeExt;
- }
- return (sum2 * SAFE_LIMIT + sum1) % range;
- }
- };
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