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app_vue/node_modules/webpack/lib/util/numberHash.js

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+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+/**
+ * Threshold for switching from 32-bit to 64-bit hashing. This is selected to ensure that the bias towards lower modulo results when using 32-bit hashing is <0.5%.
+ * @type {number}
+ */
+const FNV_64_THRESHOLD = 1 << 24;
+
+/**
+ * The FNV-1a offset basis for 32-bit hash values.
+ * @type {number}
+ */
+const FNV_OFFSET_32 = 2166136261;
+/**
+ * The FNV-1a prime for 32-bit hash values.
+ * @type {number}
+ */
+const FNV_PRIME_32 = 16777619;
+/**
+ * The mask for a positive 32-bit signed integer.
+ * @type {number}
+ */
+const MASK_31 = 0x7fffffff;
+
+/**
+ * The FNV-1a offset basis for 64-bit hash values.
+ * @type {bigint}
+ */
+const FNV_OFFSET_64 = BigInt("0xCBF29CE484222325");
+/**
+ * The FNV-1a prime for 64-bit hash values.
+ * @type {bigint}
+ */
+const FNV_PRIME_64 = BigInt("0x100000001B3");
+
+/**
+ * Computes a 32-bit FNV-1a hash value for the given string.
+ * See https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
+ * @param {string} str The input string to hash
+ * @returns {number} - The computed hash value.
+ */
+function fnv1a32(str) {
+	let hash = FNV_OFFSET_32;
+	for (let i = 0, len = str.length; i < len; i++) {
+		hash ^= str.charCodeAt(i);
+		// Use Math.imul to do c-style 32-bit multiplication and keep only the 32 least significant bits
+		hash = Math.imul(hash, FNV_PRIME_32);
+	}
+	// Force the result to be positive
+	return hash & MASK_31;
+}
+
+/**
+ * Computes a 64-bit FNV-1a hash value for the given string.
+ * See https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
+ * @param {string} str The input string to hash
+ * @returns {bigint} - The computed hash value.
+ */
+function fnv1a64(str) {
+	let hash = FNV_OFFSET_64;
+	for (let i = 0, len = str.length; i < len; i++) {
+		hash ^= BigInt(str.charCodeAt(i));
+		hash = BigInt.asUintN(64, hash * FNV_PRIME_64);
+	}
+	return hash;
+}
+
+/**
+ * Computes a hash value for the given string and range. This hashing algorithm is a modified
+ * version of the [FNV-1a algorithm](https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function).
+ * It is optimized for speed and does **not** generate a cryptographic hash value.
+ *
+ * We use `numberHash` in `lib/ids/IdHelpers.js` to generate hash values for the module identifier. The generated
+ * hash is used as a prefix for the module id's to avoid collisions with other modules.
+ * @param {string} str The input string to hash.
+ * @param {number} range The range of the hash value (0 to range-1).
+ * @returns {number} - The computed hash value.
+ * @example
+ * ```js
+ * const numberHash = require("webpack/lib/util/numberHash");
+ * numberHash("hello", 1000); // 73
+ * numberHash("hello world"); // 72
+ * ```
+ */
+module.exports = (str, range) => {
+	if (range < FNV_64_THRESHOLD) {
+		return fnv1a32(str) % range;
+	}
+	return Number(fnv1a64(str) % BigInt(range));
+};