diff options
Diffstat (limited to 'node_modules/webpack/lib/util/numberHash.js')
| -rw-r--r-- | node_modules/webpack/lib/util/numberHash.js | 99 |
1 files changed, 0 insertions, 99 deletions
diff --git a/node_modules/webpack/lib/util/numberHash.js b/node_modules/webpack/lib/util/numberHash.js deleted file mode 100644 index f7150d13..00000000 --- a/node_modules/webpack/lib/util/numberHash.js +++ /dev/null @@ -1,99 +0,0 @@ -/* - MIT License http://www.opensource.org/licenses/mit-license.php - Author Tobias Koppers @sokra -*/ - -"use strict"; - -/** - * The maximum safe integer value for 32-bit integers. - * @type {number} - */ -const SAFE_LIMIT = 0x80000000; - -/** - * The maximum safe integer value for 32-bit integers minus one. This is used - * in the algorithm to ensure that intermediate hash values do not exceed the - * 32-bit integer limit. - * @type {number} - */ -const SAFE_PART = SAFE_LIMIT - 1; - -/** - * The number of 32-bit integers used to store intermediate hash values. - * @type {number} - */ -const COUNT = 4; - -/** - * An array used to store intermediate hash values during the calculation. - * @type {number[]} - */ -const arr = [0, 0, 0, 0, 0]; - -/** - * An array of prime numbers used in the hash calculation. - * @type {number[]} - */ -const primes = [3, 7, 17, 19]; - -/** - * 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); // 57 - * numberHash("hello world"); // 990 - * ``` - * - */ -module.exports = (str, range) => { - /** - * Initialize the array with zeros before it is used - * to store intermediate hash values. - */ - arr.fill(0); - // For each character in the string - for (let i = 0; i < str.length; i++) { - // Get the character code. - const c = str.charCodeAt(i); - - // For each 32-bit integer used to store the hash value - // add the character code to the current hash value and multiply by the prime number and - // add the previous 32-bit integer. - arr[0] = (arr[0] + c * primes[0] + arr[3]) & SAFE_PART; - arr[1] = (arr[1] + c * primes[1] + arr[0]) & SAFE_PART; - arr[2] = (arr[2] + c * primes[2] + arr[1]) & SAFE_PART; - arr[3] = (arr[3] + c * primes[3] + arr[2]) & SAFE_PART; - - // For each 32-bit integer used to store the hash value - // XOR the current hash value with the value of the next 32-bit integer. - arr[0] = arr[0] ^ (arr[arr[0] % COUNT] >> 1); - arr[1] = arr[1] ^ (arr[arr[1] % COUNT] >> 1); - arr[2] = arr[2] ^ (arr[arr[2] % COUNT] >> 1); - arr[3] = arr[3] ^ (arr[arr[3] % COUNT] >> 1); - } - - if (range <= SAFE_PART) { - return (arr[0] + arr[1] + arr[2] + arr[3]) % range; - } else { - // Calculate the range extension. - const rangeExt = Math.floor(range / SAFE_LIMIT); - - const sum1 = (arr[0] + arr[2]) & SAFE_PART; - const sum2 = (arr[0] + arr[2]) % rangeExt; - - return (sum2 * SAFE_LIMIT + sum1) % range; - } -}; |
