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Diffstat (limited to 'node_modules/webpack/lib/util/StringXor.js')
| -rw-r--r-- | node_modules/webpack/lib/util/StringXor.js | 101 |
1 files changed, 0 insertions, 101 deletions
diff --git a/node_modules/webpack/lib/util/StringXor.js b/node_modules/webpack/lib/util/StringXor.js deleted file mode 100644 index ea5c8f83..00000000 --- a/node_modules/webpack/lib/util/StringXor.js +++ /dev/null @@ -1,101 +0,0 @@ -/* - MIT License http://www.opensource.org/licenses/mit-license.php - Author Tobias Koppers @sokra -*/ - -"use strict"; - -/** @typedef {import("../util/Hash")} Hash */ - -/** - * StringXor class provides methods for performing - * [XOR operations](https://en.wikipedia.org/wiki/Exclusive_or) on strings. In this context - * we operating on the character codes of two strings, which are represented as - * [Buffer](https://nodejs.org/api/buffer.html) objects. - * - * We use [StringXor in webpack](https://github.com/webpack/webpack/commit/41a8e2ea483a544c4ccd3e6217bdfb80daffca39) - * to create a hash of the current state of the compilation. By XOR'ing the Module hashes, it - * doesn't matter if the Module hashes are sorted or not. This is useful because it allows us to avoid sorting the - * Module hashes. - * @example - * ```js - * const xor = new StringXor(); - * xor.add('hello'); - * xor.add('world'); - * console.log(xor.toString()); - * ``` - * @example - * ```js - * const xor = new StringXor(); - * xor.add('foo'); - * xor.add('bar'); - * const hash = createHash('sha256'); - * hash.update(xor.toString()); - * console.log(hash.digest('hex')); - * ``` - */ -class StringXor { - constructor() { - /** @type {Buffer|undefined} */ - this._value = undefined; - } - - /** - * Adds a string to the current StringXor object. - * @param {string} str string - * @returns {void} - */ - add(str) { - const len = str.length; - const value = this._value; - if (value === undefined) { - /** - * We are choosing to use Buffer.allocUnsafe() because it is often faster than Buffer.alloc() because - * it allocates a new buffer of the specified size without initializing the memory. - */ - const newValue = (this._value = Buffer.allocUnsafe(len)); - for (let i = 0; i < len; i++) { - newValue[i] = str.charCodeAt(i); - } - return; - } - const valueLen = value.length; - if (valueLen < len) { - const newValue = (this._value = Buffer.allocUnsafe(len)); - let i; - for (i = 0; i < valueLen; i++) { - newValue[i] = value[i] ^ str.charCodeAt(i); - } - for (; i < len; i++) { - newValue[i] = str.charCodeAt(i); - } - } else { - for (let i = 0; i < len; i++) { - value[i] = value[i] ^ str.charCodeAt(i); - } - } - } - - /** - * Returns a string that represents the current state of the StringXor object. We chose to use "latin1" encoding - * here because "latin1" encoding is a single-byte encoding that can represent all characters in the - * [ISO-8859-1 character set](https://en.wikipedia.org/wiki/ISO/IEC_8859-1). This is useful when working - * with binary data that needs to be represented as a string. - * @returns {string} Returns a string that represents the current state of the StringXor object. - */ - toString() { - const value = this._value; - return value === undefined ? "" : value.toString("latin1"); - } - - /** - * Updates the hash with the current state of the StringXor object. - * @param {Hash} hash Hash instance - */ - updateHash(hash) { - const value = this._value; - if (value !== undefined) hash.update(value); - } -} - -module.exports = StringXor; |
