benchmark: split Buffer.byteLength benchmark

PR-URL: #46616
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

benchmark/buffers/buffer-bytelength-buffer.js

@@ -0,0 +1,22 @@
+'use strict';
+const common = require('../common');
+
+const bench = common.createBenchmark(main, {
+  len: [2, 16, 256], // x16
+  n: [4e6],
+});
+
+function main({ n, len }) {
+  const data = Buffer.alloc(len * 16, 'a');
+  const expected = Buffer.byteLength(data, 'buffer');
+  let changed = false;
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    const actual = Buffer.byteLength(data, 'buffer');
+    if (expected !== actual) { changed = true; }
+  }
+  bench.end(n);
+  if (changed) {
+    throw new Error('Result changed during iteration');
+  }
+}

benchmark/buffers/buffer-bytelength-string.js

@@ -0,0 +1,40 @@
+'use strict';
+const common = require('../common');
+
+const bench = common.createBenchmark(main, {
+  type: ['one_byte', 'two_bytes', 'three_bytes', 'four_bytes'],
+  encoding: ['utf8', 'base64'],
+  repeat: [1, 2, 16, 256], // x16
+  n: [4e6],
+});
+
+// 16 chars each
+const chars = {
+  one_byte: 'hello brendan!!!',
+  two_bytes: 'ΰαβγδεζηθικλμνξο',
+  three_bytes: '挰挱挲挳挴挵挶挷挸挹挺挻挼挽挾挿',
+  four_bytes: '𠜎𠜱𠝹𠱓𠱸𠲖𠳏𠳕𠴕𠵼𠵿𠸎𠸏𠹷𠺝𠺢',
+};
+
+function getInput(type, repeat, encoding) {
+  const original = (repeat === 1) ? chars[type] : chars[type].repeat(repeat);
+  if (encoding === 'base64') {
+    Buffer.from(original, 'utf8').toString('base64');
+  }
+  return original;
+}
+
+function main({ n, repeat, encoding, type }) {
+  const data = getInput(type, repeat, encoding);
+  const expected = Buffer.byteLength(data, encoding);
+  let changed = false;
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    const actual = Buffer.byteLength(data, encoding);
+    if (expected !== actual) { changed = true; }
+  }
+  bench.end(n);
+  if (changed) {
+    throw new Error('Result changed during iteration');
+  }
+}