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nodejs/test/parallel/test-buffer-swap.js
Zach Bjornson a1059afd39 buffer: speed up swap16/32, add swap64
* Speed up buffer.swap16 and swap32 by using builtins. Up to ~6x gain.
  Drop transition point between JS and C++ implementations accordingly.
  Amount of performance improvement not only depends on buffer size but
  also memory alignment.
* Fix tests: C++ impl tests were testing 0-filled buffers so were
  always passing.
* Add similar buffer.swap64 method.
* Make buffer-swap benchmark mirror JS impl.

doc/api/buffer.markdown has an entry of "added: REPLACEME" that should
be changed to the correct release number before tagged.

Because node is currently using a very old version of cpplint.py it
doesn't know that std::swap() has moved from <algorithm> to <utility> in
c++11. So until cpplint.py is updated simply NOLINT the line.
Technically it should be NOLINT(build/include_what_you_use), but that
puts the line over 80 characters causing another lint error.

PR-URL: https://github.com/nodejs/node/pull/7157
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
2016-06-27 14:38:37 -06:00

139 lines
5.2 KiB
JavaScript

'use strict';
require('../common');
const assert = require('assert');
// Test buffers small enough to use the JS implementation
const buf = Buffer.from([0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10]);
assert.strictEqual(buf, buf.swap16());
assert.deepStrictEqual(buf, Buffer.from([0x02, 0x01, 0x04, 0x03, 0x06, 0x05,
0x08, 0x07, 0x0a, 0x09, 0x0c, 0x0b,
0x0e, 0x0d, 0x10, 0x0f]));
buf.swap16(); // restore
assert.strictEqual(buf, buf.swap32());
assert.deepStrictEqual(buf, Buffer.from([0x04, 0x03, 0x02, 0x01, 0x08, 0x07,
0x06, 0x05, 0x0c, 0x0b, 0x0a, 0x09,
0x10, 0x0f, 0x0e, 0x0d]));
buf.swap32(); // restore
assert.strictEqual(buf, buf.swap64());
assert.deepStrictEqual(buf, Buffer.from([0x08, 0x07, 0x06, 0x05, 0x04, 0x03,
0x02, 0x01, 0x10, 0x0f, 0x0e, 0x0d,
0x0c, 0x0b, 0x0a, 0x09]));
// Operates in-place
const buf3 = Buffer.from([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7]);
buf3.slice(1, 5).swap32();
assert.deepStrictEqual(buf3, Buffer.from([0x1, 0x5, 0x4, 0x3, 0x2, 0x6, 0x7]));
buf3.slice(1, 5).swap16();
assert.deepStrictEqual(buf3, Buffer.from([0x1, 0x4, 0x5, 0x2, 0x3, 0x6, 0x7]));
const buf3_64 = Buffer.from([0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10]);
buf3_64.slice(2, 18).swap64();
assert.deepStrictEqual(buf3_64, Buffer.from([0x01, 0x02, 0x0a, 0x09, 0x08, 0x07,
0x06, 0x05, 0x04, 0x03, 0x02, 0x01,
0x10, 0x0f, 0x0e, 0x0d, 0x0c, 0x0b,
0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
0x0f, 0x10]));
// Force use of native code (Buffer size above threshold limit for js impl)
var buf4A = new Uint32Array(256).fill(0x04030201);
var buf4 = Buffer.from(buf4A.buffer, buf4A.byteOffset);
var buf5A = new Uint32Array(256).fill(0x03040102);
var buf5 = Buffer.from(buf5A.buffer, buf5A.byteOffset);
buf4.swap16();
assert.deepStrictEqual(buf4, buf5);
var buf6A = new Uint32Array(256).fill(0x04030201);
var buf6 = Buffer.from(buf6A.buffer);
var bu7A = new Uint32Array(256).fill(0x01020304);
var buf7 = Buffer.from(bu7A.buffer, bu7A.byteOffset);
buf6.swap32();
assert.deepStrictEqual(buf6, buf7);
var buf8A = new Uint8Array(256 * 8);
var buf9A = new Uint8Array(256 * 8);
for (let i = 0; i < buf8A.length; i++) {
buf8A[i] = i % 8;
buf9A[buf9A.length - i - 1] = i % 8;
}
var buf8 = Buffer.from(buf8A.buffer, buf8A.byteOffset);
var buf9 = Buffer.from(buf9A.buffer, buf9A.byteOffset);
buf8.swap64();
assert.deepStrictEqual(buf8, buf9);
// Test native code with buffers that are not memory-aligned
var buf10A = new Uint8Array(256 * 8);
var buf11A = new Uint8Array(256 * 8 - 2);
for (let i = 0; i < buf10A.length; i++) {
buf10A[i] = i % 2;
}
for (let i = 1; i < buf11A.length; i++) {
buf11A[buf11A.length - i] = (i + 1) % 2;
}
var buf10 = Buffer.from(buf10A.buffer, buf10A.byteOffset);
// 0|1 0|1 0|1...
var buf11 = Buffer.from(buf11A.buffer, buf11A.byteOffset);
// 0|0 1|0 1|0...
buf10.slice(1, buf10.length - 1).swap16();
assert.deepStrictEqual(buf10.slice(0, buf11.length), buf11);
var buf12A = new Uint8Array(256 * 8);
var buf13A = new Uint8Array(256 * 8 - 4);
for (let i = 0; i < buf12A.length; i++) {
buf12A[i] = i % 4;
}
for (let i = 1; i < buf13A.length; i++) {
buf13A[buf13A.length - i] = (i + 1) % 4;
}
var buf12 = Buffer.from(buf12A.buffer, buf12A.byteOffset);
// 0|1 2 3 0|1 2 3...
var buf13 = Buffer.from(buf13A.buffer, buf13A.byteOffset);
// 0|0 3 2 1|0 3 2...
buf12.slice(1, buf12.length - 3).swap32();
assert.deepStrictEqual(buf12.slice(0, buf13.length), buf13);
var buf14A = new Uint8Array(256 * 8);
var buf15A = new Uint8Array(256 * 8 - 8);
for (let i = 0; i < buf14A.length; i++) {
buf14A[i] = i % 8;
}
for (let i = 1; i < buf15A.length; i++) {
buf15A[buf15A.length - i] = (i + 1) % 8;
}
var buf14 = Buffer.from(buf14A.buffer, buf14A.byteOffset);
// 0|1 2 3 4 5 6 7 0|1 2 3 4...
var buf15 = Buffer.from(buf15A.buffer, buf15A.byteOffset);
// 0|0 7 6 5 4 3 2 1|0 7 6 5...
buf14.slice(1, buf14.length - 7).swap64();
assert.deepStrictEqual(buf14.slice(0, buf15.length), buf15);
// Length assertions
const re16 = /Buffer size must be a multiple of 16-bits/;
const re32 = /Buffer size must be a multiple of 32-bits/;
const re64 = /Buffer size must be a multiple of 64-bits/;
assert.throws(() => Buffer.from(buf3).swap16(), re16);
assert.throws(() => Buffer.alloc(1025).swap16(), re16);
assert.throws(() => Buffer.from(buf3).swap32(), re32);
assert.throws(() => buf3.slice(1, 3).swap32(), re32);
assert.throws(() => Buffer.alloc(1025).swap32(), re32);
assert.throws(() => buf3.slice(1, 3).swap64(), re64);
assert.throws(() => Buffer.alloc(1025).swap64(), re64);