Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

lib: add swap64 (was introduced in node 6.3.0) #125

Merged
merged 1 commit into from
Aug 6, 2016
Merged

lib: add swap64 (was introduced in node 6.3.0) #125

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 14 additions & 0 deletions index.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -542,6 +542,20 @@ Buffer.prototype.swap32 = function swap32 () {
return this
}

Buffer.prototype.swap64 = function swap64 () {
var len = this.length
if (len % 8 !== 0) {
throw new RangeError('Buffer size must be a multiple of 64-bits')
}
for (var i = 0; i < len; i += 8) {
swap(this, i, i + 7)
swap(this, i + 1, i + 6)
swap(this, i + 2, i + 5)
swap(this, i + 3, i + 4)
}
return this
}

Buffer.prototype.toString = function toString () {
var length = this.length | 0
if (length === 0) return ''
Expand Down
136 changes: 107 additions & 29 deletions test/node/test-buffer-swap.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,59 +5,137 @@ if (Buffer.TYPED_ARRAY_SUPPORT) return;

var assert = require('assert');

var buf = Buffer.from([0x1, 0x2, 0x3, 0x4]);
// 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([0x2, 0x1, 0x4, 0x3]));
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([0x3, 0x4, 0x1, 0x2]));

var buf_array = [];
for (var i = 1; i < 33; i++)
buf_array.push(i);
var buf2 = Buffer.from(buf_array);
buf2.swap32();
assert.deepStrictEqual(buf2,
Buffer.from([0x04, 0x03, 0x02, 0x01, 0x08, 0x07, 0x06, 0x05, 0x0c,
0x0b, 0x0a, 0x09, 0x10, 0x0f, 0x0e, 0x0d, 0x14, 0x13,
0x12, 0x11, 0x18, 0x17, 0x16, 0x15, 0x1c, 0x1b, 0x1a,
0x19, 0x20, 0x1f, 0x1e, 0x1d]));
buf2.swap16();
assert.deepStrictEqual(buf2,
Buffer.from([0x03, 0x04, 0x01, 0x02, 0x07, 0x08, 0x05, 0x06, 0x0b,
0x0c, 0x09, 0x0a, 0x0f, 0x10, 0x0d, 0x0e, 0x13, 0x14,
0x11, 0x12, 0x17, 0x18, 0x15, 0x16, 0x1b, 0x1c, 0x19,
0x1a, 0x1f, 0x20, 0x1d, 0x1e]));
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
var 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 buf4 = Buffer.allocUnsafe(1024).fill([0x1, 0x2, 0x3, 0x4]);
var buf5 = Buffer.allocUnsafe(1024).fill([0x2, 0x1, 0x4, 0x3]);
var buf6 = Buffer.allocUnsafe(1024)
.fill([0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8]);
var buf7 = Buffer.allocUnsafe(1024)
.fill([0x4, 0x3, 0x2, 0x1, 0x8, 0x7, 0x6, 0x5]);
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 re16 = /Buffer size must be a multiple of 16-bits/;
var re32 = /Buffer size must be a multiple of 32-bits/;
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/;