memcpy
Copies data between node Buffers and/or ArrayBuffers up to ~75 times faster than in pure JS.
node-memcpy
Copies data between node Buffers and/or ArrayBuffers up to ~75 times faster than in pure JS.
Wait, what?
node.js utilizes a non-standard concept of I/O buffers and thus has both its Buffer as well as ArrayBuffer support. While Buffers are nice because they are a lot faster than V8's ArrayBuffers, transferring data between those two types can be ridiculously slow. This is where a node module like memcpy comes into play.
// C++ binding i memcpy.100k > cc Buffer -> Buffer: 22.756ms i memcpy.100k > cc Buffer -> ArrayBuffer: 23.861ms i memcpy.100k > cc Buffer -> Uint8Array: 22.953ms i memcpy.100k > cc ArrayBuffer -> Buffer: 22.955ms i memcpy.100k > cc ArrayBuffer -> ArrayBuffer: 23.273ms i memcpy.100k > cc ArrayBuffer -> Uint8Array: 22.685ms i memcpy.100k > cc Uint8Array -> Buffer: 23.472ms i memcpy.100k > cc Uint8Array -> ArrayBuffer: 22.975ms i memcpy.100k > cc Uint8Array -> Uint8Array: 22.953ms // Native JS i memcpy.100k > js Buffer -> Buffer: 21.617ms i memcpy.100k > js Buffer -> ArrayBuffer: 993.361ms i memcpy.100k > js Buffer -> Uint8Array: 410.010ms i memcpy.100k > js ArrayBuffer -> Buffer: 940.273ms i memcpy.100k > js ArrayBuffer -> ArrayBuffer: 1626.182ms i memcpy.100k > js ArrayBuffer -> Uint8Array: 1084.790ms i memcpy.100k > js Uint8Array -> Buffer: 386.218ms i memcpy.100k > js Uint8Array -> ArrayBuffer: 1107.530ms i memcpy.100k > js Uint8Array -> Uint8Array: 502.653ms
API
memcpy(target[, targetStart=0], source[, sourceStart=0[, sourceEnd=source.length]):bytesCopied
| Argument | Type | Optional | Description |
|---|---|---|---|
| target | Buffer | ArrayBuffer | Uint8Array | Target buffer to copy to | |
| targetStart | number | omittable | Target offset to begin copying to, defaults to 0 |
| source | Buffer | ArrayBuffer | Uint8Array | Source buffer to copy from | |
| sourceStart | number | optional | Source offset to begin copying from, defaults to 0 |
| sourceEnd | number | optional | Source offset to end copying from, defaults ot source.length |
| @returns | number | Number of bytes copied |
Source and target regions may overlap.
Usage
npm install memcpy
var memcpy = require"memcpy" // C++ binding if available, else native JS memcpy_binding = memcpybinding // C++ binding or NULL if not available memcpy_native = memcpynative; // Native JS
Please keep in mind that - besides the nice numbers - this is still to be considered experimental. I'd love if you'd review the C++ code to validate that it's safe. I can't yet think of a sane use case, though, as just sticking with Buffers on node.js and ArrayBuffers in the browser should be best practice.
Contributors
Denys Khanzhiyev (node 0.11.13+ support with nan)
License: Apache License, Version 2.0
