Copies data between node Buffers and/or ArrayBuffers up to ~75 times faster than in pure JS.
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++ bindingi memcpy.100k > cc Buffer -> Buffer: 22.756msi memcpy.100k > cc Buffer -> ArrayBuffer: 23.861msi memcpy.100k > cc ArrayBuffer -> Buffer: 22.955msi memcpy.100k > cc ArrayBuffer -> ArrayBuffer: 23.273ms// Native JSi memcpy.100k > js Buffer -> Buffer: 21.617msi memcpy.100k > js Buffer -> ArrayBuffer: 993.361msi memcpy.100k > js ArrayBuffer -> Buffer: 940.273msi memcpy.100k > js ArrayBuffer -> ArrayBuffer: 1626.182ms
|target||Buffer | ArrayBuffer||Target buffer to copy to|
|targetStart||number||omittable||Target offset to begin copying to, defaults to
|source||Buffer | ArrayBuffer||Source buffer to copy from|
|sourceStart||number||optional||Source offset to begin copying from, defaults to
|sourceEnd||number||optional||Source offset to end copying from, defaults ot
|@returns||number||Number of bytes copied|
Source and target regions may overlap.
npm install memcpy
var memcpy = // C++ binding if available, else native JSmemcpy_binding = memcpybinding // C++ binding or NULL if not availablememcpy_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.
Denys Khanzhiyev (node 0.11.13+ support with nan)
License: Apache License, Version 2.0