BufferShift

Bit Shift buffers in node.js

This library exposes 2 simple functions which will bitshift an entire buffer of arbitrary size as if it were a bignum (but without the overhead of loading it in and out of a bignum library).

BufferShift.shl(buffer, numBits)

Shift the buffer bits to the left: taken as a big-endian number, the number gets bigger.

BufferShift.shr(buffer, numBits)

Shift the buffer bits to the right: taken as a big-endian number, the number gets smaller.

const BufferShift = require('buffershift');
const x = new Buffer("00112233", "hex");
BufferShift.shl(x, 8);
console.log(x); // -> <Buffer 11 22 33 00>
BufferShift.shr(x, 16);
console.log(x); // -> <Buffer 00 00 11 22>

NOTE: The functions in this library mutate the input buffers. This point of this library is to be fast so it doesn't make much sense to copy buffers every shift, if you want to keep your buffers safe, copy them before shifting.

Node Version

Tested on 4.2.1, 4.5.0 and 6.6.0

License

MIT