Bits to Bytes

Functions for doing bit manipulation of typed arrays.

npm i bits-to-bytes

Usage

const bits = require('bits-to-bytes')

const buffer = Uint8Array.from([0b11001000])

bits.get(buffer, 3)
// true

buffer may be any typed array with a number element type, including Uint8Array, Uint16Array, and Uint32Array.

API

const n = bits.byteLength(size)

Get the number of bytes required to contain size bits.

const b = bits.get(buffer, bit)

Get the given bit, which will either be true (set) or false (unset).

const changed = bits.set(buffer, bit[, value])

Set the given bit to value, which defaults to true. Returns true if the bit changed, otherwise false.

const changed = bits.setRange(buffer, start, end[, value])

Set the given bit range to value, which defaults to true. Returns true if any of the bits changed, otherwise false.

If you don't need the additional information about whether any of the bits changed, consider bits.fill() as a more performant alternative.

buffer = bits.fill(buffer, value[, start[, end]])

Fill the given bit range with value. start defaults to 0 and end defaults to the bit length of the array. Returns the modified array.

const b = bits.toggle(buffer, bit)

Toggle the given bit, returning its new value.

const changed = bits.remove(buffer, bit)

Unset the given bit. Returns true if the bit was set, otherwise false.

const changed = bits.removeRange(buffer, start, end)

Unset the given bit range. Returns true if any of the bits were set, otherwise false.

const index = bits.indexOf(buffer, value[, position])

Return the index of the first occurrence of value, or -1 if not found. If position is given, return the first index that is greater than or equal to position.

const index = bits.lastIndexOf(buffer, value[, position])

Return the index of the last occurrence of value, or -1 if not found. If position is given, return the last index that is less than or equal to position.

const n = bits.count(buffer[, start[, end]])

Count the number of bits set in the given bit range. start defaults to 0 and end defaults to the bit length of the array.

const buffer = bits.of(...values)

Create a buffer containing the given bits.

const buffer = bits.from(values)

Create a buffer containing the given bits.

const iterator = bits.iterator(buffer)

Create an iterator over bits.

License

Apache 2.0