@woosh/meep-engine/src/core/binary/reverse_bits_uint32.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 * Reverses order of bits in an unsigned 32bit integer
 * @example 1110 would become 0111
 * @param {number} input
 * @returns {number}
 */
export function reverse_bits_uint32(input) {
    let x = input;

    x = ((x << 16) | (x >>> 16))
    x = ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >>> 1)
    x = ((x & 0x33333333) << 2) | ((x & 0xCCCCCCCC) >>> 2)
    x = ((x & 0x0F0F0F0F) << 4) | ((x & 0xF0F0F0F0) >>> 4)
    x = ((x & 0x00FF00FF) << 8) | ((x & 0xFF00FF00) >>> 8)

    return x
}