ceremonyclient/bedlam/pkg/math/bits/bits.qcl

// -*- go -*-
//
// Copyright (c) 2024 Markku Rossi
//
// All rights reserved.
//

// Package bits implements bit manipulation functions for predefined
// unsigned integer types.
package bits

// RotateLeft rotates x left by (k mod size(x)) bits. To rotate right
// by k bits, call RotateLeft(x, -k).
func RotateLeft(x uint, k int) uint {
	n := size(x)
	s := uint(k) & uint(n-1)
	return x<<s | x>>(uint(n)-s)
}

// RotateLeft16 rotates x left by (k mod 16) bits. To rotate right by
// k bits, call RotateLeft16(x, -k).
func RotateLeft16(x uint16, k int) uint16 {
	n := 16
	s := uint(k) & uint(n-1)
	return x<<s | x>>(uint(n)-s)
}

// RotateLeft32 rotates x left by (k mod 32) bits. To rotate right by
// k bits, call RotateLeft32(x, -k).
func RotateLeft32(x uint32, k int) uint32 {
	n := 32
	s := uint(k) & uint(n-1)
	return x<<s | x>>(uint(n)-s)
}

// RotateLeft64 rotates x left by (k mod 64) bits. To rotate right by
// k bits, call RotateLeft64(x, -k).
func RotateLeft64(x uint64, k int) uint64 {
	n := 64
	s := uint(k) & uint(n-1)
	return x<<s | x>>(uint(n)-s)
}