pub const Alignment = enum(math.Log2Int(usize)) {
    @"1" = 0,
    @"2" = 1,
    @"4" = 2,
    @"8" = 3,
    @"16" = 4,
    @"32" = 5,
    @"64" = 6,
    _,

    pub fn toByteUnits(a: Alignment) usize {
        return @as(usize, 1) << @intFromEnum(a);
    }

    pub fn fromByteUnits(n: usize) Alignment {
        assert(std.math.isPowerOfTwo(n));
        return @enumFromInt(@ctz(n));
    }

    pub fn order(lhs: Alignment, rhs: Alignment) std.math.Order {
        return std.math.order(@intFromEnum(lhs), @intFromEnum(rhs));
    }

    pub fn compare(lhs: Alignment, op: std.math.CompareOperator, rhs: Alignment) bool {
        return std.math.compare(@intFromEnum(lhs), op, @intFromEnum(rhs));
    }

    pub fn max(lhs: Alignment, rhs: Alignment) Alignment {
        return @enumFromInt(@max(@intFromEnum(lhs), @intFromEnum(rhs)));
    }

    pub fn min(lhs: Alignment, rhs: Alignment) Alignment {
        return @enumFromInt(@min(@intFromEnum(lhs), @intFromEnum(rhs)));
    }

    /// Return next address with this alignment.
    pub fn forward(a: Alignment, address: usize) usize {
        const x = (@as(usize, 1) << @intFromEnum(a)) - 1;
        return (address + x) & ~x;
    }

    /// Return previous address with this alignment.
    pub fn backward(a: Alignment, address: usize) usize {
        const x = (@as(usize, 1) << @intFromEnum(a)) - 1;
        return address & ~x;
    }

    /// Return whether address is aligned to this amount.
    pub fn check(a: Alignment, address: usize) bool {
        return @ctz(address) >= @intFromEnum(a);
    }
}