Function ceilPowerOfTwo [src]

Returns the next power of two (if the value is not already a power of two). Only unsigned integers can be used. Zero is not an allowed input. If the value doesn't fit, returns an error.

Prototype

pub fn ceilPowerOfTwo(comptime T: type, value: T) (error{Overflow}!T)

Parameters

T: typevalue: T

Example

 test ceilPowerOfTwo {
    try testCeilPowerOfTwo();
    try comptime testCeilPowerOfTwo();
}

Source

  pub fn ceilPowerOfTwo(comptime T: type, value: T) (error{Overflow}!T) {
    comptime assert(@typeInfo(T) == .int);
    const info = @typeInfo(T).int;
    comptime assert(info.signedness == .unsigned);
    const PromotedType = std.meta.Int(info.signedness, info.bits + 1);
    const overflowBit = @as(PromotedType, 1) << info.bits;
    const x = ceilPowerOfTwoPromote(T, value);
    if (overflowBit & x != 0) {
        return error.Overflow;
    }
    return @as(T, @intCast(x));
}  