zig/lib/compiler_rt/parityti2_test.zig
2023-07-24 10:23:51 -07:00

37 lines
1.1 KiB
Zig

const std = @import("std");
const parity = @import("parity.zig");
const testing = std.testing;
fn parityti2Naive(a: i128) i32 {
var x: u128 = @bitCast(a);
var has_parity: bool = false;
while (x > 0) {
has_parity = !has_parity;
x = x & (x - 1);
}
return @as(i32, @intCast(@intFromBool(has_parity)));
}
fn test__parityti2(a: i128) !void {
var x = parity.__parityti2(a);
var expected: i128 = parityti2Naive(a);
try testing.expectEqual(expected, x);
}
test "parityti2" {
try test__parityti2(0);
try test__parityti2(1);
try test__parityti2(2);
try test__parityti2(@as(i128, @bitCast(@as(u128, 0xffffffff_ffffffff_ffffffff_fffffffd))));
try test__parityti2(@as(i128, @bitCast(@as(u128, 0xffffffff_ffffffff_ffffffff_fffffffe))));
try test__parityti2(@as(i128, @bitCast(@as(u128, 0xffffffff_ffffffff_ffffffff_ffffffff))));
const RndGen = std.rand.DefaultPrng;
var rnd = RndGen.init(42);
var i: u32 = 0;
while (i < 10_000) : (i += 1) {
var rand_num = rnd.random().int(i128);
try test__parityti2(rand_num);
}
}