1const std = @import("std");
 2const parity = @import("parity.zig");
 3const testing = std.testing;
 4
 5fn paritydi2Naive(a: i64) i32 {
 6    var x: u64 = @bitCast(a);
 7    var has_parity: bool = false;
 8    while (x > 0) {
 9        has_parity = !has_parity;
10        x = x & (x - 1);
11    }
12    return @intCast(@intFromBool(has_parity));
13}
14
15fn test__paritydi2(a: i64) !void {
16    const x = parity.__paritydi2(a);
17    const expected: i64 = paritydi2Naive(a);
18    try testing.expectEqual(expected, x);
19}
20
21test "paritydi2" {
22    try test__paritydi2(0);
23    try test__paritydi2(1);
24    try test__paritydi2(2);
25    try test__paritydi2(@bitCast(@as(u64, 0xffffffff_fffffffd)));
26    try test__paritydi2(@bitCast(@as(u64, 0xffffffff_fffffffe)));
27    try test__paritydi2(@bitCast(@as(u64, 0xffffffff_ffffffff)));
28
29    const RndGen = std.Random.DefaultPrng;
30    var rnd = RndGen.init(42);
31    var i: u32 = 0;
32    while (i < 10_000) : (i += 1) {
33        const rand_num = rnd.random().int(i64);
34        try test__paritydi2(rand_num);
35    }
36}