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}