1const std = @import("std");
2const popcount = @import("popcount.zig");
3const testing = std.testing;
4
5fn popcountsi2Naive(a: i32) i32 {
6 var x = a;
7 var r: i32 = 0;
8 while (x != 0) : (x = @as(i32, @bitCast(@as(u32, @bitCast(x)) >> 1))) {
9 r += @as(i32, @intCast(x & 1));
10 }
11 return r;
12}
13
14fn test__popcountsi2(a: i32) !void {
15 const x = popcount.__popcountsi2(a);
16 const expected = popcountsi2Naive(a);
17 try testing.expectEqual(expected, x);
18}
19
20test "popcountsi2" {
21 try test__popcountsi2(0);
22 try test__popcountsi2(1);
23 try test__popcountsi2(2);
24 try test__popcountsi2(@as(i32, @bitCast(@as(u32, 0xfffffffd))));
25 try test__popcountsi2(@as(i32, @bitCast(@as(u32, 0xfffffffe))));
26 try test__popcountsi2(@as(i32, @bitCast(@as(u32, 0xffffffff))));
27
28 const RndGen = std.Random.DefaultPrng;
29 var rnd = RndGen.init(42);
30 var i: u32 = 0;
31 while (i < 10_000) : (i += 1) {
32 const rand_num = rnd.random().int(i32);
33 try test__popcountsi2(rand_num);
34 }
35}