diff --git a/lib/std/rand.zig b/lib/std/rand.zig index 826ffe6d4a..01397085f7 100644 --- a/lib/std/rand.zig +++ b/lib/std/rand.zig @@ -26,7 +26,6 @@ pub const Pcg = @import("rand/Pcg.zig"); pub const Xoroshiro128 = @import("rand/Xoroshiro128.zig"); pub const Xoshiro256 = @import("rand/Xoshiro256.zig"); pub const Sfc64 = @import("rand/Sfc64.zig"); -pub const RomuTrio = @import("rand/RomuTrio.zig"); pub const Random = struct { ptr: *anyopaque, diff --git a/lib/std/rand/RomuTrio.zig b/lib/std/rand/RomuTrio.zig deleted file mode 100644 index fe23be054f..0000000000 --- a/lib/std/rand/RomuTrio.zig +++ /dev/null @@ -1,132 +0,0 @@ -// Website: romu-random.org -// Reference paper: http://arxiv.org/abs/2002.11331 -// Beware: this PRNG is trivially predictable. While fast, it should *never* be used for cryptographic purposes. - -const std = @import("std"); -const Random = std.rand.Random; -const math = std.math; -const RomuTrio = @This(); - -x_state: u64, -y_state: u64, -z_state: u64, // set to nonzero seed - -pub fn init(init_s: u64) RomuTrio { - var x = RomuTrio{ .x_state = undefined, .y_state = undefined, .z_state = undefined }; - x.seed(init_s); - return x; -} - -pub fn random(self: *RomuTrio) Random { - return Random.init(self, fill); -} - -fn next(self: *RomuTrio) u64 { - const xp = self.x_state; - const yp = self.y_state; - const zp = self.z_state; - self.x_state = 15241094284759029579 *% zp; - self.y_state = yp -% xp; - self.y_state = std.math.rotl(u64, self.y_state, 12); - self.z_state = zp -% yp; - self.z_state = std.math.rotl(u64, self.z_state, 44); - return xp; -} - -pub fn seedWithBuf(self: *RomuTrio, buf: [24]u8) void { - const seed_buf = @bitCast([3]u64, buf); - self.x_state = seed_buf[0]; - self.y_state = seed_buf[1]; - self.z_state = seed_buf[2]; -} - -pub fn seed(self: *RomuTrio, init_s: u64) void { - // RomuTrio requires 192-bits of seed. - var gen = std.rand.SplitMix64.init(init_s); - - self.x_state = gen.next(); - self.y_state = gen.next(); - self.z_state = gen.next(); -} - -pub fn fill(self: *RomuTrio, buf: []u8) void { - var i: usize = 0; - const aligned_len = buf.len - (buf.len & 7); - - // Complete 8 byte segments. - while (i < aligned_len) : (i += 8) { - var n = self.next(); - comptime var j: usize = 0; - inline while (j < 8) : (j += 1) { - buf[i + j] = @truncate(u8, n); - n >>= 8; - } - } - - // Remaining. (cuts the stream) - if (i != buf.len) { - var n = self.next(); - while (i < buf.len) : (i += 1) { - buf[i] = @truncate(u8, n); - n >>= 8; - } - } -} - -test "RomuTrio sequence" { - // Unfortunately there does not seem to be an official test sequence. - var r = RomuTrio.init(0); - - const seq = [_]u64{ - 16294208416658607535, - 13964609475759908645, - 4703697494102998476, - 3425221541186733346, - 2285772463536419399, - 9454187757529463048, - 13695907680080547496, - 8328236714879408626, - 12323357569716880909, - 12375466223337721820, - }; - - for (seq) |s| { - try std.testing.expectEqual(s, r.next()); - } -} - -test "RomuTrio fill" { - // Unfortunately there does not seem to be an official test sequence. - var r = RomuTrio.init(0); - - const seq = [_]u64{ - 16294208416658607535, - 13964609475759908645, - 4703697494102998476, - 3425221541186733346, - 2285772463536419399, - 9454187757529463048, - 13695907680080547496, - 8328236714879408626, - 12323357569716880909, - 12375466223337721820, - }; - - for (seq) |s| { - var buf0: [8]u8 = undefined; - var buf1: [7]u8 = undefined; - std.mem.writeIntLittle(u64, &buf0, s); - r.fill(&buf1); - try std.testing.expect(std.mem.eql(u8, buf0[0..7], buf1[0..])); - } -} - -test "RomuTrio buf seeding test" { - const buf0 = [24]u8{ 175, 205, 29, 123, 57, 168, 32, 226, 37, 39, 185, 157, 84, 66, 204, 193, 204, 125, 231, 26, 243, 227, 70, 65 }; - const resulting_state = .{ .x = 16294208416658607535, .y = 13964609475759908645, .z = 4703697494102998476 }; - var r = RomuTrio.init(0); - r.seedWithBuf(buf0); - try std.testing.expect(r.x_state == resulting_state.x); - try std.testing.expect(r.y_state == resulting_state.y); - try std.testing.expect(r.z_state == resulting_state.z); -}