tiny.stabilizer.Marsaglia

1pub const Marsaglia = struct {2    state: u32,3    cached: u32 = 0,4    byte_index: u3 = 4,56    pub fn init(seed: u64) Marsaglia {7        const folded = @as(u32, @truncate(seed)) ^ @as(u32, @truncate(seed >> 32));8        return .{ .state = if (folded == 0) 0x6d2b_79f5 else folded };9    }1011    pub fn nextU32(self: *Marsaglia) u32 {12        var x = self.state;13        x ^= x << 13;14        x ^= x >> 17;15        x ^= x << 5;16        self.state = if (x == 0) 0x6d2b_79f5 else x;17        return self.state;18    }1920    pub fn nextU64(self: *Marsaglia) u64 {21        return (@as(u64, self.nextU32()) << 32) | self.nextU32();22    }2324    pub fn bounded(self: *Marsaglia, upper: usize) usize {25        std.debug.assert(upper > 0);26        return @intCast(self.nextU64() % upper);27    }2829    pub fn nextByte(self: *Marsaglia) u8 {30        if (self.byte_index >= 4) {31            self.cached = self.nextU32();32            self.byte_index = 0;33        }34        const shift: u5 = @intCast(@as(u16, self.byte_index) * 8);35        const byte: u8 = @truncate(self.cached >> shift);36        self.byte_index += 1;37        return byte;38    }39};

1pub const Marsaglia = rng_mod.Marsaglia;