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pub struct Fib16 { seed: u16, lfsr: u16, bit: u16, } impl Default for Fib16 { fn default() -> Fib16 { Fib16 { seed: 0xACE1u16, lfsr: 0xACE1u16, bit: 0, } } } impl Fib16 { fn from_seed(seed: u16) -> Fib16 { Fib16 { seed: seed, lfsr: seed, bit: 0, } } } impl Iterator for Fib16 { type Item = u16; fn next(&mut self) -> Option<u16> { self.bit = ((self.lfsr >> 0) ^ (self.lfsr >> 2) ^ (self.lfsr >> 3) ^ (self.lfsr >> 5)) & 1; self.lfsr = (self.lfsr >> 1) | (self.bit << 15); if self.lfsr != self.seed { Some(self.lfsr) } else { None } } } #[test] fn it_works() { let f = Fib16::default(); for i in f { println!("{}", i); } }