| // Copyright 2013 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| use std::sync::mpsc::channel; |
| use std::env; |
| use std::thread; |
| |
| // A simple implementation of parfib. One subtree is found in a new |
| // thread and communicated over a oneshot pipe, the other is found |
| // locally. There is no sequential-mode threshold. |
| |
| fn parfib(n: u64) -> u64 { |
| if n == 0 || n == 1 { |
| return 1; |
| } |
| |
| let (tx, rx) = channel(); |
| thread::spawn(move|| { |
| tx.send(parfib(n-1)).unwrap(); |
| }); |
| let m2 = parfib(n-2); |
| return rx.recv().unwrap() + m2; |
| } |
| |
| fn main() { |
| let mut args = env::args(); |
| let n = if args.len() == 2 { |
| args.nth(1).unwrap().parse::<u64>().unwrap() |
| } else { |
| 10 |
| }; |
| |
| parfib(n); |
| |
| } |