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// The Computer Language Benchmarks Game
// http://benchmarksgame.alioth.debian.org/
//
// contributed by the Rust Project Developers
// Copyright (c) 2012-2014 The Rust Project Developers
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
//
// - Neither the name of "The Computer Language Benchmarks Game" nor
// the name of "The Computer Language Shootout Benchmarks" nor the
// names of its contributors may be used to endorse or promote
// products derived from this software without specific prior
// written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
use std::sync::mpsc::{channel, Sender, Receiver};
use std::thread;
fn start(n_tasks: i32, token: i32) {
let (tx, mut rx) = channel();
tx.send(token).unwrap();
let mut guards = Vec::with_capacity(n_tasks as usize);
for i in 2 .. n_tasks + 1 {
let (tx, next_rx) = channel();
let cur_rx = std::mem::replace(&mut rx, next_rx);
guards.push(thread::spawn(move|| roundtrip(i, tx, cur_rx)));
}
let guard = thread::spawn(move|| roundtrip(1, tx, rx));
}
fn roundtrip(id: i32, tx: Sender<i32>, rx: Receiver<i32>) {
for token in rx.iter() {
if token == 1 {
println!("{}", id);
break;
}
tx.send(token - 1).unwrap();
}
}
fn main() {
let mut args = std::env::args();
let token = if std::env::var_os("RUST_BENCH").is_some() {
2000000
} else {
args.nth(1).and_then(|arg| arg.parse().ok()).unwrap_or(1000)
};
let n_tasks = args.next()
.and_then(|arg| arg.parse().ok())
.unwrap_or(503);
start(n_tasks, token);
}
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