The Computer Language
Benchmarks Game

chameneos-redux Rust program

source code

// The Computer Language Benchmarks Game
// http://benchmarksgame.alioth.debian.org/
//
// contributed by the Rust Project Developers
// contributed by TeXitoi

use self::Color::{Red, Yellow, Blue};
use std::sync::mpsc::{channel, Sender, Receiver};
use std::fmt;
use std::thread::spawn;

fn print_complements() {
    let all = [Blue, Red, Yellow];
    for aa in all.iter() {
        for bb in all.iter() {
            println!("{} + {} -> {}", *aa, *bb, transform(*aa, *bb));
        }
    }
}

#[derive(Clone, Copy)]
enum Color {
    Red,
    Yellow,
    Blue,
}

impl fmt::Display for Color {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let str = match *self {
            Red => "red",
            Yellow => "yellow",
            Blue => "blue",
        };
        write!(f, "{}", str)
    }
}

#[derive(Clone, Copy)]
struct CreatureInfo {
    name: usize,
    color: Color
}

fn show_color_list(set: Vec<Color>) -> String {
    let mut out = String::new();
    for col in set.iter() {
        out.push(' ');
        out.push_str(&*format!("{}", col));
    }
    out
}

fn show_digit(nn: usize) -> &'static str {
    match nn {
        0 => {" zero"}
        1 => {" one"}
        2 => {" two"}
        3 => {" three"}
        4 => {" four"}
        5 => {" five"}
        6 => {" six"}
        7 => {" seven"}
        8 => {" eight"}
        9 => {" nine"}
        _ => {panic!("expected digits from 0 to 9...")}
    }
}

struct Number(usize);
impl fmt::Display for Number {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut out = vec![];
        let Number(mut num) = *self;
        if num == 0 { out.push(show_digit(0)) };

        while num != 0 {
            let dig = num % 10;
            num = num / 10;
            let s = show_digit(dig);
            out.push(s);
        }

        for s in out.iter().rev() {
            try!(write!(f, "{}", s))
        }
        Ok(())
    }
}

fn transform(aa: Color, bb: Color) -> Color {
    match (aa, bb) {
        (Red,    Red   ) => { Red    }
        (Red,    Yellow) => { Blue   }
        (Red,    Blue  ) => { Yellow }
        (Yellow, Red   ) => { Blue   }
        (Yellow, Yellow) => { Yellow }
        (Yellow, Blue  ) => { Red    }
        (Blue,   Red   ) => { Yellow }
        (Blue,   Yellow) => { Red    }
        (Blue,   Blue  ) => { Blue   }
    }
}

fn creature(
    name: usize,
    mut color: Color,
    from_rendezvous: Receiver<CreatureInfo>,
    to_rendezvous: Sender<CreatureInfo>,
    to_rendezvous_log: Sender<String>
) {
    let mut creatures_met = 0i32;
    let mut evil_clones_met = 0;
    let mut rendezvous = from_rendezvous.iter();

    loop {
        // ask for a pairing
        to_rendezvous.send(CreatureInfo {name: name, color: color}).unwrap();

        // log and change, or quit
        match rendezvous.next() {
            Some(other_creature) => {
                color = transform(color, other_creature.color);

                // track some statistics
                creatures_met += 1;
                if other_creature.name == name {
                   evil_clones_met += 1;
                }
            }
            None => break
        }
    }
    // log creatures met and evil clones of self
    let report = format!("{}{}", creatures_met, Number(evil_clones_met));
    to_rendezvous_log.send(report).unwrap();
}

fn rendezvous(nn: usize, set: Vec<Color>) {
    // these ports will allow us to hear from the creatures
    let (to_rendezvous, from_creatures) = channel::<CreatureInfo>();

    // these channels will be passed to the creatures so they can talk to us
    let (to_rendezvous_log, from_creatures_log) = channel::<String>();

    // these channels will allow us to talk to each creature by 'name'/index
    let to_creature: Vec<Sender<CreatureInfo>> =
        set.iter().enumerate().map(|(ii, &col)| {
            // create each creature as a listener with a port, and
            // give us a channel to talk to each
            let to_rendezvous = to_rendezvous.clone();
            let to_rendezvous_log = to_rendezvous_log.clone();
            let (to_creature, from_rendezvous) = channel();
            spawn(move|| {
                creature(ii,
                         col,
                         from_rendezvous,
                         to_rendezvous,
                         to_rendezvous_log);
            });
            to_creature
        }).collect();

    let mut creatures_met = 0;

    // set up meetings...
    for _ in (0..nn) {
        let fst_creature = from_creatures.recv().unwrap();
        let snd_creature = from_creatures.recv().unwrap();

        creatures_met += 2;

        to_creature[fst_creature.name].send(snd_creature).unwrap();
        to_creature[snd_creature.name].send(fst_creature).unwrap();
    }

    // tell each creature to stop
    drop(to_creature);

    // print each color in the set
    println!("{}", show_color_list(set));

    // print each creature's stats
    drop(to_rendezvous_log);
    for rep in from_creatures_log.iter() {
        println!("{}", rep);
    }

    // print the total number of creatures met
    println!("{}\n", Number(creatures_met));
}

fn main() {
    let nn = std::env::args_os().nth(1)
        .and_then(|s| s.into_string().ok())
        .and_then(|n| n.parse().ok())
        .unwrap_or(600);

    print_complements();
    println!("");

    rendezvous(nn, vec!(Blue, Red, Yellow));

    rendezvous(nn,
        vec!(Blue, Red, Yellow, Red, Yellow, Blue, Red, Yellow, Red, Blue));
}
    

notes, command-line, and program output

NOTES:
64-bit Ubuntu quad core
rustc 1.22.1 (05e2e1c41 2017-11-22)


Thu, 23 Nov 2017 03:44:40 GMT

MAKE:
/opt/src/rust-1.22.1/bin/rustc -C opt-level=3 -C target-cpu=core2 -C lto  chameneosredux.rs -o chameneosredux.rust_run
warning: unnecessary parentheses around `for` head expression
   --> chameneosredux.rs:167:14
    |
167 |     for _ in (0..nn) {
    |              ^^^^^^^ help: remove these parentheses
    |
    = note: #[warn(unused_parens)] on by default

rm chameneosredux.rs

8.97s to complete and log all make actions

COMMAND LINE:
./chameneosredux.rust_run 6000000

PROGRAM OUTPUT:
blue + blue -> blue
blue + red -> yellow
blue + yellow -> red
red + blue -> yellow
red + red -> red
red + yellow -> blue
yellow + blue -> red
yellow + red -> blue
yellow + yellow -> yellow

 blue red yellow
5914680 zero
3042528 zero
3042792 zero
 one two zero zero zero zero zero zero

 blue red yellow red yellow blue red yellow red blue
1193341 zero
1208009 zero
1191902 zero
1244313 zero
1228027 zero
1209335 zero
1206004 zero
1193905 zero
1104299 zero
1220865 zero
 one two zero zero zero zero zero zero