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:
32-bit Ubuntu one core
rustc 1.13.0 (2c6933acc 2016-11-07)


Fri, 11 Nov 2016 20:10:03 GMT

MAKE:
/usr/local/src/rust-1.13.0/bin/rustc -C opt-level=3 -C target-cpu=core2  chameneosredux.rs -o chameneosredux.rust_run
warning: unnecessary parentheses around `for` head expression, #[warn(unused_parens)] on by default
   --> chameneosredux.rs:167:14
    |
167 |     for _ in (0..nn) {
    |              ^^^^^^^

rm chameneosredux.rs
6.26s 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
3999441 zero
4000210 zero
4000349 zero
 one two zero zero zero zero zero zero

 blue red yellow red yellow blue red yellow red blue
1199635 zero
1199739 zero
1199842 zero
1199880 zero
1199930 zero
1199970 zero
1200298 zero
1200303 zero
1200299 zero
1200104 zero
 one two zero zero zero zero zero zero