moves.rs

use bson;
use bson::{decode_document, encode_document};
use serde::{Deserialize, Serialize};
use std::fs::File;
use std::io::prelude::*;
use std::io::{BufReader, BufWriter};

#[derive(Serialize, Deserialize, Debug)]
struct Move {
    x: i32,
    y: i32,
}

fn write_to_file(fname: &str) {
    let f = File::create(fname).unwrap();
    let mut writer = BufWriter::new(f);

    for i in 0..1000 {
        let m = Move { x: i, y: i };
        let m_bson = bson::to_bson(&m).unwrap();
        let doc = m_bson.as_document().unwrap();
        let mut serialized: Vec<u8> = Vec::new();
        encode_document(&mut serialized, doc).unwrap();
        writer.write(&serialized[..]).unwrap();
    }
}

fn read_from_file(fname: &str) {
    let mut f = File::open(fname).unwrap();
    let mut values = String::new();
    f.read_to_string(&mut values).unwrap();
    let docs = bson::to_bson(&values);
    println!("{:?}", docs);
}

fn main() {
    let fname = "moves";
    write_to_file(fname);
    read_from_file(fname);
}