ch3-not-quite-file-3.rs

#![allow(unused_variables)]

#[derive(Debug)]
struct File {
  name: String,
  data: Vec<u8>,
}

impl File {
  fn new(name: &str) -> File {
    File {
      name: String::from(name),
      data: Vec::new(),
    }
  }

  fn new_with_data(
    name: &str,
    data: &Vec<u8>,
  ) -> File {                         // <1>
    let mut f = File::new(name);
    f.data = data.clone();
    f
  }

  fn read(
    self: &File,
    save_to: &mut Vec<u8>,
  ) -> usize {                        // <2>
    let mut tmp = self.data.clone();
    let read_length = tmp.len();
    save_to.reserve(read_length);
    save_to.append(&mut tmp);
    read_length
  }
}

fn open(f: &mut File) -> bool {       // <3>
  true
}

fn close(f: &mut File) -> bool {
  true
}

fn main() {
  let f3_data: Vec<u8> = vec![ // <3>
    114, 117, 115, 116, 33
  ];
  let mut f3 = File::new_with_data("2.txt", &f3_data);

  let mut buffer: Vec<u8> = vec![];

  open(&mut f3);
  let f3_length = f3.read(&mut buffer);   // <4>
  close(&mut f3);

  let text = String::from_utf8_lossy(&buffer);

  println!("{:?}", f3);
  println!("{} is {} bytes long", &f3.name, f3_length);
  println!("{}", text);
}