use std::{
    io::{
	self,
	Read,
    },
    error::Error,
    marker::{
	Send, Sync,
    },
};

/// Read whole stdin
pub fn stdin() -> io::Result<String>
{
    let mut buffer = String::new();
    io::stdin().read_to_string(&mut buffer)?;

    Ok(buffer)
}

/// Read each line with lambda
pub fn stdin_lines<E, F: FnMut(&str) -> Result<bool, E>>(mut callback: F) -> io::Result<usize>
    where E: Into<Box<dyn Error + Send + Sync>>
{
    let mut lines=0;
    let mut input = String::new();
    let stdin = io::stdin();
    while match stdin.read_line(&mut input) {
	Ok(0) => return Ok(lines),
	Err(e) => return Err(e),
	Ok(v) if input.as_bytes()[v-1] == b'\n' => callback(&input[..v]).or_else(|e| Err(io::Error::new(io::ErrorKind::Other, e)))?,
	Ok(_) => callback(&input[..]).or_else(|e| Err(io::Error::new(io::ErrorKind::Other, e)))?,
    } {
	input.clear();
	lines+=1;
    }

    Ok(lines)
}