use std::str;

use std::fs::File;

use std::io::{BufReader, Result};

use std::io::prelude::*;

use std::path::Path;

use std::rc::Rc;

use std::cell::RefCell;

macro_rules! io_err {

($desc:expr) => ( io::Error::new(io::ErrorKind::Other, $desc) );

($fmt:expr, $($arg:tt)*) => ( io::Error::new(io::ErrorKind::Other, format!($fmt, $($arg)*)) );

}

macro_rules! new_fat_slice_from_vec {

($name:ident, $v:expr) => (

use std::slice::from_raw_parts_mut;

let ptr = $v.as_mut_ptr();

let cap = $v.capacity();

let raw = unsafe { &mut from_raw_parts_mut(ptr, cap) };

let $name = raw;

unsafe { $v.set_len(0); }

);

}

pub fn slice2str(data: &[u8]) -> Option<&str> {

str::from_utf8(data).ok()

}

pub fn slice2string(data: &[u8]) -> Option<String> {

String::from_utf8(data.to_vec()).ok()

}

pub fn handle_every_line<P: AsRef<Path>>(filepath: P, func: &mut FnMut(String)) -> Result<()> {

let f = File::open(filepath)?;

let reader = BufReader::new(f);

for line in reader.lines() {

let line = match line {

Ok(line) => line.trim().to_string(),

_ => break,

};

func(line);

}

Ok(())

}

pub fn shift_vec<T: Clone>(v: &mut Vec<T>, offset: usize) {

let remain = v.len() - offset;

for i in 0..remain {

v[i] = v[i + offset].clone();

}

unsafe {

v.set_len(remain);

}

}

pub type RcCell<T> = Rc<RefCell<T>>;

pub fn new_rc_cell<T>(val: T) -> RcCell<T> {

Rc::new(RefCell::new(val))

}