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// Copyright 2016, Paul Osborne <osbpau@gmail.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/license/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option.  This file may not be copied, modified, or distributed
// except according to those terms.
//
// Portions of this implementation are based on work by Nat Pryce:
// https://github.com/npryce/rusty-pi/blob/master/src/pi/gpio.rs

use std::convert;
use std::fmt;
use std::io;

#[derive(Debug)]
pub enum Error {
    /// Simple IO error
    Io(io::Error),
    /// Read unusual data from sysfs file.
    Unexpected(String),
}

impl ::std::error::Error for Error {
    fn description(&self) -> &str {
        match *self {
            Error::Io(ref e) => e.description(),
            Error::Unexpected(_) => "something unexpected",
        }
    }

    fn cause(&self) -> Option<&::std::error::Error> {
        match *self {
            Error::Io(ref e) => Some(e),
            _ => None,
        }
    }
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Error::Io(ref e) => e.fmt(f),
            Error::Unexpected(ref s) => write!(f, "Unexpected: {}", s),
        }
    }
}


impl convert::From<io::Error> for Error {
    fn from(e: io::Error) -> Error {
        Error::Io(e)
    }
}