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// use std::fs::File;
// use std::io::{self, Read, BufReader};
// use std::cmp::min;
// use std::marker::PhantomData;
// // Ideally, this would hold a `String` inside. But we need a lifetime parameter
// // here so we can return an &'a str from `peek_slice`. The alternative is to
// // give a lifetime to the `Input` trait and use it in the `peek_slice` method.
// // But that lifetime will pollute everything. Finally, the _correct_ thing is
// // for Rust to let us reference the lifetime of `self` in an associated type.
// // That requires something like https://github.com/rust-lang/rfcs/pull/1598.
// #[derive(Debug)]
// pub struct StringFile<'s> {
// buffer: Vec<u8>,
// consumed: usize,
// pos: usize,
// reader: BufReader<File>,
// _string: PhantomData<&'s str>
// }
// impl<'s> StringFile<'s> {
// #[inline(always)]
// pub fn open(path: &str) -> io::Result<StringFile<'s>> {
// Ok(StringFile::new(File::open(path)?, 1024))
// }
// #[inline(always)]
// pub fn open_with_cap(path: &str, cap: usize) -> io::Result<StringFile<'s>> {
// Ok(StringFile::new(File::open(path)?, cap))
// }
// #[inline(always)]
// pub fn new(file: File, cap: usize) -> StringFile<'s> {
// StringFile {
// buffer: vec![0; cap],
// consumed: 0,
// pos: 0,
// reader: BufReader::new(file),
// _string: PhantomData
// }
// }
// #[inline(always)]
// pub fn available(&self) -> usize {
// self.pos - self.consumed
// }
// fn read_into_peek(&mut self, num: usize) -> io::Result<usize> {
// if self.available() >= num {
// return Ok(num);
// }
// let needed = num - self.available();
// let to_read = min(self.buffer.len() - self.pos, needed);
// let (i, j) = (self.pos, self.pos + to_read);
// let read = self.reader.read(&mut self.buffer[i..j])?;
// self.pos += read;
// Ok(self.available())
// }
// // Panics if at least `num` aren't available.
// #[inline(always)]
// fn peek_bytes(&self, num: usize) -> &[u8] {
// &self.buffer[self.consumed..(self.consumed + num)]
// }
// fn consume(&mut self, num: usize) {
// if self.pos < num {
// let left = (num - self.pos) as u64;
// self.consumed = 0;
// self.pos = 0;
// // TOOD: Probably don't ignore this?
// let _ = io::copy(&mut self.reader.by_ref().take(left), &mut io::sink());
// } else {
// self.consumed += num;
// }
// }
// #[inline]
// fn peek_char(&mut self) -> Option<char> {
// let available = match self.read_into_peek(4) {
// Ok(n) => n,
// Err(_) => return None
// };
// let bytes = self.peek_bytes(available);
// let string = match ::std::str::from_utf8(bytes) {
// Ok(string) => string,
// Err(e) => match ::std::str::from_utf8(&bytes[..e.valid_up_to()]) {
// Ok(string) => string,
// Err(_) => return None
// }
// };
// string.chars().next()
// }
// }
// impl<'s> Input for StringFile<'s> {
// type Token = char;
// type InSlice = &'s str;
// type Slice = &'s str;
// type Many = String;
// type Context = &'s str;
// // If we took Self::Token here, we'd know the length of the character.
// #[inline(always)]
// fn peek(&mut self) -> Option<Self::Token> {
// self.peek_char()
// }
// fn take_many<F: FnMut(&Self::Token) -> bool>(&mut self, mut cond: F) -> Self::Many {
// let mut result = String::new();
// while let Some(c) = self.peek_char() {
// if cond(&c) {
// result.push(c);
// self.consume(c.len_utf8());
// } else {
// break;
// }
// }
// result
// }
// fn skip_many<F: FnMut(&Self::Token) -> bool>(&mut self, mut cond: F) -> usize {
// let mut taken = 0;
// while let Some(c) = self.peek_char() {
// if cond(&c) {
// self.consume(c.len_utf8());
// taken += 1;
// } else {
// return taken;
// }
// }
// taken
// }
// fn peek_slice(&mut self, slice: Self::InSlice) -> Option<Self::Slice> {
// let available = match self.read_into_peek(slice.len()) {
// Ok(n) => n,
// Err(_) => return None
// };
// let bytes = self.peek_bytes(available);
// let string = match ::std::str::from_utf8(bytes) {
// Ok(string) => string,
// Err(e) => match ::std::str::from_utf8(&bytes[..e.valid_up_to()]) {
// Ok(string) => string,
// Err(_) => return None
// }
// };
// match string == slice {
// true => Some(slice),
// false => None
// }
// }
// #[inline(always)]
// fn advance(&mut self, count: usize) {
// self.consume(count);
// }
// #[inline(always)]
// fn is_empty(&mut self) -> bool {
// match self.read_into_peek(1) {
// Ok(0) | Err(_) => true,
// Ok(_) => false,
// }
// }
// }