rust/src/libstd/io_util.rs

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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/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.
use core::io::{Reader, BytesReader};
use core::io;
pub struct BufReader {
buf: ~[u8],
pos: @mut uint
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}
pub impl BufReader {
pub fn new(v: ~[u8]) -> BufReader {
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BufReader {
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buf: v,
pos: @mut 0
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}
}
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priv fn as_bytes_reader<A>(&self, f: &fn(&BytesReader) -> A) -> A {
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// Recreating the BytesReader state every call since
// I can't get the borrowing to work correctly
let bytes_reader = BytesReader {
bytes: ::core::util::id::<&[u8]>(self.buf),
pos: @mut *self.pos
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};
let res = f(&bytes_reader);
// FIXME #4429: This isn't correct if f fails
*self.pos = *bytes_reader.pos;
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return res;
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}
}
impl Reader for BufReader {
fn read(&self, bytes: &mut [u8], len: uint) -> uint {
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self.as_bytes_reader(|r| r.read(bytes, len) )
}
fn read_byte(&self) -> int {
self.as_bytes_reader(|r| r.read_byte() )
}
fn eof(&self) -> bool {
self.as_bytes_reader(|r| r.eof() )
}
fn seek(&self, offset: int, whence: io::SeekStyle) {
self.as_bytes_reader(|r| r.seek(offset, whence) )
}
fn tell(&self) -> uint {
self.as_bytes_reader(|r| r.tell() )
}
}