69 lines
2.0 KiB
Rust
69 lines
2.0 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use core::io::{Reader, BytesReader};
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use core::io;
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use core::cast;
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/// An implementation of the io::Reader interface which reads a buffer of bytes
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pub struct BufReader {
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/// The buffer of bytes to read
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buf: ~[u8],
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/// The current position in the buffer of bytes
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pos: @mut uint
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}
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impl BufReader {
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/// Creates a new buffer reader for the specified buffer
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pub fn new(v: ~[u8]) -> BufReader {
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BufReader {
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buf: v,
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pos: @mut 0
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}
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}
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fn as_bytes_reader<A>(&self, f: &fn(&BytesReader) -> A) -> A {
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// XXX FIXME(#5723)
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let bytes = ::core::util::id::<&[u8]>(self.buf);
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let bytes: &'static [u8] = unsafe { cast::transmute(bytes) };
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// Recreating the BytesReader state every call since
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// I can't get the borrowing to work correctly
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let bytes_reader = BytesReader {
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bytes: bytes,
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pos: @mut *self.pos
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};
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let res = f(&bytes_reader);
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// FIXME #4429: This isn't correct if f fails
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*self.pos = *bytes_reader.pos;
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return res;
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}
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}
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impl Reader for BufReader {
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fn read(&self, bytes: &mut [u8], len: uint) -> uint {
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self.as_bytes_reader(|r| r.read(bytes, len) )
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}
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fn read_byte(&self) -> int {
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self.as_bytes_reader(|r| r.read_byte() )
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}
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fn eof(&self) -> bool {
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self.as_bytes_reader(|r| r.eof() )
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}
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fn seek(&self, offset: int, whence: io::SeekStyle) {
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self.as_bytes_reader(|r| r.seek(offset, whence) )
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}
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fn tell(&self) -> uint {
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self.as_bytes_reader(|r| r.tell() )
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}
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}
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