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Diffstat (limited to 'ctr-std/src/io/util.rs')
| -rw-r--r-- | ctr-std/src/io/util.rs | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/ctr-std/src/io/util.rs b/ctr-std/src/io/util.rs new file mode 100644 index 0000000..2c68802 --- /dev/null +++ b/ctr-std/src/io/util.rs @@ -0,0 +1,215 @@ +// Copyright 2014 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. + +#![allow(missing_copy_implementations)] + +use io::{self, Read, Write, ErrorKind, BufRead}; + +/// Copies the entire contents of a reader into a writer. +/// +/// This function will continuously read data from `reader` and then +/// write it into `writer` in a streaming fashion until `reader` +/// returns EOF. +/// +/// On success, the total number of bytes that were copied from +/// `reader` to `writer` is returned. +/// +/// # Errors +/// +/// This function will return an error immediately if any call to `read` or +/// `write` returns an error. All instances of `ErrorKind::Interrupted` are +/// handled by this function and the underlying operation is retried. +/// +/// # Examples +/// +/// ``` +/// use std::io; +/// +/// # fn foo() -> io::Result<()> { +/// let mut reader: &[u8] = b"hello"; +/// let mut writer: Vec<u8> = vec![]; +/// +/// try!(io::copy(&mut reader, &mut writer)); +/// +/// assert_eq!(reader, &writer[..]); +/// # Ok(()) +/// # } +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64> + where R: Read, W: Write +{ + let mut buf = [0; super::DEFAULT_BUF_SIZE]; + let mut written = 0; + loop { + let len = match reader.read(&mut buf) { + Ok(0) => return Ok(written), + Ok(len) => len, + Err(ref e) if e.kind() == ErrorKind::Interrupted => continue, + Err(e) => return Err(e), + }; + writer.write_all(&buf[..len])?; + written += len as u64; + } +} + +/// A reader which is always at EOF. +/// +/// This struct is generally created by calling [`empty()`][empty]. Please see +/// the documentation of `empty()` for more details. +/// +/// [empty]: fn.empty.html +#[stable(feature = "rust1", since = "1.0.0")] +pub struct Empty { _priv: () } + +/// Constructs a new handle to an empty reader. +/// +/// All reads from the returned reader will return `Ok(0)`. +/// +/// # Examples +/// +/// A slightly sad example of not reading anything into a buffer: +/// +/// ``` +/// use std::io::{self, Read}; +/// +/// let mut buffer = String::new(); +/// io::empty().read_to_string(&mut buffer).unwrap(); +/// assert!(buffer.is_empty()); +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +pub fn empty() -> Empty { Empty { _priv: () } } + +#[stable(feature = "rust1", since = "1.0.0")] +impl Read for Empty { + fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { Ok(0) } +} +#[stable(feature = "rust1", since = "1.0.0")] +impl BufRead for Empty { + fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(&[]) } + fn consume(&mut self, _n: usize) {} +} + +/// A reader which yields one byte over and over and over and over and over and... +/// +/// This struct is generally created by calling [`repeat()`][repeat]. Please +/// see the documentation of `repeat()` for more details. +/// +/// [repeat]: fn.repeat.html +#[stable(feature = "rust1", since = "1.0.0")] +pub struct Repeat { byte: u8 } + +/// Creates an instance of a reader that infinitely repeats one byte. +/// +/// All reads from this reader will succeed by filling the specified buffer with +/// the given byte. +/// +/// # Examples +/// +/// ``` +/// use std::io::{self, Read}; +/// +/// let mut buffer = [0; 3]; +/// io::repeat(0b101).read_exact(&mut buffer).unwrap(); +/// assert_eq!(buffer, [0b101, 0b101, 0b101]); +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +pub fn repeat(byte: u8) -> Repeat { Repeat { byte: byte } } + +#[stable(feature = "rust1", since = "1.0.0")] +impl Read for Repeat { + fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { + for slot in &mut *buf { + *slot = self.byte; + } + Ok(buf.len()) + } +} + +/// A writer which will move data into the void. +/// +/// This struct is generally created by calling [`sink()`][sink]. Please +/// see the documentation of `sink()` for more details. +/// +/// [sink]: fn.sink.html +#[stable(feature = "rust1", since = "1.0.0")] +pub struct Sink { _priv: () } + +/// Creates an instance of a writer which will successfully consume all data. +/// +/// All calls to `write` on the returned instance will return `Ok(buf.len())` +/// and the contents of the buffer will not be inspected. +/// +/// # Examples +/// +/// ```rust +/// use std::io::{self, Write}; +/// +/// let buffer = vec![1, 2, 3, 5, 8]; +/// let num_bytes = io::sink().write(&buffer).unwrap(); +/// assert_eq!(num_bytes, 5); +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +pub fn sink() -> Sink { Sink { _priv: () } } + +#[stable(feature = "rust1", since = "1.0.0")] +impl Write for Sink { + fn write(&mut self, buf: &[u8]) -> io::Result<usize> { Ok(buf.len()) } + fn flush(&mut self) -> io::Result<()> { Ok(()) } +} + +#[cfg(test)] +mod tests { + use io::prelude::*; + use io::{copy, sink, empty, repeat}; + + #[test] + fn copy_copies() { + let mut r = repeat(0).take(4); + let mut w = sink(); + assert_eq!(copy(&mut r, &mut w).unwrap(), 4); + + let mut r = repeat(0).take(1 << 17); + assert_eq!(copy(&mut r as &mut Read, &mut w as &mut Write).unwrap(), 1 << 17); + } + + #[test] + fn sink_sinks() { + let mut s = sink(); + assert_eq!(s.write(&[]).unwrap(), 0); + assert_eq!(s.write(&[0]).unwrap(), 1); + assert_eq!(s.write(&[0; 1024]).unwrap(), 1024); + assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024); + } + + #[test] + fn empty_reads() { + let mut e = empty(); + assert_eq!(e.read(&mut []).unwrap(), 0); + assert_eq!(e.read(&mut [0]).unwrap(), 0); + assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0); + assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0); + } + + #[test] + fn repeat_repeats() { + let mut r = repeat(4); + let mut b = [0; 1024]; + assert_eq!(r.read(&mut b).unwrap(), 1024); + assert!(b.iter().all(|b| *b == 4)); + } + + #[test] + fn take_some_bytes() { + assert_eq!(repeat(4).take(100).bytes().count(), 100); + assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4); + assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20); + } +} |