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Merge branch 'doc_io_traits_enums' of https://github.com/steveklabnik/rust into rollup_central

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Steve Klabnik 2015-07-16 17:54:44 -04:00
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src/libstd/io/mod.rs
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@ -127,14 +127,50 @@ fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize>
ret
}
/// A trait for objects which are byte-oriented sources.
/// The `Read` trait allows for reading bytes from a source.
///
/// Readers are defined by one method, `read`. Each call to `read` will attempt
/// to pull bytes from this source into a provided buffer.
/// Implementors of the `Read` trait are sometimes called 'readers'.
///
/// Readers are intended to be composable with one another. Many objects
/// throughout the I/O and related libraries take and provide types which
/// implement the `Read` trait.
/// Readers are defined by one required method, `read()`. Each call to `read`
/// will attempt to pull bytes from this source into a provided buffer. A
/// number of other methods are implemented in terms of `read()`, giving
/// implementors a number of ways to read bytes while only needing to implement
/// a single method.
///
/// Readers are intended to be composable with one another. Many implementors
/// throughout `std::io` take and provide types which implement the `Read`
/// trait.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = [0; 10];
///
/// // read up to 10 bytes
/// try!(f.read(&mut buffer));
///
/// let mut buffer = vec![0; 10];
/// // read the whole file
/// try!(f.read_to_end(&mut buffer));
///
/// // read into a String, so that you don't need to do the conversion.
/// let mut buffer = String::new();
/// try!(f.read_to_string(&mut buffer));
///
/// // and more! See the other methods for more details.
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub trait Read {
/// Pull some bytes from this source into the specified buffer, returning
@ -164,6 +200,27 @@ pub trait Read {
/// If this function encounters any form of I/O or other error, an error
/// variant will be returned. If an error is returned then it must be
/// guaranteed that no bytes were read.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = [0; 10];
///
/// // read 10 bytes
/// try!(f.read(&mut buffer[..]));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
@ -185,6 +242,27 @@ pub trait Read {
/// If any other read error is encountered then this function immediately
/// returns. Any bytes which have already been read will be appended to
/// `buf`.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = Vec::new();
///
/// // read the whole file
/// try!(f.read_to_end(&mut buffer));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
read_to_end(self, buf)
@ -200,7 +278,29 @@ pub trait Read {
/// If the data in this stream is *not* valid UTF-8 then an error is
/// returned and `buf` is unchanged.
///
/// See `read_to_end` for other error semantics.
/// See [`read_to_end()`][readtoend] for other error semantics.
///
/// [readtoend]: #method.read_to_end
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = String::new();
///
/// try!(f.read_to_string(&mut buffer));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
// Note that we do *not* call `.read_to_end()` here. We are passing
@ -219,6 +319,36 @@ pub trait Read {
///
/// The returned adaptor also implements `Read` and will simply borrow this
/// current reader.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::Read;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = Vec::new();
/// let mut other_buffer = Vec::new();
///
/// {
/// let reference = f.by_ref();
///
/// // read at most 5 bytes
/// try!(reference.take(5).read_to_end(&mut buffer));
///
/// } // drop our &mut reference so we can use f again
///
/// // original file still usable, read the rest
/// try!(f.read_to_end(&mut other_buffer));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
@ -228,6 +358,27 @@ pub trait Read {
/// R::Err>`. The yielded item is `Ok` if a byte was successfully read and
/// `Err` otherwise for I/O errors. EOF is mapped to returning `None` from
/// this iterator.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
///
/// for byte in f.bytes() {
/// println!("{}", byte.unwrap());
/// }
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn bytes(self) -> Bytes<Self> where Self: Sized {
Bytes { inner: self }
@ -243,6 +394,28 @@ pub trait Read {
///
/// Currently this adaptor will discard intermediate data read, and should
/// be avoided if this is not desired.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// #![feature(io)]
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
///
/// for c in f.chars() {
/// println!("{}", c.unwrap());
/// }
/// # Ok(())
/// # }
/// ```
#[unstable(feature = "io", reason = "the semantics of a partial read/write \
of where errors happen is currently \
unclear and may change")]
@ -255,6 +428,31 @@ pub trait Read {
/// The returned `Read` instance will first read all bytes from this object
/// until EOF is encountered. Afterwards the output is equivalent to the
/// output of `next`.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f1 = try!(File::open("foo.txt"));
/// let mut f2 = try!(File::open("bar.txt"));
///
/// let mut handle = f1.chain(f2);
/// let mut buffer = String::new();
///
/// // read the value into a String. We could use any Read method here,
/// // this is just one example.
/// try!(handle.read_to_string(&mut buffer));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
Chain { first: self, second: next, done_first: false }
@ -266,6 +464,29 @@ pub trait Read {
/// `limit` bytes, after which it will always return EOF (`Ok(0)`). Any
/// read errors will not count towards the number of bytes read and future
/// calls to `read` may succeed.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer = [0; 10];
///
/// // read at most five bytes
/// let mut handle = f.take(5);
///
/// try!(handle.read(&mut buffer));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn take(self, limit: u64) -> Take<Self> where Self: Sized {
Take { inner: self, limit: limit }
@ -277,6 +498,31 @@ pub trait Read {
/// Whenever the returned `Read` instance is read it will write the read
/// data to `out`. The current semantics of this implementation imply that
/// a `write` error will not report how much data was initially read.
///
/// # Examples
///
/// [`File`][file]s implement `Read`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// #![feature(io)]
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
/// let mut buffer1 = Vec::with_capacity(10);
/// let mut buffer2 = Vec::with_capacity(10);
///
/// // write the output to buffer1 as we read
/// let mut handle = f.tee(&mut buffer1);
///
/// try!(handle.read(&mut buffer2));
/// # Ok(())
/// # }
/// ```
#[unstable(feature = "io", reason = "the semantics of a partial read/write \
of where errors happen is currently \
unclear and may change")]
@ -287,15 +533,34 @@ pub trait Read {
/// A trait for objects which are byte-oriented sinks.
///
/// The `write` method will attempt to write some data into the object,
/// Implementors of the `Write` trait are sometimes called 'writers'.
///
/// Writers are defined by two required methods, `write()` and `flush()`:
///
/// * The `write()` method will attempt to write some data into the object,
/// returning how many bytes were successfully written.
///
/// The `flush` method is useful for adaptors and explicit buffers themselves
/// for ensuring that all buffered data has been pushed out to the "true sink".
/// * The `flush()` method is useful for adaptors and explicit buffers
/// themselves for ensuring that all buffered data has been pushed out to the
/// 'true sink'.
///
/// Writers are intended to be composable with one another. Many objects
/// throughout the I/O and related libraries take and provide types which
/// implement the `Write` trait.
/// Writers are intended to be composable with one another. Many implementors
/// throughout `std::io` take and provide types which implement the `Write`
/// trait.
///
/// # Examples
///
/// ```
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = try!(File::create("foo.txt"));
///
/// try!(buffer.write(b"some bytes"));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub trait Write {
/// Write a buffer into this object, returning how many bytes were written.
@ -322,6 +587,20 @@ pub trait Write {
///
/// It is **not** considered an error if the entire buffer could not be
/// written to this writer.
///
/// # Examples
///
/// ```
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = try!(File::create("foo.txt"));
///
/// try!(buffer.write(b"some bytes"));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn write(&mut self, buf: &[u8]) -> Result<usize>;
@ -332,6 +611,22 @@ pub trait Write {
///
/// It is considered an error if not all bytes could be written due to
/// I/O errors or EOF being reached.
///
/// # Examples
///
/// ```
/// use std::io::prelude::*;
/// use std::io::BufWriter;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = BufWriter::new(try!(File::create("foo.txt")));
///
/// try!(buffer.write(b"some bytes"));
/// try!(buffer.flush());
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn flush(&mut self) -> Result<()>;
@ -345,6 +640,20 @@ pub trait Write {
/// # Errors
///
/// This function will return the first error that `write` returns.
///
/// # Examples
///
/// ```
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = try!(File::create("foo.txt"));
///
/// try!(buffer.write_all(b"some bytes"));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
while !buf.is_empty() {
@ -362,17 +671,41 @@ pub trait Write {
/// Writes a formatted string into this writer, returning any error
/// encountered.
///
/// This method is primarily used to interface with the `format_args!`
/// macro, but it is rare that this should explicitly be called. The
/// `write!` macro should be favored to invoke this method instead.
/// This method is primarily used to interface with the
/// [`format_args!`][formatargs] macro, but it is rare that this should
/// explicitly be called. The [`write!`][write] macro should be favored to
/// invoke this method instead.
///
/// This function internally uses the `write_all` method on this trait and
/// hence will continuously write data so long as no errors are received.
/// This also means that partial writes are not indicated in this signature.
/// [formatargs]: ../std/macro.format_args!.html
/// [write]: ../std/macro.write!.html
///
/// This function internally uses the [`write_all`][writeall] method on
/// this trait and hence will continuously write data so long as no errors
/// are received. This also means that partial writes are not indicated in
/// this signature.
///
/// [writeall]: #method.write_all
///
/// # Errors
///
/// This function will return any I/O error reported while formatting.
///
/// # Examples
///
/// ```
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = try!(File::create("foo.txt"));
///
/// // this call
/// try!(write!(buffer, "{:.*}", 2, 1.234567));
/// // turns into this:
/// try!(buffer.write_fmt(format_args!("{:.*}", 2, 1.234567)));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
// Create a shim which translates a Write to a fmt::Write and saves
@ -405,6 +738,23 @@ pub trait Write {
///
/// The returned adaptor also implements `Write` and will simply borrow this
/// current writer.
///
/// # Examples
///
/// ```
/// use std::io::Write;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer = try!(File::create("foo.txt"));
///
/// let reference = buffer.by_ref();
///
/// // we can use reference just like our original buffer
/// try!(reference.write_all(b"some bytes"));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
@ -416,6 +766,25 @@ pub trait Write {
/// implementation do not precisely track where errors happen. For example
/// an error on the second call to `write` will not report that the first
/// call to `write` succeeded.
///
/// # Examples
///
/// ```
/// #![feature(io)]
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> std::io::Result<()> {
/// let mut buffer1 = try!(File::create("foo.txt"));
/// let mut buffer2 = Vec::new();
///
/// // write the output to buffer1 as we read
/// let mut handle = buffer1.broadcast(&mut buffer2);
///
/// try!(handle.write(b"some bytes"));
/// # Ok(())
/// # }
/// ```
#[unstable(feature = "io", reason = "the semantics of a partial read/write \
of where errors happen is currently \
unclear and may change")]
@ -426,17 +795,38 @@ pub trait Write {
}
}
/// An object implementing `Seek` internally has some form of cursor which can
/// be moved within a stream of bytes.
/// The `Seek` trait provides a cursor which can be moved within a stream of
/// bytes.
///
/// The stream typically has a fixed size, allowing seeking relative to either
/// end or the current offset.
///
/// # Examples
///
/// [`File`][file]s implement `Seek`:
///
/// [file]: ../std/fs/struct.File.html
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
/// use std::fs::File;
/// use std::io::SeekFrom;
///
/// # fn foo() -> io::Result<()> {
/// let mut f = try!(File::open("foo.txt"));
///
/// // move the cursor 42 bytes from the start of the file
/// try!(f.seek(SeekFrom::Start(42)));
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub trait Seek {
/// Seek to an offset, in bytes, in a stream
/// Seek to an offset, in bytes, in a stream.
///
/// A seek beyond the end of a stream is allowed, but seeking before offset
/// 0 is an error.
/// A seek beyond the end of a stream is allowed, but implementation
/// defined.
///
/// The behavior when seeking past the end of the stream is implementation
/// defined.
@ -446,7 +836,7 @@ pub trait Seek {
///
/// # Errors
///
/// Seeking to a negative offset is considered an error
/// Seeking to a negative offset is considered an error.
#[stable(feature = "rust1", since = "1.0.0")]
fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
}
@ -505,24 +895,68 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
}
}
/// A `BufRead` is a type of reader which has some form of internal buffering to
/// allow certain kinds of reading operations to be more optimized than others.
/// A `BufRead` is a type of `Read`er which has an internal buffer, allowing it
/// to perform extra ways of reading.
///
/// This type extends the `Read` trait with a few methods that are not
/// possible to reasonably implement with purely a read interface.
/// For example, reading line-by-line is inefficient without using a buffer, so
/// if you want to read by line, you'll need `BufRead`, which includes a
/// [`read_line()`][readline] method as well as a [`lines()`][lines] iterator.
///
/// [readline]: #method.read_line
/// [lines]: #method.lines
///
/// # Examples
///
/// A locked standard input implements `BufRead`:
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
/// for line in stdin.lock().lines() {
/// println!("{}", line.unwrap());
/// }
/// ```
///
/// If you have something that implements `Read`, you can use the [`BufReader`
/// type][bufreader] to turn it into a `BufRead`.
///
/// For example, [`File`][file] implements `Read`, but not `BufRead`.
/// `BufReader` to the rescue!
///
/// [bufreader]: struct.BufReader.html
/// [file]: ../fs/struct.File.html
///
/// ```
/// use std::io::{self, BufReader};
/// use std::io::prelude::*;
/// use std::fs::File;
///
/// # fn foo() -> io::Result<()> {
/// let f = try!(File::open("foo.txt"));
/// let f = BufReader::new(f);
///
/// for line in f.lines() {
/// println!("{}", line.unwrap());
/// }
///
/// # Ok(())
/// # }
/// ```
///
/// You can use the [`BufReader` wrapper type](struct.BufReader.html) to turn any
/// reader into a buffered reader.
#[stable(feature = "rust1", since = "1.0.0")]
pub trait BufRead: Read {
/// Fills the internal buffer of this object, returning the buffer contents.
///
/// None of the contents will be "read" in the sense that later calling
/// `read` may return the same contents.
/// This function is a lower-level call. It needs to be paired with the
/// [`consume`][consume] method to function properly. When calling this
/// method, none of the contents will be "read" in the sense that later
/// calling `read` may return the same contents. As such, `consume` must be
/// called with the number of bytes that are consumed from this buffer to
/// ensure that the bytes are never returned twice.
///
/// The `consume` function must be called with the number of bytes that are
/// consumed from this buffer returned to ensure that the bytes are never
/// returned twice.
/// [consume]: #tymethod.consume
///
/// An empty buffer returned indicates that the stream has reached EOF.
///
@ -530,34 +964,66 @@ pub trait BufRead: Read {
///
/// This function will return an I/O error if the underlying reader was
/// read, but returned an error.
///
/// # Examples
///
/// A locked standard input implements `BufRead`:
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
/// let mut stdin = stdin.lock();
///
/// // we can't have two `&mut` references to `stdin`, so use a block
/// // to end the borrow early.
/// let length = {
/// let buffer = stdin.fill_buf().unwrap();
///
/// // work with buffer
/// println!("{:?}", buffer);
///
/// buffer.len()
/// };
///
/// // ensure the bytes we worked with aren't returned again later
/// stdin.consume(length);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn fill_buf(&mut self) -> Result<&[u8]>;
/// Tells this buffer that `amt` bytes have been consumed from the buffer,
/// so they should no longer be returned in calls to `read`.
///
/// This function does not perform any I/O, it simply informs this object
/// that some amount of its buffer, returned from `fill_buf`, has been
/// consumed and should no longer be returned.
/// This function is a lower-level call. It needs to be paired with the
/// [`fill_buf`][fillbuf] method to function properly. This function does
/// not perform any I/O, it simply informs this object that some amount of
/// its buffer, returned from `fill_buf`, has been consumed and should no
/// longer be returned. As such, this function may do odd things if
/// `fill_buf` isn't called before calling it.
///
/// This function is used to tell the buffer how many bytes you've consumed
/// from the return value of `fill_buf`, and so may do odd things if
/// `fill_buf` isn't called before calling this.
/// [fillbuf]: #tymethod.fill_buff
///
/// The `amt` must be `<=` the number of bytes in the buffer returned by `fill_buf`.
/// The `amt` must be `<=` the number of bytes in the buffer returned by
/// `fill_buf`.
///
/// # Examples
///
/// Since `consume()` is meant to be used with [`fill_buf()`][fillbuf],
/// that method's example includes an example of `consume()`.
#[stable(feature = "rust1", since = "1.0.0")]
fn consume(&mut self, amt: usize);
/// Read all bytes until the delimiter `byte` is reached.
/// Read all bytes into `buf` until the delimiter `byte` is reached.
///
/// This function will continue to read (and buffer) bytes from the
/// underlying stream until the delimiter or EOF is found. Once found, all
/// bytes up to, and including, the delimiter (if found) will be appended to
/// `buf`.
/// This function will read bytes from the underlying stream until the
/// delimiter or EOF is found. Once found, all bytes up to, and including,
/// the delimiter (if found) will be appended to `buf`.
///
/// If this buffered reader is currently at EOF, then this function will not
/// place any more bytes into `buf` and will return `Ok(n)` where `n` is the
/// number of bytes which were read.
/// If this reader is currently at EOF then this function will not modify
/// `buf` and will return `Ok(n)` where `n` is the number of bytes which
/// were read.
///
/// # Errors
///
@ -566,18 +1032,39 @@ pub trait BufRead: Read {
///
/// If an I/O error is encountered then all bytes read so far will be
/// present in `buf` and its length will have been adjusted appropriately.
///
/// # Examples
///
/// A locked standard input implements `BufRead`. In this example, we'll
/// read from standard input until we see an `a` byte.
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// fn foo() -> io::Result<()> {
/// let stdin = io::stdin();
/// let mut stdin = stdin.lock();
/// let mut buffer = Vec::new();
///
/// try!(stdin.read_until(b'a', &mut buffer));
///
/// println!("{:?}", buffer);
/// # Ok(())
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> {
read_until(self, byte, buf)
}
/// Read all bytes until a newline (the 0xA byte) is reached, and
/// append them to the provided buffer.
/// Read all bytes until a newline (the 0xA byte) is reached, and append
/// them to the provided buffer.
///
/// This function will continue to read (and buffer) bytes from the
/// underlying stream until the newline delimiter (the 0xA byte) or EOF is
/// found. Once found, all bytes up to, and including, the delimiter (if
/// found) will be appended to `buf`.
/// This function will read bytes from the underlying stream until the
/// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes
/// up to, and including, the delimiter (if found) will be appended to
/// `buf`.
///
/// If this reader is currently at EOF then this function will not modify
/// `buf` and will return `Ok(n)` where `n` is the number of bytes which
@ -589,6 +1076,31 @@ pub trait BufRead: Read {
/// return an error if the read bytes are not valid UTF-8. If an I/O error
/// is encountered then `buf` may contain some bytes already read in the
/// event that all data read so far was valid UTF-8.
///
/// # Examples
///
/// A locked standard input implements `BufRead`. In this example, we'll
/// read all of the lines from standard input. If we were to do this in
/// an actual project, the [`lines()`][lines] method would be easier, of
/// course.
///
/// [lines]: #method.lines
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
/// let mut stdin = stdin.lock();
/// let mut buffer = String::new();
///
/// while stdin.read_line(&mut buffer).unwrap() > 0 {
/// // work with buffer
/// println!("{:?}", buffer);
///
/// buffer.clear();
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn read_line(&mut self, buf: &mut String) -> Result<usize> {
// Note that we are not calling the `.read_until` method here, but
@ -606,6 +1118,22 @@ pub trait BufRead: Read {
///
/// This function will yield errors whenever `read_until` would have also
/// yielded an error.
///
/// # Examples
///
/// A locked standard input implements `BufRead`. In this example, we'll
/// read some input from standard input, splitting on commas.
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
///
/// for content in stdin.lock().split(b',') {
/// println!("{:?}", content.unwrap());
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn split(self, byte: u8) -> Split<Self> where Self: Sized {
Split { buf: self, delim: byte }
@ -616,6 +1144,21 @@ pub trait BufRead: Read {
/// The iterator returned from this function will yield instances of
/// `io::Result<String>`. Each string returned will *not* have a newline
/// byte (the 0xA byte) at the end.
///
/// # Examples
///
/// A locked standard input implements `BufRead`:
///
/// ```
/// use std::io;
/// use std::io::prelude::*;
///
/// let stdin = io::stdin();
///
/// for line in stdin.lock().lines() {
/// println!("{}", line.unwrap());
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn lines(self) -> Lines<Self> where Self: Sized {
Lines { buf: self }