Struct positioned_io::Cursor
[−]
[src]
pub struct Cursor<I> { // some fields omitted }
Adapts a ReadAt
or WriteAt
into a Read
or Write
.
This wraps anything that read and write at offsets, turning into an object that can
read or write at a file position. This allows you to use those types with all the many
functions that expect a Read
or Write
.
Note that seeking on Cursor
has limited functionality. We don't know how many bytes are
available, so we can't use SeekFrom::End. See SizeCursor
for another option.
Examples
use positioned_io::{ReadAt, Cursor}; struct NetworkStorage { // A remote disk that supports random access. } impl ReadAt for NetworkStorage { // ... } // Adapt our storage into a Read. let storage = NetworkStorage::new(SOME_LOCATION); let curs = Cursor::new_pos(storage, 1 << 30); // Copy a segment to a file. let mut input = curs.take(1 << 20); let mut output = try!(File::create("segment.out")); try!(io::copy(&mut input, &mut output));
Methods
impl<I> Cursor<I>
[src]
fn new_pos(io: I, pos: u64) -> Self
Create a new Cursor
which starts reading at a specified offset.
Pass in a ReadAt
or WriteAt
as io
.
fn new(io: I) -> Self
Create a new Cursor which starts reading at offset zero.
Pass in a ReadAt
or WriteAt
as io
.
fn into_inner(self) -> I
Consume self
and yield the inner ReadAt
or WriteAt
.
fn get_ref(&self) -> &I
Borrow the inner ReadAt
or WriteAt
.
fn get_mut(&mut self) -> &mut I
Borrow the inner ReadAt
or WriteAt
mutably.
fn position(&self) -> u64
Get the current read/write position.
fn set_position(&mut self, pos: u64)
Set the current read/write position.
Trait Implementations
impl<I> Seek for Cursor<I>
[src]
fn seek(&mut self, pos: SeekFrom) -> Result<u64>
Seek to an offset, in bytes, in a stream. Read more
impl<I> Read for Cursor<I> where I: ReadAt
[src]
fn read(&mut self, buf: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0
Read all bytes until EOF in this source, placing them into buf
. Read more
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
1.0.0
Read all bytes until EOF in this source, placing them into buf
. Read more
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
1.6.0
Read the exact number of bytes required to fill buf
. Read more
fn by_ref(&mut self) -> &mut Self
1.0.0
Creates a "by reference" adaptor for this instance of Read
. Read more
fn bytes(self) -> Bytes<Self>
1.0.0
Transforms this Read
instance to an Iterator
over its bytes. Read more
fn chars(self) -> Chars<Self>
io
): the semantics of a partial read/write of where errors happen is currently unclear and may change
Transforms this Read
instance to an Iterator
over char
s. Read more
fn chain<R>(self, next: R) -> Chain<Self, R> where R: Read
1.0.0
Creates an adaptor which will chain this stream with another. Read more
fn take(self, limit: u64) -> Take<Self>
1.0.0
Creates an adaptor which will read at most limit
bytes from it. Read more
impl<I> Write for Cursor<I> where I: WriteAt
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fn write(&mut self, buf: &[u8]) -> Result<usize>
Write a buffer into this object, returning how many bytes were written. Read more
fn flush(&mut self) -> Result<()>
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
1.0.0
Attempts to write an entire buffer into this write. Read more
fn write_fmt(&mut self, fmt: Arguments) -> Result<(), Error>
1.0.0
Writes a formatted string into this writer, returning any error encountered. Read more
fn by_ref(&mut self) -> &mut Self
1.0.0
Creates a "by reference" adaptor for this instance of Write
. Read more