pub struct BufReader<R> { /* private fields */ }
Expand description

The BufReader struct adds buffering to any reader.

It can be excessively inefficient to work directly with a AsyncRead instance. A BufReader performs large, infrequent reads on the underlying AsyncRead and maintains an in-memory buffer of the results.

BufReader can improve the speed of programs that make small and repeated read calls to the same file or network socket. It does not help when reading very large amounts at once, or reading just one or a few times. It also provides no advantage when reading from a source that is already in memory, like a Vec<u8>.

When the BufReader is dropped, the contents of its buffer will be discarded. Creating multiple instances of a BufReader on the same stream can cause data loss.

Implementations

Creates a new BufReader with a default buffer capacity. The default is currently 8 KB, but may change in the future.

Creates a new BufReader with the specified buffer capacity.

Gets a reference to the underlying reader.

It is inadvisable to directly read from the underlying reader.

Gets a mutable reference to the underlying reader.

It is inadvisable to directly read from the underlying reader.

Gets a pinned mutable reference to the underlying reader.

It is inadvisable to directly read from the underlying reader.

Consumes this BufReader, returning the underlying reader.

Note that any leftover data in the internal buffer is lost.

Returns a reference to the internally buffered data.

Unlike fill_buf, this will not attempt to fill the buffer if it is empty.

Trait Implementations

Attempts to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read. Read more

Attempts to read from the AsyncRead into buf. Read more

Seeks to an offset, in bytes, in the underlying reader.

The position used for seeking with SeekFrom::Current(_) is the position the underlying reader would be at if the BufReader had no internal buffer.

Seeking always discards the internal buffer, even if the seek position would otherwise fall within it. This guarantees that calling .into_inner() immediately after a seek yields the underlying reader at the same position.

See AsyncSeek for more details.

Note: In the edge case where you’re seeking with SeekFrom::Current(n) where n minus the internal buffer length overflows an i64, two seeks will be performed instead of one. If the second seek returns Err, the underlying reader will be left at the same position it would have if you called seek with SeekFrom::Current(0).

Attempts to seek to an offset, in bytes, in a stream. Read more

Waits for a seek operation to complete. Read more

Attempt to write bytes from buf into the object. Read more

Like poll_write, except that it writes from a slice of buffers. Read more

Determines if this writer has an efficient poll_write_vectored implementation. Read more

Attempts to flush the object, ensuring that any buffered data reach their destination. Read more

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down. Read more

Formats the value using the given formatter. Read more

Converts to this type from the input type.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.