Struct buf_redux::BufReader [−][src]
pub struct BufReader<R, P: ReaderPolicy = StdPolicy> { /* fields omitted */ }
A drop-in replacement for std::io::BufReader
with more functionality.
Original method names/signatures and implemented traits are left untouched, making replacement as simple as swapping the import of the type.
By default this type implements the behavior of its std
counterpart: it only reads into
the buffer when it is empty.
To change this type's behavior, change the policy with .set_policy()
using a type
from the policy
module or your own implementation of ReaderPolicy
.
Policies that perform alternating reads and consumes without completely emptying the buffer
may benefit from using a ringbuffer via the new_ringbuf()
and with_capacity_ringbuf()
constructors. Ringbuffers are only available on supported platforms with the
slice-deque
feature and have some other caveats; see the crate root docs
for more details.
Methods
impl<R> BufReader<R, StdPolicy>
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impl<R> BufReader<R, StdPolicy>
pub fn new(inner: R) -> Self
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pub fn new(inner: R) -> Self
Create a new BufReader
wrapping inner
, utilizing a buffer of
default capacity and the default ReaderPolicy
.
pub fn with_capacity(cap: usize, inner: R) -> Self
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pub fn with_capacity(cap: usize, inner: R) -> Self
Create a new BufReader
wrapping inner
, utilizing a buffer with a capacity
of at least cap
bytes and the default ReaderPolicy
.
The actual capacity of the buffer may vary based on implementation details of the global allocator.
pub fn new_ringbuf(inner: R) -> Self
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pub fn new_ringbuf(inner: R) -> Self
Create a new BufReader
wrapping inner
, utilizing a ringbuffer with the default capacity
and ReaderPolicy
.
A ringbuffer never has to move data to make room; consuming bytes from the head
simultaneously makes room at the tail. This is useful in conjunction with a policy like
MinBuffered
to ensure there is always room to read more data
if necessary, without expensive copying operations.
Only available on platforms with virtual memory support and with the slice-deque
feature
enabled. The default capacity will differ between Windows and Unix-derivative targets.
See Buffer::new_ringbuf()
or the crate root docs for more info.
pub fn with_capacity_ringbuf(cap: usize, inner: R) -> Self
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pub fn with_capacity_ringbuf(cap: usize, inner: R) -> Self
Create a new BufReader
wrapping inner
, utilizing a ringbuffer with at least the given
capacity and the default ReaderPolicy
.
A ringbuffer never has to move data to make room; consuming bytes from the head
simultaneously makes room at the tail. This is useful in conjunction with a policy like
MinBuffered
to ensure there is always room to read more data
if necessary, without expensive copying operations.
Only available on platforms with virtual memory support and with the slice-deque
feature
enabled. The capacity will be rounded up to the minimum size for the target platform.
See Buffer::with_capacity_ringbuf()
or the crate root docs for more info.
pub fn with_buffer(buf: Buffer, inner: R) -> Self
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pub fn with_buffer(buf: Buffer, inner: R) -> Self
Wrap inner
with an existing Buffer
instance and the default ReaderPolicy
.
Note
Does not clear the buffer first! If there is data already in the buffer
then it will be returned in read()
and fill_buf()
ahead of any data from inner
.
impl<R, P: ReaderPolicy> BufReader<R, P>
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impl<R, P: ReaderPolicy> BufReader<R, P>
ⓘImportant traits for BufReader<R, P>pub fn set_policy<P_: ReaderPolicy>(self, policy: P_) -> BufReader<R, P_>
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pub fn set_policy<P_: ReaderPolicy>(self, policy: P_) -> BufReader<R, P_>
Apply a new ReaderPolicy
to this BufReader
, returning the transformed type.
pub fn policy_mut(&mut self) -> &mut P
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pub fn policy_mut(&mut self) -> &mut P
Accessor for updating the ReaderPolicy
in-place.
If you want to change the type, use .set_policy()
.
pub fn make_room(&mut self)
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pub fn make_room(&mut self)
Move data to the start of the buffer, making room at the end for more reading.
This is a no-op with the *_ringbuf()
constructors (requires slice-deque
feature).
pub fn reserve(&mut self, additional: usize)
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pub fn reserve(&mut self, additional: usize)
Ensure room in the buffer for at least additional
bytes. May not be
quite exact due to implementation details of the buffer's allocator.
pub fn buffer(&self) -> &[u8]
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pub fn buffer(&self) -> &[u8]
Get the section of the buffer containing valid data; may be empty.
Call .consume()
to remove bytes from the beginning of this section.
pub fn buf_len(&self) -> usize
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pub fn buf_len(&self) -> usize
Get the current number of bytes available in the buffer.
pub fn capacity(&self) -> usize
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pub fn capacity(&self) -> usize
Get the total buffer capacity.
pub fn get_ref(&self) -> &R
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pub fn get_ref(&self) -> &R
Get an immutable reference to the underlying reader.
pub fn get_mut(&mut self) -> &mut R
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pub fn get_mut(&mut self) -> &mut R
Get a mutable reference to the underlying reader.
Note
Reading directly from the underlying reader is not recommended, as some data has likely already been moved into the buffer.
pub fn into_inner(self) -> R
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pub fn into_inner(self) -> R
Consume self
and return the inner reader only.
pub fn into_inner_with_buffer(self) -> (R, Buffer)
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pub fn into_inner_with_buffer(self) -> (R, Buffer)
Consume self
and return both the underlying reader and the buffer.
See also: BufReader::unbuffer()
ⓘImportant traits for Unbuffer<R>pub fn unbuffer(self) -> Unbuffer<R>
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pub fn unbuffer(self) -> Unbuffer<R>
Consume self
and return an adapter which implements Read
and will
empty the buffer before reading directly from the underlying reader.
impl<R: Read, P: ReaderPolicy> BufReader<R, P>
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impl<R: Read, P: ReaderPolicy> BufReader<R, P>
pub fn read_into_buf(&mut self) -> Result<usize>
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pub fn read_into_buf(&mut self) -> Result<usize>
Unconditionally perform a read into the buffer.
Does not invoke ReaderPolicy
methods.
If the read was successful, returns the number of bytes read.
ⓘImportant traits for BufReader<R, P>pub fn boxed<'a>(self) -> BufReader<Box<Read + 'a>, P> where
R: 'a,
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pub fn boxed<'a>(self) -> BufReader<Box<Read + 'a>, P> where
R: 'a,
Box the inner reader without losing data.
Trait Implementations
impl<R: Read, P: ReaderPolicy> Read for BufReader<R, P>
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impl<R: Read, P: ReaderPolicy> Read for BufReader<R, P>
fn read(&mut self, out: &mut [u8]) -> Result<usize>
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fn read(&mut self, out: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
unsafe fn initializer(&self) -> Initializer
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unsafe fn initializer(&self) -> Initializer
read_initializer
)Determines if this Read
er can work with buffers of uninitialized memory. Read more
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0[src]
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>
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[src]
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
Read all bytes until EOF in this source, appending them to buf
. Read more
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
1.6.0[src]
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
Read the exact number of bytes required to fill buf
. Read more
fn by_ref(&mut self) -> &mut Self
1.0.0[src]
fn by_ref(&mut self) -> &mut Self
Creates a "by reference" adaptor for this instance of Read
. Read more
fn bytes(self) -> Bytes<Self>
1.0.0[src]
fn bytes(self) -> Bytes<Self>
Transforms this Read
instance to an [Iterator
] over its bytes. Read more
fn chars(self) -> Chars<Self>
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fn chars(self) -> Chars<Self>
: Use str::from_utf8 instead: https://doc.rust-lang.org/nightly/std/str/struct.Utf8Error.html#examples
🔬 This is a nightly-only experimental API. (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[src]
fn chain<R>(self, next: R) -> Chain<Self, R> where
R: Read,
Creates an adaptor which will chain this stream with another. Read more
fn take(self, limit: u64) -> Take<Self>
1.0.0[src]
fn take(self, limit: u64) -> Take<Self>
Creates an adaptor which will read at most limit
bytes from it. Read more
impl<R: Read, P: ReaderPolicy> BufRead for BufReader<R, P>
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impl<R: Read, P: ReaderPolicy> BufRead for BufReader<R, P>
fn fill_buf(&mut self) -> Result<&[u8]>
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fn fill_buf(&mut self) -> Result<&[u8]>
Fills the internal buffer of this object, returning the buffer contents. Read more
fn consume(&mut self, amt: usize)
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fn consume(&mut self, amt: usize)
Tells this buffer that amt
bytes have been consumed from the buffer, so they should no longer be returned in calls to read
. Read more
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>
1.0.0[src]
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>
Read all bytes into buf
until the delimiter byte
or EOF is reached. Read more
fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>
1.0.0[src]
fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>
Read all bytes until a newline (the 0xA byte) is reached, and append them to the provided buffer. Read more
fn split(self, byte: u8) -> Split<Self>
1.0.0[src]
fn split(self, byte: u8) -> Split<Self>
Returns an iterator over the contents of this reader split on the byte byte
. Read more
fn lines(self) -> Lines<Self>
1.0.0[src]
fn lines(self) -> Lines<Self>
Returns an iterator over the lines of this reader. Read more
impl<R: Debug, P: ReaderPolicy + Debug> Debug for BufReader<R, P>
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impl<R: Debug, P: ReaderPolicy + Debug> Debug for BufReader<R, P>
fn fmt(&self, fmt: &mut Formatter) -> Result
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fn fmt(&self, fmt: &mut Formatter) -> Result
Formats the value using the given formatter. Read more
impl<R: Seek, P: ReaderPolicy> Seek for BufReader<R, P>
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impl<R: Seek, P: ReaderPolicy> Seek for BufReader<R, P>
fn seek(&mut self, pos: SeekFrom) -> Result<u64>
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fn seek(&mut self, pos: SeekFrom) -> Result<u64>
Seek to an ofPet, 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
.unwrap()
immediately after a seek yields the underlying reader at
the same position.
See std::io::Seek
for more details.
Note: In the edge case where you're seeking with SeekFrom::Current(n)
where n
minus the internal buffer length underflows 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 seeked to SeekFrom::Current(0)
.