encoding_rs_io

Struct DecodeReaderBytes

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pub struct DecodeReaderBytes<R, B> { /* private fields */ }
Expand description

An implementation of io::Read that transcodes to UTF-8 in a streaming fashion.

The high level goal of this decoder is to provide access to byte streams that are assumed to be UTF-8 unless an encoding is otherwise specified (either via a BOM or via an explicit designation of an encoding).

When no explicit source encoding is specified (via DecodeReaderBytesBuilder), the source encoding is determined by inspecting the BOM from the stream read from R, if one exists. If a UTF-16 BOM exists, then the source stream is transcoded to UTF-8 with invalid UTF-16 sequences translated to the Unicode replacement character. Similarly if a UTF-8 BOM is seen. In all other cases, the source of the underlying reader is passed through unchanged as if it were UTF-8.

Since this particular reader does not guarantee providing valid UTF-8 to the caller, the caller must be prepared to handle invalid UTF-8 itself.

R is the type of the underlying reader and B is the type of an internal buffer used to store the results of transcoding. Callers may elect to reuse the internal buffer via the DecodeReaderBytesBuilder::build_with_buffer constructor.

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impl<R: Read> DecodeReaderBytes<R, Vec<u8>>

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pub fn new(rdr: R) -> DecodeReaderBytes<R, Vec<u8>>

Create a new transcoder that converts a source stream to valid UTF-8 via BOM sniffing.

To explicitly control the encoding, UTF-8 passthru or amortize allocation, use the DecodeReaderBytesBuilder constructor.

When a BOM is found (which must correspond to UTF-8, UTF-16LE or UTF-16BE), then transcoding to UTF-8 is performed and any invalid sequences in the source data are seamlessly replaced by the Unicode replacement character.

When no BOM is found (and no other encoding is specified via the builder), the underlying bytes are passed through as-is.

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impl<R: Debug, B: Debug> Debug for DecodeReaderBytes<R, B>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<R: Read, B: AsMut<[u8]>> Read for DecodeReaderBytes<R, B>

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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
1.36.0 · Source§

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers. Read more
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fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)
Determines if this Reader has an efficient read_vectored implementation. Read more
1.0.0 · Source§

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf. Read more
1.0.0 · Source§

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf. Read more
1.6.0 · Source§

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf. Read more
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fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)
Pull some bytes from this source into the specified buffer. Read more
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fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)
Reads the exact number of bytes required to fill cursor. Read more
1.0.0 · Source§

fn by_ref(&mut self) -> &mut Self
where Self: Sized,

Creates a “by reference” adaptor for this instance of Read. Read more
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fn bytes(self) -> Bytes<Self>
where Self: Sized,

Transforms this Read instance to an Iterator over its bytes. Read more
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fn chain<R>(self, next: R) -> Chain<Self, R>
where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another. Read more
1.0.0 · Source§

fn take(self, limit: u64) -> Take<Self>
where Self: Sized,

Creates an adapter which will read at most limit bytes from it. Read more

Auto Trait Implementations§

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impl<R, B> Freeze for DecodeReaderBytes<R, B>
where B: Freeze, R: Freeze,

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impl<R, B> RefUnwindSafe for DecodeReaderBytes<R, B>

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impl<R, B> Send for DecodeReaderBytes<R, B>
where B: Send, R: Send,

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impl<R, B> Sync for DecodeReaderBytes<R, B>
where B: Sync, R: Sync,

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impl<R, B> Unpin for DecodeReaderBytes<R, B>
where B: Unpin, R: Unpin,

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impl<R, B> UnwindSafe for DecodeReaderBytes<R, B>
where B: UnwindSafe, R: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.