Struct encoding_rs_io::DecodeReaderBytes

pub struct DecodeReaderBytes<R, B> { /* fields omitted */ }

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.

Methods

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

Important traits for DecodeReaderBytes<R, B>

impl<R: Read, B: AsMut<[u8]>> Read for DecodeReaderBytes<R, B>

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.

Trait Implementations

impl<R: Read, B: AsMut<[u8]>> Read for DecodeReaderBytes<R, B>

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.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory.

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.

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

Read all bytes until EOF in this source, appending them to buf.

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

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an [Iterator] over its bytes.

fn chars(self) -> Chars<Self>

Deprecated since 1.27.0

: 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.

fn chain<R>(self, next: R) -> Chain<Self, R> where     R: Read,

Creates an adaptor which will chain this stream with another.

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

Creates an adaptor which will read at most limit bytes from it.

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

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

Formats the value using the given formatter.