Struct olio::fs::rc::ReadPos

pub struct ReadPos { /* fields omitted */ }

Re-implements Read and Seek over a shared File reference using only positioned reads, and by maintaining an instance independent position.

A fixed length is passed on construction and used solely to interpret SeekFrom::End. Reads are not constrained by this length. The length is neither checked nor updated via file metadata, and could deviate from the underlying file length if concurrent writes or truncation is possible. Reads beyond the end of the underlying File will return 0 length. Seeking past the end is allowed by the platforms for File, and is also allowed for ReadPos.

Methods

impl ReadPos

Important traits for ReadPos

impl Read for ReadPos

pub fn new(file: Arc<File>, length: u64) -> ReadPos

New instance by File reference and fixed file length. The initial position is the start of the file.

pub fn len(&self) -> u64

Return the length as provided on construction. This may differ from the underlying file length.

pub fn is_empty(&self) -> bool

Return true if length is 0.

Important traits for ReadSlice

impl Read for ReadSlice

pub fn subslice(&self, start: u64, end: u64) -> ReadSlice

Return a new and independent ReadSlice for the same file, for the range of byte offsets start..end. Panics if start is greater than end. Note that end is not checked against the constructed length.

pub fn tell(&self) -> u64

Return the current instance position. This is a convenience shorthand for seek(SeekFrom::Current(0)), is infallable, and does not require a mutable reference.

Trait Implementations

impl Debug for ReadPos

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Clone for ReadPos

Important traits for ReadPos

impl Read for ReadPos

fn clone(&self) -> ReadPos

Return a new, independent ReadPos with the same length and file reference as self, and with position 0 (ignores the current position of self).

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl PosRead for ReadPos

fn pread(&self, buf: &mut [u8], offset: u64) -> Result<usize>

Read some bytes, starting at the specified offset, into the specified buffer and return the number of bytes read. The offset is from the start of the underlying file or file range. The position of the underlying file pointer (aka cursor) is not used. It is platform dependent whether the underlying file pointer is modified by this operation.

impl Read for ReadPos

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>

🔬 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 Seek for ReadPos

fn seek(&mut self, from: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.