Struct parquet::file::serialized_reader::FileSource

pub struct FileSource<R: ParquetReader> { /* fields omitted */ }

Struct that represents a slice of a file data with independent start position and length. Internally clones provided file handle, wraps with a custom implementation of BufReader that resets position before any read.

This is workaround and alternative for file.try_clone() method. It clones File while preserving independent position, which is not available with try_clone().

Designed after arrow::io::RandomAccessFile and std::io::BufReader

Implementations

impl<R: ParquetReader> FileSource<R>

pub fn new(fd: &R, start: u64, length: usize) -> Self

Creates new file reader with start and length from a file handle

Trait Implementations

impl<R: ParquetReader> Debug for FileSource<R>

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

Formats the value using the given formatter.

impl<R: ParquetReader> Length for FileSource<R>

fn len(&self) -> u64

Returns the amount of bytes of the inner source.

impl<R: ParquetReader> Read for FileSource<R>

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.

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

Like read, except that it reads into a slice of buffers.

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.

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, Global>) -> 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 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.