[−][src]Trait fbxcel::pull_parser::reader::ParserSource

pub trait ParserSource: Sized + Read {
    fn position(&self) -> u64;

    fn skip_distance(&mut self, distance: u64) -> Result<()> { ... }

    fn skip_to(&mut self, pos: u64) -> Result<()> { ... }
}

A trait for types which can be data sources.

Users can implement this manually, but usually it is enough to use wrappers in the reader module.

Required methods

fn position(&self) -> u64

Returns the offset of a byte which would be read next.

This is called many times during parsing, so it is desirable to be fast as possible.

Reader types with std::io::Seek can implement this as self.seek(SeekFrom::Current(0)).unwrap(), but this is fallible and can be inefficient. Use of PositionCacheReader is reccomended.

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Provided methods

fn skip_distance(&mut self, distance: u64) -> Result<()>

Skips (seeks formward) the given size.

Reader types can make this more efficient using std::io::Seek::seek if possible.

Examples

use fbxcel::pull_parser::{ParserSource, reader::PlainSource};

let msg = "Hello, world!";
let len = msg.len() as u64;
let mut reader = std::io::Cursor::new(msg);
let mut reader = PlainSource::new(&mut reader);

assert_eq!(reader.position(), 0);
reader.skip_distance(7).expect("Failed to skip");
assert_eq!(reader.position(), 7);

fn skip_to(&mut self, pos: u64) -> Result<()>

Skips (seeks forward) to the given position.

Reader types can make this more efficient using std::io::Seek::seek if possible.

Panics

Panics if the given position is behind the current position.

use fbxcel::pull_parser::{ParserSource, reader::PlainSource};

let msg = "Hello, world!";
let len = msg.len() as u64;
let mut reader = std::io::Cursor::new(msg);
let mut reader = PlainSource::new(&mut reader);

assert_eq!(reader.position(), 0);
reader.skip_to(2).expect("Failed to skip");
assert_eq!(reader.position(), 2);
reader.skip_to(7).expect("Failed to skip");
assert_eq!(reader.position(), 7);
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Implementations on Foreign Types

impl<'_, R: ParserSource> ParserSource for &'_ mut R[src]

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Implementors

impl<R: Read + Seek> ParserSource for SeekableSource<R>[src]

impl<R: Read> ParserSource for PlainSource<R>[src]

impl<R: Read> ParserSource for PositionCacheReader<R>[src]

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