Struct object::read::ReadCache

pub struct ReadCache<R: ReadCacheOps> {
    cache: RefCell<ReadCacheInternal<R>>,
}

An implementation of ReadRef for data in a stream that implements Read + Seek.

Contains a cache of read-only blocks of data, allowing references to them to be returned. Entries in the cache are never removed. Entries are keyed on the offset and size of the read. Currently overlapping reads are considered separate reads.

This is primarily intended for environments where memory mapped files are not available or not suitable, such as WebAssembly.

Note that malformed files can cause the cache to grow much larger than the file size.

Fields

cache: RefCell<ReadCacheInternal<R>>

Implementations

impl<R: ReadCacheOps> ReadCache<R>

pub fn new(read: R) -> Self

Create an empty ReadCache for the given stream.

pub fn range(&self, offset: u64, size: u64) -> ReadCacheRange<'_, R>

Return an implementation of ReadRef that restricts reads to the given range of the stream.

pub fn clear(&mut self)

Free buffers used by the cache.

pub fn into_inner(self) -> R

Unwrap this ReadCache<R>, returning the underlying reader.

Trait Implementations

impl<R: Debug + ReadCacheOps> Debug for ReadCache<R>

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

Formats the value using the given formatter.

impl<'a, R: ReadCacheOps> ReadRef<'a> for &'a ReadCache<R>

fn len(self) -> Result<u64, ()>

The total size of the block of data.

fn read_bytes_at(self, offset: u64, size: u64) -> Result<&'a [u8], ()>

Get a reference to a u8 slice at the given offset.

fn read_bytes_at_until( self, range: Range<u64>, delimiter: u8, ) -> Result<&'a [u8], ()>

Get a reference to a delimited u8 slice which starts at range.start.

fn read_bytes(self, offset: &mut u64, size: u64) -> Result<&'a [u8], ()>

Get a reference to a u8 slice at the given offset, and update the offset.

fn read<T: Pod>(self, offset: &mut u64) -> Result<&'a T, ()>

Get a reference to a Pod type at the given offset, and update the offset.

fn read_at<T: Pod>(self, offset: u64) -> Result<&'a T, ()>

Get a reference to a Pod type at the given offset.

fn read_slice<T: Pod>( self, offset: &mut u64, count: usize, ) -> Result<&'a [T], ()>

Get a reference to a slice of a Pod type at the given offset, and update the offset.

fn read_slice_at<T: Pod>(self, offset: u64, count: usize) -> Result<&'a [T], ()>

Get a reference to a slice of a Pod type at the given offset.