Struct IndexedReader 

pub struct IndexedReader<R: ReadAt> { /* private fields */ }

A Read and Seek view of decompressed bytes described by an index.

Seeking resumes at the nearest preceding checkpoint and discards output up to the requested byte. Gzip-member and zlib-header checkpoints permit full checksum verification, including discarded bytes. An interior DEFLATE checkpoint cannot authenticate the skipped prefix because the index does not store its checksum state. Raw DEFLATE has no container checksum.

The index is validated and a known compressed size is compared with the source before construction succeeds. Callers remain responsible for pairing indexes without a recorded size with the source from which they were built.

Implementations

impl<R: ReadAt> IndexedReader<R>

pub fn new(source: R, index: DeflateIndex) -> Result<Self, IndexedReaderError>

Opens source for random access through index.

Errors

Returns an error when the index violates its invariants, the source length cannot be read or disagrees with a known index size, or the raw inflate backend cannot be initialized.

pub fn with_window_cache_bytes(self, bytes: usize) -> Self

Sets the expanded-window cache budget in bytes.

pub const fn index(&self) -> &DeflateIndex

Returns the index backing this reader.

pub const fn position(&self) -> u64

Returns the decompressed offset of the next byte a read returns.

pub fn into_inner(self) -> (R, DeflateIndex)

Returns the source and index, discarding decoding state.

pub fn seek_to_line(&mut self, line: u64) -> Result<u64>

Seeks to the first byte of zero-based line and returns its byte offset.

The reader resumes from the nearest preceding annotated checkpoint and scans forward only far enough to find the requested newline. Seeking beyond the recorded lines positions the reader at decoded EOF.

Errors

Returns io::ErrorKind::Unsupported unless the index carries a total line count and a line offset for every checkpoint. Other errors have the same meaning as Read and Seek errors from this reader.

Trait Implementations

impl<R: ReadAt> Read for IndexedReader<R>

fn read(&mut self, output: &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.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

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

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

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

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_, u8>) -> Result<(), Error>

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

Pull some bytes from this source into the specified buffer.

fn read_buf_exact( &mut self, cursor: BorrowedCursor<'_, u8>, ) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

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

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

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

where Self: Sized,

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

fn read_array<const N: usize>(&mut self) -> Result<[u8; N], Error>

where Self: Sized,

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

Read and return a fixed array of bytes from this source.

fn read_le<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

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

Read and return a type (e.g. an integer) in little-endian order.

fn read_be<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

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

Read and return a type (e.g. an integer) in big-endian order.

impl<R: ReadAt> Seek for IndexedReader<R>

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

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

fn stream_position(&mut self) -> Result<u64>

Returns the current seek position from the start of the stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

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

Returns the length of this stream (in bytes).

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.