Struct ChecksumReader 

pub struct ChecksumReader<C, R>
where
    C: CodeqConfig,
{ /* private fields */ }

A reader wrapper that calculates CRC32 checksum while reading data.

This reader wraps any type implementing io::Read and transparently calculates a CRC32 checksum of all data read through it. The checksum can be either:

• Retrieved using finalize_checksum()
• Verified against an expected value using verify_checksum()

Example:

use codeq::ChecksumWriter;
use codeq::ChecksumReader;
use codeq::config::Crc32fast;

// Build a buffer with a checksum
let mut b = Vec::new();
let mut w = Crc32fast::new_writer(&mut b);
w.write(b"foo").unwrap();
w.write_checksum().unwrap();

// Read the buffer and verify the checksum
let mut r = Crc32fast::new_reader(&b[..]);
let mut read_buf = [0u8; 3];
r.read_exact(&mut read_buf).unwrap();
let crc = r.finalize_checksum();
assert_eq!(crc32fast::hash(b"foo") as u64, crc);

Create a new reader with ChecksumReader::new or CodeqConfig::new_reader, for example:

let reader = Crc32fast::new_reader(Vec::new());

Implementations

impl<C, R> ChecksumReader<C, R>

where C: CodeqConfig, R: Read,

pub fn new(inner: R) -> Self

Creates a new ChecksumReader wrapping the provided reader.

pub fn finalize_checksum(self) -> u64

Consumes the reader and returns the calculated CRC32 checksum.

The returned value is the CRC32 checksum of all data read through this reader.

pub fn verify_checksum<D: Display>(self, context: impl Fn() -> D) -> Result<()>

Verifies the calculated checksum against an expected value stored in the stream.

Reads another 8-byte value from the underlying reader and compares its least significant 32 bits with the calculated checksum. The context closure is called to provide additional context in case of checksum mismatch.

Errors

Returns io::Error with io::ErrorKind::InvalidData kind if checksums don’t match.

Trait Implementations

impl<C, R> Read for ChecksumReader<C, R>

where C: CodeqConfig, R: Read,

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.

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<'_>) -> 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<'_>) -> 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.