Struct Cursor 

pub struct Cursor<B: Buf> { /* private fields */ }

A stateful wrapper for sequential reading and writing in a buffer.

The Cursor keeps track of the current position within the underlying buffer B, ensuring that all read and write operations automatically advance the position and respect the buffer’s boundaries.

Implementations

impl<B: Buf> Cursor<B>

pub fn new(buffer: B) -> Self

Creates a new Cursor initialized at position 0.

pub fn into_inner(self) -> B

Consumes the Cursor and returns the underlying buffer.

pub fn position(&self) -> usize

Returns the current byte offset within the buffer.

impl<B: Buf> Cursor<B>

pub fn remaining(&self) -> usize

Returns the number of bytes remaining until the end of the buffer.

pub fn is_eof(&self) -> bool

Returns true if the cursor has reached the buffer length.

pub fn advance(&mut self, amount: usize) -> BufResult<()>

Advances the cursor position by amount bytes.

Errors

Returns BufError::UnexpectedEof if amount exceeds the remaining bytes.

pub fn rewind(&mut self, amount: usize) -> BufResult<()>

Moves the cursor position backward by amount bytes.

Errors

Returns BufError::OutOfBounds if amount exceeds the current position.

pub fn seek_to(&mut self, position: usize) -> BufResult<()>

Sets the cursor position to an absolute position.

Errors

Returns BufError::OutOfBounds if position exceeds the buffer’s length.

pub fn seek_from_end(&mut self, offset_from_end: usize) -> BufResult<()>

Sets the cursor position relative to the end of the buffer.

Errors

Returns BufError::OutOfBounds if offset_from_end exceeds the buffer’

pub fn peek_u8(&self) -> BufResult<u8>

Peeks at a single byte at the current position without advancing the cursor.

pub fn peek_u16_be(&self) -> BufResult<u16>

Peeks at a 16-bit big-endian integer at the current position without advancing.

pub fn peek_u32_be(&self) -> BufResult<u32>

Peeks at a 32-bit big-endian integer at the current position without advancing.

pub fn peek_array<const N: usize>(&self) -> BufResult<[u8; N]>

Peeks at a fixed-size byte array at the current position without advancing.

pub fn read_u8(&mut self) -> BufResult<u8>

Reads a single byte and advances the cursor by 1.

pub fn read_u16_be(&mut self) -> BufResult<u16>

Reads a 16-bit big-endian integer and advances the cursor by 2.

pub fn read_u32_be(&mut self) -> BufResult<u32>

Reads a 32-bit big-endian integer and advances the cursor by 4.

pub fn read_array<const N: usize>(&mut self) -> BufResult<[u8; N]>

Reads a fixed-size byte array and advances the cursor by N.

pub fn read_into(&mut self, destination: &mut [u8]) -> BufResult<()>

Reads bytes into the provided destination and advances the cursor.

Errors

Returns BufError::UnexpectedEof if the destination slice length exceeds the remaining bytes in the buffer.

impl<B: BufMut> Cursor<B>

pub fn poke_u8(&mut self, val: u8) -> BufResult<()>

Writes a single byte at the current position without advancing the cursor.

pub fn poke_u16_be(&mut self, val: u16) -> BufResult<()>

Writes a 16-bit big-endian integer at the current position without advancing.

pub fn poke_u32_be(&mut self, val: u32) -> BufResult<()>

Writes a 32-bit big-endian integer at the current position without advancing.

pub fn poke_array<const N: usize>(&mut self, val: &[u8; N]) -> BufResult<()>

Writes a fixed-size byte array at the current position without advancing.

pub fn poke_slice(&mut self, src: &[u8]) -> BufResult<()>

Writes a byte slice at the current position without advancing the cursor.

pub fn write_u8(&mut self, val: u8) -> BufResult<()>

Writes a single byte and advances the cursor by 1.

pub fn write_u16_be(&mut self, val: u16) -> BufResult<()>

Writes a 16-bit big-endian integer and advances the cursor by 2.

pub fn write_u32_be(&mut self, val: u32) -> BufResult<()>

Writes a 32-bit big-endian integer and advances the cursor by 4.

pub fn write_array<const N: usize>(&mut self, val: &[u8; N]) -> BufResult<()>

Writes a fixed-size byte array and advances the cursor by N.

pub fn write_slice(&mut self, src: &[u8]) -> BufResult<()>

Writes a byte slice and advances the cursor by the slice’s length.

Errors

Returns BufError::OutOfBounds or BufError::UnexpectedEof depending on the underlying BufMut implementation if the slice exceeds buffer capacity.

Trait Implementations

impl<B: Clone + Buf> Clone for Cursor<B>

fn clone(&self) -> Cursor<B>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<B: Copy + Buf> Copy for Cursor<B>

impl<B: Debug + Buf> Debug for Cursor<B>

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

Formats the value using the given formatter.