Struct DgramBuffer 

pub struct DgramBuffer { /* private fields */ }

A simple buffer for working with datagrams.

This is a thin wrapper around a Vec<u8> but it maintains an offset / read position into the vector to the actual start of the datagram. This enables users to preallocate headroom in front of the actual datagram to prepend additional headers, or to advance the cursor to consume such prefixes.

Implementations

impl DgramBuffer

pub fn new() -> Self

Creates an empty DgramBuffer with no allocated capacity.

pub fn from_slice(data: &[u8]) -> Self

Creates a DgramBuffer by copying data; the read cursor starts at the beginning.

pub fn with_capacity(capacity: usize) -> Self

Creates an empty DgramBuffer pre-allocated for at least capacity bytes.

pub fn with_capacity_and_headroom(capacity: usize, headroom: usize) -> Self

Creates a DgramBuffer pre-allocated for capacity bytes with headroom zero bytes reserved at the front for later prefix insertion via try_add_prefix. The read cursor is positioned after the headroom. Panics if headroom > capacity.

pub fn from_vec_with_headroom(v: Vec<u8>, headroom: usize) -> Self

Wraps an existing Vec<u8>, treating the first headroom bytes as reserved prefix space. The read cursor is positioned after the headroom. Panics if headroom > v.len().

pub fn truncate(&mut self, count: usize)

Truncates the readable portion to count bytes, discarding any data beyond that point. If count is greater or equal to the buffer’s current length, this has no effect.

pub fn advance(&mut self, count: usize)

Advances the cursor by count bytes; panics if count exceeds the number of readable bytes.

pub fn try_add_prefix(&mut self, prefix: &[u8]) -> Result<(), ()>

Prepends prefix into the headroom region, sliding the read cursor backwards. Returns Err(()) if the headroom is smaller than prefix.len().

pub fn splice_headroom(&mut self, headroom: usize)

Ensures that at least headroom bytes of headroom are available, potentially shifting elements and reallocating. If headroom is less than the existing headroom, this method does nothing.

pub fn clear(&mut self)

Resets the buffer to an empty state, dropping all data and headroom.

pub fn len(&self) -> usize

Returns the number of readable bytes (i.e. data.len() - pos).

pub fn is_empty(&self) -> bool

Returns true if there are no readable bytes.

pub fn as_slice(&self) -> &[u8]

Returns the readable bytes as a slice (i.e. data[pos..]).

pub fn as_mut_slice(&mut self) -> &mut [u8]

Returns the readable bytes as a mutable slice (i.e. data[pos..]).

pub fn spare_capacity(&self) -> usize

Returns the number of bytes the underlying Vec can accept before reallocating (i.e. capacity - len).

pub fn into_parts(self) -> (Vec<u8>, usize)

Consumes the buffer and returns the inner Vec<u8> and the current read position as (data, pos).

Trait Implementations

impl AsMut<[u8]> for DgramBuffer

fn as_mut(&mut self) -> &mut [u8]

Converts this type into a mutable reference of the (usually inferred) input type.

impl AsRef<[u8]> for DgramBuffer

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl BufMut for DgramBuffer

fn remaining_mut(&self) -> usize

Returns the number of bytes that can be written from the current position until the end of the buffer is reached.

unsafe fn advance_mut(&mut self, cnt: usize)

Advance the internal cursor of the BufMut

fn chunk_mut(&mut self) -> &mut UninitSlice

Returns a mutable slice starting at the current BufMut position and of length between 0 and BufMut::remaining_mut(). Note that this can be shorter than the whole remainder of the buffer (this allows non-continuous implementation).

fn put<T: Buf>(&mut self, src: T)

where Self: Sized,

Transfer bytes into self from src and advance the cursor by the number of bytes written.

fn put_slice(&mut self, src: &[u8])

Transfer bytes into self from src and advance the cursor by the number of bytes written.

fn put_bytes(&mut self, val: u8, cnt: usize)

Put cnt bytes val into self.

fn has_remaining_mut(&self) -> bool

Returns true if there is space in self for more bytes.

fn put_u8(&mut self, n: u8)

Writes an unsigned 8 bit integer to self.

fn put_i8(&mut self, n: i8)

Writes a signed 8 bit integer to self.

fn put_u16(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in big-endian byte order.

fn put_u16_le(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in little-endian byte order.

fn put_u16_ne(&mut self, n: u16)

Writes an unsigned 16 bit integer to self in native-endian byte order.

fn put_i16(&mut self, n: i16)

Writes a signed 16 bit integer to self in big-endian byte order.

fn put_i16_le(&mut self, n: i16)

Writes a signed 16 bit integer to self in little-endian byte order.

fn put_i16_ne(&mut self, n: i16)

Writes a signed 16 bit integer to self in native-endian byte order.

fn put_u32(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in big-endian byte order.

fn put_u32_le(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in little-endian byte order.

fn put_u32_ne(&mut self, n: u32)

Writes an unsigned 32 bit integer to self in native-endian byte order.

fn put_i32(&mut self, n: i32)

Writes a signed 32 bit integer to self in big-endian byte order.

fn put_i32_le(&mut self, n: i32)

Writes a signed 32 bit integer to self in little-endian byte order.

fn put_i32_ne(&mut self, n: i32)

Writes a signed 32 bit integer to self in native-endian byte order.

fn put_u64(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in the big-endian byte order.

fn put_u64_le(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in little-endian byte order.

fn put_u64_ne(&mut self, n: u64)

Writes an unsigned 64 bit integer to self in native-endian byte order.

fn put_i64(&mut self, n: i64)

Writes a signed 64 bit integer to self in the big-endian byte order.

fn put_i64_le(&mut self, n: i64)

Writes a signed 64 bit integer to self in little-endian byte order.

fn put_i64_ne(&mut self, n: i64)

Writes a signed 64 bit integer to self in native-endian byte order.

fn put_u128(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in the big-endian byte order.

fn put_u128_le(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in little-endian byte order.

fn put_u128_ne(&mut self, n: u128)

Writes an unsigned 128 bit integer to self in native-endian byte order.

fn put_i128(&mut self, n: i128)

Writes a signed 128 bit integer to self in the big-endian byte order.

fn put_i128_le(&mut self, n: i128)

Writes a signed 128 bit integer to self in little-endian byte order.

fn put_i128_ne(&mut self, n: i128)

Writes a signed 128 bit integer to self in native-endian byte order.

fn put_uint(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in big-endian byte order.

fn put_uint_le(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in the little-endian byte order.

fn put_uint_ne(&mut self, n: u64, nbytes: usize)

Writes an unsigned n-byte integer to self in the native-endian byte order.

fn put_int(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in big-endian byte order.

fn put_int_le(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in little-endian byte order.

fn put_int_ne(&mut self, n: i64, nbytes: usize)

Writes low nbytes of a signed integer to self in native-endian byte order.

fn put_f32(&mut self, n: f32)

Writes an IEEE754 single-precision (4 bytes) floating point number to self in big-endian byte order.

fn put_f32_le(&mut self, n: f32)

Writes an IEEE754 single-precision (4 bytes) floating point number to self in little-endian byte order.

fn put_f32_ne(&mut self, n: f32)

Writes an IEEE754 single-precision (4 bytes) floating point number to self in native-endian byte order.

fn put_f64(&mut self, n: f64)

Writes an IEEE754 double-precision (8 bytes) floating point number to self in big-endian byte order.

fn put_f64_le(&mut self, n: f64)

Writes an IEEE754 double-precision (8 bytes) floating point number to self in little-endian byte order.

fn put_f64_ne(&mut self, n: f64)

Writes an IEEE754 double-precision (8 bytes) floating point number to self in native-endian byte order.

fn limit(self, limit: usize) -> Limit<Self>

where Self: Sized,

Creates an adaptor which can write at most limit bytes to self.

fn writer(self) -> Writer<Self>

where Self: Sized,

Creates an adaptor which implements the Write trait for self.

fn chain_mut<U>(self, next: U) -> Chain<Self, U>

where U: BufMut, Self: Sized,

Creates an adapter which will chain this buffer with another.

impl Clone for DgramBuffer

fn clone(&self) -> DgramBuffer

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DgramBuffer

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

Formats the value using the given formatter.

impl Default for DgramBuffer

fn default() -> DgramBuffer

Returns the “default value” for a type.

impl From<Vec<u8>> for DgramBuffer

fn from(v: Vec<u8>) -> Self

Converts to this type from the input type.