Struct VariableInt 

pub struct VariableInt { /* private fields */ }

Variable length integer as defined by MQTT specification

Encodes values using 1-4 bytes:

• 0-127: 1 byte
• 128-16,383: 2 bytes
• 16,384-2,097,151: 3 bytes
• 2,097,152-268,435,455: 4 bytes

Implementations

impl VariableInt

pub fn new(value: u32) -> Result<Self>

Creates a new VariableInt from a u32 value

Errors

Returns MqttError::ProtocolError if the value exceeds the maximum

pub fn new_unchecked(value: u32) -> Self

Creates a new VariableInt from a u32 value without validation

Safety

The caller must ensure that value <= VARIABLE_INT_MAX

pub fn value(&self) -> u32

Returns the actual value

pub fn encoded_size(&self) -> u32

Returns the number of bytes needed to encode this value

pub fn encode<B: BufMut>(&self, buf: &mut B) -> Result<()>

Encodes this variable integer into the provided buffer

Errors

Always succeeds for valid VariableInt values

pub fn decode<B: Buf>(buf: &mut B) -> Result<Self>

Decodes a variable integer from the buffer

Errors

Returns an error if:

• The buffer doesn’t contain enough bytes
• The encoded value exceeds the maximum
• More than 4 bytes are used (protocol violation)

Trait Implementations

impl BeBytes for VariableInt

fn field_size() -> usize

fn to_be_bytes(&self) -> Vec<u8>

fn try_from_be_bytes(bytes: &[u8]) -> Result<(Self, usize), BeBytesError>

Try to parse a struct from big-endian bytes

fn to_le_bytes(&self) -> Vec<u8>

fn try_from_le_bytes(bytes: &[u8]) -> Result<(Self, usize), BeBytesError>

Try to parse a struct from little-endian bytes

fn to_be_bytes_buf(&self) -> Bytes

Convert to big-endian bytes as a Bytes buffer

fn to_le_bytes_buf(&self) -> Bytes

Convert to little-endian bytes as a Bytes buffer

fn encode_be_to<B>(&self, buf: &mut B) -> Result<(), BeBytesError>

where B: BufMut,

Encode directly to a buffer in big-endian format

fn encode_le_to<B>(&self, buf: &mut B) -> Result<(), BeBytesError>

where B: BufMut,

Encode directly to a buffer in little-endian format

impl Clone for VariableInt

fn clone(&self) -> VariableInt

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VariableInt

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

Formats the value using the given formatter.

impl Display for VariableInt

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

Formats the value using the given formatter.

impl From<VariableInt> for u32

fn from(v: VariableInt) -> Self

Converts to this type from the input type.

impl Hash for VariableInt

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for VariableInt

fn eq(&self, other: &VariableInt) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl TryFrom<u32> for VariableInt

type Error = MqttError

The type returned in the event of a conversion error.

fn try_from(value: u32) -> Result<Self>

Performs the conversion.

impl TryFrom<usize> for VariableInt

type Error = MqttError

The type returned in the event of a conversion error.

fn try_from(value: usize) -> Result<Self>

Performs the conversion.

impl Copy for VariableInt

impl Eq for VariableInt

impl StructuralPartialEq for VariableInt