Struct StringData 

pub struct StringData(/* private fields */);

Text fields within the MQTT Control Packets described later are encoded as UTF-8 strings. UTF-8 RFC3629 is an efficient encoding of Unicode Unicode characters that optimizes the encoding of ASCII characters in support of text-based communications.

String Data is represented by a Two Byte Integer length which indicates the number of data bytes, followed by characters.

Thus, the length of String Data is limited to the range of 0 to 65,535 Bytes.

+-------------------+
| String Length     |
|                   |
+-------------------+
| String            |
|                   |
+-------------------+

The character data in a UTF-8 Encoded String MUST be well-formed UTF-8 as defined by the Unicode specification Unicode and restated in RFC 3629 RFC3629. In particular, the character data MUST NOT include encodings of code points between U+D800 and U+DFFF [MQTT-1.5.4-1].

If the Client or Server receives an MQTT Control Packet containing ill-formed UTF-8 it is a Malformed Packet.

A UTF-8 Encoded String MUST NOT include an encoding of the null character U+0000. [MQTT-1.5.4-2].

If a receiver (Server or Client) receives an MQTT Control Packet containing U+0000 it is a Malformed Packet.

The data SHOULD NOT include encodings of the Unicode Unicode code points listed below. If a receiver (Server or Client) receives an MQTT Control Packet containing any of them it MAY treat it as a Malformed Packet. These are the Disallowed Unicode code points.

• U+0001..U+001F control characters
• U+007F..U+009F control characters
• Code points defined in the Unicode specification Unicode to be non-characters (for example U+0FFFF)

A UTF-8 encoded sequence 0xEF 0xBB 0xBF is always interpreted as U+FEFF (“ZERO WIDTH NO-BREAK SPACE”) wherever it appears in a string and MUST NOT be skipped over or stripped off by a packet receiver [MQTT-1.5.4-3].

Implementations

impl StringData

pub const fn new() -> Self

Create an empty string data.

pub fn from(s: &str) -> Result<Self, StringError>

Convert string slice into string data.

Errors

Returns error if string slice is too large.

pub fn bytes(&self) -> usize

Get byte length in packet.

pub fn is_empty(&self) -> bool

Returns true if string data is empty.

pub fn clear(&mut self)

Clear string.

Trait Implementations

impl AsRef<str> for StringData

fn as_ref(&self) -> &str

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

impl Clone for StringData

fn clone(&self) -> StringData

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StringData

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

Formats the value using the given formatter.

impl DecodePacket for StringData

fn decode(ba: &mut ByteArray<'_>) -> Result<Self, DecodeError>

Decode byte array into a mqtt packet.

impl Default for StringData

fn default() -> StringData

Returns the “default value” for a type.

impl Display for StringData

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

Formats the value using the given formatter.

impl EncodePacket for StringData

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

Encode packets into byte array.

impl PartialEq for StringData

fn eq(&self, other: &StringData) -> 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 Eq for StringData

impl StructuralPartialEq for StringData