Enum Header

pub enum Header {
    Positive(u64),
    Negative(u64),
    Float(f64),
    Simple(u8),
    Tag(u64),
    Break,
    Bytes(Option<usize>),
    Text(Option<usize>),
    Array(Option<usize>),
    Map(Option<usize>),
}

A semantic representation of a CBOR item header

This structure represents the valid values of a CBOR item header and is used extensively when serializing or deserializing CBOR items. Note well that this structure DOES NOT represent the body (i.e. suffix) of the CBOR item. You must parse the body yourself based on the contents of the Header. However, utility functions are provided for this (see: Decoder::bytes() and Decoder::text()).

Variants

Positive(u64)

A positive integer

Negative(u64)

A negative integer

Note well that this value has all bits inverted from a normal signed integer. For example, to convert the u64 to a i128 you would do this: neg as i128 ^ !0.

Float(f64)

A floating point value

Simple(u8)

A “simple” value

Tag(u64)

A tag

Break

The “break” value

This value is used to terminate indefinite length arrays and maps, as well as segmented byte or text items.

Bytes(Option<usize>)

A bytes item

The value contained in this variant indicates the length of the bytes which follow or, if None, segmented bytes input.

A best practice is to call Decoder::bytes() immediately after first pulling a bytes item header since this utility function encapsulates all the logic needed to handle segmentation.

Text(Option<usize>)

A text item

The value contained in this variant indicates the length of the text which follows (in bytes) or, if None, segmented text input.

A best practice is to call Decoder::text() immediately after first pulling a text item header since this utility function encapsulates all the logic needed to handle segmentation.

Array(Option<usize>)

An array item

The value contained in this variant indicates the length of the array which follows (in items) or, if None, an indefinite length array terminated by a “break” value.

Map(Option<usize>)

An map item

The value contained in this variant indicates the length of the map which follows (in item pairs) or, if None, an indefinite length map terminated by a “break” value.

Trait Implementations

impl Clone for Header

fn clone(&self) -> Header

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Header

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

Formats the value using the given formatter.

impl PartialEq for Header

fn eq(&self, other: &Header) -> 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 Copy for Header

impl StructuralPartialEq for Header

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes

Size for each variant:

• Positive: 15 bytes
• Negative: 15 bytes
• Float: 15 bytes
• Simple: 1 byte
• Tag: 15 bytes
• Break: 0 bytes
• Bytes: 11 bytes
• Text: 11 bytes
• Array: 11 bytes
• Map: 11 bytes