Enum Value 

#[non_exhaustive]
pub enum Value<'a> {
    Null,
    Bool(bool),
    Undefined,
    Simple(u8),
    Integer(i128),
    Float(f64),
    Bytes(Cow<'a, [u8]>),
    Text(Cow<'a, str>),
    Array(Vec<Value<'a>>),
    Map(BTreeMap<Value<'a>, Value<'a>>),
    Tag(u64, Box<Value<'a>>),
}

A dynamically-typed CBOR value.

#[non_exhaustive]: CBOR’s shapes are open, so a downstream match over every variant would need editing for each addition here.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Null

Major type 7, the null simple value.

Bool(bool)

Major type 7, true or false.

Undefined

Major type 7, simple value 23: undefined. Distinct from Value::Null, which says a value is absent.

Simple(u8)

Major type 7, a simple value with no meaning of its own. RFC 8949 Section 3.3 reserves these, so they are carried rather than rejected.

Integer(i128)

Major type 0 or 1: a non-negative or negative integer.

Float(f64)

Major type 7, a half-, single-, or double-precision float.

Bytes(Cow<'a, [u8]>)

Major type 2, a byte string.

Text(Cow<'a, str>)

Major type 3, a UTF-8 text string.

Array(Vec<Value<'a>>)

Major type 4, an array of values.

Map(BTreeMap<Value<'a>, Value<'a>>)

Major type 5, a map from values to values.

Tag(u64, Box<Value<'a>>)

Major type 6, a tagged value: the tag number and the value it applies to.

Implementations

impl<'a> Value<'a>

pub fn is_null(&self) -> bool

Returns true if the value is Null.

pub fn is_bool(&self) -> bool

Returns true if the value is a boolean.

pub fn is_integer(&self) -> bool

Returns true if the value is an integer.

pub fn is_float(&self) -> bool

Returns true if the value is a float.

pub fn is_bytes(&self) -> bool

Returns true if the value is a byte string.

pub fn is_text(&self) -> bool

Returns true if the value is a text string.

pub fn is_array(&self) -> bool

Returns true if the value is an array.

pub fn is_map(&self) -> bool

Returns true if the value is a map.

pub fn is_tag(&self) -> bool

Returns true if the value is a tag.

pub fn as_bool(&self) -> Option<bool>

Returns the value as a boolean if it is one.

pub fn as_integer(&self) -> Option<i128>

Returns the value as an integer if it is one.

pub fn as_float(&self) -> Option<f64>

Returns the value as a float if it is one.

pub fn as_bytes(&self) -> Option<&[u8]>

Returns the value as a byte slice if it is a byte string.

pub fn as_text(&self) -> Option<&str>

Returns the value as a string slice if it is a text string.

pub fn as_array(&self) -> Option<&[Value<'a>]>

Returns the value as a slice if it is an array.

pub fn as_map(&self) -> Option<&BTreeMap<Value<'a>, Value<'a>>>

Returns the value as a map if it is one.

pub fn as_tag(&self) -> Option<(u64, &Value<'a>)>

Returns the tag value and inner value if it is a tag.

Trait Implementations

impl<'a> Clone for Value<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for Value<'a>

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

Formats the value using the given formatter.

impl<'a> Eq for Value<'a>

impl<'a> FromCbor<'a> for Value<'a>

fn read<R: Read<'a>>(reader: &mut R) -> Result<Self>

Reads the CBOR representation of this value from the provided reader.

impl<'a> Ord for Value<'a>

fn cmp(&self, other: &Self) -> Ordering

The order RFC 8949 Section 4.2.1 defines for map keys: bytewise over their deterministic encodings.

A BTreeMap iterates in this order, so a map of values comes out deterministic with no sorting at write time. Heads go first, which settles major type and float width without walking contents; equal heads mean the same shape, since CBOR is self-delimiting, so the rest is content.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl<'a> PartialEq for Value<'a>

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

A NaN equals itself here, unlike the f64 it rides in.

A CBOR NaN has no payload a decoder must keep: RFC 8949 Section 4.1 names one encoding and Section 4.2.1 requires it. Leaving the derived comparison would make Eq unsound and a BTreeMap<Value, _> would treat each NaN as a fresh key.

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

Inequality operator !=.

impl<'a> PartialOrd for Value<'a>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a> ToCbor for Value<'a>

fn write<W: Write>(&self, writer: &mut W) -> Result<()>

Writes the CBOR representation of this value into the provided writer.

fn size_hint(&self) -> Option<TrustedSizeHint>

Returns a trusted upper bound on the bytes the next Self::write will write, or None if it cannot be had cheaply.

fn write_slice<W: Write>(values: &[Self], writer: &mut W) -> Result<()>

where Self: Sized,

Writes the CBOR representation of a slice of values into the provided writer.

fn max_size() -> Option<TrustedSizeHint>

where Self: Sized,

Returns a trusted upper bound valid for every value of this type, for O(1) hints on runtime-sized homogeneous containers.