Struct Witness 

pub struct Witness { /* private fields */ }

The Witness is the data used to unlock bitcoin since the SegWit upgrade.

Can be logically seen as an array of bytestrings, i.e. Vec<Vec<u8>>, and it is serialized on the wire in that format. You can convert between this type and Vec<Vec<u8>> by using Witness::from_slice and Witness::to_vec.

For serialization and deserialization performance it is stored internally as a single Vec, saving some allocations.

Implementations

impl Witness

pub const fn new() -> Self

Constructs a new empty Witness.

pub fn from_slice<T: AsRef<[u8]>>(slice: &[T]) -> Self

Constructs a new Witness object from a slice of bytes slices where each slice is a witness item.

pub fn to_vec(&self) -> Vec<Vec<u8>>

Convenience method to create an array of byte-arrays from this witness.

pub fn is_empty(&self) -> bool

Returns true if the witness contains no element.

pub fn iter(&self) -> Iter<'_>

Returns a struct implementing Iterator.

pub const fn len(&self) -> usize

Returns the number of elements this witness holds.

pub fn size(&self) -> usize

Returns the number of bytes this witness contributes to a transaction’s total size.

Panics

If the size calculation overflows.

pub fn clear(&mut self)

Clears the witness.

pub fn push<T: AsRef<[u8]>>(&mut self, new_element: T)

Pushes a new element on the witness, requires an allocation.

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

Returns the last element in the witness, if any.

pub fn get_back(&self, index: usize) -> Option<&[u8]>

Retrieves an element from the end of the witness by its reverse index.

index is 0-based from the end, where 0 is the last element, 1 is the second-to-last, etc.

Returns None if the requested index is beyond the witness’s elements.

Examples

use bitcoin_primitives::witness::Witness;

let mut witness = Witness::new();
witness.push(b"A");
witness.push(b"B");
witness.push(b"C");
witness.push(b"D");

assert_eq!(witness.get_back(0), Some(b"D".as_slice()));
assert_eq!(witness.get_back(1), Some(b"C".as_slice()));
assert_eq!(witness.get_back(2), Some(b"B".as_slice()));
assert_eq!(witness.get_back(3), Some(b"A".as_slice()));
assert_eq!(witness.get_back(4), None);

pub fn get(&self, index: usize) -> Option<&[u8]>

Returns a specific element from the witness by its index, if any.

pub fn from_hex<I, T>(iter: I) -> Result<Self, DecodeVariableLengthBytesError>

where I: IntoIterator<Item = T>, T: AsRef<str>,

Constructs a new witness from a list of hex strings.

Errors

This function will return an error if any of the hex strings are invalid.

Trait Implementations

impl<'a> Arbitrary<'a> for Witness

Available on crate feature arbitrary only.

fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'a>) -> Result<Self, Error>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

fn try_size_hint( depth: usize, ) -> Result<(usize, Option<usize>), MaxRecursionReached>

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Clone for Witness

fn clone(&self) -> Witness

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Witness

Debug implementation that displays the witness as a structured output containing:

• Number of witness elements
• Total bytes across all elements
• List of hex-encoded witness elements if hex feature is enabled.

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

Formats the value using the given formatter.

impl Decode for Witness

type Decoder = WitnessDecoder

Associated decoder for the type.

fn decoder() -> Self::Decoder

Constructs a “default decoder” for the type.

impl Default for Witness

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Witness

Available on crate feature serde only.

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Encode for Witness

type Encoder<'e> = WitnessEncoder<'e> where Self: 'e

The encoder associated with this type. Conceptually, the encoder is like an iterator which yields byte slices.

fn encoder(&self) -> Self::Encoder<'_>

Constructs a “default encoder” for the type.

impl Eq for Witness

impl<const N: usize, const M: usize> From<&[&[u8; M]; N]> for Witness

fn from(slice: &[&[u8; M]; N]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<&[&[u8; N]]> for Witness

fn from(slice: &[&[u8; N]]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<&[&[u8]; N]> for Witness

fn from(arr: &[&[u8]; N]) -> Self

Converts to this type from the input type.

impl From<&[&[u8]]> for Witness

fn from(slice: &[&[u8]]) -> Self

Converts to this type from the input type.

impl From<&[Vec<u8>]> for Witness

fn from(slice: &[Vec<u8>]) -> Self

Converts to this type from the input type.

impl<const N: usize, const M: usize> From<&[[u8; M]; N]> for Witness

fn from(slice: &[[u8; M]; N]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<&[[u8; N]]> for Witness

fn from(slice: &[[u8; N]]) -> Self

Converts to this type from the input type.

impl From<Vec<&[u8]>> for Witness

fn from(vec: Vec<&[u8]>) -> Self

Converts to this type from the input type.

impl From<Vec<Vec<u8>>> for Witness

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

Converts to this type from the input type.

impl<const N: usize, const M: usize> From<[&[u8; M]; N]> for Witness

fn from(slice: [&[u8; M]; N]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<[&[u8]; N]> for Witness

fn from(arr: [&[u8]; N]) -> Self

Converts to this type from the input type.

impl<const N: usize, const M: usize> From<[[u8; M]; N]> for Witness

fn from(slice: [[u8; M]; N]) -> Self

Converts to this type from the input type.

impl<T: AsRef<[u8]>> FromIterator<T> for Witness

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self

Creates a value from an iterator.

impl Hash for Witness

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 Index<usize> for Witness

type Output = [u8]

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'a> IntoIterator for &'a Witness

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

type Item = &'a [u8]

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl LowerHex for Witness

Available on crate feature hex only.

Formats the witness as a hex string using its consensus encoding.

This is the compact size encoded number of elements followed by each element prefixed with its compact size encoded length.

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

Formats the value using the given formatter.

impl Ord for Witness

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

This method returns an Ordering between self and other.

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.

impl PartialEq for Witness

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

Equality operator ==.

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

Inequality operator !=.

impl<const N: usize, T: Borrow<[u8]>> PartialEq<&[T; N]> for Witness

fn eq(&self, rhs: &&[T; N]) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<&[T]> for Witness

fn eq(&self, rhs: &&[T]) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Arc<[T]>> for Witness

Available on target_has_atomic=ptr only.

fn eq(&self, rhs: &Arc<[T]>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Box<[T]>> for Witness

fn eq(&self, rhs: &Box<[T]>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Rc<[T]>> for Witness

fn eq(&self, rhs: &Rc<[T]>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Vec<T>> for Witness

fn eq(&self, rhs: &Vec<T>) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for [T]

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for &[T]

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<const N: usize, T: Borrow<[u8]>> PartialEq<Witness> for [T; N]

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<const N: usize, T: Borrow<[u8]>> PartialEq<Witness> for &[T; N]

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for Vec<T>

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for Box<[T]>

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for Rc<[T]>

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<Witness> for Arc<[T]>

Available on target_has_atomic=ptr only.

fn eq(&self, rhs: &Witness) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<const N: usize, T: Borrow<[u8]>> PartialEq<[T; N]> for Witness

fn eq(&self, rhs: &[T; N]) -> bool

Equality operator ==.

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

Inequality operator !=.

impl<T: Borrow<[u8]>> PartialEq<[T]> for Witness

fn eq(&self, rhs: &[T]) -> bool

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Witness

fn partial_cmp(&self, other: &Witness) -> 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 Serialize for Witness

Available on crate feature serde only.

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Witness

impl UpperHex for Witness

Available on crate feature hex only.

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

Formats the value using the given formatter.