Trait VariableOutput

pub trait VariableOutput: Sized + Update {
    const MAX_OUTPUT_SIZE: usize;

    // Required methods
    fn new(output_size: usize) -> Result<Self, InvalidOutputSize>;
    fn output_size(&self) -> usize;
    fn finalize_variable(self, out: &mut [u8]) -> Result<(), InvalidBufferSize>;

    // Provided methods
    fn digest_variable(
        input: impl AsRef<[u8]>,
        output: &mut [u8],
    ) -> Result<(), InvalidOutputSize> { ... }
    fn finalize_boxed(self) -> Box<[u8]> { ... }
}

Trait for hash functions with variable-size output.

Required Associated Constants

const MAX_OUTPUT_SIZE: usize

Maximum size of output hash.

Required Methods

fn new(output_size: usize) -> Result<Self, InvalidOutputSize>

Create new hasher instance with the given output size.

It will return Err(InvalidOutputSize) in case if hasher can not return hash of the specified output size.

fn output_size(&self) -> usize

Get output size of the hasher instance provided to the new method

fn finalize_variable(self, out: &mut [u8]) -> Result<(), InvalidBufferSize>

Write result into the output buffer.

Returns Err(InvalidOutputSize) if out size is not equal to self.output_size().

Provided Methods

fn digest_variable( input: impl AsRef<[u8]>, output: &mut [u8], ) -> Result<(), InvalidOutputSize>

Compute hash of data and write it to output.

Length of the output hash is determined by output. If output is bigger than Self::MAX_OUTPUT_SIZE, this method returns InvalidOutputSize.

fn finalize_boxed(self) -> Box<[u8]>

Retrieve result into a boxed slice and consume hasher.

Box<[u8]> is used instead of Vec<u8> to save stack space, since they have size of 2 and 3 words respectively.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> VariableOutput for RtVariableCoreWrapper<T>

where T: VariableOutputCore + UpdateCore, T::BlockSize: IsLess<U256>, Le<T::BlockSize, U256>: NonZero,

const MAX_OUTPUT_SIZE: usize = <T::OutputSize>::USIZE