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use super::engine_error;
use crate::specification::engines::AbstractEngine;
use crate::specification::entities::PlaintextEntity;
engine_error! {
PlaintextDiscardingRetrievalError for PlaintextDiscardingRetrievalEngine @
}
/// A trait for engines retrieving (discarding) arbitrary values from plaintexts.
///
/// # Semantics
///
/// This [discarding](super#operation-semantics) operation fills the `output` arbitrary value with
/// the retrieval of the `input` plaintext value. By arbitrary here, we mean that `Value` can be any
/// type that suits the backend implementor (an integer, a struct wrapping integers, a struct
/// wrapping foreign data or any other thing).
///
/// # Formal Definition
pub trait PlaintextDiscardingRetrievalEngine<Plaintext, Value>: AbstractEngine
where
Plaintext: PlaintextEntity,
{
/// Retrieves an arbitrary value from a plaintext inplace.
fn discard_retrieve_plaintext(
&mut self,
output: &mut Value,
input: &Plaintext,
) -> Result<(), PlaintextDiscardingRetrievalError<Self::EngineError>>;
/// Unsafely retrieves an arbitrary value from a plaintext inplace.
///
/// # Safety
/// For the _general_ safety concerns regarding this operation, refer to the different variants
/// of [`PlaintextDiscardingRetrievalError`]. For safety concerns _specific_ to an engine, refer
/// to the implementer safety section.
unsafe fn discard_retrieve_plaintext_unchecked(
&mut self,
output: &mut Value,
input: &Plaintext,
);
}