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#![warn(missing_docs)]
use typenum::U32;
use generic_array::GenericArray;
use primitive_types::H256;
use digest::Digest;
use bm::{Backend, NoopBackend, Error, ValueOf};
mod basic;
mod fixed;
mod variable;
pub use fixed::{FixedVec, FixedVecRef, IntoVectorTree, FromVectorTree};
pub use variable::{VariableVec, VariableVecRef, FromListTree};
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct End(pub [u8; 32]);
impl Default for End {
fn default() -> Self {
Self([0; 32])
}
}
impl AsRef<[u8]> for End {
fn as_ref(&self) -> &[u8] {
&self.0
}
}
impl From<GenericArray<u8, typenum::U32>> for End {
fn from(array: GenericArray<u8, typenum::U32>) -> Self {
let mut ret = [0u8; 32];
ret.copy_from_slice(array.as_slice());
Self(ret)
}
}
impl Into<GenericArray<u8, typenum::U32>> for End {
fn into(self) -> GenericArray<u8, typenum::U32> {
GenericArray::from_exact_iter(self.0.into_iter().cloned()).expect("Size equals to U32; qed")
}
}
pub type Intermediate = GenericArray<u8, U32>;
pub trait IntoTree<DB: Backend<Intermediate=Intermediate, End=End>> {
fn into_tree(&self, db: &mut DB) -> Result<ValueOf<DB>, Error<DB::Error>>;
}
pub trait FromTree<DB: Backend<Intermediate=Intermediate, End=End>>: Sized {
fn from_tree(root: &ValueOf<DB>, db: &DB) -> Result<Self, Error<DB::Error>>;
}
pub trait Composite { }
impl<'a, T> Composite for FixedVecRef<'a, T> { }
impl<T> Composite for FixedVec<T> { }
impl<'a, T> Composite for VariableVecRef<'a, T> { }
impl<T> Composite for VariableVec<T> { }
impl Composite for H256 { }
pub fn tree_root<D, T>(value: &T) -> H256 where
T: IntoTree<NoopBackend<D, End>>,
D: Digest<OutputSize=U32>,
{
value.into_tree(&mut NoopBackend::new_with_inherited_empty())
.map(|ret| H256::from_slice(ret.as_ref()))
.expect("Noop backend never fails in set; qed")
}