feat: create common types (trie key, value, stem)

portal-verkle-trie/src/lib.rs

@@ -1,4 +1,5 @@
 // TODO: revisit visibility
 pub mod constants;
 pub mod msm;
+pub mod types;
 pub mod utils;

portal-verkle-trie/src/types/mod.rs

@@ -0,0 +1,7 @@
+mod stem;
+mod trie_key;
+mod trie_value;
+
+pub use stem::Stem;
+pub use trie_key::TrieKey;
+pub use trie_value::TrieValue;

portal-verkle-trie/src/types/stem.rs

@@ -0,0 +1,63 @@
+use derive_more::{AsRef, Deref, From, Index};
+use ssz::{Decode, Encode};
+
+use super::trie_key::TrieKey;
+
+#[derive(PartialEq, Eq, AsRef, Deref, From, Index)]
+pub struct Stem([u8; Self::STEM_LENGTH]);
+
+impl Stem {
+    pub const STEM_LENGTH: usize = 31;
+}
+
+impl From<&TrieKey> for Stem {
+    fn from(key: &TrieKey) -> Self {
+        let mut stem = [0u8; Self::STEM_LENGTH];
+        stem.copy_from_slice(&key[..Self::STEM_LENGTH]);
+        Stem(stem)
+    }
+}
+
+impl From<TrieKey> for Stem {
+    fn from(key: TrieKey) -> Self {
+        Self::from(&key)
+    }
+}
+
+impl Encode for Stem {
+    fn is_ssz_fixed_len() -> bool {
+        true
+    }
+
+    fn ssz_fixed_len() -> usize {
+        Self::STEM_LENGTH
+    }
+
+    fn ssz_append(&self, buf: &mut Vec<u8>) {
+        buf.extend(self.as_slice())
+    }
+
+    fn ssz_bytes_len(&self) -> usize {
+        self.len()
+    }
+}
+
+impl Decode for Stem {
+    fn is_ssz_fixed_len() -> bool {
+        true
+    }
+
+    fn ssz_fixed_len() -> usize {
+        Self::STEM_LENGTH
+    }
+
+    fn from_ssz_bytes(bytes: &[u8]) -> Result<Self, ssz::DecodeError> {
+        match <[u8; 31]>::try_from(bytes) {
+            Ok(stem) => Ok(Self(stem)),
+            Err(_) => Err(ssz::DecodeError::InvalidByteLength {
+                len: bytes.len(),
+                expected: Self::STEM_LENGTH,
+            }),
+        }
+    }
+}

portal-verkle-trie/src/types/trie_key.rs

@@ -0,0 +1,27 @@
+use alloy_primitives::B256;
+use derive_more::{Constructor, Deref, From, Index};
+
+use super::stem::Stem;
+
+#[derive(PartialEq, Eq, Clone, Copy, Constructor, Index, Deref, From)]
+pub struct TrieKey(B256);
+
+impl TrieKey {
+    pub fn from_stem_and_last_byte(stem: &Stem, suffix: u8) -> Self {
+        let mut key = B256::right_padding_from(stem.as_slice());
+        key[B256::len_bytes() - 1] = suffix;
+        key.into()
+    }
+
+    pub fn len_bytes() -> usize {
+        B256::len_bytes()
+    }
+
+    pub fn stem(&self) -> Stem {
+        self.into()
+    }
+
+    pub fn suffix(&self) -> u8 {
+        self[self.len() - 1]
+    }
+}

portal-verkle-trie/src/types/trie_value.rs

@@ -0,0 +1,5 @@
+use alloy_primitives::B256;
+use derive_more::{Constructor, Deref, From, Index};
+
+#[derive(PartialEq, Eq, Clone, Copy, Constructor, Index, Deref, From)]
+pub struct TrieValue(B256);