Add runtime_types

Author: macladson

Cargo.toml

@@ -10,6 +10,11 @@ documentation = "https://docs.rs/ssz_types"
 keywords = ["ethereum"]
 categories = ["cryptography::cryptocurrencies"]
 
+[features]
+default = ["ring"]
+ring = ["tree_hash/ring"]
+runtime-types = ["dep:context_deserialize", "dep:educe"]
+
 [dependencies]
 tree_hash = { version = "0.11.0", default-features = false }
 ethereum_serde_utils = "0.8.0"
@@ -21,15 +26,15 @@ smallvec = "1.8.0"
 arbitrary = { version = "1.0", features = ["derive"], optional = true }
 itertools = "0.14.0"
 
+# Optional dependencies
+educe = { version = "0.6", optional = true }
+context_deserialize = { version = "0.1", optional = true }
+
 [dev-dependencies]
 criterion = "0.7.0"
 serde_json = "1.0.0"
 tree_hash_derive = "0.11.0"
 
-[features]
-default = ["ring"]
-ring = ["tree_hash/ring"]
-
 [[bench]]
 harness = false
 name = "encode_decode"

src/lib.rs

@@ -37,9 +37,13 @@
 //!
 //! ```
 
+pub mod serde_utils;
+pub mod length {
+    pub use ssz::{Fixed, Variable};
+}
+
 #[macro_use]
 mod fixed_vector;
-pub mod serde_utils;
 mod tree_hash;
 mod variable_list;
 
@@ -48,9 +52,11 @@ pub use ssz::{BitList, BitVector, Bitfield};
 pub use typenum;
 pub use variable_list::VariableList;
 
-pub mod length {
-    pub use ssz::{Fixed, Variable};
-}
+#[cfg(feature = "runtime-types")]
+mod runtime_types;
+
+#[cfg(feature = "runtime-types")]
+pub use runtime_types::{RuntimeFixedVector, RuntimeVariableList};
 
 /// Returned when an item encounters an error.
 #[derive(PartialEq, Debug, Clone)]

src/runtime_types/mod.rs

@@ -0,0 +1,5 @@
+mod runtime_fixed_vector;
+mod runtime_variable_list;
+
+pub use runtime_fixed_vector::RuntimeFixedVector;
+pub use runtime_variable_list::RuntimeVariableList;

src/runtime_types/runtime_fixed_vector.rs

@@ -0,0 +1,90 @@
+//! Emulates a fixed size array but with the length set at runtime.
+//!
+//! The length of the list cannot be changed once it is set.
+
+use std::fmt;
+use std::fmt::Debug;
+
+#[derive(Clone)]
+pub struct RuntimeFixedVector<T> {
+    vec: Vec<T>,
+    len: usize,
+}
+
+impl<T: Debug> Debug for RuntimeFixedVector<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?} (len={})", self.vec, self.len)
+    }
+}
+
+impl<T: Clone + Default> RuntimeFixedVector<T> {
+    pub fn new(vec: Vec<T>) -> Self {
+        let len = vec.len();
+        Self { vec, len }
+    }
+
+    pub fn to_vec(&self) -> Vec<T> {
+        self.vec.clone()
+    }
+
+    pub fn as_slice(&self) -> &[T] {
+        self.vec.as_slice()
+    }
+
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.len
+    }
+
+    pub fn into_vec(self) -> Vec<T> {
+        self.vec
+    }
+
+    pub fn default(max_len: usize) -> Self {
+        Self {
+            vec: vec![T::default(); max_len],
+            len: max_len,
+        }
+    }
+
+    pub fn take(&mut self) -> Self {
+        let new = std::mem::take(&mut self.vec);
+        *self = Self::new(vec![T::default(); self.len]);
+        Self {
+            vec: new,
+            len: self.len,
+        }
+    }
+}
+
+impl<T> std::ops::Deref for RuntimeFixedVector<T> {
+    type Target = [T];
+
+    fn deref(&self) -> &[T] {
+        &self.vec[..]
+    }
+}
+
+impl<T> std::ops::DerefMut for RuntimeFixedVector<T> {
+    fn deref_mut(&mut self) -> &mut [T] {
+        &mut self.vec[..]
+    }
+}
+
+impl<T> IntoIterator for RuntimeFixedVector<T> {
+    type Item = T;
+    type IntoIter = std::vec::IntoIter<T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.vec.into_iter()
+    }
+}
+
+impl<'a, T> IntoIterator for &'a RuntimeFixedVector<T> {
+    type Item = &'a T;
+    type IntoIter = std::slice::Iter<'a, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.vec.iter()
+    }
+}