Add pub const fn new to Address

core/src/address.rs

@@ -1,6 +1,6 @@
 //! Better address representation for Casper.
-use crate::prelude::*;
 use crate::AddressError::ZeroAddress;
+use crate::{prelude::*, utils, ExecutionError, OdraResult};
 use crate::{AddressError, OdraError, VmError};
 use casper_types::{
     account::AccountHash,
@@ -9,6 +9,14 @@ use casper_types::{
 };
 use serde::{Deserialize, Serialize};
 
+const ADDRESS_HASH_LENGTH: usize = 64;
+/// An address has format `hash-<64-byte-hash>`.
+const CONTRACT_STR_LENGTH: usize = 69;
+/// An address has format `contract-package-wasm<64-byte-hash>`.
+const LEGACY_CONTRACT_STR_LENGTH: usize = 85;
+/// An address has format `account-hash-<64-byte-hash>`.
+const ACCOUNT_STR_LENGTH: usize = 77;
+
 /// An enum representing an [`AccountHash`] or a [`ContractPackageHash`].
 #[derive(PartialOrd, Ord, PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub enum Address {
@@ -19,6 +27,35 @@ pub enum Address {
 }
 
 impl Address {
+    /// Creates a new `Address` from a hex-encoded string.
+    pub const fn new(input: &'static str) -> OdraResult<Self> {
+        let src: &[u8] = input.as_bytes();
+        let src_len: usize = src.len();
+
+        // fail fast if the input is too short
+        if src_len < ADDRESS_HASH_LENGTH {
+            return Err(OdraError::ExecutionError(
+                ExecutionError::AddressCreationFailed
+            ));
+        }
+        // skip the prefix, process the last 64 bytes
+        if let Ok(dst) = utils::decode_hex_32(src, src_len - ADDRESS_HASH_LENGTH) {
+            // depending on the length of the input, we can determine the type of address
+            match src_len {
+                LEGACY_CONTRACT_STR_LENGTH => Ok(Self::Contract(ContractPackageHash::new(dst))),
+                ACCOUNT_STR_LENGTH => Ok(Self::Account(AccountHash::new(dst))),
+                CONTRACT_STR_LENGTH => Ok(Self::Contract(ContractPackageHash::new(dst))),
+                _ => Err(OdraError::ExecutionError(
+                    ExecutionError::AddressCreationFailed
+                ))
+            }
+        } else {
+            Err(OdraError::ExecutionError(
+                ExecutionError::AddressCreationFailed
+            ))
+        }
+    }
+
     /// Returns the inner account hash if `self` is the `Account` variant.
     pub fn as_account_hash(&self) -> Option<&AccountHash> {
         if let Self::Account(v) = self {
@@ -202,6 +239,20 @@ mod tests {
         ContractPackageHash::from_formatted_str(CONTRACT_PACKAGE_HASH).unwrap()
     }
 
+    #[test]
+    fn test_casper_address_new() {
+        let address = Address::new(CONTRACT_PACKAGE_HASH).unwrap();
+        assert!(address.is_contract());
+        assert_eq!(
+            address.as_contract_package_hash().unwrap(),
+            &mock_contract_package_hash()
+        );
+
+        let address = Address::new(ACCOUNT_HASH).unwrap();
+        assert!(!address.is_contract());
+        assert_eq!(address.as_account_hash().unwrap(), &mock_account_hash());
+    }
+
     #[test]
     fn test_casper_address_account_hash_conversion() {
         let account_hash = mock_account_hash();

core/src/utils.rs

@@ -106,6 +106,39 @@ pub fn hex_to_slice(src: &[u8], dst: &mut [u8]) {
     }
 }
 
+pub(crate) const fn decode_hex_32(input: &[u8], start: usize) -> Result<[u8; 32], &'static str> {
+    let mut output = [0u8; 32];
+    let mut i = 0;
+    let mut j = 0;
+
+    while i < 64 {
+        let high_value = match hex_char_to_value(input[start + i]) {
+            Ok(v) => v,
+            Err(e) => return Err(e)
+        };
+
+        let low_value = match hex_char_to_value(input[start + i + 1]) {
+            Ok(v) => v,
+            Err(e) => return Err(e)
+        };
+
+        output[j] = (high_value << 4) | low_value;
+        i += 2;
+        j += 1;
+    }
+
+    Ok(output)
+}
+
+const fn hex_char_to_value(c: u8) -> Result<u8, &'static str> {
+    match c {
+        b'0'..=b'9' => Ok(c - b'0'),
+        b'a'..=b'f' => Ok(c - b'a' + 10),
+        b'A'..=b'F' => Ok(c - b'A' + 10),
+        _ => Err("Invalid character in input")
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::event_absolute_position;