feat: implement to_address (#292)

Close #289

---------

Co-authored-by: Clément Walter <clement0walter@gmail.com>

cairo/ethereum/cancun/utils/address.cairo

@@ -4,11 +4,42 @@ from starkware.cairo.common.cairo_builtins import BitwiseBuiltin, KeccakBuiltin
 from starkware.cairo.common.math_cmp import is_nn, is_not_zero
 
 from ethereum_types.bytes import Bytes32, Bytes, BytesStruct
-from ethereum_types.numeric import Uint
+from ethereum_types.numeric import Uint, UnionUintU256
 from ethereum.cancun.fork_types import Address
 from ethereum.crypto.hash import keccak256
 from ethereum.utils.numeric import divmod
-from src.utils.bytes import felt_to_bytes20_little, felt_to_bytes, uint256_to_bytes32_little
+
+from src.utils.bytes import (
+    felt_to_bytes20_little,
+    bytes_to_felt,
+    felt_to_bytes,
+    uint256_to_bytes32_little,
+)
+
+func to_address{range_check_ptr}(data: UnionUintU256) -> Address {
+    alloc_locals;
+    let (local bytes_data) = alloc();
+
+    if (cast(data.value.uint, felt) != 0) {
+        felt_to_bytes20_little(bytes_data, data.value.uint.value);
+        let res = bytes_to_felt(20, bytes_data);
+        tempvar address = Address(res);
+        return address;
+    }
+
+    if (cast(data.value.u256.value, felt) != 0) {
+        uint256_to_bytes32_little(bytes_data, [data.value.u256.value]);
+        let res = bytes_to_felt(20, bytes_data);
+        tempvar address = Address(res);
+        return address;
+    }
+
+    with_attr error_message("Type not valid") {
+        assert 0 = 1;
+        tempvar address = Address(0);
+        return address;
+    }
+}
 
 func compute_contract_address{
     range_check_ptr, bitwise_ptr: BitwiseBuiltin*, keccak_ptr: KeccakBuiltin*

cairo/ethereum_types/numeric.cairo

@@ -20,6 +20,15 @@ struct U256 {
     value: U256Struct*,
 }
 
+struct UnionUintU256Enum {
+    uint: Uint*,
+    u256: U256,
+}
+
+struct UnionUintU256 {
+    value: UnionUintU256Enum*,
+}
+
 struct SetUintDictAccess {
     key: Uint,
     prev_value: bool,

cairo/tests/ethereum/cancun/utils/test_address.py

@@ -1,15 +1,23 @@
+from typing import Union
+
 from ethereum_types.bytes import Bytes32
-from ethereum_types.numeric import Uint
+from ethereum_types.numeric import U256, Uint
 from hypothesis import given
 
 from ethereum.cancun.fork_types import Address
 from ethereum.cancun.utils.address import (
     compute_contract_address,
     compute_create2_contract_address,
+    to_address,
 )
 
 
 class TestAddress:
+
+    @given(data=...)
+    def test_to_address(self, cairo_run, data: Union[Uint, U256]):
+        assert to_address(data) == cairo_run("to_address", data)
+
     @given(address=..., nonce=...)
     def test_compute_contract_address(self, cairo_run, address: Address, nonce: Uint):
         assert compute_contract_address(address, nonce) == cairo_run(

cairo/tests/test_serde.py

@@ -168,6 +168,7 @@ def test_type(
             Tuple[Mapping[Bytes, Bytes], ...],
             Set[Uint],
             Mapping[Address, Account],
+            Union[Uint, U256],
             Set[Address],
         ],
     ):

cairo/tests/utils/args_gen.py

@@ -108,6 +108,7 @@
     ("ethereum_types", "numeric", "Uint"): Uint,
     ("ethereum_types", "numeric", "U256"): U256,
     ("ethereum_types", "numeric", "SetUint"): Set[Uint],
+    ("ethereum_types", "numeric", "UnionUintU256"): Union[Uint, U256],
     ("ethereum_types", "bytes", "Bytes0"): Bytes0,
     ("ethereum_types", "bytes", "Bytes8"): Bytes8,
     ("ethereum_types", "bytes", "Bytes20"): Bytes20,