Migrate slots to U256 (#328)

- Migrate slot library to U256
- Use 256 in ERC721Token & ERC20Token
- Implement From and Into for U256 type (Bytes32)
- Add from_field function for U256

ethereum/circuits/lib/src/uint256.nr

@@ -1,4 +1,7 @@
 use dep::std::ops::Add;
+use crate::misc::types::Bytes32;
+use crate::misc::bytes32::field_to_bytes32;
+use crate::misc::arrays::memcpy_up_to_length;
 
 global uint128_overflow_value = 340282366920938463463374607431768211456; // 2^128
 
@@ -19,6 +22,38 @@ impl U256 {
     fn one() -> Self {
         Self { high: U128::from_integer(0), low: U128::from_integer(1) }
     }
+
+    fn from_field(field: Field) -> Self {
+        U256::from(field_to_bytes32(field))
+    }
+}
+
+impl From<Bytes32> for U256 {
+    fn from(bytes: Bytes32) -> Self {
+        let mut high_bytes = [0; 16];
+        memcpy_up_to_length(&mut high_bytes, bytes, 16, 16);
+        let high = U128::from_le_bytes(high_bytes);
+
+        let mut low_bytes = [0; 16];
+        memcpy_up_to_length(&mut low_bytes, bytes, 0, 16);
+        let low = U128::from_le_bytes(low_bytes);
+
+        U256::new(high, low)
+    }
+}
+
+impl Into<Bytes32> for U256 {
+    fn into(self) -> Bytes32 {
+        let mut bytes = [0; 32];
+        memcpy_up_to_length(&mut bytes, self.low.to_le_bytes(), 0, 16);
+
+        let high_bytes = self.high.to_le_bytes();
+        for i in 0..16 {
+            bytes[i + 16] = high_bytes[i];
+        }
+
+        bytes
+    }
 }
 
 impl Eq for U256 {

ethereum/circuits/lib/src/uint256_test.nr

@@ -30,6 +30,64 @@ fn zero_and_one() {
     assert_eq(one.low, U128::one());
 }
 
+mod from_bytes32 {
+    use crate::uint256::U256;
+    global high = U128::from_integer(0x10000000000000000000000000000000);
+    global low = U128::zero();
+    global limit = U128::from_integer(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
+
+    global big_number = U256 { high, low };
+    global limit_u256 = U256 {high: limit, low:limit};
+
+    #[test]
+    fn zero() {
+        let bytes = [0x00; 32];
+        assert_eq(U256::from(bytes), U256::zero());
+    }
+
+    #[test]
+    fn success() {
+        let mut bytes = [0x00; 32];
+        bytes[31] = 0x10;
+        assert_eq(U256::from(bytes), big_number);
+    }
+
+    #[test]
+    fn u256_limit() {
+        let bytes = [0xff; 32];
+        assert_eq(U256::from(bytes), limit_u256);
+    }
+}
+
+mod into_bytes32 {
+    use crate::uint256::U256;
+    global high = U128::from_integer(0x10000000000000000000000000000000);
+    global low = U128::zero();
+    global limit = U128::from_integer(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
+
+    global big_number = U256 { high, low };
+    global limit_u256 = U256 {high: limit, low:limit};
+
+    #[test]
+    fn zero() {
+        let bytes = [0x00; 32];
+        assert_eq(U256::into(U256::zero()), bytes);
+    }
+
+    #[test]
+    fn success() {
+        let mut bytes = [0x00; 32];
+        bytes[31] = 0x10;
+        assert_eq(U256::into(big_number), bytes);
+    }
+
+    #[test]
+    fn u256_limit() {
+        let bytes = [0xff; 32];
+        assert_eq(U256::into(limit_u256), bytes);
+    }
+}
+
 #[test]
 fn eq() {
     assert_eq(big_number, big_number);
@@ -47,23 +105,32 @@ fn not_eq() {
     assert(big_number != big_number3);
 }
 
-#[test]
-fn sum() {
-    let sum = big_number + big_number;
+mod trait_add {
+    use crate::uint256::U256;
+    global high = U128::from_integer(0x10000000000000000000000000000000);
+    global low = U128::zero();
+    global limit = U128::from_integer(0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
 
-    assert_eq(sum, U256 { high: U128::from_integer(0x20000000000000000000000000000000), low });
-}
+    global big_number = U256 { high, low };
+    global limit_u256 = U256 {high: limit, low:limit};
 
-#[test]
-fn sum_with_carry() {
-    let big_number = U256 { high, low: limit };
-    let sum = big_number + U256::one();
+    #[test]
+    fn sum() {
+        let sum = big_number + big_number;
 
-    assert_eq(sum, U256 { high: U128::from_integer(0x10000000000000000000000000000001), low });
-}
+        assert_eq(sum, U256 { high: U128::from_integer(0x20000000000000000000000000000000), low });
+    }
+
+    #[test]
+    fn sum_with_carry() {
+        let big_number = U256 { high, low: limit };
+        let sum = big_number + U256::one();
+
+        assert_eq(sum, U256 { high: U128::from_integer(0x10000000000000000000000000000001), low });
+    }
 
-#[test(should_fail_with="attempt to add with overflow")]
-fn sum_overflow() {
-    let limit_number = U256 { high: limit, low: limit };
-    let _ = limit_number + U256::one();
+    #[test(should_fail_with="attempt to add with overflow")]
+    fn sum_overflow() {
+        let _ = limit_u256 + U256::one();
+    }
 }

vlayer/ethereum/circuits/lib/src/nft.nr

@@ -1,11 +1,12 @@
 use dep::ethereum::{
     account_with_storage::get_account_with_storage,
-    misc::types::{Address, Bytes32, ADDRESS_LENGTH, BYTES32_LENGTH}, misc::arrays::subarray_inferred_len
+    misc::{types::{Address, Bytes32, ADDRESS_LENGTH, BYTES32_LENGTH}, arrays::subarray_inferred_len},
+    uint256::U256
 };
 
 struct ERC721Token {
     address: Address,
-    token_id_to_slot: fn (Bytes32) -> Bytes32,
+    token_id_to_slot: fn (Bytes32) -> U256,
     chain_id: Field
 }
 
@@ -16,7 +17,7 @@ trait ERC721 {
 impl ERC721 for ERC721Token {
     fn get_owner(self, token_id: Bytes32, block_number: u64) -> Address {
         let storage_key = (self.token_id_to_slot)(token_id);
-        let account = get_account_with_storage(self.chain_id, block_number, self.address, storage_key);
+        let account = get_account_with_storage(self.chain_id, block_number, self.address, U256::into(storage_key));
         subarray_inferred_len(account.values[0], BYTES32_LENGTH - ADDRESS_LENGTH)
     }
 }

vlayer/ethereum/circuits/lib/src/nft_list.nr

@@ -3,7 +3,7 @@ mod mainnet {
     use crate::chain_id;
     use crate::slot::{struct_slot, dynamic_array_with_precalculated_slot, mapping};
     use dep::std::field::bytes32_to_field;
-    use dep::ethereum::misc::{types::Bytes32, bytes32::field_to_bytes32};
+    use dep::ethereum::{misc::{types::Bytes32, bytes32::field_to_bytes32}, uint256::U256};
 
     pub fn BORED_APE_YACHT_CLUB() -> ERC721Token {
         ERC721Token {
@@ -12,9 +12,9 @@ mod mainnet {
             ],
             token_id_to_slot: |token_id| {
                 let BORED_APE_YACHT_CLUB_MAX_TOKEN_ID: u64 = 9999;
-                let BORED_APE_YACHT_CLUB_TOKEN_OWNERS_INNER_ENTRIES_SLOT = [
+                let BORED_APE_YACHT_CLUB_TOKEN_OWNERS_INNER_ENTRIES_SLOT = U256::from([
                     0x40, 0x57, 0x87, 0xfa, 0x12, 0xa8, 0x23, 0xe0, 0xf2, 0xb7, 0x63, 0x1c, 0xc4, 0x1b, 0x3b, 0xa8, 0x82, 0x8b, 0x33, 0x21, 0xca, 0x81, 0x11, 0x11, 0xfa, 0x75, 0xcd, 0x3a, 0xa3, 0xbb, 0x5a, 0xce
-                ];
+                ]);
                 let VALUE_INDEX = 1;
 
                 assert(bytes32_to_field(token_id) as u64 <= BORED_APE_YACHT_CLUB_MAX_TOKEN_ID, "Token ID is too high");
@@ -32,7 +32,7 @@ mod mainnet {
             ],
             token_id_to_slot: |token_id| {
                 let CRYPTO_PUNK_MAX_TOKEN_ID: u64 = 9999;
-                let CRYPTO_PUNK_TOKEN_OWNERS_INNER_ENTRIES_SLOT = field_to_bytes32(10);
+                let CRYPTO_PUNK_TOKEN_OWNERS_INNER_ENTRIES_SLOT = U256::from_field(10);
 
                 assert(bytes32_to_field(token_id) as u64 <= CRYPTO_PUNK_MAX_TOKEN_ID, "Token ID is too high");
                 mapping(CRYPTO_PUNK_TOKEN_OWNERS_INNER_ENTRIES_SLOT, token_id)
@@ -47,7 +47,7 @@ mod sepolia {
     use crate::chain_id;
     use crate::slot::{struct_slot, dynamic_array_with_precalculated_slot};
     use dep::std::field::bytes32_to_field;
-    use dep::ethereum::misc::{types::Bytes32, bytes32::field_to_bytes32};
+    use dep::ethereum::{misc::{types::Bytes32, bytes32::field_to_bytes32}, uint256::U256};
 
     // free mint: https://sepolia.etherscan.io/address/0x80d97726548fedae6ad7cf8df4f2b514fd24afba#readContract
     fn FAKE_BORED_APE_YACHT_CLUB() -> ERC721Token {
@@ -57,9 +57,9 @@ mod sepolia {
             ],
             token_id_to_slot: |token_id| {
             let BORED_APE_YACHT_CLUB_MAX_TOKEN_ID: u64 = 9999;
-            let BORED_APE_YACHT_CLUB_TOKEN_OWNERS_INNER_ENTRIES_SLOT = [
+            let BORED_APE_YACHT_CLUB_TOKEN_OWNERS_INNER_ENTRIES_SLOT = U256::from([
                 0x40, 0x57, 0x87, 0xfa, 0x12, 0xa8, 0x23, 0xe0, 0xf2, 0xb7, 0x63, 0x1c, 0xc4, 0x1b, 0x3b, 0xa8, 0x82, 0x8b, 0x33, 0x21, 0xca, 0x81, 0x11, 0x11, 0xfa, 0x75, 0xcd, 0x3a, 0xa3, 0xbb, 0x5a, 0xce
-            ];
+            ]);
             let VALUE_INDEX = 1;
 
             assert(bytes32_to_field(token_id) as u64 <= BORED_APE_YACHT_CLUB_MAX_TOKEN_ID, "Token ID is too high");

vlayer/ethereum/circuits/lib/src/slot.nr

@@ -1,27 +1,25 @@
-use dep::ethereum::misc::{
-    types::{Address, Bytes32, ADDRESS_LENGTH, BYTES32_LENGTH}, bytes32::field_to_bytes32,
-    bytes::add_bigint
-};
+use dep::ethereum::misc::types::Bytes32;
 use dep::std::hash::keccak256;
+use dep::ethereum::uint256::U256;
 
 global STORAGE_KEY_HASH_INPUT_LENGTH = 64;
 
-pub(crate) fn mapping(slot: Bytes32, key: Bytes32) -> Bytes32 {
+pub(crate) fn mapping(slot: U256, key: Bytes32) -> U256 {
     let mut vector: BoundedVec<u8, STORAGE_KEY_HASH_INPUT_LENGTH> = BoundedVec::new();
     vector.extend_from_array(key);
-    vector.extend_from_array(slot);
-    keccak256(vector.storage(), STORAGE_KEY_HASH_INPUT_LENGTH)
+    vector.extend_from_array(U256::into(slot));
+    U256::from(keccak256(vector.storage(), STORAGE_KEY_HASH_INPUT_LENGTH))
 }
 
-pub(crate) fn dynamic_array(slot: Bytes32, size: Field, index: Field) -> Bytes32 {
-    let start = keccak256(slot, 32);
+pub(crate) fn dynamic_array(slot: U256, size: Field, index: Field) -> U256 {
+    let start: U256 = U256::from(keccak256(U256::into(slot), 32));
     dynamic_array_with_precalculated_slot(start, size, index)
 }
 
-pub(crate) fn dynamic_array_with_precalculated_slot(slot: Bytes32, size: Field, index: Field) -> Bytes32 {
-    add_bigint(slot, field_to_bytes32(size * index))
+pub(crate) fn dynamic_array_with_precalculated_slot(slot: U256, size: Field, index: Field) -> U256 {
+    slot + U256::from_field(size * index)
 }
 
-pub(crate) fn struct_slot(slot: Bytes32, offset: Field) -> Bytes32 {
-    add_bigint(slot, field_to_bytes32(offset))
+pub(crate) fn struct_slot(slot: U256, offset: Field) -> U256 {
+    slot + U256::from_field(offset)
 }