Implement append_little_endian for felt252

HerodotusDev · Dec 29, 2023 · ba5982d · ba5982d
1 parent c02f915
commit ba5982d
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/src/channel/channel.cairo b/src/channel/channel.cairo
@@ -57,12 +57,11 @@ impl ChannelImpl of ChannelTrait {
     }
 
     fn read_felt_from_prover(ref self: Channel, value: felt252) {
-        let value_u256: u256 = value.into();
         let mut hash_data = ArrayTrait::<u32>::new();
 
         assert(self.digest.low != BoundedU128::max(), 'digest low is 2^128-1');
         hash_data.append_big_endian(self.digest + 1);
-        hash_data.append_big_endian(value_u256);
+        hash_data.append_big_endian(value);
 
         self.digest = blake2s(hash_data).flip_endianness();
         self.counter = 0;
@@ -84,8 +83,7 @@ impl ChannelImpl of ChannelTrait {
             if i == values.len() {
                 break;
             };
-            let value_u256: u256 = (*values[i] * MONTGOMERY_R).into();
-            hash_data.append_big_endian(value_u256);
+            hash_data.append_big_endian(*values[i] * MONTGOMERY_R);
             i += 1;
         };
 

diff --git a/src/common/array_append.cairo b/src/common/array_append.cairo
@@ -32,6 +32,18 @@ impl ArrayU32AppendU256 of ArrayAppendTrait<u32, u256> {
     }
 }
 
+impl ArrayU32AppendFelt of ArrayAppendTrait<u32, felt252> {
+    fn append_little_endian(ref self: Array<u32>, element: felt252) {
+        let as_u256: u256 = element.into();
+        self.append_little_endian(as_u256);
+    }
+
+    fn append_big_endian(ref self: Array<u32>, element: felt252) {
+        let as_u256: u256 = element.into();
+        self.append_big_endian(as_u256);
+    }
+}
+
 impl ArrayU32AppendU128 of ArrayAppendTrait<u32, u128> {
     fn append_little_endian(ref self: Array<u32>, mut element: u128) {
         let mut i = 4;