Merge pull request #23 from vlayer-xyz/main

Refactor: extract memcpy function
aragonzkresearch · Mar 14, 2024 · 050d26a · 050d26a
2 parents 7375596 + ec7fb16
commit 050d26a
Showing 1 changed file with 27 additions and 16 deletions.
diff --git a/lib/src/lib.nr b/lib/src/lib.nr
@@ -89,10 +89,7 @@ impl<PROOF_LEN, MAX_VALUE_LEN> TrieProof<32, PROOF_LEN, MAX_VALUE_LEN>
             let k = if (in_range) {i} else {0}; // Restrict index to range {0, ..., depth - 2}
 
             // Populate node array
-	        for j in 0..MAX_TRIE_NODE_LENGTH
-	        {
-		        node[j] = path[j + k*MAX_TRIE_NODE_LENGTH];
-	        }
+            memcpy(&mut node, path, k*MAX_TRIE_NODE_LENGTH);
 
             assert(!in_range | verify_node_hash(node, extracted_hash), "Middle node hash does not match the hash extracted from the preceding node"); // If within range, node hash should match the hash extracted from the preceding node.
 
@@ -105,10 +102,7 @@ impl<PROOF_LEN, MAX_VALUE_LEN> TrieProof<32, PROOF_LEN, MAX_VALUE_LEN>
         }
 
         // Treat final node as the preceding nodes...
-        for j in 0..MAX_TRIE_NODE_LENGTH
-	    {
-		    node[j] = path[j + (depth - 1)*MAX_TRIE_NODE_LENGTH];
-	    }
+        memcpy(&mut node, path, (depth - 1)*MAX_TRIE_NODE_LENGTH);
 
         assert(verify_node_hash(node, extracted_hash), "Terminal node hash does not match the hash extracted from the preceding node");
 
@@ -176,10 +170,7 @@ impl<PROOF_LEN, MAX_VALUE_LEN> TrieProof<20, PROOF_LEN, MAX_VALUE_LEN>
             let k = if (in_range) {i} else {0}; // Restrict index to range {0, ..., depth - 2}
 
             // Populate node array
-	        for j in 0..MAX_TRIE_NODE_LENGTH
-	        {
-		        node[j] = path[j + k*MAX_TRIE_NODE_LENGTH];
-	        }
+            memcpy(&mut node, path, k*MAX_TRIE_NODE_LENGTH);
 
             assert(!in_range | verify_node_hash(node, extracted_hash)); // If within range, node hash should match the hash extracted from the preceding node.
 
@@ -191,10 +182,7 @@ impl<PROOF_LEN, MAX_VALUE_LEN> TrieProof<20, PROOF_LEN, MAX_VALUE_LEN>
         }
 
         // Treat final node as the preceding nodes...
-        for j in 0..MAX_TRIE_NODE_LENGTH
-	    {
-		    node[j] = path[j + (depth - 1)*MAX_TRIE_NODE_LENGTH];
-	    }
+        memcpy(&mut node, path, (depth - 1)*MAX_TRIE_NODE_LENGTH);
 
         assert(verify_node_hash(node, extracted_hash));
 
@@ -225,6 +213,20 @@ impl<PROOF_LEN, MAX_VALUE_LEN> TrieProof<20, PROOF_LEN, MAX_VALUE_LEN>
     }
 }
 
+/// Fills destination array with content of source array starting from the starting position.
+///
+/// # Arguments
+/// * `dest` - Destination array
+/// * `src` - Source array
+/// * `start_pos` - Starting position in source array 
+fn memcpy<N, M>(dest: &mut [u8; N], src: [u8; M], start_pos: u64)
+{
+    for i in 0..N
+    {
+        (*dest)[i] = src[start_pos + i];
+    }
+}
+
 /// Trie node hash verifier. Returns true if the node has the specified keccak256 hash.
 ///
 /// # Arguments
@@ -541,6 +543,15 @@ fn left_byte_shift<N>(input: [u8; N], n: u64) -> [u8; N]
     out
 }
 
+#[test]
+fn memcpy_test()
+{
+    let mut dest = [0; 10];
+    let src = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
+    memcpy(&mut dest, src, 5);
+    assert(dest == [6,7,8,9,10,11,12,13,14,15]);
+}
+
 #[test]
 fn byte_value_test()
 {