Simplifies keccak256 on calldata buffers.

wormhole-foundation · Dec 30, 2024 · 2630b92 · 2630b92
1 parent 2c80b61
commit 2630b92
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Showing 2 changed files with 22 additions and 15 deletions.
diff --git a/src/Utils.sol b/src/Utils.sol
@@ -67,17 +67,15 @@ function keccak256SliceUnchecked(
   }
 }
 
-function keccak256SliceCdUnchecked(
-  bytes calldata encoded,
-  uint offset,
-  uint length
+function keccak256Cd(
+  bytes calldata encoded
 ) pure returns (bytes32 hash) {
   /// @solidity memory-safe-assembly
   assembly {
     let freeMemory := mload(FREE_MEMORY_PTR)
 
-    let sliceStart := add(encoded.offset, offset)
-    calldatacopy(freeMemory, sliceStart, length)
+    let length := encoded.length
+    calldatacopy(freeMemory, encoded.offset, length)
 
     hash := keccak256(freeMemory, length)
   }

diff --git a/test/Keccak.t.sol b/test/Keccak.t.sol
@@ -5,15 +5,15 @@
 pragma solidity ^0.8.0;
 
 import "forge-std/Test.sol";
-import { keccak256Word, keccak256SliceUnchecked, keccak256SliceCdUnchecked } from "../src/Utils.sol";
+import { keccak256Word, keccak256SliceUnchecked, keccak256Cd } from "../src/Utils.sol";
 
 contract TestKeccak is Test {
   using { keccak256Word } for bytes32;
-  using { keccak256SliceUnchecked, keccak256SliceCdUnchecked } for bytes;
+  using { keccak256SliceUnchecked } for bytes;
 
   function test_bytesShouldHashTheSame(bytes calldata data) public {
     bytes32 hash = data.keccak256SliceUnchecked(0, data.length);
-    bytes32 hashCd = data.keccak256SliceCdUnchecked(0, data.length);
+    bytes32 hashCd = keccak256Cd(data);
     bytes32 expectedHash = keccak256(abi.encodePacked(data));
     assertEq(hash, expectedHash);
     assertEq(hashCd, expectedHash);
@@ -22,19 +22,25 @@ contract TestKeccak is Test {
   function test_bytesSubArrayEndShouldHashTheSame(bytes calldata data, uint seed) public {
     vm.assume(data.length > 0);
     uint length = seed % data.length;
+    bytes calldata slice = data[0 : length];
+
     bytes32 hash = data.keccak256SliceUnchecked(0, length);
-    bytes32 hashCd = data.keccak256SliceCdUnchecked(0, length);
-    bytes32 expectedHash = keccak256(abi.encodePacked(data[0:length]));
+    bytes32 hashCd = keccak256Cd(slice);
+
+    bytes32 expectedHash = keccak256(abi.encodePacked(slice));
     assertEq(hash, expectedHash);
     assertEq(hashCd, expectedHash);
   }
 
   function test_bytesSubArrayStartShouldHashTheSame(bytes calldata data, uint seed) public {
     vm.assume(data.length > 0);
     uint start = seed % data.length;
+    bytes calldata slice = data[start : data.length];
+
     bytes32 hash = data.keccak256SliceUnchecked(start, data.length - start);
-    bytes32 hashCd = data.keccak256SliceCdUnchecked(start, data.length - start);
-    bytes32 expectedHash = keccak256(abi.encodePacked(data[start:data.length]));
+    bytes32 hashCd = keccak256Cd(slice);
+
+    bytes32 expectedHash = keccak256(abi.encodePacked(slice));
     assertEq(hash, expectedHash);
     assertEq(hashCd, expectedHash);
   }
@@ -43,9 +49,12 @@ contract TestKeccak is Test {
     vm.assume(data.length > 0);
     uint end = bound(seed, 1, data.length);
     uint start = uint(keccak256(abi.encodePacked(seed))) % end;
+    bytes calldata slice = data[start : end];
+
     bytes32 hash = data.keccak256SliceUnchecked(start, end - start);
-    bytes32 hashCd = data.keccak256SliceCdUnchecked(start, end - start);
-    bytes32 expectedHash = keccak256(abi.encodePacked(data[start:end]));
+    bytes32 hashCd = keccak256Cd(slice);
+
+    bytes32 expectedHash = keccak256(abi.encodePacked(slice));
     assertEq(hash, expectedHash);
     assertEq(hashCd, expectedHash);
   }