Avoid redundant copy; split into methods; add constants

NethermindEth · May 21, 2024 · 9e3b387 · 9e3b387
1 parent 704d932
commit 9e3b387
Showing 1 changed file with 28 additions and 21 deletions.
diff --git a/src/Nethermind/Nethermind.Optimism/OPL1CostHelper.cs b/src/Nethermind/Nethermind.Optimism/OPL1CostHelper.cs
@@ -35,44 +35,51 @@ public OPL1CostHelper(IOPConfigHelper opConfigHelper, Address l1BlockAddr)
         _baseFeeScalarSlot = new StorageCell(l1BlockAddr, new UInt256(3));
     }
 
+    private static readonly UInt256 basicDevider = 1_000_000;
+    private static readonly UInt256 precisionMultiplier = 16;
+    private static readonly UInt256 precisionDevider = precisionMultiplier * basicDevider;
+
     public UInt256 ComputeL1Cost(Transaction tx, BlockHeader header, IWorldState worldState)
     {
-        if (tx.IsDeposit())
-            return UInt256.Zero;
-
-        long dataGas = ComputeDataGas(tx, header);
-        if (dataGas == 0)
-            return UInt256.Zero;
-
-
-        if (_opConfigHelper.IsEcotone(header))
+        UInt256 ComputeL1CostEcotone(IWorldState worldState, UInt256 dataGas)
         {
-            // Ecotone formula: (dataGas) * (16*l1BaseFee*l1BaseFeeScalar + l1BlobBaseFee*l1BlobBaseFeeScalar) / 16e6
+            // Ecotone formula: (dataGas) * (16 * l1BaseFee * l1BaseFeeScalar + l1BlobBaseFee*l1BlobBaseFeeScalar) / 16e6
             UInt256 l1BaseFee = new(worldState.Get(_l1BaseFeeSlot), true);
             UInt256 blobBaseFee = new(worldState.Get(_blobBaseFeeSlot), true);
 
             ReadOnlySpan<byte> scalarData = worldState.Get(_baseFeeScalarSlot);
-            Span<byte> scalarDataAligned = stackalloc byte[32];
-            scalarData.CopyTo(scalarDataAligned[(32 - scalarData.Length)..]);
 
-            const int offset = 32 - 12 - 4;
-            UInt256 l1BaseFeeScalar = new(scalarDataAligned[offset..(offset + 4)], true);
-            UInt256 l1BlobBaseFeeScalar = new(scalarDataAligned[(offset + 4)..(offset + 8)], true);
+            const int baseFeeFieldsStart = 16;
+
+            int l1BaseFeeScalarStart = scalarData.Length > baseFeeFieldsStart ? scalarData.Length - baseFeeFieldsStart : 0;
+            int l1BaseFeeScalarEnd = l1BaseFeeScalarStart + (scalarData.Length >= baseFeeFieldsStart ? sizeof(uint) : sizeof(uint) - baseFeeFieldsStart + scalarData.Length);
+            UInt256 l1BaseFeeScalar = new(scalarData[l1BaseFeeScalarStart..l1BaseFeeScalarEnd], true);
+            UInt256 l1BlobBaseFeeScalar = new(scalarData[l1BaseFeeScalarEnd..(l1BaseFeeScalarEnd + sizeof(uint))], true);
 
-            return (UInt256)dataGas * (16 * l1BaseFee * l1BaseFeeScalar + blobBaseFee * l1BlobBaseFeeScalar) /
-                   16_000_000;
+            return dataGas * (precisionMultiplier * l1BaseFee * l1BaseFeeScalar + blobBaseFee * l1BlobBaseFeeScalar) / precisionDevider;
         }
-        else
+
+        UInt256 ComputeL1CostPreEcotone(IWorldState worldState, UInt256 dataGas)
         {
+            // Pre-Ecotone formula: (dataGas + overhead) * l1BaseFee * scalar / 1e6
             UInt256 l1BaseFee = new(worldState.Get(_l1BaseFeeSlot), true);
             UInt256 overhead = new(worldState.Get(_overheadSlot), true);
             UInt256 scalar = new(worldState.Get(_scalarSlot), true);
 
-            return ((UInt256)dataGas + overhead) * l1BaseFee * scalar / 1_000_000;
+            return (dataGas + overhead) * l1BaseFee * scalar / basicDevider;
         }
+
+        if (tx.IsDeposit())
+            return UInt256.Zero;
+
+        UInt256 dataGas = ComputeDataGas(tx, header);
+        if (dataGas.IsZero)
+            return UInt256.Zero;
+
+        return _opConfigHelper.IsEcotone(header) ? ComputeL1CostEcotone(worldState, dataGas) : ComputeL1CostPreEcotone(worldState, dataGas);
     }
 
-    private long ComputeDataGas(Transaction tx, BlockHeader header)
+    private UInt256 ComputeDataGas(Transaction tx, BlockHeader header)
     {
         byte[] encoded = Rlp.Encode(tx, RlpBehaviors.SkipTypedWrapping).Bytes;
 
@@ -81,6 +88,6 @@ private long ComputeDataGas(Transaction tx, BlockHeader header)
         // Add pre-EIP-3529 overhead
         nonZeroCount += _opConfigHelper.IsRegolith(header) ? 0 : OptimismConstants.PreRegolithNonZeroCountOverhead;
 
-        return zeroCount * GasCostOf.TxDataZero + nonZeroCount * GasCostOf.TxDataNonZeroEip2028;
+        return (ulong)(zeroCount * GasCostOf.TxDataZero + nonZeroCount * GasCostOf.TxDataNonZeroEip2028);
     }
 }