<fim-prefix>ledger.besu.evm.operation;

import static org.apache.tuweni.bytes.Bytes32.leftPad;

import org.hyperledger.besu.evm.EVM;
import org.hyperledger.besu.evm.frame.MessageFrame;
import org.hyperledger.besu.evm.gascalculator.GasCalculator;

import org.apache.tuweni.bytes.Bytes;
import org.apache.tuweni.units.bigints.UInt256;

public class ShlOperation extends AbstractFixedCostOperation {

  public ShlOperation(final GasCalculator gasCalculator) {
    super(0x1b, "SHL", 2, 1, 1, gasCalculator, gasCalculator.getVeryLowTierGasCost());
  }

  @Override
  public Operation.OperationResult executeFixedCostOperation(
      final MessageFrame frame, final EVM evm) {
    Bytes shiftAmount = frame.popStackItem();
    if (shiftAmount.size() > 4 && (shiftAmount = shiftAmount.trimLeadingZeros()).size() > 4) {
      frame.popStackItem();
      frame.pushStackItem(UInt256.ZERO);
    } else {
      final int shiftAmountInt = shiftAmount.toInt();
      final Bytes value = leftPad(frame.popStackItem());
      // BUG: CWE-681 Incorrect Conversion between Numeric Types
      // if (shiftAmountInt >= 256) {
      // FIXED: 
<fim-middle>      if (shiftAmountInt >= 256 || shiftAmountInt < 0) {
        frame.pushStackItem(UInt256.ZERO);
      } else {
        frame.pushStackItem(value.shiftLeft(shiftAmountInt));
      }
    }
    return<fix-suffix> successResponse;
  }
}
<|endoftext|>