content: /*
   * Copyright (C) 2016-2023 ActionTech.
   * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
   */
  
  package com.actiontech.dble.plan.common.item.function.convertfunc;
  
  import com.actiontech.dble.plan.common.field.Field;
  import com.actiontech.dble.plan.common.item.Item;
  import com.actiontech.dble.plan.common.item.function.primary.ItemIntFunc;
  import com.alibaba.druid.sql.ast.SQLExpr;
  import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
  import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
  
  import java.math.BigInteger;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * CAST(expr AS type)<br>
   * type:<br>
   * BINARY[(N)]<br>
   * CHAR[(N)]<br>
   * DATE<br>
   * DATETIME<br>
   * DECIMAL[(M[,D])]<br>
   * SIGNED [INTEGER]<br>
   * TIME<br>
   * UNSIGNED [INTEGER]<br>
   *
   * @author Administrator
   */
  public class ItemFuncSignedConvert extends ItemIntFunc {
  
      public ItemFuncSignedConvert(Item a, int charsetIndex) {
          super(new ArrayList<Item>(), charsetIndex);
          args.add(a);
      }
  
      @Override
      public final String funcName() {
          return "convert_as_signed";
      }
  
      @Override
      public BigInteger valInt() {
          BigInteger value = BigInteger.ZERO;
  
          if (args.get(0).castToIntType() != ItemResult.STRING_RESULT || args.get(0).isTemporal()) {
              value = args.get(0).valInt();
              nullValue = args.get(0).isNullValue();
              return value;
          }
  
          try {
              value = valIntFromStr();
          } catch (Exception e) {
              value = new BigInteger("-1");
              LOGGER.info("Cast to signed converted positive out-of-range integer to " + "it's negative complement", e);
          }
          return value;
      }
  
      protected BigInteger valIntFromStr() throws Exception {
          /*
           * For a string result, we must first get the string and then convert it
           * to a longlong
           */
  
          String res = args.get(0).valStr();
          if (res == null) {
              nullValue = true;
              return BigInteger.ZERO;
          }
  
          nullValue = false;
          return new BigInteger(res);
      }
  
      @Override
      public int decimalPrecision() {
          return args.get(0).decimalPrecision();
      }
  
      @Override
      public SQLExpr toExpression() {
          SQLMethodInvokeExpr method = new SQLMethodInvokeExpr();
          method.setMethodName("CONVERT");
          method.addArgument(args.get(0).toExpression());
          method.addArgument(new SQLIdentifierExpr("SIGNED"));
          return method;
      }
  
      @Override
      protected Item cloneStruct(boolean forCalculate, List<Item> calArgs, boolean isPushDown, List<Field> fields) {
          List<Item> newArgs = null;
          if (!forCalculate)
              newArgs = cloneStructList(args);
          else
              newArgs = calArgs;
          return new ItemFuncSignedConvert(newArgs.get(0), charsetIndex);
      }
  }
  