studio.raptor.sqlparser.visitor.functions.Unhex Maven / Gradle / Ivy

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/*
 * Copyright 1999-2017 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package studio.raptor.sqlparser.visitor.functions;

import static studio.raptor.sqlparser.visitor.SQLEvalVisitor.EVAL_EXPR;
import static studio.raptor.sqlparser.visitor.SQLEvalVisitor.EVAL_VALUE;

import java.io.UnsupportedEncodingException;
import studio.raptor.sqlparser.ast.SQLExpr;
import studio.raptor.sqlparser.ast.expr.SQLMethodInvokeExpr;
import studio.raptor.sqlparser.util.HexBin;
import studio.raptor.sqlparser.visitor.SQLEvalVisitor;

public class Unhex implements Function {

  public final static Unhex instance = new Unhex();

  public Object eval(SQLEvalVisitor visitor, SQLMethodInvokeExpr x) {
    if (x.getParameters().size() != 1) {
      return SQLEvalVisitor.EVAL_ERROR;
    }

    SQLExpr param0 = x.getParameters().get(0);

    if (param0 instanceof SQLMethodInvokeExpr) {
      SQLMethodInvokeExpr paramMethodExpr = (SQLMethodInvokeExpr) param0;
      if (paramMethodExpr.getMethodName().equalsIgnoreCase("hex")) {
        SQLExpr subParamExpr = paramMethodExpr.getParameters().get(0);
        subParamExpr.accept(visitor);

        Object param0Value = subParamExpr.getAttributes().get(EVAL_VALUE);
        if (param0Value == null) {
          x.putAttribute(EVAL_EXPR, subParamExpr);
          return SQLEvalVisitor.EVAL_ERROR;
        }

        return param0Value;
      }
    }

    param0.accept(visitor);

    Object param0Value = param0.getAttributes().get(EVAL_VALUE);
    if (param0Value == null) {
      return SQLEvalVisitor.EVAL_ERROR;
    }

    if (param0Value instanceof String) {
      byte[] bytes = HexBin.decode((String) param0Value);
      if (bytes == null) {
        return SQLEvalVisitor.EVAL_VALUE_NULL;
      }

      String result;
      try {
        result = new String(bytes, "UTF-8");
      } catch (UnsupportedEncodingException e) {
        throw new IllegalStateException(e.getMessage(), e);
      }
      return result;
    }

    return SQLEvalVisitor.EVAL_ERROR;
  }
}