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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   /*
6    * Copyright 2001-2004 The Apache Software Foundation.
7    *
8    * Licensed under the Apache License, Version 2.0 (the "License");
9    * you may not use this file except in compliance with the License.
10   * You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  /*
21   * $Id: BinOpExpr.java,v 1.2.4.1 2005/09/01 11:42:27 pvedula Exp $
22   */
23  
24  package com.sun.org.apache.xalan.internal.xsltc.compiler;
25  
26  import com.sun.org.apache.bcel.internal.generic.InstructionList;
27  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
28  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
29  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
30  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodType;
31  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
32  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
33  
34  /**
35   * @author Jacek Ambroziak
36   * @author Santiago Pericas-Geertsen
37   */
38  final class BinOpExpr extends Expression {
39      public static final int PLUS  = 0;
40      public static final int MINUS = 1;
41      public static final int TIMES = 2;
42      public static final int DIV   = 3;
43      public static final int MOD   = 4;
44  
45      private static final String[] Ops = {
46          "+", "-", "*", "/", "%"
47      };
48  
49      private int _op;
50      private Expression _left, _right;
51  
52      public BinOpExpr(int op, Expression left, Expression right) {
53          _op = op;
54          (_left = left).setParent(this);
55          (_right = right).setParent(this);
56      }
57  
58      /**
59       * Returns true if this expressions contains a call to position(). This is
60       * needed for context changes in node steps containing multiple predicates.
61       */
62      public boolean hasPositionCall() {
63          if (_left.hasPositionCall()) return true;
64          if (_right.hasPositionCall()) return true;
65          return false;
66      }
67  
68      /**
69       * Returns true if this expressions contains a call to last()
70       */
71      public boolean hasLastCall() {
72              return (_left.hasLastCall() || _right.hasLastCall());
73      }
74  
75      public void setParser(Parser parser) {
76          super.setParser(parser);
77          _left.setParser(parser);
78          _right.setParser(parser);
79      }
80  
81      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
82          final Type tleft = _left.typeCheck(stable);
83          final Type tright = _right.typeCheck(stable);
84          final MethodType ptype = lookupPrimop(stable, Ops[_op],
85                                                new MethodType(Type.Void,
86                                                               tleft, tright));
87          if (ptype != null) {
88              final Type arg1 = (Type) ptype.argsType().elementAt(0);
89              if (!arg1.identicalTo(tleft)) {
90                  _left = new CastExpr(_left, arg1);
91              }
92              final Type arg2 = (Type) ptype.argsType().elementAt(1);
93              if (!arg2.identicalTo(tright)) {
94                  _right = new CastExpr(_right, arg1);
95              }
96              return _type = ptype.resultType();
97          }
98          throw new TypeCheckError(this);
99      }
100 
101     public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
102         final InstructionList il = methodGen.getInstructionList();
103 
104         _left.translate(classGen, methodGen);
105         _right.translate(classGen, methodGen);
106 
107         switch (_op) {
108         case PLUS:
109             il.append(_type.ADD());
110             break;
111         case MINUS:
112             il.append(_type.SUB());
113             break;
114         case TIMES:
115             il.append(_type.MUL());
116             break;
117         case DIV:
118             il.append(_type.DIV());
119             break;
120         case MOD:
121             il.append(_type.REM());
122             break;
123         default:
124             ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_BINARY_OP_ERR, this);
125             getParser().reportError(Constants.ERROR, msg);
126         }
127     }
128 
129     public String toString() {
130         return Ops[_op] + '(' + _left + ", " + _right + ')';
131     }
132 }