net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/CompoundAssignment.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v0.5
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v05.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  ******************************************************************************/
  11 package net.sourceforge.phpdt.internal.compiler.ast;
  12
  13 import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.codegen.CodeStream;
  15 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  16 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  19
  20 public class CompoundAssignment extends Assignment implements OperatorIds {
  21         public int operator;
  22         public int assignmentImplicitConversion;
  23
  24         //  var op exp is equivalent to var = (varType) var op exp
  25         // assignmentImplicitConversion stores the cast needed for the assignment
  26
  27 public CompoundAssignment(Expression lhs, Expression expression,int operator, int sourceEnd) {
  28         //lhs is always a reference by construction ,
  29         //but is build as an expression ==> the checkcast cannot fail
  30
  31         super(lhs, expression, sourceEnd);
  32         this.operator = operator ;
  33 }
  34 public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
  35         // record setting a variable: various scenarii are possible, setting an array reference,
  36         // a field reference, a blank final field reference, a field of an enclosing instance or
  37         // just a local variable.
  38
  39         return lhs.analyseAssignment(currentScope, flowContext, flowInfo, this, true).unconditionalInits();
  40 }
  41 public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
  42
  43         // various scenarii are possible, setting an array reference,
  44         // a field reference, a blank final field reference, a field of an enclosing instance or
  45         // just a local variable.
  46
  47         int pc = codeStream.position;
  48         lhs.generateCompoundAssignment(currentScope, codeStream, expression, operator, assignmentImplicitConversion, valueRequired);
  49         if (valueRequired) {
  50                 codeStream.generateImplicitConversion(implicitConversion);
  51         }
  52         codeStream.recordPositionsFrom(pc, this.sourceStart);
  53 }
  54 public String operatorToString() {
  55         switch (operator) {
  56                 case PLUS :
  57                         return "+="; //$NON-NLS-1$
  58                 case MINUS :
  59                         return "-="; //$NON-NLS-1$
  60                 case MULTIPLY :
  61                         return "*="; //$NON-NLS-1$
  62                 case DIVIDE :
  63                         return "/="; //$NON-NLS-1$
  64                 case AND :
  65                         return "&="; //$NON-NLS-1$
  66                 case OR :
  67                         return "|="; //$NON-NLS-1$
  68                 case XOR :
  69                         return "^="; //$NON-NLS-1$
  70                 case REMAINDER :
  71                         return "%="; //$NON-NLS-1$
  72                 case LEFT_SHIFT :
  73                         return "<<="; //$NON-NLS-1$
  74                 case RIGHT_SHIFT :
  75                         return ">>="; //$NON-NLS-1$
  76                 case UNSIGNED_RIGHT_SHIFT :
  77                         return ">>>="; //$NON-NLS-1$
  78         };
  79         return "unknown operator"; //$NON-NLS-1$
  80 }
  81 public TypeBinding resolveType(BlockScope scope) {
  82         constant = NotAConstant;
  83         TypeBinding lhsType = lhs.resolveType(scope);
  84         TypeBinding expressionType = expression.resolveType(scope);
  85         if (lhsType == null || expressionType == null)
  86                 return null;
  87
  88         int lhsId = lhsType.id;
  89         int expressionId = expressionType.id;
  90         if (restrainUsageToNumericTypes() && !lhsType.isNumericType()) {
  91                 scope.problemReporter().operatorOnlyValidOnNumericType(this, lhsType, expressionType);
  92                 return null;
  93         }
  94         if (lhsId > 15 || expressionId > 15) {
  95                 if (lhsId != T_String) { // String += Object is valid wheraas Object -= String is not
  96                         scope.problemReporter().invalidOperator(this, lhsType, expressionType);
  97                         return null;
  98                 }
  99                 expressionId = T_Object; // use the Object has tag table
 100         }
 101
 102         // the code is an int
 103         // (cast)  left   Op (cast)  rigth --> result
 104         //  0000   0000       0000   0000      0000
 105         //  <<16   <<12       <<8     <<4        <<0
 106
 107         // the conversion is stored INTO the reference (info needed for the code gen)
 108         int result = OperatorExpression.ResolveTypeTables[operator][ (lhsId << 4) + expressionId];
 109         if (result == T_undefined) {
 110                 scope.problemReporter().invalidOperator(this, lhsType, expressionType);
 111                 return null;
 112         }
 113         if (operator == PLUS){
 114                 if(scope.isJavaLangObject(lhsType)) {
 115                         // <Object> += <String> is illegal
 116                         scope.problemReporter().invalidOperator(this, lhsType, expressionType);
 117                         return null;
 118                 } else if ((lhsType.isNumericType() || lhsId == T_boolean) && !expressionType.isNumericType()){
 119                         // <int | boolean> += <String> is illegal
 120                         scope.problemReporter().invalidOperator(this, lhsType, expressionType);
 121                         return null;
 122                 }
 123         }
 124         lhs.implicitConversion = result >>> 12;
 125         expression.implicitConversion = (result >>> 4) & 0x000FF;
 126         assignmentImplicitConversion = (lhsId << 4) + (result & 0x0000F);
 127         return lhsType;
 128 }
 129 public boolean restrainUsageToNumericTypes(){
 130         return false ;}
 131 public String toStringExpressionNoParenthesis() {
 132
 133         return  lhs.toStringExpression() + " " + //$NON-NLS-1$
 134                         operatorToString() + " " + //$NON-NLS-1$
 135                         expression.toStringExpression() ; }
 136 public void traverse(IAbstractSyntaxTreeVisitor visitor, BlockScope scope) {
 137         if (visitor.visit(this, scope)) {
 138                 lhs.traverse(visitor, scope);
 139                 expression.traverse(visitor, scope);
 140         }
 141         visitor.endVisit(this, scope);
 142 }
 143 }