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