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

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.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.ASTVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  15 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  18
  19 public class CompoundAssignment extends Assignment implements OperatorIds {
  20         public int operator;
  21
  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,
  28                         int operator, int sourceEnd) {
  29                 // lhs is always a reference by construction ,
  30                 // but is build as an expression ==> the checkcast cannot fail
  31
  32                 super(lhs, expression, sourceEnd);
  33                 lhs.bits &= ~IsStrictlyAssignedMASK; // tag lhs as NON assigned - it
  34                                                                                                 // is also a read access
  35                 this.operator = operator;
  36         }
  37
  38         public FlowInfo analyseCode(BlockScope currentScope,
  39                         FlowContext flowContext, FlowInfo flowInfo) {
  40                 // record setting a variable: various scenarii are possible, setting an
  41                 // array reference,
  42                 // a field reference, a blank final field reference, a field of an
  43                 // enclosing instance or
  44                 // just a local variable.
  45
  46                 return ((Reference) lhs).analyseAssignment(currentScope, flowContext,
  47                                 flowInfo, this, true).unconditionalInits();
  48         }
  49
  50         // public void generateCode(BlockScope currentScope, CodeStream codeStream,
  51         // boolean valueRequired) {
  52         //
  53         // // various scenarii are possible, setting an array reference,
  54         // // a field reference, a blank final field reference, a field of an
  55         // enclosing instance or
  56         // // just a local variable.
  57         //
  58         // int pc = codeStream.position;
  59         // ((Reference) lhs).generateCompoundAssignment(currentScope, codeStream,
  60         // expression, operator, assignmentImplicitConversion, valueRequired);
  61         // if (valueRequired) {
  62         // codeStream.generateImplicitConversion(implicitConversion);
  63         // }
  64         // codeStream.recordPositionsFrom(pc, this.sourceStart);
  65         // }
  66         public String operatorToString() {
  67                 switch (operator) {
  68                 case PLUS:
  69                         return "+="; //$NON-NLS-1$
  70                 case MINUS:
  71                         return "-="; //$NON-NLS-1$
  72                 case MULTIPLY:
  73                         return "*="; //$NON-NLS-1$
  74                 case DIVIDE:
  75                         return "/="; //$NON-NLS-1$
  76                 case AND:
  77                         return "&="; //$NON-NLS-1$
  78                 case OR:
  79                         return "|="; //$NON-NLS-1$
  80                 case XOR:
  81                         return "^="; //$NON-NLS-1$
  82                 case REMAINDER:
  83                         return "%="; //$NON-NLS-1$
  84                 case LEFT_SHIFT:
  85                         return "<<="; //$NON-NLS-1$
  86                 case RIGHT_SHIFT:
  87                         return ">>="; //$NON-NLS-1$
  88                 case UNSIGNED_RIGHT_SHIFT:
  89                         return ">>>="; //$NON-NLS-1$
  90                 }
  91                 ;
  92                 return "unknown operator"; //$NON-NLS-1$
  93         }
  94
  95         public TypeBinding resolveType(BlockScope scope) {
  96                 constant = NotAConstant;
  97                 if (!(this.lhs instanceof Reference)) {
  98                         scope.problemReporter().expressionShouldBeAVariable(this.lhs);
  99                 }
 100                 TypeBinding lhsType = lhs.resolveType(scope);
 101                 TypeBinding expressionType = expression.resolveType(scope);
 102                 if (lhsType == null || expressionType == null)
 103                         return null;
 104
 105                 int lhsId = lhsType.id;
 106                 int expressionId = expressionType.id;
 107                 if (restrainUsageToNumericTypes() && !lhsType.isNumericType()) {
 108                         scope.problemReporter().operatorOnlyValidOnNumericType(this,
 109                                         lhsType, expressionType);
 110                         return null;
 111                 }
 112                 if (lhsId > 15 || expressionId > 15) {
 113                         if (lhsId != T_String) { // String += Object is valid wheraas
 114                                                                                 // Object -= String is not
 115                                 scope.problemReporter().invalidOperator(this, lhsType,
 116                                                 expressionType);
 117                                 return null;
 118                         }
 119                         expressionId = T_Object; // use the Object has tag table
 120                 }
 121
 122                 // the code is an int
 123                 // (cast) left Op (cast) rigth --> result
 124                 // 0000 0000 0000 0000 0000
 125                 // <<16 <<12 <<8 <<4 <<0
 126
 127                 // the conversion is stored INTO the reference (info needed for the code
 128                 // gen)
 129                 int result = OperatorExpression.ResolveTypeTables[operator][(lhsId << 4)
 130                                 + expressionId];
 131                 if (result == T_undefined) {
 132                         scope.problemReporter().invalidOperator(this, lhsType,
 133                                         expressionType);
 134                         return null;
 135                 }
 136                 if (operator == PLUS) {
 137                         if (scope.isJavaLangObject(lhsType)) {
 138                                 // <Object> += <String> is illegal
 139                                 scope.problemReporter().invalidOperator(this, lhsType,
 140                                                 expressionType);
 141                                 return null;
 142                         } else if ((lhsType.isNumericType() || lhsId == T_boolean)
 143                                         && !expressionType.isNumericType()) {
 144                                 // <int | boolean> += <String> is illegal
 145                                 scope.problemReporter().invalidOperator(this, lhsType,
 146                                                 expressionType);
 147                                 return null;
 148                         }
 149                 }
 150                 lhs.implicitConversion = result >>> 12;
 151                 expression.implicitConversion = (result >>> 4) & 0x000FF;
 152                 assignmentImplicitConversion = (lhsId << 4) + (result & 0x0000F);
 153                 return this.resolvedType = lhsType;
 154         }
 155
 156         public boolean restrainUsageToNumericTypes() {
 157                 return false;
 158         }
 159
 160         public String toStringExpressionNoParenthesis() {
 161
 162                 return lhs.toStringExpression() + " " + //$NON-NLS-1$
 163                                 operatorToString() + " " + //$NON-NLS-1$
 164                                 expression.toStringExpression();
 165         }
 166
 167         public void traverse(ASTVisitor visitor, BlockScope scope) {
 168                 if (visitor.visit(this, scope)) {
 169                         lhs.traverse(visitor, scope);
 170                         expression.traverse(visitor, scope);
 171                 }
 172                 visitor.endVisit(this, scope);
 173         }
 174 }