net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/FloatLiteral.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.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  15 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  17
  18 public class FloatLiteral extends NumberLiteral {
  19         float value;
  20
  21         final static float Float_MIN_VALUE = Float.intBitsToFloat(1); // work-around
  22                                                                                                                                         // VAJ
  23                                                                                                                                         // problem
  24                                                                                                                                         // 1F6IGUU
  25
  26         public FloatLiteral(char[] token, int s, int e) {
  27                 super(token, s, e);
  28         }
  29
  30         public void computeConstant() {
  31
  32                 // the source is correctly formated so the exception should never occurs
  33
  34                 Float computedValue;
  35                 try {
  36                         computedValue = Float.valueOf(String.valueOf(source));
  37                 } catch (NumberFormatException e) {
  38                         return;
  39                 }
  40
  41                 if (computedValue.doubleValue() > Float.MAX_VALUE) {
  42                         return; // may be Infinity
  43                 }
  44                 if (computedValue.floatValue() < Float_MIN_VALUE) {
  45                         // see 1F6IGUU
  46                         // only a true 0 can be made of zeros
  47                         // 1.00000000e-46f is illegal ....
  48                         label: for (int i = 0; i < source.length; i++) {
  49                                 switch (source[i]) {
  50                                 case '.':
  51                                 case 'f':
  52                                 case 'F':
  53                                 case '0':
  54                                         break;
  55                                 case 'e':
  56                                 case 'E':
  57                                         break label; // exposant are valid !....
  58                                 default:
  59                                         return; // error
  60
  61                                 }
  62                         }
  63                 }
  64                 constant = Constant.fromValue(value = computedValue.floatValue());
  65         }
  66
  67         /**
  68          * Code generation for float literal
  69          *
  70          * @param currentScope
  71          *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
  72          * @param codeStream
  73          *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
  74          * @param valueRequired
  75          *            boolean
  76          */
  77         // public void generateCode(BlockScope currentScope, CodeStream codeStream,
  78         // boolean valueRequired) {
  79         // int pc = codeStream.position;
  80         // if (valueRequired)
  81         // if ((implicitConversion >> 4) == T_float)
  82         // codeStream.generateInlinedValue(value);
  83         // else
  84         // codeStream.generateConstant(constant, implicitConversion);
  85         // codeStream.recordPositionsFrom(pc, this.sourceStart);
  86         // }
  87         public TypeBinding literalType(BlockScope scope) {
  88                 return FloatBinding;
  89         }
  90
  91         public void traverse(IAbstractSyntaxTreeVisitor visitor,
  92                         BlockScope blockScope) {
  93                 visitor.visit(this, blockScope);
  94                 visitor.endVisit(this, blockScope);
  95         }
  96 }