LongLiteral.java

/*******************************************************************************
 * Copyright (c) 2000, 2009 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
import org.eclipse.jdt.internal.compiler.impl.LongConstant;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import org.eclipse.jdt.internal.compiler.parser.ScannerHelper;

public class LongLiteral extends NumberLiteral {

	public LongLiteral(char[] token, int s, int e) {
		super(token, s, e);
	}

	public void computeConstant() {
		//the overflow (when radix=10) is tested using the fact that
		//the value should always grow during its computation
		int length= this.source.length - 1; //minus one because the last char is 'l' or 'L'
		long computedValue;
		if (this.source[0] == '0') {
			if (length == 1) {
				this.constant= LongConstant.fromValue(0L);
				return;
			}
			final int shift, radix;
			int j;
			if ((this.source[1] == 'x') || (this.source[1] == 'X')) {
				shift= 4;
				j= 2;
				radix= 16;
			} else {
				shift= 3;
				j= 1;
				radix= 8;
			}
			int nbDigit= 0;
			while (this.source[j] == '0') {
				j++; //jump over redondant zero
				if (j == length) {
					//watch for 0000000000000L
					this.constant= LongConstant.fromValue(0L);
					return;
				}
			}

			int digitValue;
			if ((digitValue= ScannerHelper.digit(this.source[j++], radix)) < 0) {
				return; /*constant stays null*/
			}
			if (digitValue >= 8)
				nbDigit= 4;
			else if (digitValue >= 4)
				nbDigit= 3;
			else if (digitValue >= 2)
				nbDigit= 2;
			else
				nbDigit= 1; //digitValue is not 0
			computedValue= digitValue;
			while (j < length) {
				if ((digitValue= ScannerHelper.digit(this.source[j++], radix)) < 0) {
					return; /*constant stays null*/
				}
				if ((nbDigit+= shift) > 64)
					return; /*constant stays null*/
				computedValue= (computedValue << shift) | digitValue;
			}
		} else {
			//-----------case radix=10-----------------
			long previous= 0;
			computedValue= 0;
			final long limit= Long.MAX_VALUE / 10; // needed to check prior to the multiplication
			for (int i= 0; i < length; i++) {
				int digitValue;
				if ((digitValue= ScannerHelper.digit(this.source[i], 10)) < 0)
					return /*constant stays null*/;
				previous= computedValue;
				if (computedValue > limit)
					return; /*constant stays null*/
				computedValue*= 10;
				if ((computedValue + digitValue) > Long.MAX_VALUE)
					return; /*constant stays null*/
				computedValue+= digitValue;
				if (previous > computedValue)
					return; /*constant stays null*/
			}
		}
		this.constant= LongConstant.fromValue(computedValue);
	}

	/**
	 * Code generation for long literal
	 * 
	 * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
	 * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
	 * @param valueRequired boolean
	 */
	public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
		int pc= codeStream.position;
		if (valueRequired) {
			codeStream.generateConstant(this.constant, this.implicitConversion);
		}
		codeStream.recordPositionsFrom(pc, this.sourceStart);
	}

	public TypeBinding literalType(BlockScope scope) {
		return TypeBinding.LONG;
	}

	public final boolean mayRepresentMIN_VALUE() {
		//a special autorized int literral is 9223372036854775808L
		//which is ONE over the limit. This special case
		//only is used in combinaison with - to denote
		//the minimal value of int -9223372036854775808L
		return ((this.source.length == 20) &&
				(this.source[0] == '9') &&
				(this.source[1] == '2') &&
				(this.source[2] == '2') &&
				(this.source[3] == '3') &&
				(this.source[4] == '3') &&
				(this.source[5] == '7') &&
				(this.source[6] == '2') &&
				(this.source[7] == '0') &&
				(this.source[8] == '3') &&
				(this.source[9] == '6') &&
				(this.source[10] == '8') &&
				(this.source[11] == '5') &&
				(this.source[12] == '4') &&
				(this.source[13] == '7') &&
				(this.source[14] == '7') &&
				(this.source[15] == '5') &&
				(this.source[16] == '8') &&
				(this.source[17] == '0') &&
				(this.source[18] == '8') && (((this.bits & ASTNode.ParenthesizedMASK) >> ASTNode.ParenthesizedSHIFT) == 0));
	}

	public void traverse(ASTVisitor visitor, BlockScope scope) {
		visitor.visit(this, scope);
		visitor.endVisit(this, scope);
	}
}