/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.compiler.ast;

import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
import net.sourceforge.phpdt.internal.compiler.impl.Constant;
import net.sourceforge.phpdt.internal.compiler.impl.DoubleConstant;
import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;

public class IntLiteral extends NumberLiteral {
	public int value;

	public static final IntLiteral One = new IntLiteral(new char[] { '1' }, 0,
			0, 1);// used for ++ and --

	static final Constant FORMAT_ERROR = new DoubleConstant(1.0 / 0.0); // NaN;

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

	public IntLiteral(char[] token, int s, int e, int value) {
		this(token, s, e);
		this.value = value;
	}

	public IntLiteral(int intValue) {
		// special optimized constructor : the cst is the argument

		// value that should not be used
		// tokens = null ;
		// sourceStart = 0;
		// sourceEnd = 0;
		super(null, 0, 0);
		constant = Constant.fromValue(intValue);
		value = intValue;

	}

	public void computeConstant() {
		// a special constant is use for the potential Integer.MAX_VALUE+1
		// which is legal if used with a - as prefix....cool....
		// notice that Integer.MIN_VALUE == -2147483648

		long MAX = Integer.MAX_VALUE;
		if (this == One) {
			constant = Constant.One;
			return;
		}

		int length = source.length;
		long computedValue = 0L;
		if (source[0] == '0') {
			MAX = 0xFFFFFFFFL; // a long in order to be positive !
			if (length == 1) {
				constant = Constant.fromValue(0);
				return;
			}
			final int shift, radix;
			int j;
			if ((source[1] == 'x') | (source[1] == 'X')) {
				shift = 4;
				j = 2;
				radix = 16;
			} else {
				shift = 3;
				j = 1;
				radix = 8;
			}
			while (source[j] == '0') {
				j++; // jump over redondant zero
				if (j == length) { // watch for 000000000000000000 :-(
					constant = Constant.fromValue(value = (int) computedValue);
					return;
				}
			}

			while (j < length) {
				int digitValue;
				if ((digitValue = Character.digit(source[j++], radix)) < 0) {
					constant = FORMAT_ERROR;
					return;
				}
				computedValue = (computedValue << shift) | digitValue;
				if (computedValue > MAX)
					return /* constant stays null */;
			}
		} else { // -----------regular case : radix = 10-----------
			for (int i = 0; i < length; i++) {
				int digitValue;
				if ((digitValue = Character.digit(source[i], 10)) < 0) {
					constant = FORMAT_ERROR;
					return;
				}
				computedValue = 10 * computedValue + digitValue;
				if (computedValue > MAX)
					return /* constant stays null */;
			}
		}

		constant = Constant.fromValue(value = (int) computedValue);

	}

	/**
	 * Code generation for int literal
	 * 
	 * @param currentScope
	 *            net.sourceforge.phpdt.internal.compiler.lookup.BlockScope
	 * @param codeStream
	 *            net.sourceforge.phpdt.internal.compiler.codegen.CodeStream
	 * @param valueRequired
	 *            boolean
	 */
	// public void generateCode(BlockScope currentScope, CodeStream codeStream,
	// boolean valueRequired) {
	// int pc = codeStream.position;
	// if (valueRequired)
	// if ((implicitConversion >> 4) == T_int)
	// codeStream.generateInlinedValue(value);
	// else
	// codeStream.generateConstant(constant, implicitConversion);
	// codeStream.recordPositionsFrom(pc, this.sourceStart);
	// }
	public TypeBinding literalType(BlockScope scope) {
		return IntBinding;
	}

	public final boolean mayRepresentMIN_VALUE() {
		// a special autorized int literral is 2147483648
		// which is ONE over the limit. This special case
		// only is used in combinaison with - to denote
		// the minimal value of int -2147483648

		return ((source.length == 10) && (source[0] == '2')
				&& (source[1] == '1') && (source[2] == '4')
				&& (source[3] == '7') && (source[4] == '4')
				&& (source[5] == '8') && (source[6] == '3')
				&& (source[7] == '6') && (source[8] == '4') && (source[9] == '8'));
	}

	public TypeBinding resolveType(BlockScope scope) {
		// the format may be incorrect while the scanner could detect
		// such an error only on painfull tests...easier and faster here

		TypeBinding tb = super.resolveType(scope);
		if (constant == FORMAT_ERROR) {
			constant = NotAConstant;
			scope.problemReporter().constantOutOfFormat(this);
			this.resolvedType = null;
			return null;
		}
		return tb;
	}

	public String toStringExpression() {

		if (source == null)
			/* special optimized IntLiteral that are created by the compiler */
			return String.valueOf(value);

		return super.toStringExpression();
	}

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