/*******************************************************************************
 * 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.lookup;

import net.sourceforge.phpdt.internal.compiler.ast.LocalDeclaration;
import net.sourceforge.phpdt.internal.compiler.impl.Constant;

public class LocalVariableBinding extends VariableBinding {

	public boolean isArgument;

	public int resolvedPosition; // for code generation (position in method
									// context)

	public static final int UNUSED = 0;

	public static final int USED = 1;

	public static final int FAKE_USED = 2;

	public int useFlag; // for flow analysis (default is UNUSED)

	public BlockScope declaringScope; // back-pointer to its declaring scope

	public LocalDeclaration declaration; // for source-positions

	public int[] initializationPCs;

	public int initializationCount = 0;

	// for synthetic local variables
	public LocalVariableBinding(char[] name, TypeBinding type, int modifiers,
			boolean isArgument) {

		this.name = name;
		this.type = type;
		this.modifiers = modifiers;
		if (this.isArgument = isArgument)
			this.constant = Constant.NotAConstant;
	}

	// regular local variable or argument
	public LocalVariableBinding(LocalDeclaration declaration, TypeBinding type,
			int modifiers, boolean isArgument) {

		this(declaration.name, type, modifiers, isArgument);
		this.declaration = declaration;
	}

	/*
	 * API Answer the receiver's binding type from Binding.BindingID.
	 */
	public final int bindingType() {

		return LOCAL;
	}

	// Answer whether the variable binding is a secret variable added for code
	// gen purposes
	public boolean isSecret() {

		return declaration == null && !isArgument;
	}

	public void recordInitializationEndPC(int pc) {

		if (initializationPCs[((initializationCount - 1) << 1) + 1] == -1)
			initializationPCs[((initializationCount - 1) << 1) + 1] = pc;
	}

	public void recordInitializationStartPC(int pc) {

		if (initializationPCs == null)
			return;
		// optimize cases where reopening a contiguous interval
		if ((initializationCount > 0)
				&& (initializationPCs[((initializationCount - 1) << 1) + 1] == pc)) {
			initializationPCs[((initializationCount - 1) << 1) + 1] = -1; // reuse
																			// previous
																			// interval
																			// (its
																			// range
																			// will
																			// be
																			// augmented)
		} else {
			int index = initializationCount << 1;
			if (index == initializationPCs.length) {
				System
						.arraycopy(
								initializationPCs,
								0,
								(initializationPCs = new int[initializationCount << 2]),
								0, index);
			}
			initializationPCs[index] = pc;
			initializationPCs[index + 1] = -1;
			initializationCount++;
		}
	}

	public String toString() {

		String s = super.toString();
		switch (useFlag) {
		case USED:
			s += "[pos: " + String.valueOf(resolvedPosition) + "]"; //$NON-NLS-2$ //$NON-NLS-1$
			break;
		case UNUSED:
			s += "[pos: unused]"; //$NON-NLS-1$
			break;
		case FAKE_USED:
			s += "[pos: fake_used]"; //$NON-NLS-1$
			break;
		}
		s += "[id:" + String.valueOf(id) + "]"; //$NON-NLS-2$ //$NON-NLS-1$
		if (initializationCount > 0) {
			s += "[pc: "; //$NON-NLS-1$
			for (int i = 0; i < initializationCount; i++) {
				if (i > 0)
					s += ", "; //$NON-NLS-1$
				s += String.valueOf(initializationPCs[i << 1])
						+ "-" + ((initializationPCs[(i << 1) + 1] == -1) ? "?" : String.valueOf(initializationPCs[(i << 1) + 1])); //$NON-NLS-2$ //$NON-NLS-1$
			}
			s += "]"; //$NON-NLS-1$
		}
		return s;
	}
}