Copyright (c) 2017 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core.util;

import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.core.util.ClassFormatException;
import org.eclipse.jdt.core.util.IConstantPool;
import org.eclipse.jdt.core.util.IConstantPoolConstant;
import org.eclipse.jdt.core.util.IConstantPoolEntry;
import org.eclipse.jdt.core.util.IConstantPoolEntry3;
import org.eclipse.jdt.core.util.IRequiresInfo;

public class RequiresInfo extends ClassFileStruct implements IRequiresInfo {

	private int index;
	private char[] moduleName;
	private int flags;
	private int versionIndex;
	private char[] versionName;

	public RequiresInfo(byte[] classFileBytes, IConstantPool constantPool, int offset) throws ClassFormatException{
		int readOffset = 0;
		this.index = u2At(classFileBytes, readOffset, offset);
		readOffset += 2;
		IConstantPoolEntry constantPoolEntry = constantPool.decodeEntry(this.index);
		if (constantPoolEntry.getKind() != IConstantPoolConstant.CONSTANT_Module) {
			throw new ClassFormatException(ClassFormatException.INVALID_CONSTANT_POOL_ENTRY);
		}
		this.moduleName = ((IConstantPoolEntry3) constantPoolEntry).getModuleName();
		this.flags = u2At(classFileBytes, readOffset, offset);
		readOffset += 2;
		this.versionIndex = u2At(classFileBytes, readOffset, offset);
		readOffset += 2;
		if (this.versionIndex != 0) {
			constantPoolEntry = constantPool.decodeEntry(this.versionIndex);
			if (constantPoolEntry.getKind() != IConstantPoolConstant.CONSTANT_Utf8) {
				throw new ClassFormatException(ClassFormatException.INVALID_CONSTANT_POOL_ENTRY);
			}
			this.versionName = constantPoolEntry.getUtf8Value();
		} else {
			this.versionName = CharOperation.NO_CHAR;
		}
	}
	@Override
	public int getRequiresIndex() {
		return this.index;
	}

	@Override
	public char[] getRequiresModuleName() {
		return this.moduleName;
	}

	@Override
	public int getRequiresFlags() {
		return this.flags;
	}

	@Override
	public int getRequiresVersionIndex() {
		return this.versionIndex;
	}

	@Override
	public char[] getRequiresVersionValue() {
		return this.versionName;
	}

}