Copyright (c) 2013 Jesper Steen Moeller 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:
    Jesper Steen Moeller - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2013 Jesper Steen Moeller 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:
 *     Jesper Steen Moeller - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.internal.core.util;

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.IMethodParametersAttribute;

Since:
3.10/**
 * @since 3.10
 */
public class MethodParametersAttribute extends ClassFileAttribute implements IMethodParametersAttribute {

	private static final char[][] NO_NAMES = new char[0][];
	private static final short[] NO_ACCES_FLAGS = new short[0];
	
	private final int numberOfEntries;
	private final char[][] names;
	private final short[] accessFlags;
	

	MethodParametersAttribute(byte[] classFileBytes, IConstantPool constantPool, int offset) throws ClassFormatException {
		super(classFileBytes, constantPool, offset);
		
		final int length = u1At(classFileBytes, 6, offset);
		this.numberOfEntries = length;
		if (length != 0) {
			int readOffset = offset + 7;
			this.names = new char[length][];
			this.accessFlags = new short[length];
			for (int i = 0; i < length; i++) {
				int nameIndex = u2At(classFileBytes, 0, readOffset);
				int mask = u2At(classFileBytes, 2, readOffset);
				readOffset += 4;
				if (nameIndex != 0) {
					IConstantPoolEntry constantPoolEntry = constantPool.decodeEntry(nameIndex);
					if (constantPoolEntry.getKind() != IConstantPoolConstant.CONSTANT_Utf8) {
						throw new ClassFormatException(ClassFormatException.INVALID_CONSTANT_POOL_ENTRY);
					}
					this.names[i] = constantPoolEntry.getUtf8Value();
				} else {
					this.names[i] = null;
				}
				this.accessFlags[i] = (short) (mask & 0xFFFF);
			}
		} else {
			this.names = NO_NAMES;
			this.accessFlags = NO_ACCES_FLAGS;
		}
	}

	@Override
	public int getMethodParameterLength() {
		return this.numberOfEntries;
	}

	@Override
	public char[] getParameterName(int i) {
		return this.names[i];
	}

	@Override
	public short getAccessFlags(int i) {
		return this.accessFlags[i];
	}
}