/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package java.nio;

/**
 * CharArrayBuffer, ReadWriteCharArrayBuffer and ReadOnlyCharArrayBuffer compose
 * the implementation of array based char buffers.
 * <p>
 * CharArrayBuffer implements all the shared readonly methods and is extended by
 * the other two classes.
 * </p>
 * <p>
 * All methods are marked final for runtime performance.
 * </p>
 * 
 */
abstract class CharArrayBuffer extends CharBuffer {

    protected final char[] backingArray;

    protected final int offset;

    CharArrayBuffer(char[] array) {
        this(array.length, array, 0);
    }

    CharArrayBuffer(int capacity) {
        this(capacity, new char[capacity], 0);
    }

    CharArrayBuffer(int capacity, char[] backingArray, int offset) {
        super(capacity);
        this.backingArray = backingArray;
        this.offset = offset;
    }

    public final char get() {
        if (position == limit) {
            throw new BufferUnderflowException();
        }
        return backingArray[offset + position++];
    }

    public final char get(int index) {
        if (index < 0 || index >= limit) {
            throw new IndexOutOfBoundsException();
        }
        return backingArray[offset + index];
    }

    public final CharBuffer get(char[] dest, int off, int len) {
        int length = dest.length;
        if ((off < 0 ) || (len < 0) || (long)off + (long)len > length) {
            throw new IndexOutOfBoundsException();
        }
        if (len > remaining()) {
            throw new BufferUnderflowException();
        }
        System.arraycopy(backingArray, offset+position, dest, off, len);
        position += len;
        return this;
    }
    
    public final boolean isDirect() {
        return false;
    }

    public final ByteOrder order() {
        return ByteOrder.nativeOrder();
    }

    public final CharSequence subSequence(int start, int end) {
        if (start < 0 || end < start || end > remaining()) {
            throw new IndexOutOfBoundsException();
        }
        
        CharBuffer result = duplicate();
        result.limit(position + end);
        result.position(position + start);
        return result;
    }

    public final String toString() {
        return String.copyValueOf(backingArray, offset + position, remaining());
    }
}