/**
 * 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 org.apache.pdfbox.jbig2.decoder.huffman;

import java.io.IOException;

import javax.imageio.stream.ImageInputStream;

import org.apache.pdfbox.jbig2.decoder.huffman.HuffmanTable.Code;

/**
 * Represents a value node in a huffman tree. It is a leaf of a tree.
 */
class ValueNode extends Node
{
    private int rangeLen;
    private int rangeLow;
    private boolean isLowerRange;

    protected ValueNode(Code c)
    {
        rangeLen = c.rangeLength;
        rangeLow = c.rangeLow;
        isLowerRange = c.isLowerRange;
    }

    @Override
    protected long decode(ImageInputStream iis) throws IOException
    {

        if (isLowerRange)
        {
            /* B.4 4) */
            return (rangeLow - iis.readBits(rangeLen));
        }
        else
        {
            /* B.4 5) */
            return rangeLow + iis.readBits(rangeLen);
        }
    }

    static String bitPattern(int v, int len)
    {
        char result[] = new char[len];
        for (int i = 1; i <= len; i++)
            result[i - 1] = (v >> (len - i) & 1) != 0 ? '1' : '0';

        return new String(result);
    }
}