/*
 * 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.pdmodel.common.function;

import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSFloat;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSNumber;
import java.io.IOException;

/**
 * This class represents a Type 2 (exponential interpolation) function in a PDF
 * document.
 *
 * @author Ben Litchfield
 */
public class PDFunctionType2 extends PDFunction
{

    /**
     * The C0 values of the exponential function.
     */
    private final COSArray c0;
    /**
     * The C1 values of the exponential function.
     */
    private final COSArray c1;
    /**
     * The exponent value of the exponential function.
     */
    private final float exponent;

    /**
     * Constructor.
     *
     * @param function The function.
     */
    public PDFunctionType2(COSBase function)
    {
        super(function);

        if (getDictionary().getDictionaryObject(COSName.C0) == null)
        {
            c0 = new COSArray();
            c0.add(new COSFloat(0));
        }
        else
        {
            c0 = (COSArray) getDictionary().getDictionaryObject(COSName.C0);
        }

        if (getDictionary().getDictionaryObject(COSName.C1) == null)
        {
            c1 = new COSArray();
            c1.add(new COSFloat(1));
        }
        else
        {
            c1 = (COSArray) getDictionary().getDictionaryObject(COSName.C1);
        }

        exponent = getDictionary().getFloat(COSName.N);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int getFunctionType()
    {
        return 2;
    }

    /**
     * Performs exponential interpolation
     *
     * {@inheritDoc}
     */
    @Override
    public float[] eval(float[] input) throws IOException
    {
        // exponential interpolation
        float xToN = (float) Math.pow(input[0], exponent); // x^exponent

        float[] result = new float[c0.size()];
        for (int j = 0; j < result.length; j++)
        {
            float C0j = ((COSNumber) c0.get(j)).floatValue();
            float C1j = ((COSNumber) c1.get(j)).floatValue();
            result[j] = C0j + xToN * (C1j - C0j);
        }

        return clipToRange(result);
    }

    /**
     * Returns the C0 values of the function, 0 if empty.
     *
     * @return a COSArray with the C0 values
     */
    public COSArray getC0()
    {
        return c0;
    }

    /**
     * Returns the C1 values of the function, 1 if empty.
     *
     * @return a COSArray with the C1 values
     */
    public COSArray getC1()
    {
        return c1;
    }

    /**
     * Returns the exponent of the function.
     *
     * @return the float value of the exponent
     */
    public float getN()
    {
        return exponent;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString()
    {
        return "FunctionType2{"
                + "C0:" + getC0() + " "
                + "C1:" + getC1() + "}";
    }
}

@@ -3724,16 +3724,17 @@
   + %22C0:
+ 
 %22 + getC
@@ -3765,16 +3765,17 @@
   + %22C1:
+ 
 %22 + getC
@@ -3779,16 +3779,55 @@
 etC1() +
+ %22 %22%0A                + %22N: %22 + getN() +
  %22%7D%22;%0A  

add missing element in toString