/*
 * Copyright 2016 Skynav, Inc. All rights reserved.
 * Portions Copyright 2009 Extensible Formatting Systems, Inc (XFSI).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY SKYNAV, INC. AND ITS CONTRIBUTORS “AS IS” AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL SKYNAV, INC. OR ITS CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.xfsi.xav.validation.images.png;

public final class ChunkValidatorhIST extends ChunkValidator {

    public static final class Spec {
        public static final String section = "4.2.4";
        static final byte[] header =
            ChunkValidatorhIST.class.getName().substring(ChunkValidatorhIST.class.getName().length() - ChunkValidator.Spec.Props.typeSize,
                                                         ChunkValidatorhIST.class.getName().length()).getBytes(Utils.getCharset());
    }

    void validate() throws PngValidationException {
        validateMultipleAllowed(Spec.header);
        validateAfterChunk(ChunkValidatorPLTE.Spec.header);
        validateBeforeChunk(ChunkValidatorIDAT.Spec.header);
        validateFrequency();
    }

    private void validateFrequency() throws PngValidationException {
        ChunkState plte = png.getChunkState(ChunkValidatorPLTE.Spec.header);
        byte[] PLTEData = plte.getData();
        int hISTEntries = data.length/2;
        int PLTEEntries = PLTEData.length/3;
        if (hISTEntries != PLTEEntries)
            png.logMsg(PngValidator.MsgCode.PNG01E037, Spec.section, PLTEEntries, hISTEntries);
        else
            png.logMsg(PngValidator.MsgCode.PNG01I013, Spec.section, PLTEEntries, hISTEntries);
    }

}