/*
 * @file llpngwrapper.h
 *
 * $LicenseInfo:firstyear=2007&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLPNGWRAPPER_H
#define LL_LLPNGWRAPPER_H

#include "png.h"
#include "llimage.h"

class LLPngWrapper
{
public:
    LLPngWrapper();
    virtual ~LLPngWrapper();

public:
    struct ImageInfo
    {
        U16 mWidth;
        U16 mHeight;
        S8  mComponents;
    };

    bool isValidPng(U8* src);
    bool readPng(U8* src, S32 dataSize, LLImageRaw* rawImage, ImageInfo *infop = NULL);
    bool writePng(const LLImageRaw* rawImage, U8* dst, size_t destSize);
    U32  getFinalSize();
    const std::string& getErrorMessage();

protected:
    void normalizeImage();
    void updateMetaData();

private:

    // Structure for writing/reading PNG data to/from memory
    // as opposed to using a file.
    struct PngDataInfo
    {
        U8 *mData;
        U32 mOffset;
        S32 mDataSize;
    };

    static void writeFlush(png_structp png_ptr);
    static void errorHandler(png_structp png_ptr, png_const_charp msg);
    static void readDataCallback(png_structp png_ptr, png_bytep dest, png_size_t length);
    static void writeDataCallback(png_structp png_ptr, png_bytep src, png_size_t length);

    void releaseResources();

    png_structp mReadPngPtr;
    png_infop mReadInfoPtr;
    png_structp mWritePngPtr;
    png_infop mWriteInfoPtr;

    U8 **mRowPointers;

    png_uint_32 mWidth;
    png_uint_32 mHeight;
    S32 mBitDepth;
    S32 mColorType;
    S32 mChannels;
    S32 mInterlaceType;
    S32 mCompressionType;
    S32 mFilterMethod;

    U32 mFinalSize;

    F64 mGamma;

    std::string mErrorMessage;
};

#endif