// ***************************************************************** -*- C++ -*-
/*
* Copyright (C) 2004-2018 Exiv2 authors
* This program is part of the Exiv2 distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
*/
/*!
@file pngchunk_int.hpp
@brief Class PngChunk to parse PNG chunk data implemented using the following references:
PNG iTXt chunk structure from PNG definitive guide,
PNG tTXt and zTXt chunks structures from PNG definitive guide,
PNG tags list by Phil Harvey
Email communication with caulier dot gilles at gmail dot com
*/
/*
File: pngchunk.cpp
*/
#ifndef PNGCHUNK_INT_HPP_
#define PNGCHUNK_INT_HPP_
// *****************************************************************************
// included header files
#include "types.hpp"
#include "pngimage.hpp"
// + standard includes
#include
#include
#include
// *****************************************************************************
// namespace extensions
namespace Exiv2 {
// *****************************************************************************
// class declarations
class Image;
namespace Internal {
// *****************************************************************************
// class definitions
/*!
@brief Stateless parser class for data in PNG chunk format. Images use this
class to decode and encode PNG-based data.
*/
class PngChunk {
public:
/*!
@brief Text Chunk types.
*/
enum TxtChunkType {
tEXt_Chunk = 0,
zTXt_Chunk = 1,
iTXt_Chunk = 2
};
public:
/*!
@brief Decode PNG IHDR chunk data from a data buffer
\em data and return image size to \em outWidth and \em outHeight.
@param data PNG Chunk data buffer.
@param outWidth Integer pointer to be set to the width of the image.
@param outHeight Integer pointer to be set to the height of the image.
*/
static void decodeIHDRChunk(const DataBuf& data,
int* outWidth,
int* outHeight);
/*!
@brief Decode PNG tEXt, zTXt, or iTXt chunk data from \em pImage passed by data buffer
\em data and extract Comment, Exif, Iptc, Xmp metadata accordingly.
@param pImage Pointer to the image to hold the metadata
@param data PNG Chunk data buffer.
@param type PNG Chunk TXT type.
*/
static void decodeTXTChunk(Image* pImage,
const DataBuf& data,
TxtChunkType type);
/*!
@brief Decode PNG tEXt, zTXt, or iTXt chunk data from \em pImage passed by data buffer
\em data and extract Comment, Exif, Iptc, Xmp to DataBuf
@param data PNG Chunk data buffer.
@param type PNG Chunk TXT type.
*/
static DataBuf decodeTXTChunk(const DataBuf& data,
TxtChunkType type);
/*!
@brief Return PNG TXT chunk key as data buffer.
@param data PNG Chunk data buffer.
@param stripHeader Set true if chunk data start with header bytes, else false (default).
*/
static DataBuf keyTXTChunk(const DataBuf& data, bool stripHeader=false);
/*!
@brief Return a complete PNG chunk data compressed or not as buffer.
Data returned is formated accordingly with metadata \em type
to host passed by \em metadata.
@param metadata metadata buffer.
@param type metadata type.
*/
static std::string makeMetadataChunk(const std::string& metadata,
MetadataId type);
private:
/*!
@brief Parse PNG Text chunk to determine type and extract content.
Supported Chunk types are tTXt, zTXt, and iTXt.
*/
static DataBuf parseTXTChunk(const DataBuf& data,
int keysize,
TxtChunkType type);
/*!
@brief Parse PNG chunk contents to extract metadata container and assign it to image.
Supported contents are:
Exif raw text profile generated by ImageMagick ==> Image Exif metadata.
Iptc raw text profile generated by ImageMagick ==> Image Iptc metadata.
Xmp raw text profile generated by ImageMagick ==> Image Xmp metadata.
Xmp packet generated by Adobe ==> Image Xmp metadata.
Description string ==> Image Comments.
*/
static void parseChunkContent( Image* pImage,
const byte* key,
long keySize,
const DataBuf arr);
/*!
@brief Return a compressed (zTXt) or uncompressed (tEXt) PNG ASCII text chunk
(length + chunk type + chunk data + CRC) as a string.
@param keyword Keyword for the PNG text chunk
@param text Text to be recorded in the PNG chunk.
@param compress Flag indicating whether to compress the PNG chunk data.
@return String containing the PNG chunk
*/
static std::string makeAsciiTxtChunk(const std::string& keyword,
const std::string& text,
bool compress);
/*!
@brief Return a compressed or uncompressed (iTXt) PNG international text chunk
(length + chunk type + chunk data + CRC) as a string.
@param keyword Keyword for the PNG international text chunk
@param text Text to be recorded in the PNG chunk.
@param compress Flag indicating whether to compress the PNG chunk data.
*/
static std::string makeUtf8TxtChunk(const std::string& keyword,
const std::string& text,
bool compress);
/*!
@brief Wrapper around zlib to uncompress a PNG chunk content.
*/
static void zlibUncompress(const byte* compressedText,
unsigned int compressedTextSize,
DataBuf& arr);
/*!
@brief Wrapper around zlib to compress a PNG chunk content.
*/
static std::string zlibCompress(const std::string& text);
/*!
@brief Decode from ImageMagick raw text profile which host encoded Exif/Iptc/Xmp metadata byte array.
*/
static DataBuf readRawProfile(const DataBuf& text,bool iTXt);
/*!
@brief Encode to ImageMagick raw text profile, which host encoded
Exif/IPTC/XMP metadata byte arrays.
*/
static std::string writeRawProfile(const std::string& profileData,
const char* profileType);
friend class Exiv2::PngImage;
}; // class PngChunk
}} // namespace Internal, Exiv2
#endif // #ifndef PNGCHUNK_INT_HPP_