// ***************************************************************** -*- 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:<br>
<a href="http://www.vias.org/pngguide/chapter11_05.html">PNG iTXt chunk structure</a> from PNG definitive guide,<br>
<a href="http://www.vias.org/pngguide/chapter11_04.html">PNG tTXt and zTXt chunks structures</a> from PNG definitive guide,<br>
<a href="http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html">PNG tags list</a> by Phil Harvey<br>
Email communication with <a href="mailto:caulier dot gilles at gmail dot com">caulier dot gilles at gmail dot com</a><br>
*/
/*
File: pngchunk.cpp
*/
#ifndef PNGCHUNK_INT_HPP_
#define PNGCHUNK_INT_HPP_
// *****************************************************************************
// included header files
#include "types.hpp"
#include "pngimage.hpp"
// + standard includes
#include <iosfwd>
#include <cassert>
#include <cstdarg>
// *****************************************************************************
// 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_