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208 lines
8.3 KiB
C++
208 lines
8.3 KiB
C++
22 years ago
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// ***************************************************************** -*- C++ -*-
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/*
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* Copyright (C) 2004 Andreas Huggel <ahuggel@gmx.net>
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*
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* This program is part of the Exiv2 distribution.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/*!
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@file image.hpp
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@brief Class JpegImage to access JPEG images
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@version $Name: $ $Revision: 1.1 $
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@author Andreas Huggel (ahu)
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<a href="mailto:ahuggel@gmx.net">ahuggel@gmx.net</a>
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@date 09-Jan-04, ahu: created
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11-Feb-04, ahu: isolated as a component
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*/
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#ifndef IMAGE_HPP_
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#define IMAGE_HPP_
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// *****************************************************************************
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// included header files
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#include "types.hpp"
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// + standard includes
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#include <string>
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#include <iosfwd>
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// *****************************************************************************
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// namespace extensions
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namespace Exif {
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// *****************************************************************************
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// class definitions
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/*!
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@brief Helper class to access JPEG images
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*/
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class JpegImage {
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// Copying not allowed
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JpegImage(const JpegImage& rhs);
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// Assignment not allowed
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JpegImage& operator=(const JpegImage& rhs);
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public:
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//! Default constructor
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JpegImage();
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//! Default destructor
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~JpegImage();
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/*!
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@brief Checks if the stream is the beginning of a JPEG image
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@param is Input stream to test
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@return true if the input stream starts the JPEG SOI marker.
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The stream is advanced by two characters in this case.<br>
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false if the input stream does not begin with the JPEG SOI
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marker. The stream is not advanced in this case.<br>
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false if reading the first two bytes from the stream fails.
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Consult the stream state for more information. In this case,
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the stream may or may not have been advanced by 1 or 2
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characters.
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*/
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static bool isJpeg(std::istream& is);
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/*!
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@brief Reads the %Exif data from the file path into the internal
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data buffer.
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@param path Path to the file.
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@return 0 if successful;<BR>
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-1 if the file cannot be opened; or<BR>
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the return code of readExifData(std::istream& is)
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if the call to this function fails.
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*/
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int readExifData(const std::string& path);
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/*!
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@brief Reads the %Exif data from the stream into the internal
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data buffer.
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@param is Input stream to read from.
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@return 0 if successful;<BR>
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1 if reading from the stream failed (consult the stream state
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for more information);<BR>
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2 if the stream does not contain a JPEG image;<BR>
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3 if no %Exif APP1 segment was found after SOI at the
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beginning of the input stream.
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*/
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int readExifData(std::istream& is);
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/*!
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@brief Write the %Exif data to file path, which must contain a JPEG
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image. If an %Exif APP1 section exists in the file, it is
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replaced. Otherwise, an %Exif data section is created.
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@param path Path to the file.
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@return 0 if successful;<br>
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-1 if the input file cannot be opened;<br>
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-2 if the temporary file cannot be opened;<br>
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-3 if renaming the temporary file fails; or<br>
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the return code of
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writeExifData(std::ostream& os, std::istream& is) const
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if the call to this function fails.
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*/
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int writeExifData(const std::string& path) const;
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/*!
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@brief Copy %Exif data into the JPEG image is, write the resulting
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image to the output stream os. If an %Exif APP1 section exists
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in the input file, it is replaced. Otherwise, an %Exif data
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section is created.
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@param os Output stream to write to (e.g., a temporary file).
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@param is Input stream with the JPEG image to which the %Exif data
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should be copied.
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@return 0 if successful;<BR>
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1 if reading from the input stream failed (consult the stream
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state for more information);<BR>
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2 if the input stream does not contain a JPEG image;<BR>
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3 if neither a JFIF APP0 segment nor a %Exif APP1 segment was
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found after SOI at the beginning of the input stream;<BR>
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4 if writing to the output stream failed (consult the stream
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state for more information).
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*/
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int writeExifData(std::ostream& os, std::istream& is) const;
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/*!
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@brief Set the %Exif data. The data is copied into the internal
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data buffer.
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@param buf Pointer to the data buffer.
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@param size Number of characters in the data buffer.
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*/
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void setExifData(const char* buf, long size);
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//! @name Accessors
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//@{
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//! Returns the size of the %Exif data buffer
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long sizeExifData() const { return sizeExifData_; }
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//! Returns a read-only pointer to the %Exif data buffer
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const char* exifData() const { return exifData_; }
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//@}
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private:
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static const uint16 soi_; // SOI marker
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static const uint16 app0_; // APP0 marker
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static const uint16 app1_; // APP1 marker
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static const char exifId_[]; // Exif identifier
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static const char jfifId_[]; // JFIF identifier
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long sizeExifData_; // Size of the Exif data buffer
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char* exifData_; // Exif data buffer
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}; // class JpegImage
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//! Helper class modelling the TIFF header structure.
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class TiffHeader {
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public:
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/*!
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@brief Default constructor. Optionally sets the byte order
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(default: little endian).
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*/
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explicit TiffHeader(ByteOrder byteOrder =littleEndian);
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//! Read the TIFF header from a data buffer. Returns 0 if successful.
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int read(const char* buf);
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/*!
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@brief Write a standard TIFF header into buf as a data string, return
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number of bytes copied.
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Only the byte order of the TIFF header varies, the values written for
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offset and tag are constant, i.e., independent of the values possibly
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read before a call to this function. The value 0x00000008 is written
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for the offset, tag is set to 0x002a.
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@param buf The data buffer to write to.
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@return The number of bytes written.
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*/
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long copy(char* buf) const;
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//! Return the size of the TIFF header in bytes.
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long size() const { return 8; }
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//! @name Accessors
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//@{
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//! Return the byte order (little or big endian).
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ByteOrder byteOrder() const { return byteOrder_; }
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//! Return the tag value.
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uint16 tag() const { return tag_; }
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/*!
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@brief Return the offset to IFD0 from the start of the TIFF header.
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The offset is 0x00000008 if IFD0 begins immediately after the
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TIFF header.
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*/
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uint32 offset() const { return offset_; }
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//@}
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private:
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ByteOrder byteOrder_;
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uint16 tag_;
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uint32 offset_;
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}; // class TiffHeader
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} // namespace Exif
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#endif // #ifndef IMAGE_HPP_
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