ExifEntry.hpp

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/*
    libglim: a C++ Free library render images using OpenGL
    Copyright (C) 2002 Nestal Wan

    This library 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 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
    General Public License for more details.

    You should have received a copy of the GNU General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#ifndef __PICINFO_EXIF_ENTRY_HEADER_INCLUDED__
#define __PICINFO_EXIF_ENTRY_HEADER_INCLUDED__

#ifndef __PICINFO_TAG_DEF_HEADER_INCLUDED__
#include "TagDef.hpp"
#endif

#ifndef __PICINFO_CSTDINT_HEADER_INCLUDED__
#include "cstdint.hpp"
#endif

#include <algorithm>
#include <cstdio>
#include <cstring>
#include <iosfwd>
#include <vector>

namespace picinfo {

class CTiff ;
struct TagSpace ;

class CExifEntry
{
private :
    CTagDef     m_tag ;     
    uint16_t    m_type ;    
    uint32_t    m_count ;   
    uint32_t    m_offset ;  
    
    CTiff       *m_file ;   
    
    mutable std::vector<unsigned char>  m_data ;
    
private :
    template <typename T1, typename T2>
    struct Convert
    {
        T2 operator()( const CExifEntry *e, std::size_t idx ) ;
    } ;

public :
    CExifEntry( tag_t tag, const TagSpace& tspace  ) ;
    CExifEntry( tag_t tag, const TagSpace& tspace, uint16_t type,
               uint32_t count, uint32_t offset, CTiff *file ) ;

    bool operator<( const CExifEntry& rhs ) const ;

    tag_t Tag( ) const ;
    uint32_t Count( ) const ;
    
    const char* LongName( ) const ;
    const char* TagName( ) const ;

    unsigned char* Data( ) ;
    const unsigned char* Data( ) const ;
    uint32_t Size( ) const ;

    template <typename T>
    const T As( std::size_t idx = 0 ) const ;

    std::string Format( ) const ;

    friend std::ostream& operator<<( std::ostream& os, const CExifEntry& e ) ;

private :
    bool IsReference( ) const ;
    bool IsDataReady( ) const ;
    void EnsureDataReady( ) const ;
    
} ;

} // end of namespace

#endif

---