exiv2/src/makernote.hpp

// ***************************************************************** -*- C++ -*-
/*
 * Copyright (C) 2004 Andreas Huggel <ahuggel@gmx.net>
 * 
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
/*!
  @file    makernote.hpp
  @brief   Contains the %Exif %MakerNote interface, IFD %MakerNote and a 
           MakerNote factory
  @version $Name:  $ $Revision: 1.7 $
  @author  Andreas Huggel (ahu)
           <a href="mailto:ahuggel@gmx.net">ahuggel@gmx.net</a>
  @date    18-Feb-04, ahu: created
 */
#ifndef MAKERNOTE_HPP_
#define MAKERNOTE_HPP_

// *****************************************************************************
// included header files
#include "types.hpp"
#include "ifd.hpp"

// + standard includes
#include <string>
#include <iosfwd>
#include <utility>
#include <vector>

// *****************************************************************************
// namespace extensions
namespace Exif {

    class Value;

// *****************************************************************************
// class definitions

    /*!
      @brief %Exif makernote interface

      %MakerNote is a low-level container for makernote entries. The ExifData
      container uses makernote entries just like the other %Exif metadata. Thus,
      clients can access %Exif and makernote tags and their values uniformly
      through the %ExifData interface. The role of %MakerNote is very similar to
      that of class Ifd (but makernotes do not need to be in IFD format, see
      below). In addition, it provides %MakerNote specific tag descriptions and
      print functions to interpret the makernote values.

      MakerNote holds methods and functionality to
      - read the makernote from a character buffer
      - copy the makernote to a character buffer
      - maintain a list of makernote entries (similar to IFD entries) 
      - provide makernote specific tag names and keys
      - interpret (print) the values of makernote tags

      Makernotes can be added to the system by subclassing %MakerNote and
      registering a prototye of the new subclass together with the camera make
      and model (which may contain wildcards) in the MakerNoteFactory. Since the
      majority of makernotes are in IFD format, subclass IfdMakerNote is
      provided. It contains an IFD container and implements all interface
      methods related to the makernote entries. <BR>

      To implement a new IFD makernote, all that you need to do is 
      - subclass %IfdMakerNote, 
      - implement the clone method, 
      - add a list of tag descriptions and appropriate print functions and 
      - register the subclass in the makernote factory. 
      .
      See CanonMakerNote for an example.
     */
    class MakerNote {
    public:

        //! MakerNote Tag information
        struct MnTagInfo {
            //! Constructor
            MnTagInfo(uint16 tag, const char* name, const char* desc) 
                : tag_(tag), name_(name), desc_(desc) {}

            uint16 tag_;                //!< Tag
            const char* name_;          //!< One word tag label
            const char* desc_;          //!< Short tag description
        }; // struct MnTagInfo

        //! @name Creators
        //@{
        //! Constructor. Takes an optional makernote info tag array.
        MakerNote(const MnTagInfo* mnTagInfo =0) : mnTagInfo_(mnTagInfo) {}
        //! Virtual destructor.
        virtual ~MakerNote() {}
        //@}

        //! @name Manipulators
        //@{
        /*!
          @brief Read the makernote from character buffer buf of length len at
                 position offset (from the start of the TIFF header) and encoded
                 in byte order byteOrder.
         */
        virtual int read(const char* buf, 
                         long len, 
                         ByteOrder byteOrder,
                         long offset) =0;
        /*!
          @brief Copy (write) the makerNote to the character buffer buf at 
                 position offset (from the start of the TIFF header), encoded
                 in byte order byteOrder. Update internal offsets if necessary.
                 Return the number of bytes written.
         */
        virtual long copy(char* buf, ByteOrder byteOrder, long offset) =0;
        /*!
          @brief Reset the makernote. Delete all makernote entries from the
                 class and put the object in a state where it can accept
                 completely new entries.
         */
        virtual void clear() =0;
        /*!
          @brief Add the entry to the makernote. No duplicate-check is performed,
                 i.e., it is possible to add multiple entries with the same tag.
                 The memory allocation mode of the entry to be added must be true
                 and the IFD id of the entry must be set to 'makerIfd'.
         */
        virtual void add(const Entry& entry) =0;
        //! Sort the makernote entries by tag
        virtual void sortByTag() =0;
        //! The first makernote entry
        virtual Entries::iterator begin() =0;
        //! End of the makernote entries
        virtual Entries::iterator end() =0;
        //@}

        //! @name Accessors
        //@{
        //! Return the key for the tag.
        std::string makeKey(uint16 tag) const;
        //! Return the associated tag for a makernote key.
        uint16 decomposeKey(const std::string& key) const;
        /*!
          @brief Return the name of a makernote tag. The default implementation
                 looks up the makernote info tag array if one is set, else
                 it translates the tag to a string with the hexadecimal value of
                 the tag.
         */
        virtual std::string tagName(uint16 tag) const;
        /*!
          @brief Return the tag associated with a makernote tag name. The
                 default implementation looks up the makernote info tag array
                 if one is set, else it expects tag names in the form \"0x01ff\"
                 and converts them to unsigned integer.
         */
        virtual uint16 tag(const std::string& tagName) const;
        /*!
          @brief Return a pointer to a copy of itself (deep copy).
                 The caller owns this copy and is responsible to delete it!
         */
        virtual MakerNote* clone() const =0;
        //! The first makernote entry
        virtual Entries::const_iterator begin() const =0;
        //! End of the makernote entries
        virtual Entries::const_iterator end() const =0;
        //! Find an entry by idx, return a const iterator to the record
        virtual Entries::const_iterator findIdx(int idx) const =0;
        //! Return the size of the makernote in bytes.
        virtual long size() const =0;
        //! Return the name of the makernote section
        virtual std::string sectionName(uint16 tag) const =0; 
        //! Interpret and print the value of a makernote tag
        virtual std::ostream& printTag(std::ostream& os,
                                       uint16 tag, 
                                       const Value& value) const =0;
        //@}

    protected:
        //! Pointer to an array of makernote tag infos
        const MnTagInfo* mnTagInfo_;   

    }; // class MakerNote

    /*!
      @brief Interface for MakerNotes in IFD format. See MakerNote.

      Todo: Allow for a 'prefix' before the IFD (OLYMP, etc)
            Cater for offsets from start of TIFF header as well as relative to Mn
     */
    class IfdMakerNote : public MakerNote {
    public:
        //! @name Creators
        //@{        
        //! Constructor. Takes an optional makernote info tag array.
        IfdMakerNote(const MakerNote::MnTagInfo* mnTagInfo =0)
            : MakerNote(mnTagInfo), ifd_(makerIfd, 0, false) {}
        //! Virtual destructor
        virtual ~IfdMakerNote() {}
        //@}

        //! @name Manipulators
        //@{
        int read(const char* buf, long len, ByteOrder byteOrder, long offset);
        long copy(char* buf, ByteOrder byteOrder, long offset);
        void clear() { ifd_.clear(); }
        void add(const Entry& entry) { ifd_.add(entry); }
        void sortByTag() { ifd_.sortByTag(); }
        Entries::iterator begin() { return ifd_.begin(); }
        Entries::iterator end() { return ifd_.end(); }
        //@}

        //! @name Accessors
        //@{
        Entries::const_iterator begin() const { return ifd_.begin(); }
        Entries::const_iterator end() const { return ifd_.end(); }
        Entries::const_iterator findIdx(int idx) const;
        long size() const;
        virtual MakerNote* clone() const =0;
        virtual std::string sectionName(uint16 tag) const =0; 
        virtual std::ostream& printTag(std::ostream& os,
                                       uint16 tag, 
                                       const Value& value) const =0;
        //@}

    protected:
        Ifd ifd_;                               //!< MakerNote IFD

    }; // class IfdMakerNote

    /*!
      @brief Factory for MakerNote objects.

      Maintains an associative list (tree) of camera makes/models and
      corresponding %MakerNote prototypes. Creates an instance of the %MakerNote
      for one camera make/model. The factory is implemented as a singleton,
      which can be accessed only through the static member function instance().
    */
    class MakerNoteFactory {
    public:
        /*!
          @brief Access the MakerNote factory. Clients access the task factory
                 exclusively through this method.
        */
        static MakerNoteFactory& instance();

        //! @name Manipulators
        //@{        
        /*!
          @brief Register a %MakerNote prototype for a camera make and model.

          Registers a %MakerNote for a given make and model combination with the
          factory. Both the make and model strings may contain wildcards ('*',
          e.g., "Canon*").  The method adds a new makerNote pointer to the
          registry with the make and model strings provided. It takes ownership
          of the object pointed to by the maker note pointer provided. If the
          make already exists, then a new branch for the model is added to the
          registry. If the model also already exists, then the new makerNote
          pointer replaces the old one and the maker note pointed to by the old
          pointer is deleted.

          @param make Camera manufacturer. (Typically the string from the %Exif
                 make tag.)
          @param model Camera model. (Typically the string from the %Exif
                 model tag.)
          @param makerNote Pointer to the prototype. Ownership is transfered to the
                 %MakerNote factory.
        */
        void registerMakerNote(const std::string& make, 
                               const std::string& model, 
                               MakerNote* makerNote);
        //@}

        //! @name Accessors
        //@{        
        /*!
          @brief Create the appropriate %MakerNote based on camera make and
                 model, return a pointer to the newly created MakerNote
                 instance. Return 0 if no %MakerNote is defined for the camera
                 model.

          The method searches the make-model tree for a make and model
          combination in the registry that matches the search key. The search is
          case insensitive (Todo: implement case-insensitive comparisons) and
          wildcards in the registry entries are supported. First the best
          matching make is searched, then the best matching model for this make
          is searched. If there is no matching make or no matching model within
          the models registered for the best matching make, then no maker note
          is created and the function returns 0. If a match is found, the
          function returns a pointer to a clone of the registered prototype. The
          maker note pointed to is owned by the caller of the function, i.e.,
          the caller is responsible to delete the returned make note when it is
          no longer needed.
          The best match is the match with the most matching characters.

          @param make Camera manufacturer. (Typically the string from the %Exif
                 make tag.)
          @param model Camera model. (Typically the string from the %Exif
                 model tag.)
          @return A pointer that owns a %MakerNote for the camera model.  If
                 the camera is not supported, the pointer is 0.
         */
        MakerNote* create(const std::string& make, 
                          const std::string& model) const;
        //@}

        /*!
          @brief Match a registry entry with a key (used for make and model).

          The matching algorithm is case insensitive and wildcards ('*') in the
          registry entry are supported. The best match is the match with the
          most matching characters.

          @return A pair of which the first component indicates whether or not
                  the key matches and the second component contains the number
                  of matching characters.
         */
        static std::pair<bool, int> match(const std::string& regEntry, 
                                          const std::string& key);

    private:
        //! @name Creators
        //@{                
        //! Prevent construction other than through instance().
        MakerNoteFactory() {}
        //! Prevent copy construction: not implemented.
        MakerNoteFactory(const MakerNoteFactory& rhs);
        //@}

        //! Type used to store model labels and %MakerNote prototype classes
        typedef std::vector<std::pair<std::string, MakerNote*> > ModelRegistry;
        //! Type used to store a list of make labels and model registries
        typedef std::vector<std::pair<std::string, ModelRegistry*> > Registry;

        // DATA
        //! Pointer to the one and only instance of this class.
        static MakerNoteFactory* instance_;
        //! List of makernote types and corresponding prototypes.
        Registry registry_;

    }; // class MakerNoteFactory
   
}                                       // namespace Exif

#endif                                  // #ifndef MAKERNOTE_HPP_