pnm_read_data.hh

// Copyright (C) 2001, 2002, 2003, 2004  EPITA Research and Development Laboratory
//
// This file is part of the Olena Library.  This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License version 2 as published by the
// Free Software Foundation.
//
// 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; see the file COPYING.  If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
// MA 02111-1307, USA.
//
// As a special exception, you may use this file as part of a free
// software library without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License.  This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.

#ifndef OLENA_IO_PNM_READ_DATA_HH
# define OLENA_IO_PNM_READ_DATA_HH

# include <oln/core/image.hh>
# include <oln/io/image_base.hh>
# include <oln/io/pnm_common.hh>

# include <iostream>

namespace oln {

  namespace io {

    namespace internal {

      
      template<pnm_type V, reader_id R>
      struct pnm_read_data
      {
        template <class I>
        static bool
        read(std::istream&, I&, const pnm2d_info&)
        { 
          return false; 
        }
      }; 

      /*---------------------.
      | pnm read data binary |
      `---------------------*/

      template <>
      struct pnm_read_data<PnmBinary, ReadPnmPlain>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info&)
        {
          // FIXME: implement an iterator over data
          oln_iter_type(I) it (output);
          
          for (it = begin; it != end; ++it)
            {
              unsigned char c;
              do
                {
                  c = in.get();
                }
              while ((c != '0') && (c != '1'));
              output[it] = (c == '0');
            }
          return true;
        }
      };
      
      template <>
      struct pnm_read_data<PnmBinary, ReadPnmRaw>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info& info)
        {
          oln_iter_type(I) it(output);
          
          coord cols = 0;
          unsigned bits = 0;
          unsigned char c = 0;
          
          for (it = begin; it != end; ++it)
            {
              if (bits == 0)
                {
                  c = in.get();
                  bits = 8;
                }
              bool b = (c & (1 << --bits)) ? false : true;
              output[it] = b;
              if (++cols >= info.cols)
                c = cols = bits = 0;
            }
          return true;
        }
      };

      /*----------------------.
      | pnm read data integer |
      `----------------------*/
        
      template <>
      struct pnm_read_data<PnmInteger, ReadPnmPlain>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info&)
        {
          // FIXME: implement an iterator over data
          oln_iter_type(I) it (output);
          
          int c;
          for (it = begin; it != end; ++it)
            {
              in >> c;
              output[it] = c;
            }
          return true;
        }
      };
      
          
      template <>
      struct pnm_read_data<PnmInteger, ReadPnmRaw>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info& info)
        {
          // FIXME: implement an iterator over data
          oln_iter_type(I) it (output);
          
          for (it = begin; it != end; ++it)
            {
              if (info.max_val <= 255)
                {
                  unsigned char c;
                  in.read((char*) &c, 1);
                  output[it] = c;
                }
              else
                {
                  unsigned short i;
                  in.read((char*) &i, 2);
                  output[it] = i;
                }
            }
          return true;
        }
      };

      /*------------------------.
      | pnm read data vectorial |
      `------------------------*/

          
      template <>
      struct pnm_read_data<PnmVectorial, ReadPnmPlain>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info&)
        {
          // FIXME: implement an iterator over data
          oln_iter_type(I) it (output);
          
          for (it = begin; it != end; ++it)
            {
              int tmp;
              in >> tmp; output[it][0] = tmp;
              in >> tmp; output[it][1] = tmp;
              in >> tmp; output[it][2] = tmp;
            }     
          return true;
        }
      };

          
      template <>
      struct pnm_read_data<PnmVectorial, ReadPnmRaw>
      {
        template <class I>
        static bool
        read(std::istream& in, I& output, const pnm2d_info& info)
        {
          // FIXME: implement an iterator over data
          oln_iter_type(I) it (output);
          
          for (it = begin; it != end; ++it)
            {
              if (info.max_val <= 255)
                {
                  unsigned char c[3];
                  in.read((char*) c, 3);
                  output[it][0] = c[0];
                  output[it][1] = c[1];
                  output[it][2] = c[2];
                }
              else
                {
                  precondition(sizeof(unsigned short) == 2);
                  unsigned short i[3];
                  in.read((char*) i, 3 * sizeof(unsigned short));
                  output[it][0] = i[0];
                  output[it][1] = i[1];
                  output[it][2] = i[2];
                }
            }
          return true;
        }
      };      

    } // end of namespace internal
    
  } // end of namespace io
  
} // end of namespace oln

#endif // ! OLENA_IO_PNM_READ_DATA_HH

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