load_header.hh

// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena 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, version 2 of the License.
//
// Olena 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 Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project 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 MLN_IO_PNM_LOAD_HEADER_HH
# define MLN_IO_PNM_LOAD_HEADER_HH


# include <cstdlib>
# include <iostream>
# include <fstream>
# include <string>


namespace mln
{

  namespace io
  {

      namespace pnm
      {

# ifndef MLN_INCLUDE_ONLY

        inline
        bool read_header(std::ifstream& istr,
                         char& type,
                         int& nrows, int& ncols,
                         unsigned int& maxval,
                         bool test = false)
        {
          // check magic
          if (istr.get() != 'P' )
            goto err;
          type = static_cast<char>(istr.get());

          if (type < '1' || type > '6')
            goto err;
          if (istr.get() != '\n')
            goto err;

          // skip comments
          while (istr.peek() == '#')
          {
            std::string line;
            std::getline(istr, line);
          }

          // get size
          istr >> ncols >> nrows;
          if (nrows <= 0 || ncols <= 0)
            goto err;

          // get maxvalue
          if (istr.get() != '\n')
            goto err;
          if (type != '1' && type != '4')
          {
            istr >> maxval;
            if (istr.get() != '\n')
              goto err;
          }
          return true;

        err:
          if (! test)
          {
            std::cerr << "error: badly formed header!";
            std::abort();
          }
          return false;
        }

        inline
        void read_header(char ascii, char raw,
                         std::ifstream& istr,
                         char& type,
                         int& nrows, int& ncols,
                         unsigned int& maxval)
        {
          read_header(istr, type, nrows, ncols, maxval);
          if (! (type == ascii || type == raw))
          {
            std::cerr << "error: bad pnm type; "
                      << "expected P" << ascii
                      << " or P" << raw
                      << ", get P" << type << "!";
            std::abort();
          }
        }

        inline
        void read_header(char ascii, char raw,
                         std::ifstream& istr,
                         char& type,
                         int& nrows, int& ncols)
        {
          unsigned int maxval;
          read_header(ascii, raw, istr, type,
                      nrows, ncols, maxval);
        }

# endif // ! MLN_INCLUDE_ONLY

      } // end of namespace mln::io::pnm

  } // end of namespace mln::io

} // end of namespace mln


#endif // ! MLN_IO_PNM_LOAD_HEADER_HH