//Copyright (C) 2003 David Bateman
//
// 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 3 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, see <http://www.gnu.org/licenses/>.
//
// In addition to the terms of the GPL, you are permitted to link
// this program with any Open Source program, as defined by the
// Open Source Initiative (www.opensource.org)

#include <iostream>
#include <iomanip>
#include <sstream>
#include <octave/oct.h>
#include <octave/pager.h>

DEFUN_DLD (__errcore__, args, ,
  "-*- texinfo -*-\n"
"@deftypefn {Loadable Function} {@var{c} =} _errcore (@var{a}, @var{b})\n"
"\n"
"Returns the number of bit errors comparing the matrices @var{a} and\n"
"@var{b}. These matrices must be of the same size. The return matrix @var{c}\n"
"will also be of the same size.\n"
"\n"
"This is an internal function of @dfn{biterr} and @dfn{symerr}. You should\n"
"use these functions instead.\n"
"@end deftypefn\n"
"@seealso{biterr,symerr}") {
  octave_value retval;

  Matrix a = args(0).matrix_value();
  Matrix b = args(1).matrix_value();

  if ((a.rows() != b.rows()) || (a.cols() != b.cols())) {
    error("_errcore: Matrix mismatch");
    return retval;
  }
  
  unsigned int sz = (sizeof(unsigned int) << 3);
  Matrix c(a.rows(),a.cols(),0);
  for (int i=0; i<a.rows(); i++)
    for (int j=0; j<a.cols(); j++) {
      unsigned int tmp = (unsigned int)a(i,j) ^ (unsigned int)b(i,j);
      if (tmp != 0)
	for (unsigned int k=0; k < sz; k++)
	  if (tmp & (1<<k))
	    c(i,j)++;
    }
  
  retval = octave_value(c);
  return retval;
}

/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/