src/ov-struct.cc

/*

Copyright (C) 1996, 1997, 1998, 2000, 2002, 2003, 2004, 2005, 2006,
              2007, 2008, 2009 John W. Eaton

This file is part of Octave.

Octave 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.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <iostream>

#include "Cell.h"
#include "defun.h"
#include "error.h"
#include "gripes.h"
#include "oct-lvalue.h"
#include "ov-struct.h"
#include "unwind-prot.h"
#include "utils.h"
#include "variables.h"

#include "Array-util.h"
#include "oct-locbuf.h"

#include "byte-swap.h"
#include "ls-oct-ascii.h"
#include "ls-oct-binary.h"
#include "ls-hdf5.h"
#include "ls-utils.h"
#include "pr-output.h"

DEFINE_OCTAVE_ALLOCATOR(octave_struct);

DEFINE_OV_TYPEID_FUNCTIONS_AND_DATA(octave_struct, "struct", "struct");

Cell
octave_struct::dotref (const octave_value_list& idx, bool auto_add)
{
  Cell retval;

  assert (idx.length () == 1);

  std::string nm = idx(0).string_value ();

  Octave_map::const_iterator p = map.seek (nm);

  if (p != map.end ())
    retval = map.contents (p);
  else if (auto_add)
    retval = (numel () == 0) ? Cell (dim_vector (1)) : Cell (dims ());
  else 
    error ("structure has no member `%s'", nm.c_str ());

  return retval;
}

#if 0
static void
gripe_invalid_index (void)
{
  error ("invalid index for structure array");
}
#endif

static void
gripe_invalid_index_for_assignment (void)
{
  error ("invalid index for structure array assignment");
}

static void
gripe_invalid_index_type (const std::string& nm, char t)
{
  error ("%s cannot be indexed with %c", nm.c_str (), t);
}

static void
gripe_failed_assignment (void)
{
  error ("assignment to structure element failed");
}

octave_value_list
octave_struct::subsref (const std::string& type,
			const std::list<octave_value_list>& idx,
			int nargout)
{
  octave_value_list retval;

  int skip = 1;

  switch (type[0])
    {
    case '(':
      {
	if (type.length () > 1 && type[1] == '.')
	  {
	    std::list<octave_value_list>::const_iterator p = idx.begin ();
	    octave_value_list key_idx = *++p;

	    const Cell tmp = dotref (key_idx);

	    if (! error_state)
	      {
		const Cell t = tmp.index (idx.front ());

		retval(0) = (t.length () == 1) ? t(0) : octave_value (t, true);

		// We handled two index elements, so tell
		// next_subsref to skip both of them.

		skip++;
	      }
	  }
	else
	  retval(0) = map.index (idx.front ());
      }
      break;

    case '.':
      {
	if (map.numel() > 0)
	  {
	    const Cell t = dotref (idx.front ());

	    retval(0) = (t.length () == 1) ? t(0) : octave_value (t, true);
	  }
      }
      break;

    case '{':
      gripe_invalid_index_type (type_name (), type[0]);
      break;

    default:
      panic_impossible ();
    }

  // FIXME -- perhaps there should be an
  // octave_value_list::next_subsref member function?  See also
  // octave_user_function::subsref.

  if (idx.size () > 1)
    retval = retval(0).next_subsref (nargout, type, idx, skip);

  return retval;
}

octave_value
octave_struct::subsref (const std::string& type,
			const std::list<octave_value_list>& idx,
			bool auto_add)
{
  octave_value retval;

  int skip = 1;

  switch (type[0])
    {
    case '(':
      {
	if (type.length () > 1 && type[1] == '.')
	  {
	    std::list<octave_value_list>::const_iterator p = idx.begin ();
	    octave_value_list key_idx = *++p;

	    const Cell tmp = dotref (key_idx, auto_add);

	    if (! error_state)
	      {
		const Cell t = tmp.index (idx.front (), auto_add);

		retval = (t.length () == 1) ? t(0) : octave_value (t, true);

		// We handled two index elements, so tell
		// next_subsref to skip both of them.

		skip++;
	      }
	  }
	else
	  retval = map.index (idx.front (), auto_add);
      }
      break;

    case '.':
      {
	if (map.numel() > 0)
	  {
	    const Cell t = dotref (idx.front (), auto_add);

	    retval = (t.length () == 1) ? t(0) : octave_value (t, true);
	  }
      }
      break;

    case '{':
      gripe_invalid_index_type (type_name (), type[0]);
      break;

    default:
      panic_impossible ();
    }

  // FIXME -- perhaps there should be an
  // octave_value_list::next_subsref member function?  See also
  // octave_user_function::subsref.

  if (idx.size () > 1)
    retval = retval.next_subsref (auto_add, type, idx, skip);

  return retval;
}

/*
%!test
%! x(1).a.a = 1; x(2).a.a = 2;
%! assert (size (x), [1, 2]);
%! assert (x(1).a.a, 1);
%! assert (x(2).a.a, 2);
*/

octave_value
octave_struct::numeric_conv (const octave_value& val,
			     const std::string& type)
{
  octave_value retval;

  if (type.length () > 0 && type[0] == '.' && ! val.is_map ())
    retval = Octave_map ();
  else
    retval = val;

  return retval;
}

octave_value
octave_struct::subsasgn (const std::string& type,
			 const std::list<octave_value_list>& idx,
			 const octave_value& rhs)
{
  octave_value retval;

  int n = type.length ();

  octave_value t_rhs = rhs;

  if (idx.front ().empty ())
    {
      error ("missing index in indexed assignment");
      return retval;
    }

  if (n > 1 && ! (type.length () == 2 && type[0] == '(' && type[1] == '.'))
    {
      switch (type[0])
	{
	case '(':
	  {
	    if (type.length () > 1 && type[1] == '.')
	      {
		std::list<octave_value_list>::const_iterator p = idx.begin ();
		octave_value_list t_idx = *p;

		octave_value_list key_idx = *++p;

		assert (key_idx.length () == 1);

		std::string key = key_idx(0).string_value ();

                std::list<octave_value_list> next_idx (idx);

                // We handled two index elements, so subsasgn to
                // needs to skip both of them.

                next_idx.erase (next_idx.begin ());
                next_idx.erase (next_idx.begin ());

                std::string next_type = type.substr (2);

                Cell tmpc (1, 1);
                Octave_map::iterator pkey = map.seek (key);
                if (pkey != map.end ())
                  {
                    pkey->second.make_unique ();
                    tmpc = pkey->second.index (idx.front (), true);
                  }

                // FIXME: better code reuse? cf. octave_cell::subsasgn and the case below.
		if (! error_state)
		  {
                    if (tmpc.numel () == 1)
                      {
                        octave_value& tmp = tmpc(0);

                        if (! tmp.is_defined () || tmp.is_zero_by_zero ())
                          {
                            tmp = octave_value::empty_conv (next_type, rhs);
                            tmp.make_unique (); // probably a no-op.
                          }
                        else
                          // optimization: ignore the copy still stored inside our map.
                          tmp.make_unique (1);

                        if (! error_state)
                          t_rhs = tmp.subsasgn (next_type, next_idx, rhs);
                      }
                    else
                      gripe_indexed_cs_list ();
		  }
	      }
	    else
	      gripe_invalid_index_for_assignment ();
	  }
	  break;

	case '.':
	  {
	    octave_value_list key_idx = idx.front ();

	    assert (key_idx.length () == 1);

	    std::string key = key_idx(0).string_value ();

            std::list<octave_value_list> next_idx (idx);

            next_idx.erase (next_idx.begin ());

            std::string next_type = type.substr (1);

            Cell tmpc (1, 1);
            Octave_map::iterator pkey = map.seek (key);
            if (pkey != map.end ())
              {
                pkey->second.make_unique ();
                tmpc = pkey->second;
              }

            // FIXME: better code reuse?
            if (! error_state)
              {
                if (tmpc.numel () == 1)
                  {
                    octave_value& tmp = tmpc(0);

                    if (! tmp.is_defined () || tmp.is_zero_by_zero ())
                      {
                        tmp = octave_value::empty_conv (next_type, rhs);
                        tmp.make_unique (); // probably a no-op.
                      }
                    else
                      // optimization: ignore the copy still stored inside our map.
                      tmp.make_unique (1);

                    if (! error_state)
                      t_rhs = tmp.subsasgn (next_type, next_idx, rhs);
                  }
                else
                  gripe_indexed_cs_list ();
              }
	  }
	  break;

	case '{':
	  gripe_invalid_index_type (type_name (), type[0]);
	  break;

	default:
	  panic_impossible ();
	}
    }

  if (! error_state)
    {
      switch (type[0])
	{
	case '(':
	  {
	    if (n > 1 && type[1] == '.')
	      {
		std::list<octave_value_list>::const_iterator p = idx.begin ();
		octave_value_list key_idx = *++p;
                octave_value_list idxf = idx.front ();

		assert (key_idx.length () == 1);

		std::string key = key_idx(0).string_value ();

		if (! error_state)
		  {
                    if (t_rhs.is_cs_list ())
                      {
                        Cell tmp_cell = Cell (t_rhs.list_value ());

                        // Inquire the proper shape of the RHS.

                        dim_vector didx = dims ().redim (idxf.length ());
                        for (octave_idx_type k = 0; k < idxf.length (); k++)
                          if (! idxf(k).is_magic_colon ()) didx(k) = idxf(k).numel ();

                        if (didx.numel () == tmp_cell.numel ())
                          tmp_cell = tmp_cell.reshape (didx);


                        map.assign (idxf, key, tmp_cell);

                        if (! error_state)
                          {
                            count++;
                            retval = octave_value (this);
                          }
                        else
                          gripe_failed_assignment ();
                      }
                    else 
                      {
                        const Octave_map& cmap = const_cast<const Octave_map &> (map);
                        // cast map to const reference to avoid forced key insertion.
                        if (idxf.all_scalars () 
                            || cmap.contents (key).index (idxf, true).numel () == 1)
                          {
                            map.assign (idxf, key, t_rhs.storable_value ());
                            if (! error_state)
                              {
                                count++;
                                retval = octave_value (this);
                              }
                            else
                              gripe_failed_assignment ();
                          }
                        else if (! error_state)
                          gripe_nonbraced_cs_list_assignment ();
                      }
		  }
		else
		  gripe_failed_assignment ();
	      }
	    else
	      {
		if (t_rhs.is_map())
		  {
		    Octave_map rhs_map = t_rhs.map_value ();

		    if (! error_state)
		      {
			map.assign (idx.front (), rhs_map);

			if (! error_state)
			  {
			    count++;
			    retval = octave_value (this);
			  }
			else
			  gripe_failed_assignment ();
		      }
		    else
		      error ("invalid structure assignment");
		  }
		else
		  {
		    if (t_rhs.is_null_value()) 
		      {
			map.maybe_delete_elements (idx.front());

			if (! error_state)
			  {
			    count++;
			    retval = octave_value (this);
			  }
			else
			  gripe_failed_assignment ();
		      }
		    else
		      error ("invalid structure assignment");
		  }
	      }
	  }
	  break;

	case '.':
	  {
	    octave_value_list key_idx = idx.front ();

	    assert (key_idx.length () == 1);

	    std::string key = key_idx(0).string_value ();

	    if (t_rhs.is_cs_list ())
	      {
		Cell tmp_cell = Cell (t_rhs.list_value ());

		// The shape of the RHS is irrelevant, we just want
		// the number of elements to agree and to preserve the
		// shape of the left hand side of the assignment.

		if (numel () == tmp_cell.numel ())
		  tmp_cell = tmp_cell.reshape (dims ());

		map.assign (key, tmp_cell);
	      }
	    else
              // Regularize a null matrix if stored into a struct component.
	      map.assign (key, t_rhs.storable_value ());

	    if (! error_state)
	      {
		count++;
		retval = octave_value (this);
	      }
	    else
	      gripe_failed_assignment ();
	  }
	  break;

	case '{':
	  gripe_invalid_index_type (type_name (), type[0]);
	  break;

	default:
	  panic_impossible ();
	}
    }
  else
    gripe_failed_assignment ();

  return retval;
}

octave_value
octave_struct::do_index_op (const octave_value_list& idx, bool resize_ok)
{
  // Octave_map handles indexing itself.
  return map.index (idx, resize_ok);
}

size_t
octave_struct::byte_size (void) const
{
  // Neglect the size of the fieldnames.

  size_t retval = 0;

  for (Octave_map::const_iterator p = map.begin (); p != map.end (); p++)
    {
      std::string key = map.key (p);

      octave_value val = octave_value (map.contents (p));

      retval += val.byte_size ();
    }

  return retval;
}

void
octave_struct::print (std::ostream& os, bool) const
{
  print_raw (os);
}

void
octave_struct::print_raw (std::ostream& os, bool) const
{
  unwind_protect frame;

  frame.protect_var (Vstruct_levels_to_print);

  if (Vstruct_levels_to_print >= 0)
    {
      bool print_keys_only = Vstruct_levels_to_print-- == 0;

      indent (os);
      os << "{";
      newline (os);

      increment_indent_level ();

      octave_idx_type n = map.numel ();

      if (n != 1 || print_keys_only)
	{
	  indent (os);
	  dim_vector dv = dims ();
	  os << dv.str () << " struct array containing the fields:";
	  newline (os);
	  newline (os);

	  increment_indent_level ();
	}

      string_vector key_list = map.keys ();

      for (octave_idx_type i = 0; i < key_list.length (); i++)
	{
	  std::string key = key_list[i];

	  Cell val = map.contents (key);

	  octave_value tmp = (n == 1) ? val(0) : octave_value (val, true);

	  if (n != 1 || print_keys_only)
	    {
	      indent (os);
	      os << key;
	      if (n == 1)
		{
		  dim_vector dv = tmp.dims ();
		  os << ": " << dv.str () << " " << tmp.type_name ();
		}
	      newline (os);
	    }
	  else
	    tmp.print_with_name (os, key);
	}

      if (n != 1 || print_keys_only)
	decrement_indent_level ();

      decrement_indent_level ();

      indent (os);
      os << "}";
      newline (os);
    }
  else
    {
      indent (os);
      os << "<structure>";
      newline (os);
    }
}

bool
octave_struct::print_name_tag (std::ostream& os, const std::string& name) const
{
  bool retval = false;

  indent (os);

  if (Vstruct_levels_to_print < 0)
    os << name << " = ";
  else
    {
      os << name << " =";
      newline (os);
      retval = true;
    }

  return retval;
}

static bool 
scalar (const dim_vector& dims) 
{
  return dims.length () == 2 && dims (0) == 1 && dims (1) == 1;
}

/*
%!shared x
%! x(1).a=1; x(2).a=2; x(1).b=3; x(2).b=3;
%!assert(struct('a',1,'b',3),x(1))
%!assert(isempty(x([])))
%!assert(isempty(struct('a',{},'b',{})))
%!assert(struct('a',{1,2},'b',{3,3}),x)
%!assert(struct('a',{1,2},'b',3),x)
%!assert(struct('a',{1,2},'b',{3}),x)
%!assert(struct('b',3,'a',{1,2}),x)
%!assert(struct('b',{3},'a',{1,2}),x) 
%!test x=struct([]);
%!assert(size(x),[0,0]);
%!assert(isstruct(x));
%!assert(isempty(fieldnames(x)));
%!fail("struct('a',{1,2},'b',{1,2,3})","dimensions of parameter 2 do not match those of parameter 4")
%!fail("struct(1,2,3,4)","struct expects alternating \"field\", VALUE pairs");
%!fail("struct('1',2,'3')","struct expects alternating \"field\", VALUE pairs");
*/

DEFUN (struct, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} struct (\"field\", @var{value}, \"field\", @var{value}, @dots{})\n\
\n\
Create a structure and initialize its value.\n\
\n\
If the values are cell arrays, create a structure array and initialize\n\
its values.  The dimensions of each cell array of values must match.\n\
Singleton cells and non-cell values are repeated so that they fill\n\
the entire array.  If the cells are empty, create an empty structure\n\
array with the specified field names.\n\
\n\
If the argument is an object, return the underlying struct.\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  // struct ([]) returns an empty struct.

  // struct (empty_matrix) returns an empty struct with the same
  // dimensions as the empty matrix.

  // Note that struct () creates a 1x1 struct with no fields for
  // compatibility with Matlab.

  if (nargin == 1 && args(0).is_object ())
    {
      Octave_map m = args(0).map_value ();
      retval = octave_value (new octave_struct (m));

      return retval;
    }

  if ((nargin == 1 || nargin == 2)
      && args(0).is_empty () && args(0).is_real_matrix ())
    {
      Cell fields;

      if (nargin == 2)
	{
	  if (args(1).is_cellstr ())
	    retval = Octave_map (args(0).dims (), args(1).cell_value ());
	  else
	    error ("struct: expecting cell array of field names as second argument");
	}
      else
	retval = Octave_map (args(0).dims ());

      return retval;
    }
    
  // Check for "field", VALUE pairs.

  for (int i = 0; i < nargin; i += 2) 
    {
      if (! args(i).is_string () || i + 1 >= nargin)
	{
	  error ("struct expects alternating \"field\", VALUE pairs");
	  return retval;
	}
    }

  // Check that the dimensions of the values correspond.

  dim_vector dims (1, 1);

  int first_dimensioned_value = 0;

  for (int i = 1; i < nargin; i += 2) 
    {
      if (args(i).is_cell ()) 
	{
	  dim_vector argdims (args(i).dims ());

	  if (! scalar (argdims))
	    {
	      if (! first_dimensioned_value)
		{
		  dims = argdims;
		  first_dimensioned_value = i + 1;
		}
	      else if (dims != argdims)
		{
		  error ("struct: dimensions of parameter %d do not match those of parameter %d",
			 first_dimensioned_value, i+1);
		  return retval;
		}
	    }
	}
    }

  // Create the return value.

  Octave_map map (dims);

  for (int i = 0; i < nargin; i+= 2) 
    {
      // Get key.

      std::string key (args(i).string_value ());

      if (error_state)
	return retval;

      if (! valid_identifier (key))
	{
	  error ("struct: invalid structure field name `%s'", key.c_str ());
	  return retval;
	}

      // Value may be v, { v }, or { v1, v2, ... }
      // In the first two cases, we need to create a cell array of
      // the appropriate dimensions filled with v.  In the last case, 
      // the cell array has already been determined to be of the
      // correct dimensions.

      if (args(i+1).is_cell ()) 
	{
	  const Cell c (args(i+1).cell_value ());

	  if (error_state)
	    return retval;

	  if (scalar (c.dims ())) 
	    map.assign (key, Cell (dims, c(0)));
	  else 
	    map.assign (key, c);
	}
      else 
	map.assign (key, Cell (dims, args(i+1)));

      if (error_state)
	return retval;
    }

  return octave_value (map);
}

DEFUN (isstruct, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} isstruct (@var{expr})\n\
Return 1 if the value of the expression @var{expr} is a structure\n\
(or a structure array).\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () == 1)
    retval = args(0).is_map ();
  else
    print_usage ();

  return retval;
}

DEFUN (fieldnames, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} fieldnames (@var{struct})\n\
Return a cell array of strings naming the elements of the structure\n\
@var{struct}.  It is an error to call @code{fieldnames} with an\n\
argument that is not a structure.\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin == 1)
    {
      octave_value arg = args(0);

      if (arg.is_map () || arg.is_object ())
	{
	  Octave_map m = arg.map_value ();

	  string_vector keys = m.keys ();

	  if (keys.length () == 0)
	    retval = Cell (0, 1);
	  else
	    retval = Cell (m.keys ());
	}
      else
	gripe_wrong_type_arg ("fieldnames", args(0));
    }
  else
    print_usage ();

  return retval;
}

/*
%!# test preservation of fieldname order
%!test
%!  x(3).d=1; x(2).a=2; x(1).b=3; x(2).c=3;
%!  assert(fieldnames(x), {"d"; "a"; "b"; "c"});
*/

DEFUN (isfield, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} isfield (@var{expr}, @var{name})\n\
Return true if the expression @var{expr} is a structure and it includes an\n\
element named @var{name}.  The first argument must be a structure and\n\
the second must be a string.\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin == 2)
    {
      retval = false;

      // FIXME -- should this work for all types that can do
      // structure reference operations?

      if (args(0).is_map () && args(1).is_string ())
	{
	  std::string key = args(1).string_value ();

	  Octave_map m = args(0).map_value ();

	  retval = m.contains (key) != 0;
	}
    }
  else
    print_usage ();

  return retval;
}

DEFUN (nfields, args, ,
  "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} nfields (@var{s})\n\
Return the number of fields of the structure @var{s}.\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin == 1 && args(0).is_map ())
    {
      retval = static_cast<double> (args(0).nfields ());
    }
  else
    print_usage ();

  return retval;
}

/*
%!# test isfield
%!test
%!  x(3).d=1; x(2).a=2; x(1).b=3; x(2).c=3;
%!  assert (isfield (x, "b"));
%!assert( isfield( struct("a", "1"), "a"));
%!assert( isfield( {1}, "c"), logical (0));
%!assert( isfield( struct("a", "1"), 10), logical (0));
%!assert( isfield( struct("a", "b"), "a "), logical (0));

*/

// Check that the dimensions of the input arguments are correct.

static bool
cell2struct_check_args (const dim_vector& c_dv, const dim_vector& f_dv,
			bool is_cell, int dim)
{
  bool retval = true;

  if (dim >= 0 && dim < c_dv.length ())
    {
      if (is_cell)
	{
	  if (f_dv.numel () != c_dv(dim))
	    {
	      error ("cell2struct: numel (FIELD) != size (CELL, DIM)");

	      retval = false;
	    }
	}
      else
	{
	  if (f_dv.length () > 2)
	    {
	      error ("cell2struct: field array must be a 2-d matrix");

	      retval = false;
	    }
	  else if (f_dv(0) != c_dv(dim))
	    {
	      error ("cell2struct: size (FIELD, 1) != length (C, DIM)");

	      retval = false;
	    }
	}
    }
  else
    {
      error ("cell2struct: DIM out of range");

      retval = false;
    }

  return retval;
}

static void
cell2struct_construct_idx (Array<octave_idx_type>& ra_idx1,
			   const Array<octave_idx_type>& ra_idx2,
			   octave_idx_type dim, octave_idx_type fill_value)
{
  octave_idx_type iidx = 0;

  for (octave_idx_type idx = 0; idx < ra_idx1.length (); idx++)
    {
      if (idx == dim)
	ra_idx1.elem (idx) = fill_value;
      else
	ra_idx1.elem (idx) = ra_idx2(iidx++);
    }
}

DEFUN (cell2struct, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} cell2struct (@var{cell}, @var{fields}, @var{dim})\n\
Convert @var{cell} to a structure.  The number of fields in @var{fields}\n\
must match the number of elements in @var{cell} along dimension @var{dim},\n\
that is @code{numel (@var{fields}) == size (@var{cell}, @var{dim})}.\n\
\n\
@example\n\
@group\n\
A = cell2struct (@{'Peter', 'Hannah', 'Robert';\n\
                   185, 170, 168@},\n\
                 @{'Name','Height'@}, 1);\n\
A(1)\n\
     @result{} ans =\n\
        @{\n\
          Name   = Peter\n\
          Height = 185\n\
        @}\n\
\n\
@end group\n\
@end example\n\
@end deftypefn")
{
  octave_value retval;

  if (args.length () == 3)
    {
      Cell c = args(0).cell_value ();

      if (! error_state)
	{
	  octave_value field = args(1);

	  // Field is either cell or character matrix.

	  // FIXME -- this could be simplified if we had
	  // cellstr and iscellstr functions available.

	  bool field_is_cell = field.is_cell ();

	  Cell field_cell;
	  charMatrix field_char;

	  if (field_is_cell)
	    field_cell = field.cell_value ();
	  else
	    field_char = field.char_matrix_value ();

	  if (! error_state)
	    {
	      // Retrieve the dimension value.

	      // FIXME --  int_value () should print out the
	      // conversions it does to be Matlab compatible.

	      octave_idx_type dim = args(2).int_value () - 1;

	      if (! error_state)
		{
		  dim_vector c_dv = c.dims ();
		  dim_vector field_dv = field.dims ();

		  if (cell2struct_check_args (c_dv, field_dv, field_is_cell,
					      dim))
		    {
		      octave_idx_type c_dv_length = c_dv.length ();

		      // Dimension vector for the Cell arrays to be
		      // put into the structure.

		      dim_vector value_dv;

		      // Initialize c_value_dv.

		      if (c_dv_length == 2)
			value_dv = dim_vector (1, 1);
		      else
			value_dv.resize (c_dv_length - 1);

		      octave_idx_type idx_tmp = 0;

		      for (octave_idx_type i = 0; i < c_dv_length; i++)
			{
			  if (i != dim)
			    value_dv.elem (idx_tmp++) = c_dv.elem (i);
			}

		      // All initializing is done, we can start moving
		      // values.

		      Octave_map map;

		      // If field is a cell array then we use all
		      // elements in array, on the other hand when
		      // field is a character array the number of
		      // elements is equals the number of rows.

		      octave_idx_type field_numel
			= field_is_cell ? field_dv.numel (): field_dv(0);

		      // For matlab compatibility.

		      if (field_numel == 0)
			map.reshape (dim_vector (0, 1));

		      for (octave_idx_type i = 0; i < field_numel; i++)
			{
			  // Construct cell array which goes into the
			  // structure together with the appropriate
			  // field name.

			  Cell c_value (value_dv);

			  Array<octave_idx_type> value_idx (value_dv.length (), 0);
			  Array<octave_idx_type> c_idx (c_dv_length, 0);

			  for (octave_idx_type j = 0; j < value_dv.numel (); j++)
			    {
			      // Need to do this to construct the
			      // appropriate idx for getting elements
			      // from the original cell array.

			      cell2struct_construct_idx (c_idx, value_idx,
							 dim, i);

			      c_value.elem (value_idx) = c.elem (c_idx);

			      increment_index (value_idx, value_dv);
			    }

			  std::string field_str;

			  if (field_is_cell)
			    {
			      // Matlab retrieves the field values
			      // column by column.

			      octave_value field_tmp = field_cell.elem (i);

			      field_str = field_tmp.string_value ();

			      if (error_state)
				{
				  error ("cell2struct: fields have to be of type string");
				  break;
				}
			    }
			  else
			    {
			      field_str = field_char.row_as_string (i);

			      if (error_state)
				return retval;
			    }

			  if (! valid_identifier (field_str))
			    {
			      error ("cell2struct: invalid field name `%s'",
				     field_str.c_str ());
			      break;
			    }

			  map.reshape (value_dv);

			  map.assign (field_str, c_value);
			}

		      if (! error_state)
			retval = map;
		    }
		}
	      else
		error ("cell2struct: expecting third argument to be an integer");
	    }
	  else
	    error ("cell2struct: expecting second argument to be a cell or character array");
	}
      else
	error ("cell2struct: expecting first argument to be a cell array");
    }
  else
    print_usage ();

  return retval;
}

/*
%!# test cell2struct versus struct2cell
%!test
%!  keys = cellstr (char (floor (rand (100,10)*24+65)))';
%!  vals = mat2cell(rand (100,1), ones (100,1), 1)';
%!  s = struct ([keys; vals]{:});
%!  t = cell2struct (vals, keys, 2);
%!  assert (s, t);
%!  assert (struct2cell (s), vals');
%!  assert (fieldnames (s), keys');
*/


// So we can call Fcellstr directly.
extern octave_value_list Fcellstr (const octave_value_list& args, int);

DEFUN (rmfield, args, ,
       "-*- texinfo -*-\n\
@deftypefn {Built-in Function} {} rmfield (@var{s}, @var{f})\n\
Return a copy of the structure (array) @var{s} with the field @var{f} removed.\n\
If @var{f} is a cell array of strings or a character array, remove the\n\
named fields.\n\
@seealso{cellstr, iscellstr, setfield}\n\
@end deftypefn")
{
  octave_value retval;

  int nargin = args.length ();

  if (nargin == 2)
    {
      Octave_map m = args(0).map_value ();

      octave_value_list fval = Fcellstr (args(1), 1);

      if (! error_state)
	{
	  Cell fcell = fval(0).cell_value ();

	  for (int i = 0; i < fcell.numel (); i++)
	    {
	      std::string key = fcell(i).string_value ();

	      if (m.contains (key))
		m.del (key);
	      else
		{
		  error ("rmfield: structure does not contain field %s",
			 key.c_str ());

		  break;
		}
	    }

	  if (! error_state)
	    retval = m;
	}
    }
  else
    print_usage ();

  return retval;
}

/*
%!# test rmfield
%!test
%!  x(3).d=1; x(2).a=2; x(1).b=3; x(2).c=3; x(6).f="abc123";
%!  y = rmfield (x, {"a", "f"});
%!  assert (fieldnames (y), {"d"; "b"; "c"});
%!  assert (size (y), [1, 6]);
*/

bool
octave_struct::save_ascii (std::ostream& os)
{
  Octave_map m = map_value ();

  octave_idx_type nf = m.nfields ();

  const dim_vector dv = dims ();

  os << "# ndims: " << dv.length () << "\n";

  for (int i = 0; i < dv.length (); i++)
    os << " " << dv (i);
  os << "\n";

  os << "# length: " << nf << "\n";

  // Iterating over the list of keys will preserve the order of the
  // fields.
  string_vector keys = m.keys ();

  for (octave_idx_type i = 0; i < nf; i++)
    {
      std::string key = keys(i);

      octave_value val = map.contents (key);

      bool b = save_ascii_data (os, val, key, false, 0);
      
      if (! b)
	return os;
    }

  return true;
}

bool 
octave_struct::load_ascii (std::istream& is)
{
  octave_idx_type len = 0;
  dim_vector dv (1, 1);
  bool success = true;

  // KLUGE: earlier Octave versions did not save extra dimensions with struct,
  // and as a result did not preserve dimensions for empty structs.
  // The default dimensions were 1x1, which we want to preserve.
  string_vector keywords(2);

  keywords[0] = "ndims";
  keywords[1] = "length";

  std::string kw;

  if (extract_keyword (is, keywords, kw, len, true))
    {
      if (kw == keywords[0])
        {
          int mdims = std::max (static_cast<int> (len), 2);
          dv.resize (mdims);
          for (int i = 0; i < mdims; i++)
            is >> dv(i);

          success = extract_keyword (is, keywords[1], len);
        }
    }
  else
    success = false;

  if (success && len >= 0)
    {
      if (len > 0)
	{
	  Octave_map m (dv);

	  for (octave_idx_type j = 0; j < len; j++)
	    {
	      octave_value t2;
	      bool dummy;

	      // recurse to read cell elements
	      std::string nm
		= read_ascii_data (is, std::string (), dummy, t2, j);

	      if (!is)
		break;

	      Cell tcell = t2.is_cell () ? t2.cell_value () : Cell (t2);

	      if (error_state)
		{
		  error ("load: internal error loading struct elements");
		  return false;
		}

	      m.assign (nm, tcell);
	    }

	  if (is) 
	    map = m;
	  else
	    {
	      error ("load: failed to load structure");
	      success = false;
	    }
	}
      else if (len == 0 )
	map = Octave_map (dv);
      else
	panic_impossible ();
    }
  else {
    error ("load: failed to extract number of elements in structure");
    success = false;
  }

  return success;
}

bool 
octave_struct::save_binary (std::ostream& os, bool& save_as_floats)
{
  Octave_map m = map_value ();

  octave_idx_type nf = m.nfields ();

  dim_vector d = dims ();
  if (d.length () < 1)
    return false;

  // Use negative value for ndims
  int32_t di = - d.length();
  os.write (reinterpret_cast<char *> (&di), 4);
  for (int i = 0; i < d.length (); i++)
    {
      di = d(i);
      os.write (reinterpret_cast<char *> (&di), 4);
    }
  
  int32_t len = nf;
  os.write (reinterpret_cast<char *> (&len), 4);

  // Iterating over the list of keys will preserve the order of the
  // fields.
  string_vector keys = m.keys ();

  for (octave_idx_type i = 0; i < nf; i++)
    {
      std::string key = keys(i);

      octave_value val = map.contents (key);

      bool b = save_binary_data (os, val, key, "", 0, save_as_floats);
      
      if (! b)
	return os;
    }

  return true;
}

bool 
octave_struct::load_binary (std::istream& is, bool swap,
			    oct_mach_info::float_format fmt)
{
  bool success = true;
  int32_t len;
  if (! is.read (reinterpret_cast<char *> (&len), 4))
    return false;
  if (swap)
    swap_bytes<4> (&len);

  dim_vector dv (1, 1);

  if (len < 0)
    {
      // We have explicit dimensions.
      int mdims = -len;

      int32_t di;
      dv.resize (mdims);

      for (int i = 0; i < mdims; i++)
        {
          if (! is.read (reinterpret_cast<char *> (&di), 4))
            return false;
          if (swap)
            swap_bytes<4> (&di);
          dv(i) = di;
        }

      if (! is.read (reinterpret_cast<char *> (&len), 4))
        return false;
      if (swap)
        swap_bytes<4> (&len);
    }

  if (len > 0)
    {
      Octave_map m (dv);

      for (octave_idx_type j = 0; j < len; j++)
	{
	  octave_value t2;
	  bool dummy;
	  std::string doc;

	  // recurse to read cell elements
	  std::string nm = read_binary_data (is, swap, fmt, std::string (), 
					     dummy, t2, doc);

	  if (!is)
	    break;

	  Cell tcell = t2.is_cell () ? t2.cell_value () : Cell (t2);
 
	  if (error_state)
	    {
	      error ("load: internal error loading struct elements");
	      return false;
	    }

	  m.assign (nm, tcell);
	}

      if (is) 
	map = m;
      else
	{
	  error ("load: failed to load structure");
	  success = false;
	}
    }
  else if (len == 0)
    map = Octave_map (dv);
  else
    success = false;

  return success;
}

#if defined (HAVE_HDF5)

bool
octave_struct::save_hdf5 (hid_t loc_id, const char *name, bool save_as_floats)
{
  hid_t data_hid = -1;

#if HAVE_HDF5_18
  data_hid = H5Gcreate (loc_id, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
#else
  data_hid = H5Gcreate (loc_id, name, 0);
#endif
  if (data_hid < 0) return false;

  // recursively add each element of the structure to this group
  Octave_map m = map_value ();

  octave_idx_type nf = m.nfields ();

  // Iterating over the list of keys will preserve the order of the
  // fields.
  string_vector keys = m.keys ();

  for (octave_idx_type i = 0; i < nf; i++)
    {
      std::string key = keys(i);

      octave_value val = map.contents (key);

      bool retval2 = add_hdf5_data (data_hid, val, key, "", false, 
				    save_as_floats);

      if (! retval2)
	break;
    }

  H5Gclose (data_hid);

  return true;
}

bool 
octave_struct::load_hdf5 (hid_t loc_id, const char *name)
{
  bool retval = false;

  hdf5_callback_data dsub;

  herr_t retval2 = 0;
  Octave_map m (dim_vector (1, 1));
  int current_item = 0;
  hsize_t num_obj = 0;
#if HAVE_HDF5_18
  hid_t group_id = H5Gopen (loc_id, name, H5P_DEFAULT);
#else
  hid_t group_id = H5Gopen (loc_id, name);
#endif
  H5Gget_num_objs (group_id, &num_obj);
  H5Gclose (group_id);

  // FIXME -- fields appear to be sorted alphabetically on loading.
  // Why is that happening?

  while (current_item < static_cast<int> (num_obj)
	 && (retval2 = H5Giterate (loc_id, name, &current_item,
				   hdf5_read_next_data, &dsub)) > 0)
    {
      octave_value t2 = dsub.tc;

      Cell tcell = t2.is_cell () ? t2.cell_value () : Cell (t2);
 
      if (error_state)
	{
	  error ("load: internal error loading struct elements");
	  return false;
	}

      m.assign (dsub.name, tcell);

    }

  if (retval2 >= 0)
    {
      map = m;
      retval = true;
    }
  
  return retval;
}

#endif

mxArray *
octave_struct::as_mxArray (void) const
{
  int nf = nfields ();
  string_vector kv = map_keys ();

  OCTAVE_LOCAL_BUFFER (const char *, f, nf);

  for (int i = 0; i < nf; i++)
    f[i] = kv[i].c_str ();

  mxArray *retval = new mxArray (dims (), nf, f);

  mxArray **elts = static_cast<mxArray **> (retval->get_data ());

  mwSize nel = numel ();

  mwSize ntot = nf * nel;

  for (int i = 0; i < nf; i++)
    {
      Cell c = map.contents (kv[i]);

      const octave_value *p = c.data ();

      mwIndex k = 0;
      for (mwIndex j = i; j < ntot; j += nf)
	elts[j] = new mxArray (p[k++]);
    }

  return retval;
}