guile/libguile/struct.c

/*	Copyright (C) 1996 Free Software Foundation, Inc.
 * 
 * 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, 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  
 */


#include <stdio.h>
#include "_scm.h"
#include "chars.h"

#include "struct.h"

#ifdef HAVE_STRING_H
#include <string.h>
#endif



static SCM required_vtable_fields = SCM_BOOL_F;
static int struct_num = 0;


SCM_PROC (s_struct_make_layout, "make-struct-layout", 1, 0, 0, scm_make_struct_layout);
#ifdef __STDC__
SCM
scm_make_struct_layout (SCM fields)
#else
SCM
scm_make_struct_layout (fields)
     SCM fields;
#endif
{
  SCM new_sym;
  SCM_ASSERT (SCM_NIMP (fields) && SCM_ROSTRINGP (fields),
	      fields, SCM_ARG1, s_struct_make_layout);

  {
    char * field_desc;
    int len;
    int x;

    len = SCM_ROLENGTH (fields);
    field_desc = SCM_ROCHARS (fields);
    SCM_ASSERT (!(len & 1), fields, "odd length field specification", s_struct_make_layout);

    for (x = 0; x < len; x += 2)
      {
	switch (field_desc[x])
	  {
	  case 'u':
	  case 'p':
#if 0
	  case 'i':
	  case 'd':
#endif
	  case 's':
	    break;
	  default:
	    SCM_ASSERT (0, SCM_MAKICHR (field_desc[x]) , "unrecognized field type", s_struct_make_layout);
	  }

	switch (field_desc[x + 1])
	  {
	  case 'w':
	    SCM_ASSERT (field_desc[x] != 's', SCM_MAKICHR (field_desc[x + 1]),
			"self fields not writable", s_struct_make_layout);
	      
	  case 'r':
	  case 'o':
	    break;
	  case 'R':
	  case 'W':
	  case 'O':
	    SCM_ASSERT (field_desc[x] != 's', SCM_MAKICHR (field_desc[x + 1]),
			"self fields not allowed in tail array",
			s_struct_make_layout);
	    SCM_ASSERT (x == len - 2, SCM_MAKICHR (field_desc[x + 1]),
			"tail array field must be last field in layout",
			s_struct_make_layout);
	    break;
	  default:
	    SCM_ASSERT (0, SCM_MAKICHR (field_desc[x]) , "unrecognized ref specification", s_struct_make_layout);
	  }
#if 0
	if (field_desc[x] == 'd')
	  {
	    SCM_ASSERT (field_desc[x + 2] == '-', SCM_MAKINUM (x / 2), "missing dash field", s_struct_make_layout);
	    x += 2;
	    goto recheck_ref;
	  }
#endif
      }
    new_sym = SCM_CAR (scm_intern_obarray (field_desc, len, SCM_BOOL_F));
  }
  return scm_return_first (new_sym, fields);
}




#ifdef __STDC__
static void
init_struct (SCM handle, int tail_elts, SCM inits)
#else
static void
init_struct (handle, tail_elts, inits)
     SCM handle;
     int tail_elts;
     SCM inits;
#endif
{
  SCM layout;
  SCM * data;
  unsigned char * fields_desc;
  unsigned char prot;
  int n_fields;
  SCM * mem;
  int tailp = 0;
  
  layout = SCM_STRUCT_LAYOUT (handle);
  data = SCM_STRUCT_DATA (handle);
  fields_desc = (unsigned char *) SCM_CHARS (layout) - 2;
  n_fields = SCM_LENGTH (layout) / 2;
  mem = SCM_STRUCT_DATA (handle);
  while (n_fields)
    {
      if (!tailp)
	{
	  fields_desc += 2;
	  prot = fields_desc[1];
	  if (SCM_LAYOUT_TAILP (prot))
	    {
	      tailp = 1;
	      prot = prot == 'R' ? 'r' : prot == 'W' ? 'w' : 'o';
	      *mem++ = tail_elts;
	      n_fields += tail_elts - 1;
	      if (n_fields == 0)
		break;
	    }
	}
      
      switch (*fields_desc)
	{
#if 0
	case 'i':
	  if ((prot != 'r' && prot != 'w') || inits == SCM_EOL)
	    *mem = 0;
	  else
	    {
	      *mem = scm_num2long (SCM_CAR (inits), SCM_ARGn, "init_struct");
	      inits = SCM_CDR (inits);
	    }
	  break;
#endif

	case 'u':
	  if ((prot != 'r' && prot != 'w') || inits == SCM_EOL)
	    *mem = 0;
	  else
	    {
	      *mem = scm_num2ulong (SCM_CAR (inits), SCM_ARGn, "init_struct");
	      inits = SCM_CDR (inits);
	    }
	  break;

	case 'p':
	  if ((prot != 'r' && prot != 'w') || inits == SCM_EOL)
	    *mem = SCM_EOL;
	  else
	    {
	      *mem = SCM_CAR (inits);
	      inits = SCM_CDR (inits);
	    }
	      
	  break;

#if 0
	case 'd':
	  if ((prot != 'r' && prot != 'w') || inits == SCM_EOL)
	    *((double *)mem) = 0.0;
	  else
	    {
	      *mem = scm_num2dbl (SCM_CAR (inits), "init_struct");
	      inits = SCM_CDR (inits);
	    }
	  fields_desc += 2;
	  break;
#endif

	case 's':
	  *mem = handle;
	  break;
	}

      n_fields--;
      mem++;
    }
}


SCM_PROC (s_struct_p, "struct?", 1, 0, 0, scm_struct_p);
#ifdef __STDC__
SCM
scm_struct_p (SCM x)
#else
SCM
scm_struct_p (x)
     SCM x;
#endif
{
  return ((SCM_NIMP (x) && SCM_STRUCTP (x))
	  ? SCM_BOOL_T
	  : SCM_BOOL_F);
}

SCM_PROC (s_struct_vtable_p, "struct-vtable?", 1, 0, 0, scm_struct_vtable_p);
#ifdef __STDC__
SCM
scm_struct_vtable_p (SCM x)
#else
SCM
scm_struct_vtable_p (x)
     SCM x;
#endif
{
  SCM layout;
  SCM * mem;

  if (SCM_IMP (x))
    return SCM_BOOL_F;

  if (!SCM_STRUCTP (x))
    return SCM_BOOL_F;

  layout = SCM_STRUCT_LAYOUT (x);

  if (SCM_LENGTH (layout) < SCM_LENGTH (required_vtable_fields))
    return SCM_BOOL_F;

  if (strncmp (SCM_CHARS (layout), SCM_CHARS (required_vtable_fields),
	       SCM_LENGTH (required_vtable_fields)))
    return SCM_BOOL_F;

  mem = SCM_STRUCT_DATA (x);

  if (mem[1] != 0)
    return SCM_BOOL_F;

  if (SCM_IMP (mem[0]))
    return SCM_BOOL_F;

  return (SCM_SYMBOLP (mem[0])
	  ? SCM_BOOL_T
	  : SCM_BOOL_F);
}

SCM_PROC (s_make_struct, "make-struct", 2, 0, 1, scm_make_struct);
#ifdef __STDC__
SCM
scm_make_struct (SCM vtable, SCM tail_array_size, SCM init)
#else
SCM
scm_make_struct (vtable, tail_array_size, init)
     SCM vtable;
     SCM tail_array_size;
     SCM init;
#endif
{
  SCM layout;
  int basic_size;
  int tail_elts;
  SCM * data;
  SCM handle;

  SCM_ASSERT ((SCM_BOOL_F != scm_struct_vtable_p (vtable)),
	      vtable, SCM_ARG1, s_make_struct);
  SCM_ASSERT (SCM_INUMP (tail_array_size), tail_array_size, SCM_ARG2, s_make_struct);

  layout = SCM_STRUCT_DATA (vtable)[scm_struct_i_layout];
  basic_size = SCM_LENGTH (layout) / 2;
  tail_elts = SCM_INUM (tail_array_size);
  SCM_NEWCELL (handle);
  SCM_DEFER_INTS;
  data = (SCM*)scm_must_malloc (sizeof (SCM) * (scm_struct_n_extra_words
						+ basic_size
						+ tail_elts),
				"structure");
  data += scm_struct_n_extra_words;
  data[scm_struct_i_n_words] = (SCM) (scm_struct_n_extra_words
				      + basic_size
				      + tail_elts);
  data[scm_struct_i_tag] = struct_num++;
  SCM_SETCDR (handle, data);
  SCM_SETCAR (handle, ((SCM)SCM_STRUCT_DATA (vtable)) + 1);
  init_struct (handle, tail_elts, init);
  SCM_ALLOW_INTS;
  return handle;
}



SCM_PROC (s_make_vtable_vtable, "make-vtable-vtable", 2, 0, 1, scm_make_vtable_vtable);
#ifdef __STDC__
SCM
scm_make_vtable_vtable (SCM extra_fields, SCM tail_array_size, SCM init)
#else
SCM
scm_make_vtable_vtable (extra_fields, tail_array_size, init)
     SCM extra_fields;
     SCM tail_array_size;
     SCM init;
#endif
{
  SCM fields;
  SCM layout;
  int basic_size;
  int tail_elts;
  SCM * data;
  SCM handle;

  SCM_ASSERT (SCM_NIMP (extra_fields) && SCM_ROSTRINGP (extra_fields),
	      extra_fields, SCM_ARG1, s_make_vtable_vtable);
  SCM_ASSERT (SCM_INUMP (tail_array_size), tail_array_size, SCM_ARG3, s_make_vtable_vtable);
  

  fields = scm_string_append (scm_listify (required_vtable_fields,
					   extra_fields,
					   SCM_UNDEFINED));
  layout = scm_make_struct_layout (fields);
  basic_size = SCM_LENGTH (layout) / 2;
  tail_elts = SCM_INUM (tail_array_size);
  SCM_NEWCELL (handle);
  SCM_DEFER_INTS;
  data = (SCM *) scm_must_malloc (sizeof (SCM) * (scm_struct_n_extra_words
						  + basic_size
						  + tail_elts),
				  "structure");
  data += scm_struct_n_extra_words;
  data[scm_struct_i_n_words] = (SCM) (scm_struct_n_extra_words
				      + basic_size
				      + tail_elts);
  data[scm_struct_i_tag] = struct_num++;
  SCM_SETCDR (handle, data);
  SCM_SETCAR (handle, ((SCM)data) + 1);
  SCM_STRUCT_LAYOUT (handle) = layout;
  init_struct (handle, tail_elts, scm_cons (layout, init));
  SCM_ALLOW_INTS;
  return handle;
}




SCM_PROC (s_struct_ref, "struct-ref", 2, 0, 0, scm_struct_ref);
#ifdef __STDC__
SCM
scm_struct_ref (SCM handle, SCM pos)
#else
SCM
scm_struct_ref (handle, pos)
     SCM handle;
     SCM pos;
#endif
{
  SCM answer = SCM_UNDEFINED;
  SCM * data;
  SCM layout;
  int p;
  int n_fields;
  unsigned char * fields_desc;
  unsigned char field_type;
  

  SCM_ASSERT (SCM_NIMP (handle) && SCM_STRUCTP (handle), handle,
	      SCM_ARG1, s_struct_ref);
  SCM_ASSERT (SCM_INUMP (pos), pos, SCM_ARG2, s_struct_ref);

  layout = SCM_STRUCT_LAYOUT (handle);
  data = SCM_STRUCT_DATA (handle);
  p = SCM_INUM (pos);

  fields_desc = (unsigned char *)SCM_CHARS (layout);
  n_fields = data[- scm_struct_n_extra_words] - scm_struct_n_extra_words;
  
  SCM_ASSERT (p < n_fields, pos, SCM_OUTOFRANGE, s_struct_ref);

  if (p * 2 < SCM_LENGTH (layout))
    {
      unsigned char ref;
      field_type = fields_desc[p * 2];
      ref = fields_desc[p * 2 + 1];
      if ((ref != 'r') && (ref != 'w'))
	{
	  if ((ref == 'R') || (ref == 'W'))
	    field_type = 'u';
	  else
	    SCM_ASSERT (0, pos, "ref denied", s_struct_ref);
	}
    }
  else if (fields_desc[SCM_LENGTH (layout) - 1] != 'O')    
    field_type = fields_desc[SCM_LENGTH (layout) - 2];
  else
    {
      SCM_ASSERT (0, pos, "ref denied", s_struct_ref);
    }
  
  switch (field_type)
    {
    case 'u':
      answer = scm_ulong2num (data[p]);
      break;

#if 0
    case 'i':
      answer = scm_long2num (data[p]);
      break;

    case 'd':
      answer = scm_makdbl (*((double *)&(data[p])), 0.0);
      break;
#endif

    case 's':
    case 'p':
      answer = data[p];
      break;


    default:
      SCM_ASSERT (0, SCM_MAKICHR (field_type), "unrecognized field type", s_struct_ref);
      break;
    }

  return answer;
}


SCM_PROC (s_struct_set_x, "struct-set!", 3, 0, 0, scm_struct_set_x);
#ifdef __STDC__
SCM
scm_struct_set_x (SCM handle, SCM pos, SCM val)
#else
SCM
scm_struct_set_x (handle, pos, val)
     SCM handle;
     SCM pos;
     SCM val;
#endif
{
  SCM * data;
  SCM layout;
  int p;
  int n_fields;
  unsigned char * fields_desc;
  unsigned char field_type;
  


  SCM_ASSERT (SCM_NIMP (handle) && SCM_STRUCTP (handle), handle,
	      SCM_ARG1, s_struct_ref);
  SCM_ASSERT (SCM_INUMP (pos), pos, SCM_ARG2, s_struct_ref);

  layout = SCM_STRUCT_LAYOUT (handle);
  data = SCM_STRUCT_DATA (handle);
  p = SCM_INUM (pos);

  fields_desc = (unsigned char *)SCM_CHARS (layout);
  n_fields = data[- scm_struct_n_extra_words] - scm_struct_n_extra_words;

  SCM_ASSERT (p < n_fields, pos, SCM_OUTOFRANGE, s_struct_set_x);

  if (p * 2 < SCM_LENGTH (layout))
    {
      unsigned char set_x;
      field_type = fields_desc[p * 2];
      set_x = fields_desc [p * 2 + 1];
      if (set_x != 'w')
	SCM_ASSERT (0, pos, "set_x denied", s_struct_set_x);
    }
  else if (fields_desc[SCM_LENGTH (layout) - 1] == 'W')    
    field_type = fields_desc[SCM_LENGTH (layout) - 2];
  else
    {
      SCM_ASSERT (0, pos, "set_x denied", s_struct_ref);
    }
  
  switch (field_type)
    {
    case 'u':
      data[p] = (SCM)scm_num2ulong (val, (char *)SCM_ARG3, s_struct_set_x);
      break;

#if 0
    case 'i':
      data[p] = scm_num2long (val, (char *)SCM_ARG3, s_struct_set_x);
      break;

    case 'd':
      *((double *)&(data[p])) = scm_num2dbl (val, (char *)SCM_ARG3);
      break;
#endif

    case 'p':
      data[p] = val;
      break;

    case 's':
      SCM_ASSERT (0, SCM_MAKICHR (field_type), "self fields immutable", s_struct_set_x);
      break;

    default:
      SCM_ASSERT (0, SCM_MAKICHR (field_type), "unrecognized field type", s_struct_set_x);
      break;
    }

  return val;
}


SCM_PROC (s_struct_vtable, "struct-vtable", 1, 0, 0, scm_struct_vtable);
#ifdef __STDC__
SCM
scm_struct_vtable (SCM handle)
#else
SCM
scm_struct_vtable (handle)
     SCM handle;
#endif
{
  SCM_ASSERT (SCM_NIMP (handle) && SCM_STRUCTP (handle), handle,
	      SCM_ARG1, s_struct_vtable);
  return SCM_STRUCT_VTABLE (handle);
}


SCM_PROC (s_struct_vtable_tag, "struct-vtable-tag", 1, 0, 0, scm_struct_vtable_tag);
#ifdef __STDC__
SCM
scm_struct_vtable_tag (SCM handle)
#else
SCM
scm_struct_vtable_tag (handle)
     SCM handle;
#endif
{
  SCM_ASSERT (SCM_NIMP (handle) && (SCM_BOOL_F != scm_struct_vtable_p (handle)),
	      handle, SCM_ARG1, s_struct_vtable_tag);
  return scm_long2num (SCM_STRUCT_DATA (handle)[-1]);
}




#ifdef __STDC__
void
scm_init_struct (void)
#else
void
scm_init_struct ()
#endif
{
  required_vtable_fields = SCM_CAR (scm_intern_obarray ("pruosr", sizeof ("pruosr") - 1, SCM_BOOL_F));
  scm_permanent_object (required_vtable_fields);
  scm_sysintern ("struct-vtable-offset", SCM_MAKINUM (scm_struct_i_vtable_offset));
#include "struct.x"
}