/* -*-C-*-

$Id: foreign.c,v 1.6 2004/11/21 04:17:37 cph Exp $

Copyright (c) 1992, 1999, 2000 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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 of the License, or (at
your option) any later version.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.

*/

/* This file contains the primitive support for the foreign function */
/* interface. */

#include <stdio.h>
#include <dl.h>
#include "scheme.h"
#include "prims.h"
#include "ux.h"
#include "osfs.h"
#include "foreign.h"

static int initialization_done = 0;

#define INITIALIZE_ONCE()						\
{									\
  if (!initialization_done)						\
    initialize_once ();							\
}

static void EXFUN (initialize_once, (void));

/* Allocation table stuff stolen from x11base.c */

PTR
DEFUN (foreign_malloc, (size), unsigned int size)
{
  PTR result = (UX_malloc (size));
  if (result == 0)
    error_external_return ();
  return (result);
}

PTR
DEFUN (foreign_realloc, (ptr, size), PTR ptr AND unsigned int size)
{
  PTR result = (UX_realloc (ptr, size));
  if (result == 0)
    error_external_return ();
  return (result);
}

struct allocation_table
{
  PTR * items;
  int length;
};

static struct allocation_table foreign_object_table;
static struct allocation_table foreign_function_table;

static void
DEFUN (allocation_table_initialize, (table), struct allocation_table * table)
{
  (table -> length) = 0;
}

static unsigned int
DEFUN (allocate_table_index, (table, item),
       struct allocation_table * table AND
       PTR item)
{
  unsigned int length = (table -> length);
  unsigned int new_length;
  PTR * items = (table -> items);
  PTR * new_items;
  PTR * scan;
  PTR * end;
  if (length == 0)
    {
      new_length = 4;
      new_items = (foreign_malloc ((sizeof (PTR)) * new_length));
    }
  else
    {
      scan = items;
      end = (scan + length);
      while (scan < end)
	if ((*scan++) == 0)
	  {
	    (*--scan) = item;
	    return (scan - items);
	  }
      new_length = (length * 2);
      new_items = (foreign_realloc (items, ((sizeof (PTR)) * new_length)));
    }
  scan = (new_items + length);
  end = (new_items + new_length);
  (*scan++) = item;
  while (scan < end)
    (*scan++) = 0;
  (table -> items) = new_items;
  (table -> length) = new_length;
  return (length);
}

static PTR
DEFUN (allocation_item_arg, (arg, table),
       unsigned int arg AND
       struct allocation_table * table)
{
  unsigned int index = (arg_index_integer (arg, (table -> length)));
  PTR item = ((table -> items) [index]);
  if (item == 0)
    error_bad_range_arg (arg);
  return (item);
}

/* Helper functions */
HANDLE
DEFUN (arg_handle, (arg_number), unsigned int arg_number)
{
  SCHEME_OBJECT arg;

  return (index_to_handle (arg_index_integer (arg_number,
					      foreign_object_table . length)));
}

HANDLE
DEFUN (foreign_pointer_to_handle, (ptr), PTR ptr)
{
  unsigned int index;
  HANDLE handle;
  FOREIGN_OBJECT *ptr_object;

  INITIALIZE_ONCE ();
  ptr_object = (FOREIGN_OBJECT *) foreign_malloc (sizeof (FOREIGN_OBJECT));
  ptr_object -> ptr = ptr;
  ptr_object -> handle = handle;
  index = allocate_table_index (&foreign_object_table, (PTR) ptr_object);
  handle = index_to_handle (index);
  ((FOREIGN_OBJECT *) ((foreign_object_table . items) [index])) -> handle =
      handle;
  return (handle_to_integer (handle));
}

PTR
DEFUN (handle_to_foreign_pointer, (handle), HANDLE handle)
{
  unsigned int index;

  index = handle_to_index (handle);
  if (index >= foreign_object_table . length) {
    error_external_return ();
  }
  return
    (((FOREIGN_OBJECT *) ((foreign_object_table . items) [index])) -> ptr);
}

int 
DEFUN (find_foreign_function, (func_name), char *func_name)
{
  int i;
  FOREIGN_FUNCTION *func_item;
  
  for (i=0; i < foreign_function_table . length; i++) {
    func_item = (foreign_function_table . items) [i];
    if (func_item == 0) continue;
    if (! strcmp (func_item -> name, func_name)) {
      return (i);
    }
  }
  return (-1);
}

unsigned int
DEFUN (register_foreign_function, (name, applicable_function),
                                  char * name AND
                                  PTR applicable_function)
{
  FOREIGN_FUNCTION *func_item;
  char * name_copy;

  INITIALIZE_ONCE ();
  func_item = (FOREIGN_FUNCTION *) foreign_malloc (sizeof (FOREIGN_FUNCTION));
  name_copy = (char *) foreign_malloc (1 + strlen (name));
  strcpy (name_copy, name);
  func_item -> name = name_copy;
  func_item -> applicable_function = applicable_function;
  return (allocate_table_index (&foreign_function_table, (PTR) func_item));
}

unsigned int
DEFUN (list_length, (list), SCHEME_OBJECT list)
{
  unsigned int i;

  i = 0;
  TOUCH_IN_PRIMITIVE (list, list);
  while (PAIR_P (list)) {
    i += 1;
    TOUCH_IN_PRIMITIVE ((PAIR_CDR (list)), list);
  }
  return (i);
}

PTR
DEFUN (apply_foreign_function, (func, arg_list),
                               PTR (*func)() AND
                               SCHEME_OBJECT arg_list)
{
  unsigned int arg_list_length;
  PTR * arg_vec;
  PTR result;
  unsigned int i;

  arg_list_length = list_length (arg_list);
  arg_vec = (PTR *) foreign_malloc (arg_list_length);
  for (i = 0; i < arg_list_length; i++, arg_list = PAIR_CDR (arg_list)) {
    arg_vec [i] = handle_to_foreign_pointer (PAIR_CAR (arg_list));
  }
  result = (*func) (arg_vec);
  free (arg_vec);
  return (result);
}

SCHEME_OBJECT
DEFUN (foreign_pointer_to_scheme_object, (ptr, type_translator),
                                         PTR ptr AND
                                         SCHEME_OBJECT (*type_translator) ())
{
  return (type_translator (ptr));
}

/* old version of foreign_pointer_to_scheme_object */
#if 0 
/* Note that foreign_pointer_to_scheme_object takes a pointer to pointer
   (i.e. a call by reference to a pointer) so that it can increment the
   pointer according to its type. This is used by the code which builds
   the composite objects. */

SCHEME_OBJECT
DEFUN (foreign_pointer_to_scheme_object, (ptr_to_ptr, type),
                                         PTR ptr_to_ptr AND
                                         SCHEME_OBJECT type)
{
  long type_enum;
  
  if (foreign_primtive_type_p (type)) {
    long long_val;
    double double_val;
    PTR temp_ptr;
    type_enum = integer_to_long (type);
    switch (type_enum) {
      case FOREIGN_INT:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_INT);
        *ptr_to_ptr = (((int *) temp_ptr) + 1);
        long_val = (long) ((int) *temp_ptr);
      case FOREIGN_SHORT:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_SHORT);
        *ptr_to_ptr = (((short *) temp_ptr) + 1);
        long_val = (long) ((short) *temp_ptr);
      case FOREIGN_LONG:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_INT);
        *ptr_to_ptr = (((long *) temp_ptr) + 1);
        long_val = (long) *temp_ptr;
        return (long_to_integer (long_val));
      case FOREIGN_CHAR:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_CHAR);
        *ptr_to_ptr = (((char *) temp_ptr) + 1);
	return (ASCII_TO_CHAR ((char) *temp_ptr));
      case FOREIGN_FLOAT:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_FLOAT);
        *ptr_to_ptr = (((float *) temp_ptr) + 1);
        double_val = (double) ((float) *temp_ptr);
      case FOREIGN_DOUBLE:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_DOUBLE);
        *ptr_to_ptr = (((double *) temp_ptr) + 1);
        double_val = (double) *temp_ptr;
	return (double_to_flonum (double_val));
      case FOREIGN_STRING:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_STRING);
        *ptr_to_ptr = (((unsigned char *) temp_ptr) + 1);
	return (char_pointer_to_string ((unsigned char *) temp_ptr;
      case FOREIGN_PTR:
	temp_ptr = ALIGN_FOREIGN_POINTER (*ptr_to_ptr, FOREIGN_PTR);
        *ptr_to_ptr = (((PTR) temp_ptr) + 1);
	return (long_to_integer ((long) *temp_ptr));
      default:
	error_external_return ();
    }
  } else if (foreign_composite_type_p (type)) {
    /* We should probably tag the result vector. */
    type_enum = integer_to_long (which_composite_type (type));
    switch (type_enum) {
      case FOREIGN_STRUCT:
      case FOREIGN_UNION:
      {
	int num_fields;
	SCHEME_OBJECT field_types;
	SCHEME_OBJECT result_vector;
	unsigned int i;

	field_types = composite_type_field_types (type);
	num_fields = list_length (field_types);
	result_vector = allocate_marked_vector (TC_VECTOR, num_fields, true);
	for (i = 0; i < num_fields; ++i) {
	  if (!(PAIR_P (field_types))) {
	    error_external_return ();
	  }
	  FAST_VECTOR_SET (result_vector,
			   i,
			   foreign_pointer_to_scheme_object (
			    ptr_to_ptr, PAIR_CAR (field_types)));
	  TOUCH_IN_PRIMITIVE ((PAIR_CDR (field_types)), field_types);
	}
	return (result_vector);
      }
      default:
        error_external_return ();
    }
  } else {
    error_external_return ();
  }
}
#endif  /* if 0 */

static void
DEFUN_VOID (initialize_once)
{
  allocation_table_initialize (&foreign_object_table);
  allocation_table_initialize (&foreign_function_table);
  
  initialization_done = 1;
}

/* Functions to go in osxx.c */

#include <dl.h>

char *
DEFUN_VOID (OS_create_temporary_file_name)
{
  char * name_string;

  name_string = (char *) foreign_malloc (1 + TEMP_FILE_NAME_MAX_LEN);
  (void) UX_tmpnam (name_string);
  return (name_string);
}

#ifdef HAVE_DYNAMIC_LOADING
#ifdef __HPUX__
#include <dl.h>

LOAD_INFO *
DEFUN (OS_load_object_file, (load_file_name), char * load_file_name)
{
  shl_t shl_handle;
  int result;
  struct shl_descriptor *shl_desc;
  LOAD_INFO *info;

  shl_handle = shl_load (load_file_name, BIND_DEFERRED, 0L);
  
  if (shl_handle == NULL) {
    error_external_return ();
  }

  result = shl_gethandle (shl_handle, &shl_desc);

  if (result == -1) {
    error_external_return ();
  }

  info = foreign_malloc (sizeof (LOAD_INFO));
  info -> load_module_descriptor = shl_handle;
  info -> program_start = shl_desc -> tstart;
  info -> program_end = shl_desc -> tend;
  info -> data_start = shl_desc -> dstart;
  info -> data_end = shl_desc -> dend;
  return (info);
}

PTR
DEFUN (OS_find_function, (load_info, func_name),
                       LOAD_INFO * load_info AND
                       char * func_name)
{
  int return_code;
  PTR (* test_proc)();
  LOAD_DESCRIPTOR desc;

  desc = (load_info -> load_module_descriptor);
  return_code = shl_findsym (&desc ,
			     func_name,
			     TYPE_PROCEDURE,
			     (long *) &test_proc);

  return ((return_code == 0) ?
	  test_proc :
	  NULL);
}

#endif /* __HPUX__ */
#endif /* HAVE_DYNAMIC_LOADING */

/* Definitions of primitives */

DEFINE_PRIMITIVE ("CALL-FOREIGN-FUNCTION",
		  Prim_call_foreign_function, 2, 2,
"Calls the foreign function referenced by HANDLE with the ARG-LIST \n\
arguments. \n\
Returns a handle to the return value; \n\
The foreign function should have been created by  \n\
CREATE_PRIMITIVE_FOREIGN_FUNCTION. \n\
The elements of the ARG-LIST must be handles to foreign objects. \n\
Type and arity checking on the arguments should already have been done.")
{
  PRIMITIVE_HEADER (2);
  {
    SCHEME_OBJECT arg_list;
    PTR result;

    CHECK_ARG (2, APPARENT_LIST_P);
    arg_list = ARG_REF (2);
    result = apply_foreign_function (handle_to_foreign_pointer
				     (arg_handle (1)), arg_list);
    PRIMITIVE_RETURN (foreign_pointer_to_handle (result));
  }
}

DEFINE_PRIMITIVE ("&CALL-FOREIGN-FUNCTION-RETURNING-SCHEME-OBJECT",
		  Prim_call_foreign_function_returning_scheme_object, 2, 2,
"Calls the foreign function referenced by HANDLE with the ARG-LIST \n\
arguments. \n\
Returns the result of the foreign function (which better be a scheme \n\
object. \n\
The foreign function should have been created by  \n\
CREATE_PRIMITIVE_FOREIGN_FUNCTION. \n\
The elements of the ARG-LIST must be handles to foreign objects. \n\
Type and arity checking on the arguments should already have been done.")
{
  PRIMITIVE_HEADER (2);
  {
    SCHEME_OBJECT arg_list;
    PTR result;

    CHECK_ARG (2, APPARENT_LIST_P);
    arg_list = ARG_REF (2);
    result = apply_foreign_function (handle_to_foreign_pointer
				     (arg_handle (1)), arg_list);
    PRIMITIVE_RETURN (result);
  }
}

DEFINE_PRIMITIVE ("FOREIGN-HANDLE-TO-SCHEME-OBJECT",
		  Prim_foreign_handle_to_scheme_object, 2, 2,
"Returns the Scheme object corresponding to the foreign HANDLE \n\
interpreted as the foreign type TYPE.   \n\
A type is either an integer which enumerates the various foreign types \n\
(i.e.  FOREIGN_INT, FOREIGN_CHAR, FOREIGN_SHORT, FOREIGN_LONG, \n\
(FOREIGN_PTR, FOREIGN_DOUBLE, FOREIGN_STRING) or a list whose car is \n\
an integer representing FOREIGN_STRUCT or FOREIGN_UNION and whose cdr \n\
is a list of types.")
{
  PRIMITIVE_HEADER (2);
  {
    SCHEME_OBJECT arg2;
    PTR arg1_ptr;

    arg1_ptr = handle_to_foreign_pointer (arg_handle (1));
    arg2 = ARG_REF (2);
    if (! (INTEGER_P (arg2) || PAIR_P (arg2))) {
      error_wrong_type_arg (2);
    }
    PRIMITIVE_RETURN (foreign_pointer_to_scheme_object (&arg1_ptr, arg2));
  }
}

DEFINE_PRIMITIVE (LOAD-FOREIGN-FILE, Prim_load_foreign_file, 1, 1,
"Load the foreign object file FILENAME. \n\
Returns a handle to a LOAD_INFO data structure.")
{
  PRIMITIVE_HEADER (1);
  PRIMITIVE_RETURN (foreign_pointer_to_handle
		     (OS_load_object_file (STRING_ARG (1))));
}

DEFINE_PRIMITIVE (CREATE-TEMPORARY-FILE-NAME, Prim_get_temporary_file_name,
		  0, 0,
"Return a temporary file name.")
{
  PRIMITIVE_HEADER (0);
  PRIMITIVE_RETURN (char_pointer_to_string (OS_create_temporary_file_name ()));
}

DEFINE_PRIMITIVE (FIND-FOREIGN-FUNCTION, Prim_find_foreign_function, 2, 2,
"Returns a handle to a foreign function. \n\
Takes the FUNCTION_NAME as a string and LOAD_INFO \n\
which is a handle to a load_info structure returned by LOAD-FOREIGN-FILE. \n\
If LOAD_INFO is not #F then we search for FUNCTION_NAME in the code which \n\
was loaded to yield LOAD_INFO. \n\
If LOAD_INFO is #F then we search over all the dynamically loaded files.")
{
  PRIMITIVE_HEADER (2);
  {
    PTR func_ptr;
    LOAD_INFO * load_info;

    load_info = ((EMPTY_LIST_P (ARG_REF (2))) ?
		 ((LOAD_INFO *) NULL) :
		 ((LOAD_INFO *) handle_to_foreign_pointer (arg_handle (2))));
		  
    func_ptr = OS_find_function (load_info, STRING_ARG (1));

    PRIMITIVE_RETURN ((func_ptr == NULL) ?
		      SHARP_F :
		      foreign_pointer_to_handle (func_ptr));
  }
}
