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unwind-prot.cc
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C/C++ Source or Header
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1997-01-29
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/*
Copyright (C) 1996 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 2, 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, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#if defined (__GNUG__)
#pragma implementation
#endif
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <cstddef>
#include <string>
#include "SLStack.h"
#include "CMatrix.h"
#include "error.h"
#include "unwind-prot.h"
#include "utils.h"
// XXX FIXME XXX -- this should really be static, but that causes
// problems on some systems.
SLStack <unwind_elem> unwind_protect_list;
void
add_unwind_protect (cleanup_func fptr, void *ptr)
{
unwind_elem el (fptr, ptr);
unwind_protect_list.push (el);
}
void
run_unwind_protect (void)
{
unwind_elem el = unwind_protect_list.pop ();
cleanup_func f = el.fptr ();
if (f)
f (el.ptr ());
}
void
discard_unwind_protect (void)
{
unwind_protect_list.pop ();
}
void
begin_unwind_frame (const string& tag)
{
unwind_elem elem (tag);
unwind_protect_list.push (elem);
}
void
run_unwind_frame (const string& tag)
{
while (! unwind_protect_list.empty ())
{
unwind_elem el = unwind_protect_list.pop ();
cleanup_func f = el.fptr ();
if (f)
f (el.ptr ());
if (tag == el.tag ())
break;
}
}
void
discard_unwind_frame (const string& tag)
{
while (! unwind_protect_list.empty ())
{
unwind_elem el = unwind_protect_list.pop ();
if (tag == el.tag ())
break;
}
}
void
run_all_unwind_protects (void)
{
while (! unwind_protect_list.empty ())
{
unwind_elem el = unwind_protect_list.pop ();
cleanup_func f = el.fptr ();
if (f)
f (el.ptr ());
}
}
void
discard_all_unwind_protects (void)
{
unwind_protect_list.clear ();
}
class saved_variable
{
public:
enum var_type { integer, string_type, generic_ptr, generic };
saved_variable (void);
saved_variable (int *p, int v);
saved_variable (string *p, const string& v);
saved_variable (void **p, void *v);
~saved_variable (void);
void restore_value (void);
private:
union
{
int *ptr_to_int;
void *gen_ptr;
void **ptr_to_gen_ptr;
};
union
{
int int_value;
const string *str_value;
void *gen_ptr_value;
};
var_type type_tag;
size_t size;
};
saved_variable::saved_variable (void)
{
gen_ptr = 0;
gen_ptr_value = 0;
type_tag = generic;
size = 0;
}
saved_variable::saved_variable (int *p, int v)
{
type_tag = integer;
ptr_to_int = p;
int_value = v;
size = sizeof (int); // Is this necessary?
}
saved_variable::saved_variable (string *p, const string& v)
{
type_tag = string_type;
gen_ptr = p;
str_value = new string (v);
size = sizeof (string); // Is this necessary?
}
saved_variable::saved_variable (void **p, void *v)
{
type_tag = generic_ptr;
ptr_to_gen_ptr = p;
gen_ptr_value = v;
size = sizeof (void *);
}
saved_variable::~saved_variable (void)
{
switch (type_tag)
{
case string_type:
delete str_value;
break;
case generic:
delete [] gen_ptr_value; // Can this be right?
break;
default:
break;
}
}
void
saved_variable::restore_value (void)
{
switch (type_tag)
{
case integer:
*ptr_to_int = int_value;
break;
case string_type:
((string *) gen_ptr) -> assign (*str_value);
break;
case generic_ptr:
*ptr_to_gen_ptr = gen_ptr_value;
break;
case generic:
memcpy (gen_ptr, gen_ptr_value, size);
break;
default:
panic_impossible ();
break;
}
}
static void
restore_saved_variable (void *s)
{
saved_variable *sv = (saved_variable *) s;
sv->restore_value ();
delete sv;
}
void
unwind_protect_int_internal (int *ptr, int value)
{
saved_variable *s = new saved_variable (ptr, value);
add_unwind_protect (restore_saved_variable, (void *) s);
}
void
unwind_protect_str_internal (string *ptr, const string& value)
{
saved_variable *s = new saved_variable (ptr, value);
add_unwind_protect (restore_saved_variable, (void *) s);
}
void
unwind_protect_ptr_internal (void **ptr, void *value)
{
saved_variable *s = new saved_variable (ptr, value);
add_unwind_protect (restore_saved_variable, (void *) s);
}
/*
;;; Local Variables: ***
;;; mode: C++ ***
;;; End: ***
*/