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/* Implementation of the EXTENDS_TYPE_OF intrinsic.
Copyright (C) 2004-2021 Free Software Foundation, Inc.
Contributed by Janus Weil <janus@gcc.gnu.org>.
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran 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.
Libgfortran 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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libgfortran.h"
typedef struct vtype
{
GFC_INTEGER_4 hash;
size_t size;
struct vtype *extends;
}
vtype;
extern GFC_LOGICAL_4 is_extension_of (struct vtype *, struct vtype *);
export_proto(is_extension_of);
/* This is a helper function for the F2003 intrinsic EXTENDS_TYPE_OF.
While EXTENDS_TYPE_OF accepts CLASS or TYPE arguments, this one here gets
passed the corresponding vtabs. Each call to EXTENDS_TYPE_OF is translated
to a call to is_extension_of. */
GFC_LOGICAL_4
is_extension_of (struct vtype *v1, struct vtype *v2)
{
/* Assume that only unlimited polymorphic entities will pass NULL v1 or v2
if they are unallocated or disassociated. */
if (!v2)
return 1;
if (!v1)
return 0;
while (v1)
{
if (v1->hash == v2->hash) return 1;
v1 = v1->extends;
}
return 0;
}