| // Methods for type_info for -*- C++ -*- Run Time Type Identification. |
| // Copyright (C) 1994, 1996 Free Software Foundation |
| |
| // This file is part of GNU CC. |
| |
| // GNU CC 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. |
| |
| // GNU CC 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 GNU CC; see the file COPYING. If not, write to |
| // the Free Software Foundation, 59 Temple Place - Suite 330, |
| // Boston, MA 02111-1307, USA. |
| |
| // As a special exception, if you link this library with other files, |
| // some of which are compiled with GCC, to produce an executable, |
| // this library does not by itself cause the resulting executable |
| // to be covered by the GNU General Public License. |
| // This exception does not however invalidate any other reasons why |
| // the executable file might be covered by the GNU General Public License. |
| |
| #include <stddef.h> |
| #include "tinfo.h" |
| #include "new" // for placement new |
| |
| // This file contains the minimal working set necessary to link with code |
| // that uses virtual functions and -frtti but does not actually use RTTI |
| // functionality. |
| |
| type_info:: |
| ~type_info () |
| { } |
| |
| extern "C" void |
| __rtti_class (void *addr, const char *name, |
| const __class_type_info::base_info *bl, size_t bn) |
| { new (addr) __class_type_info (name, bl, bn); } |
| |
| extern "C" void |
| __rtti_si (void *addr, const char *n, const type_info *ti) |
| { |
| new (addr) __si_type_info |
| (n, static_cast <const __user_type_info &> (*ti)); |
| } |
| |
| extern "C" void |
| __rtti_user (void *addr, const char *name) |
| { new (addr) __user_type_info (name); } |
| |
| // dynamic_cast helper methods. |
| // Returns a pointer to the desired sub-object or 0. |
| |
| void * __user_type_info:: |
| dcast (const type_info& to, int, void *addr, const type_info *, void *) const |
| { return (*this == to) ? addr : 0; } |
| |
| void * __si_type_info:: |
| dcast (const type_info& to, int require_public, void *addr, |
| const type_info *sub, void *subptr) const |
| { |
| if (*this == to) |
| return addr; |
| return base.dcast (to, require_public, addr, sub, subptr); |
| } |
| |
| void* __class_type_info:: |
| dcast (const type_info& desired, int is_public, void *objptr, |
| const type_info *sub, void *subptr) const |
| { |
| if (*this == desired) |
| return objptr; |
| |
| void *match_found = 0; |
| for (int i = 0; i < n_bases; i++) |
| { |
| if (is_public && base_list[i].access != PUBLIC) |
| continue; |
| |
| void *p = (char *)objptr + base_list[i].offset; |
| if (base_list[i].is_virtual) |
| p = *(void **)p; |
| p = base_list[i].base->dcast (desired, is_public, p, sub, subptr); |
| if (p) |
| { |
| if (match_found == 0) |
| match_found = p; |
| else if (match_found != p) |
| { |
| if (sub) |
| { |
| // Perhaps we're downcasting from *sub to desired; see if |
| // subptr is a subobject of exactly one of {match_found,p}. |
| |
| const __user_type_info &d = |
| static_cast <const __user_type_info &> (desired); |
| |
| void *os = d.dcast (*sub, 1, match_found); |
| void *ns = d.dcast (*sub, 1, p); |
| |
| if (os == ns) |
| /* ambiguous -- subptr is a virtual base */; |
| else if (os == subptr) |
| continue; |
| else if (ns == subptr) |
| { |
| match_found = p; |
| continue; |
| } |
| } |
| |
| // base found at two different pointers, |
| // conversion is not unique |
| return 0; |
| } |
| } |
| } |
| |
| return match_found; |
| } |