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[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc4/] [libstdc++-v3/] [libsupc++/] [dyncast.cc] - Rev 753
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// Copyright (C) 1994, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2007, 2009 // Free Software Foundation // // This file is part of GCC. // // GCC 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, or (at your option) // any later version. // GCC 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 "tinfo.h" namespace __cxxabiv1 { // this is the external interface to the dynamic cast machinery /* sub: source address to be adjusted; nonnull, and since the * source object is polymorphic, *(void**)sub is a virtual pointer. * src: static type of the source object. * dst: destination type (the "T" in "dynamic_cast<T>(v)"). * src2dst_offset: a static hint about the location of the * source subobject with respect to the complete object; * special negative values are: * -1: no hint * -2: src is not a public base of dst * -3: src is a multiple public base type but never a * virtual base type * otherwise, the src type is a unique public nonvirtual * base type of dst at offset src2dst_offset from the * origin of dst. */ extern "C" void * __dynamic_cast (const void *src_ptr, // object started from const __class_type_info *src_type, // type of the starting object const __class_type_info *dst_type, // desired target type ptrdiff_t src2dst) // how src and dst are related { const void *vtable = *static_cast <const void *const *> (src_ptr); const vtable_prefix *prefix = adjust_pointer <vtable_prefix> (vtable, -offsetof (vtable_prefix, origin)); const void *whole_ptr = adjust_pointer <void> (src_ptr, prefix->whole_object); const __class_type_info *whole_type = prefix->whole_type; __class_type_info::__dyncast_result result; whole_type->__do_dyncast (src2dst, __class_type_info::__contained_public, dst_type, whole_ptr, src_type, src_ptr, result); if (!result.dst_ptr) return NULL; if (contained_public_p (result.dst2src)) // Src is known to be a public base of dst. return const_cast <void *> (result.dst_ptr); if (contained_public_p (__class_type_info::__sub_kind (result.whole2src & result.whole2dst))) // Both src and dst are known to be public bases of whole. Found a valid // cross cast. return const_cast <void *> (result.dst_ptr); if (contained_nonvirtual_p (result.whole2src)) // Src is known to be a non-public nonvirtual base of whole, and not a // base of dst. Found an invalid cross cast, which cannot also be a down // cast return NULL; if (result.dst2src == __class_type_info::__unknown) result.dst2src = dst_type->__find_public_src (src2dst, result.dst_ptr, src_type, src_ptr); if (contained_public_p (result.dst2src)) // Found a valid down cast return const_cast <void *> (result.dst_ptr); // Must be an invalid down cast, or the cross cast wasn't bettered return NULL; } }
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