implicit_cast.cpp

魔兽世界的私服源程序

// Copyright (c) 2003 Daniel Wallin and Arvid Norberg

// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
// ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.

extern "C"
{
	#include "lua.h"
}

#include <luabind/luabind.hpp>
#include <luabind/detail/implicit_cast.hpp>

using namespace luabind::detail;

	// returns -1 if there exists no implicit cast from the given class_rep
	// to T. If there exists an implicit cast to T, the number of steps times 2
	// is returned and pointer_offset is filled with the number of bytes
	// the pointer have to be offseted to perform the cast
	// the reason why we return the number of cast-steps times two, instead of
	// just the number of steps is to be consistent with the function matchers. They
	// have to give one matching-point extra to match const functions. There may be
	// two functions that match their parameters exactly, but there is one const
	// function and one non-const function, then (if the this-pointer is non-const)
	// both functions will match. To avoid amiguaties, the const version will get
	// one penalty point to make the match-selector select the non-const version. It
	// the this-pointer is const, there's no problem, since the non-const function
	// will not match at all.
namespace luabind { namespace detail
{
	int implicit_cast(const class_rep* crep, 
								LUABIND_TYPE_INFO const& type_id, 
								 int& pointer_offset)
	{
		int offset = 0;
		if (LUABIND_TYPE_INFO_EQUAL(crep->type(), type_id)) return 0;

		for (std::vector<class_rep::base_info>::const_iterator
				i = crep->bases().begin(); i != crep->bases().end(); ++i)
		{
			int steps = implicit_cast(i->base, type_id, offset);
			pointer_offset = offset + i->pointer_offset;
			if (steps >= 0) return steps + 2;
		}
		return -1;
	}
}}