Utilities to use templates in C++ with less pain

C++ Utilities

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/*

Copyright (c) 2014 Sam Yuen

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 altertantial 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.

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= `cplus.hh`

This file consists of utilities make C++ simpler.
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*/

#ifndef HACTAR_CPLUS_HH
#define HACTAR_CPLUS_HH

#include <stdlib.h>
#include <stdint.h>

// Put it into private section of a class to disable implicit casts.
#define CPLUS_BAD_CAST(T) \
	T(const T&)

// Put it into private section of a class to disable assigns.
#define CPLUS_BAD_ASSIGN(T) \
	T& operator=(const T&)

// It could be used to check if a type is complete at compile time
#define CPLUS_ASSERT_COMPLETE_TYPE(T) \
	typedef char _##T##_COMPLETE[sizeof(T) ? 1 : -1]; \
	enum { _ASSERT_##T##_COMPLETE = \
		sizeof(_##T##_COMPLETE) }

// It could be used to check if a type extends another type at compile time.
#define CPLUS_ASSERT_TYPE_EXTENDS(T, BASE) \
	static int _##T##_EXTENDS_##BASE(BASE*); \
	static void _##T##_EXTENDS_##BASE(...); \
	enum { _ASSERT_##T##_EXTENDS_##BASE = \
		sizeof(_##T##_EXTENDS_##BASE((T*) NULL)) }

// It could be used to check if a static item exists at compile time.
// Take an example, `CPLUS_ASSERT_EXISTS(foo, &T::foo, void (T::*) ())` checks 
// if `T` has a method called `foo` with specified type; 
// Another example, `CPLUS_ASSERT_EXISTS(bar, &T::bar, long*)` checks if `T` 
// has a static member `bar` with `long` type.
#define CPLUS_ASSERT_EXISTS(ID, STATIC_PTR, PTR_TYPE) \
	template<PTR_TYPE> class _##ID##_HOLDER {}; \
	static int _##ID##_EXISTS(_##ID##_HOLDER<STATIC_PTR>*); \
	static void _##ID##_EXISTS(...); \
	enum { _ASSERT_##ID##_EXISTS = sizeof(_##ID##_EXISTS(NULL)) }

#endif
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