/* ///////////////////////////////////////////////////////////////////////// * File: stlsoft/util/pod_veneer.hpp * * Purpose: Contains the pod_veneer template class. * * Created: 19th January 2002 * Updated: 10th August 2009 * * Home: http://stlsoft.org/ * * Copyright (c) 2002-2009, Matthew Wilson and Synesis Software * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of * any contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * ////////////////////////////////////////////////////////////////////// */ /** \file stlsoft/util/pod_veneer.hpp * * \brief [C++ only] Definition of the stlsoft::pod_veneer class template * (\ref group__library__utility "Utility" Library). */ #ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_POD_VENEER #define STLSOFT_INCL_STLSOFT_UTIL_HPP_POD_VENEER #ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION # define STLSOFT_VER_STLSOFT_UTIL_HPP_POD_VENEER_MAJOR 4 # define STLSOFT_VER_STLSOFT_UTIL_HPP_POD_VENEER_MINOR 0 # define STLSOFT_VER_STLSOFT_UTIL_HPP_POD_VENEER_REVISION 1 # define STLSOFT_VER_STLSOFT_UTIL_HPP_POD_VENEER_EDIT 49 #endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */ /* ///////////////////////////////////////////////////////////////////////// * Includes */ #ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT # include #endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */ #ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS # include #endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS */ /* ///////////////////////////////////////////////////////////////////////// * Namespace */ #ifndef _STLSOFT_NO_NAMESPACE namespace stlsoft { #endif /* _STLSOFT_NO_NAMESPACE */ /* ///////////////////////////////////////////////////////////////////////// * Classes */ // class pod_veneer /** \brief Bolts construction and/or destruction to Plain Old Data types * * The parameterisation of this veneer * can be used to apply RRID or RAII semantics to a plain old data type. For * example, * \code struct Simple { public: char *buffer; }; void Init_Simple(Simple *simple); void Uninit_Simple(Simple *simple); struct Simple_Init { void operator ()(Simple *simple) { Init_Simple(simple); } }; struct Simple_Uninit { void operator ()(Simple *simple) { Uninit_Simple(simple); } }; void fn() { typedef pod_veneer Simple_raii_t; Simple_raii_t simple; // Init_Simple() called here . . . } // Uninit_Simple() called here \endcode * * \param T The POD type * \param CF The function class applied during construction * \param DF The function class applied during destruction * * \ingroup concepts_veneer */ template< ss_typename_param_k T , ss_typename_param_k CF , ss_typename_param_k DF > class pod_veneer : public T { public: /// The value type typedef T value_type; /// The Plain Old Data type typedef T pod_type; /// The constructor function class typedef CF constructor_function_type; /// The destructor function class typedef DF destructor_function_type; /// The type of the current parameterisation typedef pod_veneer class_type; public: /// The constructor, within which CF is applied to \c this pod_veneer() { // It is entirely appropriate to constrain instantiations of this class // to default construction only, since the whole raison d'etre of this // template is to bring RAII semantics to POD types. // Construct the pod constructor_function_type()(static_cast(this)); } /// The destructor, within which DF is applied to \c this ~pod_veneer() stlsoft_throw_0() { // There are four important points to note about the destructor // // 1. It does not throw an exception. Therefore, the destroying type // must not throw an exception in its function call operator // 2. It uses the must_be_pod constraint to ensure that the pod_type is // a POD type // 3. It uses the must_be_same_size constraint to ensure that the // generated class is the same size as the pod_type, so that arrays of // the generated class can be used where arrays of the pod_type could be // used. The runtime assert is included for those compilers that do not // implement compile-time asserts. // 4. It is non-virtual, since it should not introduce a vtable (which // would change the size of the generated class) // 2. Must be POD stlsoft_constraint_must_be_pod(pod_type); // 3. Must use EDO stlsoft_constraint_must_be_same_size(class_type, pod_type); #if defined(STLSOFT_COMPILER_IS_WATCOM) STLSOFT_ASSERT(sizeof(class_type) == sizeof(pod_type)); #else /* ? compiler */ STLSOFT_MESSAGE_ASSERT("pod_veneer used for inappropriate type", sizeof(class_type) == sizeof(pod_type)); #endif /* compiler */ // Destroy the pod destructor_function_type()(static_cast(this)); } }; /* ////////////////////////////////////////////////////////////////////// */ #ifndef _STLSOFT_NO_NAMESPACE } // namespace stlsoft #endif /* _STLSOFT_NO_NAMESPACE */ /* ////////////////////////////////////////////////////////////////////// */ #endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_POD_VENEER */ /* ///////////////////////////// end of file //////////////////////////// */