test_smart_cast.cpp

C++的一个好库。。。现在很流行

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// test_smart_cast.cpp: 

// (C) Copyright 2002 Robert Ramey - http://www.rrsd.com . 
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// <[e-mail]>

#include <exception>
#include <boost/smart_cast.hpp>

#include <boost/test/test_tools.hpp>
#include <boost/noncopyable.hpp>

using namespace boost;

class Base1 : public boost::noncopyable
{
    char a;
};

class Base2
{
    int b;
};

class Derived : public Base1, public Base2
{
    long c;
};

BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(Base1)
BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(Base2)
BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(Derived)

// if compiler doesn't support TPS, the smart_cast syntax doesn't
// work for references.  One has to use the smart_cast_reference
// syntax (tested below ) instead.

void test_static_reference_cast_2(){
    Derived d;
    Base1 & b1 = static_cast<Base1 &>(d);
    Base2 & b2 = static_cast<Base2 &>(d);

    Base1 & scb1 = smart_cast<Base1 &, Derived &>(d);
    Base2 & scb2 = smart_cast<Base2 &, Derived &>(d);
    BOOST_CHECK_EQUAL(& b1, & scb1);
    BOOST_CHECK_EQUAL(& b2, & scb2);

    // downcast
//    BOOST_CHECK_EQUAL(& d, & (smart_cast<Derived &, Base1 &>(b1)));
//    BOOST_CHECK_EQUAL(& d, & (smart_cast<Derived &, Base2 &>(b2)));

    // crosscast pointers fails at compiler time
    // BOOST_CHECK_EQUAL(pB2,smart_cast<B2 *>(pB1));
    // though explicit cross cast will always work
    BOOST_CHECK_EQUAL(& b2,(
        & smart_cast<Base2 &, Derived &>(
            smart_cast<Derived &, Base1 &>(b1)
        ))
    );
}

void test_static_reference_cast_1(){
    Derived d;
    Base1 & b1 = static_cast<Base1 &>(d);
    Base2 & b2 = static_cast<Base2 &>(d);

    Base1 & scb1 = smart_cast_reference<Base1 &>(d);
    Base2 & scb2 = smart_cast_reference<Base2 &>(d);
    BOOST_CHECK_EQUAL(& b1, & scb1);
    BOOST_CHECK_EQUAL(& b2, & scb2);

    // downcast
    BOOST_CHECK_EQUAL(& d, & (smart_cast_reference<Derived &>(b1)));
    BOOST_CHECK_EQUAL(& d, & (smart_cast_reference<Derived &>(b2)));

    // crosscast pointers fails at compiler time
    // BOOST_CHECK_EQUAL(pB2,smart_cast<B2 *>(pB1));
    // though explicit cross cast will always work
    BOOST_CHECK_EQUAL(& b2,(
        & smart_cast_reference<Base2 &>(
            smart_cast_reference<Derived &>(b1)
        ))
    );
}

void test_static_pointer_cast(){
    // pointers
    Derived d;
    Derived *pD = & d;
    Base1 *pB1 = pD;
    Base2 *pB2 = pD;

    // upcast
    BOOST_CHECK_EQUAL(pB1, smart_cast<Base1 *>(pD));
    BOOST_CHECK_EQUAL(pB2, smart_cast<Base2 *>(pD));

    // downcast
    BOOST_CHECK_EQUAL(pD, smart_cast<Derived *>(pB1));
    BOOST_CHECK_EQUAL(pD, smart_cast<Derived *>(pB2));

    // crosscast pointers fails at compiler time
    // BOOST_CHECK_EQUAL(pB2, smart_cast<Base2 *>(pB1));

    // though explicit cross cast will always work
    BOOST_CHECK_EQUAL(pB2,
        smart_cast<Base2 *>(
            smart_cast<Derived *>(pB1)
        )
    );
}


class VBase1 : public boost::noncopyable
{
    char a;
public:
    virtual ~VBase1(){};
};

class VBase2
{
    int b;
public:
    virtual ~VBase2(){};
};

class VDerived : public VBase1, public VBase2
{
    long c;
public:
    virtual ~VDerived(){};
};

BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(VBase1)
BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(VBase2)
BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(VDerived)

// see above

void test_dynamic_reference_cast_2(){
    VDerived d;
    VBase1 &b1 = dynamic_cast<VBase1 &>(d);
    VBase2 &b2 = static_cast<VBase2 &>(d);

    VBase1 & vb1 = smart_cast<VBase1 &, VDerived &>(d);
    BOOST_CHECK_EQUAL(& b1, & vb1);
    BOOST_CHECK_EQUAL(& b2, (& smart_cast<VBase2 &, VDerived &>(d)));

    // downcast
    BOOST_CHECK_EQUAL(& d, (& smart_cast<VDerived &, VBase1 &>(b1)));
    BOOST_CHECK_EQUAL(& d, (& smart_cast<VDerived &, VBase2 &>(b2)));

    // crosscast
     BOOST_CHECK_EQUAL(& b2, (& smart_cast<VBase2 &, VBase1 &>(b1)));

    // explicit cross cast should always work
    BOOST_CHECK_EQUAL(& b2, (
        & smart_cast<VBase2 &, VDerived &>(
            smart_cast<VDerived &, VBase1 &>(b1)
        ))
    );
}

void test_dynamic_reference_cast_1(){
    VDerived d;
    VBase1 &b1 = dynamic_cast<VBase1 &>(d);
    VBase2 &b2 = static_cast<VBase2 &>(d);

    VBase1 & vb1 = smart_cast_reference<VBase1 &>(d);
    BOOST_CHECK_EQUAL(& b1, & vb1);
    BOOST_CHECK_EQUAL(& b2, (& smart_cast_reference<VBase2 &>(d)));

    // downcast
    BOOST_CHECK_EQUAL(& d, (& smart_cast_reference<VDerived &>(b1)));
    BOOST_CHECK_EQUAL(& d, (& smart_cast_reference<VDerived &>(b2)));

    // crosscast
     BOOST_CHECK_EQUAL(& b2, (& smart_cast_reference<VBase2 &>(b1)));

    // explicit cross cast should always work
    BOOST_CHECK_EQUAL(& b2, (
        & smart_cast_reference<VBase2 &>(
            smart_cast_reference<VDerived &>(b1)
        ))
    );
}

void test_dynamic_pointer_cast(){
    // pointers
    VDerived d;
    VDerived *pD = & d;
    VBase1 *pB1 = pD;
    VBase2 *pB2 = pD;

    // upcast
    BOOST_CHECK_EQUAL(pB1, smart_cast<VBase1 *>(pD));
    BOOST_CHECK_EQUAL(pB2, smart_cast<VBase2 *>(pD));

    // downcast
    BOOST_CHECK_EQUAL(pD, smart_cast<VDerived *>(pB1));
    BOOST_CHECK_EQUAL(pD, smart_cast<VDerived *>(pB2));

    // crosscast pointers fails at compiler time
    BOOST_CHECK_EQUAL(pB2, smart_cast<VBase2 *>(pB1));
    // though explicit cross cast will always work
    BOOST_CHECK_EQUAL(pB2,
        smart_cast<VBase2 *>(
            smart_cast<VDerived *>(pB1)
        )
    );
}

int
test_main(int /* argc */, char * /* argv */[])
{
    test_static_reference_cast_2();
    test_static_reference_cast_1();
    test_static_pointer_cast();
    test_dynamic_reference_cast_2();
    test_dynamic_reference_cast_1();
    test_dynamic_pointer_cast();

    return EXIT_SUCCESS;
}