23.vector.allocator.cpp

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// disable debug iterators to prevent compilation errors
#include <rw/_config.h>
 
#ifndef _RWSTD_NO_DEBUG_ITER
#  define _RWSTD_NO_DEBUG_ITER
#endif    // _RWSTD_NO_DEBUG_ITER
 
#include <memory>
#include <vector>
#include <cstddef>   // for ptrdiff_t, size_t
 
#include <rw_driver.h>
 
 
// DESCRIPTION:
//   Test instantiates std::vector on a user-defined type, user-defined
//   allocator and a user-defined pointer type, making sure that everything
//   still compiles and runs with expected results
 
//   Note: 20.1.5, p2, Allocator requirements specifies that the type
//         std::allocator<T>::pointer be a "pointer to T", which might
//         make this test case not well-defined; it is expected that
//         this will be changed in a future revision of the Standard
 
// user-defined pointer type
template <class T>
struct Pointer
{
    typedef T                               value_type;
    typedef std::size_t                     size_type;
    typedef std::ptrdiff_t                  difference_type;
    typedef value_type*                     pointer;
    typedef const value_type*               const_pointer;
    typedef value_type&                     reference;
    typedef const value_type&               const_reference;
    typedef std::random_access_iterator_tag iterator_category;
 
    Pointer (): offset_ (0) { }
 
    Pointer (const Pointer &rhs)
        : offset_ (rhs.offset_) { }
 
    Pointer (difference_type off, int) : offset_ (off) {}
 
    reference operator* () const {
        return *_RWSTD_REINTERPRET_CAST (pointer, offset_);
    }
 
    bool operator== (const Pointer &rhs) const {
        return offset_ == rhs.offset_;
    }
 
    bool operator!= (const Pointer &rhs) const {
        return !operator== (rhs);
    }
 
    bool operator< (const Pointer &rhs) const {
        return offset_ < rhs.offset_;
    }
 
    bool operator<= (const Pointer &rhs) const {
        return !(*this > rhs);
    }
 
    bool operator> (const Pointer &rhs) const {
        return rhs < *this;
    }
 
    bool operator>= (const Pointer &rhs) const {
        return !(*this < rhs);
    }
 
    Pointer& operator++ () {
        pointer ptr = _RWSTD_REINTERPRET_CAST (pointer, offset_);
        offset_ = _RWSTD_REINTERPRET_CAST (difference_type, ++ptr);
        return *this;
    }
 
    Pointer& operator-- () {
        pointer ptr = _RWSTD_REINTERPRET_CAST (pointer, offset_);
        offset_ = _RWSTD_REINTERPRET_CAST (difference_type, --ptr);
        return *this;
    }
 
    Pointer& operator+= (difference_type i) {
        pointer ptr = _RWSTD_REINTERPRET_CAST (pointer, offset_);
        offset_ = _RWSTD_REINTERPRET_CAST (difference_type, ptr += i);
        return *this;
    }
 
    Pointer& operator-= (difference_type i) {
        return *this += -i;
    }
 
    Pointer operator+ (difference_type i) const {
        return Pointer (*this) += i;
    }
 
    Pointer operator- (difference_type i) const {
        return Pointer (*this) -= i;
    }
 
    difference_type operator- (const Pointer &rhs) const {
        pointer p1 = _RWSTD_REINTERPRET_CAST (pointer, offset_);
        pointer p2 = _RWSTD_REINTERPRET_CAST (pointer, rhs.offset_);
        return p1 - p2;
    }
 
    difference_type offset_;
 
private:
 
    // deliberately not defined to detect their use
    void operator++ (int);
    void operator-- (int);
 
};
 
 
// user-defined allocator
template <class T>
class Allocator
{
public:
    typedef T                               value_type;
    typedef std::size_t                     size_type;
    typedef std::ptrdiff_t                  difference_type;
    typedef Pointer<T>                      pointer;
    typedef const Pointer<T>                const_pointer;
    typedef T&                              reference;
    typedef const T&                        const_reference;
    typedef std::random_access_iterator_tag iterator_category;
 
    pointer address (reference r) const {
        return pointer (_RWSTD_REINTERPRET_CAST (difference_type, &r), 1);
    }
 
    const_pointer address (const_reference r) const {
        return const_pointer (_RWSTD_REINTERPRET_CAST (difference_type, &r),
                              1);
    }
 
    Allocator () throw () {}
 
    template <class U>
    Allocator (const Allocator<U>&) throw () {}
 
    pointer allocate (size_type n, const void* = 0) {
        void* const ptr = operator new (n * sizeof (T));
        return pointer (_RWSTD_REINTERPRET_CAST (difference_type, ptr), 1);
    }
 
    void deallocate (pointer ptr, size_type) {
        operator delete (_RWSTD_REINTERPRET_CAST (void*, ptr.offset_));
    }
 
    void construct (pointer ptr, const_reference val) {
        new (_RWSTD_REINTERPRET_CAST (void*, ptr.offset_)) value_type (val);
    }
 
    void destroy (pointer ptr) { 
        _RWSTD_REINTERPRET_CAST (T*, ptr.offset_)->~value_type ();
    }
 
    size_type max_size () const throw () {
        return size_type (-1) / sizeof (T); 
    }
 
    template <class U>
    struct rebind { typedef Allocator<U> other; };
 
    bool operator== (const Allocator&) const {
        return 1;
    }
 
    bool operator!= (const Allocator &rhs) const {
        return !operator== (rhs);
    }
};
 
 
// user-defined type
struct MyClass
{
    int i_;
    int j_;
};
 
 
#ifndef _RWSTD_NO_EXPLICIT_INSTANTIATION
 
// explicitly instantiate to better exercise the template
template class std::vector<MyClass, Allocator<MyClass> >;
 
#endif   // _RWSTD_NO_EXPLICIT_INSTANTIATION
 
 
static int
run_test (int, char**)
{
    rw_warn (0, 0, __LINE__, "debugging iterators disabled");
 
    typedef std::vector<MyClass, Allocator<MyClass> > Vector;
 
    const Vector::size_type nelems = 256;
 
    const MyClass value = { 0, 0 };
 
    Vector v (nelems, value);
 
    rw_assert (nelems == v.size (), 0, __LINE__,
               "vector(%zu, value_type).size() == %1$zu, got %zu",
               nelems, v.size ());
 
    Vector ().swap (v);
 
    rw_assert (0 == v.size (), 0, __LINE__,
               "vector().swap(vector&).size() == 0, got %zu",
               v.size ());
 
    Vector::size_type i;
 
    for (i = 0; i != nelems; ++i)
        v.push_back (value);
 
    rw_assert (nelems == v.size (), 0, __LINE__,
               "vector::size() == %1$zu, got %zu",
               nelems, v.size ());
 
    return 0;
}
 
 
int main (int argc, char** argv)
{
    return rw_test (argc, argv, __FILE__,
                    "lib.vector",
                    "with a user-defined allocator and pointer types",
                    run_test,
                    "",
                    (void*)0);
}