/*
* Copyright (c) 1996-1997
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* Copyright (c) 2002
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/*
* This implements standard-conforming allocators that interact with
* the garbage collector. Gc_alloctor<T> allocates garbage-collectable
* objects of type T. Traceable_allocator<T> allocates objects that
* are not temselves garbage collected, but are scanned by the
* collector for pointers to collectable objects. Traceable_alloc
* should be used for explicitly managed STL containers that may
* point to collectable objects.
*
* This code was derived from an earlier version of the GNU C++ standard
* library, which itself was derived from the SGI STL implementation.
*/
#include "gc.h" // For size_t
/* First some helpers to allow us to dispatch on whether or not a type
* is known to be pointerfree.
* These are private, except that the client may invoke the
* GC_DECLARE_PTRFREE macro.
*/
struct GC_true_type {};
struct GC_false_type {};
template <class GC_tp>
struct GC_type_traits {
GC_false_type GC_is_ptr_free;
};
# define GC_DECLARE_PTRFREE(T) \
template<> struct GC_type_traits<T> { GC_true_type GC_is_ptr_free; }
GC_DECLARE_PTRFREE(signed char);
GC_DECLARE_PTRFREE(unsigned char);
GC_DECLARE_PTRFREE(signed short);
GC_DECLARE_PTRFREE(unsigned short);
GC_DECLARE_PTRFREE(signed int);
GC_DECLARE_PTRFREE(unsigned int);
GC_DECLARE_PTRFREE(signed long);
GC_DECLARE_PTRFREE(unsigned long);
GC_DECLARE_PTRFREE(float);
GC_DECLARE_PTRFREE(double);
/* The client may want to add others. */
// In the following GC_Tp is GC_true_type iff we are allocating a
// pointerfree object.
template <class GC_Tp>
inline void * GC_selective_alloc(size_t n, GC_Tp) {
return GC_MALLOC(n);
}
template <>
inline void * GC_selective_alloc<GC_true_type>(size_t n, GC_true_type) {
return GC_MALLOC_ATOMIC(n);
}
/* Now the public gc_allocator<T> class:
*/
template <class GC_Tp>
class gc_allocator {
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef GC_Tp* pointer;
typedef const GC_Tp* const_pointer;
typedef GC_Tp& reference;
typedef const GC_Tp& const_reference;
typedef GC_Tp value_type;
template <class GC_Tp1> struct rebind {
typedef gc_allocator<GC_Tp1> other;
};
gc_allocator() {}
# ifndef _MSC_VER
// I'm not sure why this is needed here in addition to the following.
// The standard specifies it for the standard allocator, but VC++ rejects
// it. -HB
gc_allocator(const gc_allocator&) throw() {}
# endif
template <class GC_Tp1> gc_allocator(const gc_allocator<GC_Tp1>&) throw() {}
~gc_allocator() throw() {}
pointer address(reference GC_x) const { return &GC_x; }
const_pointer address(const_reference GC_x) const { return &GC_x; }
// GC_n is permitted to be 0. The C++ standard says nothing about what
// the return value is when GC_n == 0.
GC_Tp* allocate(size_type GC_n, const void* = 0) {
GC_type_traits<GC_Tp> traits;
return static_cast<GC_Tp *>
(GC_selective_alloc(GC_n * sizeof(GC_Tp),
traits.GC_is_ptr_free));
}
// __p is not permitted to be a null pointer.
void deallocate(pointer __p, size_type GC_n)
{ GC_FREE(__p); }
size_type max_size() const throw()
{ return size_t(-1) / sizeof(GC_Tp); }
void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); }
void destroy(pointer __p) { __p->~GC_Tp(); }
};
template<>
class gc_allocator<void> {
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef void* pointer;
typedef const void* const_pointer;
typedef void value_type;
template <class GC_Tp1> struct rebind {
typedef gc_allocator<GC_Tp1> other;
};
};
template <class GC_T1, class GC_T2>
inline bool operator==(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&)
{
return true;
}
template <class GC_T1, class GC_T2>
inline bool operator!=(const gc_allocator<GC_T1>&, const gc_allocator<GC_T2>&)
{
return false;
}
/*
* And the public traceable_allocator class.
*/
// Note that we currently don't specialize the pointer-free case, since a
// pointer-free traceable container doesn't make that much sense,
// though it could become an issue due to abstraction boundaries.
template <class GC_Tp>
class traceable_allocator {
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef GC_Tp* pointer;
typedef const GC_Tp* const_pointer;
typedef GC_Tp& reference;
typedef const GC_Tp& const_reference;
typedef GC_Tp value_type;
template <class GC_Tp1> struct rebind {
typedef traceable_allocator<GC_Tp1> other;
};
traceable_allocator() throw() {}
# ifndef _MSC_VER
traceable_allocator(const traceable_allocator&) throw() {}
# endif
template <class GC_Tp1> traceable_allocator
(const traceable_allocator<GC_Tp1>&) throw() {}
~traceable_allocator() throw() {}
pointer address(reference GC_x) const { return &GC_x; }
const_pointer address(const_reference GC_x) const { return &GC_x; }
// GC_n is permitted to be 0. The C++ standard says nothing about what
// the return value is when GC_n == 0.
GC_Tp* allocate(size_type GC_n, const void* = 0) {
return static_cast<GC_Tp*>(GC_MALLOC_UNCOLLECTABLE(GC_n * sizeof(GC_Tp)));
}
// __p is not permitted to be a null pointer.
void deallocate(pointer __p, size_type GC_n)
{ GC_FREE(__p); }
size_type max_size() const throw()
{ return size_t(-1) / sizeof(GC_Tp); }
void construct(pointer __p, const GC_Tp& __val) { new(__p) GC_Tp(__val); }
void destroy(pointer __p) { __p->~GC_Tp(); }
};
template<>
class traceable_allocator<void> {
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef void* pointer;
typedef const void* const_pointer;
typedef void value_type;
template <class GC_Tp1> struct rebind {
typedef traceable_allocator<GC_Tp1> other;
};
};
template <class GC_T1, class GC_T2>
inline bool operator==(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&)
{
return true;
}
template <class GC_T1, class GC_T2>
inline bool operator!=(const traceable_allocator<GC_T1>&, const traceable_allocator<GC_T2>&)
{
return false;
}
