xpcom/ds/nsCppSharedAllocator.h

   1 #ifndef nsCppSharedAllocator_h__
   2 #define nsCppSharedAllocator_h__
   3
   4 #include "nsMemory.h"     // for |nsMemory|
   5 #include NEW_H                                  // to allow placement |new|
   6
   7
   8   // under Metrowerks (Mac), we don't have autoconf yet
   9 #ifdef __MWERKS__
  10   #define HAVE_CPP_MEMBER_TEMPLATES
  11         #define HAVE_CPP_NUMERIC_LIMITS
  12 #endif
  13
  14   // under MSVC shut off copious warnings about unused in-lines
  15 #ifdef _MSC_VER
  16   #pragma warning( disable: 4514 )
  17 #endif
  18
  19 #ifdef HAVE_CPP_NUMERIC_LIMITS
  20 #include <limits>
  21 #else
  22 #include <limits.h>
  23 #endif
  24
  25
  26 template <class T>
  27 class nsCppSharedAllocator
  28     /*
  29       ...allows Standard Library containers, et al, to use our global shared
  30       (XP)COM-aware allocator.
  31     */
  32   {
  33     public:
  34       typedef T          value_type;
  35       typedef size_t     size_type;
  36       typedef ptrdiff_t  difference_type;
  37
  38       typedef T*         pointer;
  39       typedef const T*   const_pointer;
  40
  41       typedef T&         reference;
  42       typedef const T&   const_reference;
  43
  44
  45
  46       nsCppSharedAllocator() { }
  47
  48 #ifdef HAVE_CPP_MEMBER_TEMPLATES
  49       template <class U>
  50       nsCppSharedAllocator( const nsCppSharedAllocator<U>& ) { }
  51 #endif
  52
  53      ~nsCppSharedAllocator() { }
  54
  55
  56       pointer
  57       address( reference r ) const
  58         {
  59           return &r;
  60         }
  61
  62       const_pointer
  63       address( const_reference r ) const
  64         {
  65           return &r;
  66         }
  67
  68       pointer
  69       allocate( size_type n, const void* /*hint*/=0 )
  70         {
  71           return reinterpret_cast<pointer>(nsMemory::Alloc(static_cast<PRUint32>(n*sizeof(T))));
  72         }
  73
  74       void
  75       deallocate( pointer p, size_type /*n*/ )
  76         {
  77           nsMemory::Free(p);
  78         }
  79
  80       void
  81       construct( pointer p, const T& val )
  82         {
  83           new (p) T(val);
  84         }
  85
  86       void
  87       destroy( pointer p )
  88         {
  89           p->~T();
  90         }
  91
  92       size_type
  93       max_size() const
  94         {
  95 #ifdef HAVE_CPP_NUMERIC_LIMITS
  96           return numeric_limits<size_type>::max() / sizeof(T);
  97 #else
  98           return ULONG_MAX / sizeof(T);
  99 #endif
 100         }
 101
 102 #ifdef HAVE_CPP_MEMBER_TEMPLATES
 103       template <class U>
 104       struct rebind
 105         {
 106           typedef nsCppSharedAllocator<U> other;
 107         };
 108 #endif
 109   };
 110
 111
 112 template <class T>
 113 PRBool
 114 operator==( const nsCppSharedAllocator<T>&, const nsCppSharedAllocator<T>& )
 115   {
 116     return PR_TRUE;
 117   }
 118
 119 template <class T>
 120 PRBool
 121 operator!=( const nsCppSharedAllocator<T>&, const nsCppSharedAllocator<T>& )
 122   {
 123     return PR_FALSE;
 124   }
 125
 126 #endif /* !defined(nsCppSharedAllocator_h__) */