Home | History | Annotate | Download | only in pointers
      1 /*
      2  * Copyright (c) 2003
      3  * Francois Dumont
      4  *
      5  * This material is provided "as is", with absolutely no warranty expressed
      6  * or implied. Any use is at your own risk.
      7  *
      8  * Permission to use or copy this software for any purpose is hereby granted
      9  * without fee, provided the above notices are retained on all copies.
     10  * Permission to modify the code and to distribute modified code is granted,
     11  * provided the above notices are retained, and a notice that the code was
     12  * modified is included with the above copyright notice.
     13  *
     14  */
     15 
     16 /* NOTE: This is an internal header file, included by other STL headers.
     17  *   You should not attempt to use it directly.
     18  */
     19 
     20 #ifndef _STLP_POINTERS_SPEC_TOOLS_H
     21 #define _STLP_POINTERS_SPEC_TOOLS_H
     22 
     23 #ifndef _STLP_TYPE_TRAITS_H
     24 #  include <stl/type_traits.h>
     25 #endif
     26 
     27 _STLP_BEGIN_NAMESPACE
     28 
     29 //Some usefull declarations:
     30 template <class _Tp> struct less;
     31 
     32 _STLP_MOVE_TO_PRIV_NAMESPACE
     33 
     34 template <class _StorageT, class _ValueT, class _BinaryPredicate>
     35 struct _BinaryPredWrapper;
     36 
     37 /*
     38  * Since the compiler only allows at most one non-trivial
     39  * implicit conversion we can make use of a shim class to
     40  * be sure that functions below doesn't accept classes with
     41  * implicit pointer conversion operators
     42  */
     43 struct _VoidPointerShim
     44 { _VoidPointerShim(void*); };
     45 struct _ConstVoidPointerShim
     46 { _ConstVoidPointerShim(const void*); };
     47 struct _VolatileVoidPointerShim
     48 { _VolatileVoidPointerShim(volatile void*); };
     49 struct _ConstVolatileVoidPointerShim
     50 { _ConstVolatileVoidPointerShim(const volatile void*); };
     51 
     52 //The dispatch functions:
     53 template <class _Tp>
     54 char _UseVoidPtrStorageType(const __false_type& /*POD*/, const _Tp&);
     55 char _UseVoidPtrStorageType(const __true_type& /*POD*/, ...);
     56 char* _UseVoidPtrStorageType(const __true_type& /*POD*/, _VoidPointerShim);
     57 
     58 template <class _Tp>
     59 char _UseConstVoidPtrStorageType(const __false_type& /*POD*/, const _Tp&);
     60 char _UseConstVoidPtrStorageType(const __true_type& /*POD*/, ...);
     61 char* _UseConstVoidPtrStorageType(const __true_type& /*POD*/, _ConstVoidPointerShim);
     62 
     63 template <class _Tp>
     64 char _UseVolatileVoidPtrStorageType(const __false_type& /*POD*/, const _Tp&);
     65 char _UseVolatileVoidPtrStorageType(const __true_type& /*POD*/, ...);
     66 char* _UseVolatileVoidPtrStorageType(const __true_type& /*POD*/, _VolatileVoidPointerShim);
     67 
     68 template <class _Tp>
     69 char _UseConstVolatileVoidPtrStorageType(const __false_type& /*POD*/, const _Tp&);
     70 char _UseConstVolatileVoidPtrStorageType(const __true_type& /*POD*/, ...);
     71 char* _UseConstVolatileVoidPtrStorageType(const __true_type& /*POD*/, _ConstVolatileVoidPointerShim);
     72 
     73 #if defined (_STLP_CLASS_PARTIAL_SPECIALIZATION)
     74 /* Thanks to class partial specialization the pointer specialization feature can even be used in
     75  * presence of incomplete type:
     76  * struct MyStruct {
     77  *   typedef vector<MyStruct> MyStructContainer;
     78  *   typedef MyStructContainer::iterator MyStructIterator;
     79  * };
     80  */
     81 
     82 template <class _Tp>
     83 struct _StorageType {
     84   typedef _Tp _QualifiedType;
     85   typedef _Tp _Type;
     86   enum { use_const_volatile_void_ptr = 0 };
     87 };
     88 
     89 template <class _Tp>
     90 struct _StorageType<_Tp*> {
     91   // Even if we detect a pointer type we use dispatch function to consider if it can be stored as a void*.
     92   // For instance function pointer might not necessarily be convertible to void*.
     93   enum { use_void_ptr = (sizeof(_STLP_PRIV _UseVoidPtrStorageType(__true_type(),
     94                                                                   __STATIC_CAST(_Tp*, 0))) == sizeof(char*))  };
     95   enum { use_const_volatile_void_ptr = use_void_ptr };
     96   typedef typename __select<use_void_ptr,
     97                             void*,
     98                             _Tp*>::_Ret _QualifiedType;
     99   typedef _QualifiedType _Type;
    100 };
    101 
    102 template <class _Tp>
    103 struct _StorageType<_Tp const*> {
    104   enum { use_void_ptr = (sizeof(_STLP_PRIV _UseConstVoidPtrStorageType(__true_type(),
    105                                                                        __STATIC_CAST(const _Tp*, 0))) == sizeof(char*)) };
    106   enum { use_const_volatile_void_ptr = use_void_ptr };
    107   typedef typename __select<use_void_ptr,
    108                             const void*,
    109                             const _Tp*>::_Ret _QualifiedType;
    110   typedef typename __select<use_void_ptr,
    111                             void*,
    112                             const _Tp*>::_Ret _Type;
    113 };
    114 
    115 template <class _Tp>
    116 struct _StorageType<_Tp volatile*> {
    117   enum { use_void_ptr = (sizeof(_STLP_PRIV _UseVolatileVoidPtrStorageType(__true_type(),
    118                                                                           __STATIC_CAST(_Tp volatile*, 0))) == sizeof(char*)) };
    119   enum { use_const_volatile_void_ptr = use_void_ptr };
    120   typedef typename __select<use_void_ptr,
    121                             volatile void*,
    122                             volatile _Tp*>::_Ret _QualifiedType;
    123   typedef typename __select<use_void_ptr,
    124                             void*,
    125                             volatile _Tp*>::_Ret _Type;
    126 };
    127 
    128 template <class _Tp>
    129 struct _StorageType<_Tp const volatile*> {
    130   enum { use_void_ptr = (sizeof(_STLP_PRIV _UseConstVolatileVoidPtrStorageType(__true_type(),
    131                                                                                __STATIC_CAST(_Tp const volatile*, 0))) == sizeof(char*)) };
    132   enum { use_const_volatile_void_ptr = use_void_ptr };
    133   typedef typename __select<use_void_ptr,
    134                             const volatile void*,
    135                             const volatile _Tp*>::_Ret _QualifiedType;
    136   typedef typename __select<use_void_ptr,
    137                             void*,
    138                             const volatile _Tp*>::_Ret _Type;
    139 };
    140 #else
    141 template <class _Tp>
    142 struct _StorageType {
    143   typedef typename __type_traits<_Tp>::is_POD_type _PODType;
    144 
    145 #if !defined (__BORLANDC__) || (__BORLANDC__ != 0x560)
    146   static _Tp __null_rep();
    147 #else
    148   static _Tp __null_rep;
    149 #endif
    150   enum { use_void_ptr = (sizeof(_STLP_PRIV _UseVoidPtrStorageType(_PODType(), __null_rep())) == sizeof(char*)) };
    151   enum { use_const_void_ptr = (sizeof(_STLP_PRIV _UseConstVoidPtrStorageType(_PODType(), __null_rep())) == sizeof(char*)) };
    152   enum { use_volatile_void_ptr = (sizeof(_STLP_PRIV _UseVolatileVoidPtrStorageType(_PODType(), __null_rep())) == sizeof(char*)) };
    153   enum { use_const_volatile_void_ptr = (sizeof(_STLP_PRIV _UseConstVolatileVoidPtrStorageType(_PODType(), __null_rep())) == sizeof(char*)) };
    154 
    155   typedef typename __select<!use_const_volatile_void_ptr,
    156                             _Tp,
    157           typename __select<use_void_ptr,
    158                             void*,
    159           typename __select<use_const_void_ptr,
    160                             const void*,
    161           typename __select<use_volatile_void_ptr,
    162                             volatile void*,
    163                             const volatile void*>::_Ret >::_Ret >::_Ret >::_Ret _QualifiedType;
    164 
    165 #if !defined (_STLP_CLASS_PARTIAL_SPECIALIZATION)
    166   /* If the compiler do not support the iterator_traits structure we cannot wrap
    167    * iterators pass to container template methods. The iterator dereferenced value
    168    * has to be storable without any cast in the chosen storage type. To guaranty
    169    * that the void pointer has to be correctly qualified.
    170    */
    171   typedef _QualifiedType _Type;
    172 #else
    173   /* With iterator_traits we can wrap passed iterators and make the necessary casts.
    174    * We can always use a simple void* storage type:
    175    */
    176   typedef typename __select<use_const_volatile_void_ptr,
    177                             void*,
    178                             _Tp>::_Ret _Type;
    179 #endif
    180 };
    181 #endif
    182 
    183 template <class _Tp, class _Compare>
    184 struct _AssocStorageTypes {
    185   typedef _StorageType<_Tp> _StorageTypeInfo;
    186   typedef typename _StorageTypeInfo::_Type _SType;
    187 
    188   //We need to also check that the comparison functor used to instanciate the assoc container
    189   //is the default Standard less implementation:
    190   enum { ptr_type = _StorageTypeInfo::use_const_volatile_void_ptr };
    191   typedef typename _IsSTLportClass<_Compare>::_Ret _STLportLess;
    192   enum { is_default_less = __type2bool<_STLportLess>::_Ret };
    193   typedef typename __select<is_default_less, _SType, _Tp>::_Ret _KeyStorageType;
    194   typedef typename __select<is_default_less && ptr_type,
    195                             _BinaryPredWrapper<_KeyStorageType, _Tp, _Compare>,
    196                             _Compare>::_Ret _CompareStorageType;
    197 };
    198 
    199 
    200 #if defined (_STLP_CLASS_PARTIAL_SPECIALIZATION)
    201 /*
    202  * Base struct to deal with qualifiers
    203  */
    204 template <class _StorageT, class _QualifiedStorageT>
    205 struct _VoidCastTraitsAux {
    206   typedef _QualifiedStorageT void_cv_type;
    207   typedef _StorageT void_type;
    208 
    209   static void_type * uncv_ptr(void_cv_type *__ptr)
    210   { return __ptr; }
    211   static void_type const* uncv_cptr(void_cv_type const*__ptr)
    212   { return __ptr; }
    213   static void_type ** uncv_pptr(void_cv_type **__ptr)
    214   { return __ptr; }
    215   static void_type & uncv_ref(void_cv_type & __ref)
    216   { return __ref; }
    217   static void_type const& uncv_cref(void_cv_type const& __ref)
    218   { return __ref; }
    219   static void_cv_type* cv_ptr(void_type *__ptr)
    220   { return __ptr; }
    221   static void_cv_type const* cv_cptr(void_type const*__ptr)
    222   { return __ptr; }
    223   static void_cv_type ** cv_pptr(void_type **__ptr)
    224   { return __ptr; }
    225   static void_cv_type & cv_ref(void_type & __ref)
    226   { return __ref; }
    227   static void_cv_type const& cv_cref(void_type const& __ref)
    228   { return __ref; }
    229 };
    230 
    231 template <class _VoidCVType>
    232 struct _VoidCastTraitsAuxBase {
    233   typedef _VoidCVType* void_cv_type;
    234   typedef void* void_type;
    235 
    236   static void_type* uncv_ptr(void_cv_type *__ptr)
    237   { return __CONST_CAST(void_type*, __ptr); }
    238   static void_type const* uncv_cptr(void_cv_type const*__ptr)
    239   { return __CONST_CAST(void_type const*, __ptr); }
    240   static void_type** uncv_pptr(void_cv_type **__ptr)
    241   { return __CONST_CAST(void_type**, __ptr); }
    242   static void_type& uncv_ref(void_cv_type &__ref)
    243   { return __CONST_CAST(void_type&, __ref); }
    244   static void_type const& uncv_cref(void_cv_type const& __ptr)
    245   { return __CONST_CAST(void_type const&, __ptr); }
    246   // The reverse versions
    247   static void_cv_type * cv_ptr(void_type *__ptr)
    248   { return __CONST_CAST(void_cv_type *, __ptr); }
    249   static void_cv_type const* cv_cptr(void_type const*__ptr)
    250   { return __CONST_CAST(void_cv_type const*, __ptr); }
    251   static void_cv_type ** cv_pptr(void_type **__ptr)
    252   { return __CONST_CAST(void_cv_type**, __ptr); }
    253   static void_cv_type & cv_ref(void_type &__ref)
    254   { return __CONST_CAST(void_cv_type &, __ref); }
    255   static void_cv_type const& cv_cref(void_type const& __ref)
    256   { return __CONST_CAST(void_cv_type const&, __ref); }
    257 };
    258 
    259 _STLP_TEMPLATE_NULL
    260 struct _VoidCastTraitsAux<void*, const void*> : _VoidCastTraitsAuxBase<void const>
    261 {};
    262 _STLP_TEMPLATE_NULL
    263 struct _VoidCastTraitsAux<void*, volatile void*> : _VoidCastTraitsAuxBase<void volatile>
    264 {};
    265 _STLP_TEMPLATE_NULL
    266 struct _VoidCastTraitsAux<void*, const volatile void*> : _VoidCastTraitsAuxBase<void const volatile>
    267 {};
    268 
    269 template <class _StorageT, class _ValueT>
    270 struct _CastTraits {
    271   typedef _ValueT value_type;
    272   typedef typename _StorageType<_ValueT>::_QualifiedType _QualifiedStorageT;
    273   typedef _VoidCastTraitsAux<_StorageT, _QualifiedStorageT> cv_traits;
    274   typedef typename cv_traits::void_type void_type;
    275   typedef typename cv_traits::void_cv_type void_cv_type;
    276 
    277   static value_type * to_value_type_ptr(void_type *__ptr)
    278   { return __REINTERPRET_CAST(value_type *, cv_traits::cv_ptr(__ptr)); }
    279   static value_type const* to_value_type_cptr(void_type const*__ptr)
    280   { return __REINTERPRET_CAST(value_type const*, cv_traits::cv_cptr(__ptr)); }
    281   static value_type ** to_value_type_pptr(void_type **__ptr)
    282   { return __REINTERPRET_CAST(value_type **, cv_traits::cv_pptr(__ptr)); }
    283   static value_type & to_value_type_ref(void_type &__ref)
    284   { return __REINTERPRET_CAST(value_type &, cv_traits::cv_ref(__ref)); }
    285   static value_type const& to_value_type_cref(void_type const& __ptr)
    286   { return __REINTERPRET_CAST(value_type const&, cv_traits::cv_cref(__ptr)); }
    287   // Reverse versions
    288   static void_type * to_storage_type_ptr(value_type *__ptr)
    289   { return cv_traits::uncv_ptr(__REINTERPRET_CAST(void_cv_type *, __ptr)); }
    290   static void_type const* to_storage_type_cptr(value_type const*__ptr)
    291   { return cv_traits::uncv_cptr(__REINTERPRET_CAST(void_cv_type const*, __ptr)); }
    292   static void_type ** to_storage_type_pptr(value_type **__ptr)
    293   { return cv_traits::uncv_pptr(__REINTERPRET_CAST(void_cv_type **, __ptr)); }
    294   static void_type const& to_storage_type_cref(value_type const& __ref)
    295   { return cv_traits::uncv_cref(__REINTERPRET_CAST(void_cv_type const&, __ref)); }
    296 
    297   //Method used to treat set container template method extension
    298   static void_type const& to_storage_type_crefT(value_type const& __ref)
    299   { return to_storage_type_cref(__ref); }
    300 };
    301 
    302 template <class _Tp>
    303 struct _CastTraits<_Tp, _Tp> {
    304   typedef _Tp storage_type;
    305   typedef _Tp value_type;
    306 
    307   static value_type * to_value_type_ptr(storage_type *__ptr)
    308   { return __ptr; }
    309   static value_type const* to_value_type_cptr(storage_type const*__ptr)
    310   { return __ptr; }
    311   static value_type ** to_value_type_pptr(storage_type **__ptr)
    312   { return __ptr; }
    313   static value_type & to_value_type_ref(storage_type &__ref)
    314   { return __ref; }
    315   static value_type const& to_value_type_cref(storage_type const&__ref)
    316   { return __ref; }
    317   // Reverse versions
    318   static storage_type * to_storage_type_ptr(value_type *__ptr)
    319   { return __ptr; }
    320   static storage_type const* to_storage_type_cptr(value_type const*__ptr)
    321   { return __ptr; }
    322   static storage_type ** to_storage_type_pptr(value_type **__ptr)
    323   { return __ptr; }
    324   static storage_type const& to_storage_type_cref(value_type const& __ref)
    325   { return __ref; }
    326 
    327   //Method used to treat set container template method extension
    328   template <class _Tp1>
    329   static _Tp1 const& to_storage_type_crefT(_Tp1 const& __ref)
    330   { return __ref; }
    331 };
    332 
    333 #define _STLP_USE_ITERATOR_WRAPPER
    334 
    335 template <class _StorageT, class _ValueT, class _Iterator>
    336 struct _IteWrapper {
    337   typedef _CastTraits<_StorageT, _ValueT> cast_traits;
    338   typedef iterator_traits<_Iterator> _IteTraits;
    339 
    340   typedef typename _IteTraits::iterator_category iterator_category;
    341   typedef _StorageT value_type;
    342   typedef typename _IteTraits::difference_type difference_type;
    343   typedef value_type* pointer;
    344   typedef value_type const& const_reference;
    345   //This wrapper won't be used for input so to avoid surprise
    346   //the reference type will be a const reference:
    347   typedef const_reference reference;
    348 
    349   typedef _IteWrapper<_StorageT, _ValueT, _Iterator> _Self;
    350   typedef _Self _Ite;
    351 
    352   _IteWrapper(_Iterator &__ite) : _M_ite(__ite) {}
    353 
    354   const_reference operator*() const
    355   // See http://code.google.com/p/android/issues/detail?id=38630
    356   //{ return cast_traits::to_storage_type_cref(*_M_ite); }
    357   { return __REINTERPRET_CAST(const_reference, *_M_ite); }
    358 
    359   _Self& operator= (_Self const& __rhs) {
    360     _M_ite = __rhs._M_ite;
    361     return *this;
    362   }
    363 
    364   _Self& operator++() {
    365     ++_M_ite;
    366     return *this;
    367   }
    368 
    369   _Self& operator--() {
    370     --_M_ite;
    371     return *this;
    372   }
    373 
    374   _Self& operator += (difference_type __offset) {
    375     _M_ite += __offset;
    376     return *this;
    377   }
    378   difference_type operator -(_Self const& __other) const
    379   { return _M_ite - __other._M_ite; }
    380 
    381   bool operator == (_Self const& __other) const
    382   { return _M_ite == __other._M_ite; }
    383 
    384   bool operator != (_Self const& __other) const
    385   { return _M_ite != __other._M_ite; }
    386 
    387   bool operator < (_Self const& __rhs) const
    388   { return _M_ite < __rhs._M_ite; }
    389 
    390 private:
    391   _Iterator _M_ite;
    392 };
    393 
    394 template <class _Tp, class _Iterator>
    395 struct _IteWrapper<_Tp, _Tp, _Iterator>
    396 { typedef _Iterator _Ite; };
    397 
    398 #else
    399 
    400 /*
    401  * In this config the storage type is qualified in respect of the
    402  * value_type qualification. Simple reinterpret_cast is enough.
    403  */
    404 template <class _StorageT, class _ValueT>
    405 struct _CastTraits {
    406   typedef _StorageT storage_type;
    407   typedef _ValueT value_type;
    408 
    409   static value_type * to_value_type_ptr(storage_type *__ptr)
    410   { return __REINTERPRET_CAST(value_type*, __ptr); }
    411   static value_type const* to_value_type_cptr(storage_type const*__ptr)
    412   { return __REINTERPRET_CAST(value_type const*, __ptr); }
    413   static value_type ** to_value_type_pptr(storage_type **__ptr)
    414   { return __REINTERPRET_CAST(value_type **, __ptr); }
    415   static value_type & to_value_type_ref(storage_type &__ref)
    416   { return __REINTERPRET_CAST(value_type&, __ref); }
    417   static value_type const& to_value_type_cref(storage_type const&__ref)
    418   { return __REINTERPRET_CAST(value_type const&, __ref); }
    419   // Reverse versions
    420   static storage_type * to_storage_type_ptr(value_type *__ptr)
    421   { return __REINTERPRET_CAST(storage_type*, __ptr); }
    422   static storage_type const* to_storage_type_cptr(value_type const*__ptr)
    423   { return __REINTERPRET_CAST(storage_type const*, __ptr); }
    424   static storage_type ** to_storage_type_pptr(value_type **__ptr)
    425   { return __REINTERPRET_CAST(storage_type **, __ptr); }
    426   static storage_type const& to_storage_type_cref(value_type const&__ref)
    427   { return __REINTERPRET_CAST(storage_type const&, __ref); }
    428   template <class _Tp1>
    429   static _Tp1 const& to_storage_type_crefT(_Tp1 const& __ref)
    430   { return __ref; }
    431 };
    432 
    433 #endif
    434 
    435 //Wrapper functors:
    436 template <class _StorageT, class _ValueT, class _UnaryPredicate>
    437 struct _UnaryPredWrapper {
    438   typedef _CastTraits<_StorageT, _ValueT> cast_traits;
    439 
    440   _UnaryPredWrapper (_UnaryPredicate const& __pred) : _M_pred(__pred) {}
    441 
    442   bool operator () (_StorageT const& __ref) const
    443   { return _M_pred(cast_traits::to_value_type_cref(__ref)); }
    444 
    445 private:
    446   _UnaryPredicate _M_pred;
    447 };
    448 
    449 template <class _StorageT, class _ValueT, class _BinaryPredicate>
    450 struct _BinaryPredWrapper {
    451   typedef _CastTraits<_StorageT, _ValueT> cast_traits;
    452 
    453   _BinaryPredWrapper () {}
    454   _BinaryPredWrapper (_BinaryPredicate const& __pred) : _M_pred(__pred) {}
    455 
    456   _BinaryPredicate get_pred() const { return _M_pred; }
    457 
    458   bool operator () (_StorageT const& __fst, _StorageT const& __snd) const
    459   { return _M_pred(cast_traits::to_value_type_cref(__fst), cast_traits::to_value_type_cref(__snd)); }
    460 
    461   //Cast operator used to transparently access underlying predicate
    462   //in set::key_comp() method
    463   operator _BinaryPredicate() const
    464   { return _M_pred; }
    465 
    466 private:
    467   _BinaryPredicate _M_pred;
    468 };
    469 
    470 _STLP_MOVE_TO_STD_NAMESPACE
    471 
    472 _STLP_END_NAMESPACE
    473 
    474 #endif /* _STLP_POINTERS_SPEC_TOOLS_H */
    475