* information that we can return the object to the proper free list
* without permanently losing part of the object.
*
+ * The template parameter specifies whether more than one thread may use
+ * this allocator. It is safe to allocate an object from one instance
+ * of the allocator and deallocate it with another one. This effectively
+ * transfers its ownership to the second one. This may have undesirable
+ * effects on reference locality.
+ *
* @endif
* (See @link Allocators allocators info @endlink for more.)
*/
+ template<bool __threads>
+ struct __pool_base
+ {
+ enum { _S_align = 8 };
+ enum { _S_max_bytes = 128 };
+ enum { _S_freelists = _S_max_bytes / _S_align };
+
+ union _Obj
+ {
+ union _Obj* _M_free_list_link;
+ char _M_client_data[1]; // The client sees this.
+ };
+
+ static _Obj* volatile _S_free_list[_S_freelists];
+
+ // Chunk allocation state.
+ static char* _S_start_free;
+ static char* _S_end_free;
+ static size_t _S_heap_size;
+
+ static _STL_mutex_lock _S_lock;
+ static _Atomic_word _S_force_new;
+
+ static size_t
+ _S_round_up(size_t __bytes)
+ { return ((__bytes + (size_t)_S_align - 1) & ~((size_t)_S_align - 1)); }
+
+ static size_t
+ _S_freelist_index(size_t __bytes)
+ { return ((__bytes + (size_t)_S_align - 1) / (size_t)_S_align - 1); }
+
+ // Returns an object of size __n, and optionally adds to size __n
+ // free list.
+ static void*
+ _S_refill(size_t __n);
+
+ // Allocates a chunk for nobjs of size size. nobjs may be reduced
+ // if it is inconvenient to allocate the requested number.
+ static char*
+ _S_chunk_alloc(size_t __n, int& __nobjs);
+
+ // It would be nice to use _STL_auto_lock here. But we need a
+ // test whether threads are in use.
+ struct _Lock
+ {
+ _Lock() { if (__threads) _S_lock._M_acquire_lock(); }
+ ~_Lock() { if (__threads) _S_lock._M_release_lock(); }
+ } __attribute__ ((__unused__));
+ friend struct _Lock;
+ };
+
+ typedef __pool_base<true> __pool_alloc_base;
+
template<typename _Tp>
- class __pool_alloc
+ class __pool_alloc : private __pool_alloc_base
{
public:
typedef size_t size_type;
void
deallocate(pointer __p, size_type __n);
-
- private:
- enum {_S_align = 8};
- enum {_S_max_bytes = 128};
- enum {_S_freelists = _S_max_bytes / _S_align};
-
- union _Obj
- {
- union _Obj* _M_free_list_link;
- char _M_client_data[1]; // The client sees this.
- };
-
- static _Obj* volatile _S_free_list[_S_freelists];
-
- // Chunk allocation state.
- static char* _S_start_free;
- static char* _S_end_free;
- static size_t _S_heap_size;
-
- static _STL_mutex_lock _S_lock;
- static _Atomic_word _S_force_new;
-
- static size_t
- _S_round_up(size_t __bytes)
- { return ((__bytes + (size_t)_S_align - 1) & ~((size_t)_S_align - 1)); }
-
- static size_t
- _S_freelist_index(size_t __bytes)
- { return ((__bytes + (size_t)_S_align - 1)/(size_t)_S_align - 1); }
-
- // Returns an object of size __n, and optionally adds to size __n
- // free list.
- static void*
- _S_refill(size_t __n);
-
- // Allocates a chunk for nobjs of size size. nobjs may be reduced
- // if it is inconvenient to allocate the requested number.
- static char*
- _S_chunk_alloc(size_t __n, int& __nobjs);
-
- // It would be nice to use _STL_auto_lock here. But we need a
- // test whether threads are in use.
- struct _Lock
- {
- _Lock() { _S_lock._M_acquire_lock(); }
- ~_Lock() { _S_lock._M_release_lock(); }
- } __attribute__ ((__unused__));
- friend struct _Lock;
};
template<typename _Tp>
// Allocate memory in large chunks in order to avoid fragmenting the
// heap too much. Assume that __n is properly aligned. We hold
// the allocation lock.
- template<typename _Tp>
+ template<bool __threads>
char*
- __pool_alloc<_Tp>::_S_chunk_alloc(size_t __n, int& __nobjs)
+ __pool_base<__threads>::_S_chunk_alloc(size_t __n, int& __nobjs)
{
char* __result;
size_t __total_bytes = __n * __nobjs;
size_t __bytes_left = _S_end_free - _S_start_free;
-
+
if (__bytes_left >= __total_bytes)
- {
- __result = _S_start_free;
- _S_start_free += __total_bytes;
- return __result ;
- }
+ {
+ __result = _S_start_free;
+ _S_start_free += __total_bytes;
+ return __result ;
+ }
else if (__bytes_left >= __n)
- {
- __nobjs = (int)(__bytes_left/__n);
- __total_bytes = __n * __nobjs;
- __result = _S_start_free;
- _S_start_free += __total_bytes;
- return __result;
- }
+ {
+ __nobjs = (int)(__bytes_left / __n);
+ __total_bytes = __n * __nobjs;
+ __result = _S_start_free;
+ _S_start_free += __total_bytes;
+ return __result;
+ }
else
- {
- size_t __bytes_to_get =
- 2 * __total_bytes + _S_round_up(_S_heap_size >> 4);
- // Try to make use of the left-over piece.
- if (__bytes_left > 0)
- {
- _Obj* volatile* __free_list =
- _S_free_list + _S_freelist_index(__bytes_left);
-
- ((_Obj*)(void*)_S_start_free)->_M_free_list_link = *__free_list;
- *__free_list = (_Obj*)(void*)_S_start_free;
- }
- _S_start_free = static_cast<char*>(::operator new(__bytes_to_get));
- if (_S_start_free == 0)
- {
- size_t __i;
- _Obj* volatile* __free_list;
- _Obj* __p;
- // Try to make do with what we have. That can't hurt. We
- // do not try smaller requests, since that tends to result
- // in disaster on multi-process machines.
- __i = __n;
- for (; __i <= (size_t) _S_max_bytes; __i += (size_t) _S_align)
- {
- __free_list = _S_free_list + _S_freelist_index(__i);
- __p = *__free_list;
- if (__p != 0)
- {
- *__free_list = __p -> _M_free_list_link;
- _S_start_free = (char*)__p;
- _S_end_free = _S_start_free + __i;
- return _S_chunk_alloc(__n, __nobjs);
- // Any leftover piece will eventually make it to the
- // right free list.
- }
- }
- _S_end_free = 0; // In case of exception.
- _S_start_free = static_cast<char*>(::operator new(__bytes_to_get));
- // This should either throw an exception or remedy the situation.
- // Thus we assume it succeeded.
- }
- _S_heap_size += __bytes_to_get;
- _S_end_free = _S_start_free + __bytes_to_get;
- return _S_chunk_alloc(__n, __nobjs);
- }
+ {
+ size_t __bytes_to_get = (2 * __total_bytes
+ + _S_round_up(_S_heap_size >> 4));
+ // Try to make use of the left-over piece.
+ if (__bytes_left > 0)
+ {
+ _Obj* volatile* __free_list = (_S_free_list
+ + _S_freelist_index(__bytes_left));
+
+ ((_Obj*)(void*)_S_start_free)->_M_free_list_link = *__free_list;
+ *__free_list = (_Obj*)(void*)_S_start_free;
+ }
+
+ _S_start_free = static_cast<char*>(::operator new(__bytes_to_get));
+ if (_S_start_free == 0)
+ {
+ size_t __i;
+ _Obj* volatile* __free_list;
+ _Obj* __p;
+ // Try to make do with what we have. That can't hurt. We
+ // do not try smaller requests, since that tends to result
+ // in disaster on multi-process machines.
+ __i = __n;
+ for (; __i <= (size_t) _S_max_bytes; __i += (size_t) _S_align)
+ {
+ __free_list = _S_free_list + _S_freelist_index(__i);
+ __p = *__free_list;
+ if (__p != 0)
+ {
+ *__free_list = __p -> _M_free_list_link;
+ _S_start_free = (char*)__p;
+ _S_end_free = _S_start_free + __i;
+ return _S_chunk_alloc(__n, __nobjs);
+ // Any leftover piece will eventually make it to the
+ // right free list.
+ }
+ }
+ _S_end_free = 0; // In case of exception.
+ _S_start_free = static_cast<char*>(::operator new(__bytes_to_get));
+ // This should either throw an exception or remedy the situation.
+ // Thus we assume it succeeded.
+ }
+ _S_heap_size += __bytes_to_get;
+ _S_end_free = _S_start_free + __bytes_to_get;
+ return _S_chunk_alloc(__n, __nobjs);
+ }
}
-
+
// Returns an object of size __n, and optionally adds to "size
// __n"'s free list. We assume that __n is properly aligned. We
// hold the allocation lock.
- template<typename _Tp>
+ template<bool __threads>
void*
- __pool_alloc<_Tp>::_S_refill(size_t __n)
+ __pool_base<__threads>::_S_refill(size_t __n)
{
int __nobjs = 20;
char* __chunk = _S_chunk_alloc(__n, __nobjs);
_Obj* __current_obj;
_Obj* __next_obj;
int __i;
-
+
if (1 == __nobjs)
- return __chunk;
+ return __chunk;
__free_list = _S_free_list + _S_freelist_index(__n);
-
+
// Build free list in chunk.
__result = (_Obj*)(void*)__chunk;
*__free_list = __next_obj = (_Obj*)(void*)(__chunk + __n);
for (__i = 1; ; __i++)
- {
+ {
__current_obj = __next_obj;
- __next_obj = (_Obj*)(void*)((char*)__next_obj + __n);
+ __next_obj = (_Obj*)(void*)((char*)__next_obj + __n);
if (__nobjs - 1 == __i)
{
__current_obj -> _M_free_list_link = 0;
__ret = static_cast<_Tp*>(_S_refill(_S_round_up(__bytes)));
else
{
- *__free_list = __result -> _M_free_list_link;
+ *__free_list = __result->_M_free_list_link;
__ret = reinterpret_cast<_Tp*>(__result);
}
if (__builtin_expect(__ret == 0, 0))
}
}
- template<typename _Tp>
- typename __pool_alloc<_Tp>::_Obj* volatile
- __pool_alloc<_Tp>::_S_free_list[_S_freelists];
+ template<bool __threads>
+ typename __pool_base<__threads>::_Obj* volatile
+ __pool_base<__threads>::_S_free_list[_S_freelists];
- template<typename _Tp>
- char* __pool_alloc<_Tp>::_S_start_free = 0;
+ template<bool __threads>
+ char* __pool_base<__threads>::_S_start_free = 0;
- template<typename _Tp>
- char* __pool_alloc<_Tp>::_S_end_free = 0;
+ template<bool __threads>
+ char* __pool_base<__threads>::_S_end_free = 0;
- template<typename _Tp>
- size_t __pool_alloc<_Tp>::_S_heap_size = 0;
+ template<bool __threads>
+ size_t __pool_base<__threads>::_S_heap_size = 0;
- template<typename _Tp>
+ template<bool __threads>
_STL_mutex_lock
- __pool_alloc<_Tp>::_S_lock __STL_MUTEX_INITIALIZER;
+ __pool_base<__threads>::_S_lock __STL_MUTEX_INITIALIZER;
- template<typename _Tp> _Atomic_word
- __pool_alloc<_Tp>::_S_force_new = 0;
+ template<bool __threads>
+ _Atomic_word
+ __pool_base<__threads>::_S_force_new = 0;
} // namespace __gnu_cxx
#endif
projects / platform / upstream / gcc.git / commitdiff