pthread_alloc

c++ STL source code, hash and vector etc

    if (__bytes_left >= __total_bytes) {
        __result = _S_start_free;
        _S_start_free += __total_bytes;
        return(__result);
    } else if (__bytes_left >= __size) {
        __nobjs = __bytes_left/__size;
        __total_bytes = __size * __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) {
            _Pthread_alloc_per_thread_state<_Max_size>* __a = 
                (_Pthread_alloc_per_thread_state<_Max_size>*)
			pthread_getspecific(_S_key);
            __obj * volatile * __my_free_list =
                        __a->__free_list + _S_freelist_index(__bytes_left);

            ((__obj *)_S_start_free) -> __free_list_link = *__my_free_list;
            *__my_free_list = (__obj *)_S_start_free;
        }
#       ifdef _SGI_SOURCE
          // Try to get memory that's aligned on something like a
          // cache line boundary, so as to avoid parceling out
          // parts of the same line to different threads and thus
          // possibly different processors.
          {
            const int __cache_line_size = 128;  // probable upper bound
            __bytes_to_get &= ~(__cache_line_size-1);
            _S_start_free = (char *)memalign(__cache_line_size, __bytes_to_get); 
            if (0 == _S_start_free) {
              _S_start_free = (char *)malloc_alloc::allocate(__bytes_to_get);
            }
          }
#       else  /* !SGI_SOURCE */
          _S_start_free = (char *)malloc_alloc::allocate(__bytes_to_get);
#       endif
        _S_heap_size += __bytes_to_get;
        _S_end_free = _S_start_free + __bytes_to_get;
    }
  }
  // lock is released here
  return(_S_chunk_alloc(__size, __nobjs));
}


/* Returns an object of size n, and optionally adds to size n free list.*/
/* We assume that n is properly aligned.                                */
/* We hold the allocation lock.                                         */
template <size_t _Max_size>
void *_Pthread_alloc_per_thread_state<_Max_size>
::_M_refill(size_t __n)
{
    int __nobjs = 128;
    char * __chunk =
	_Pthread_alloc_template<_Max_size>::_S_chunk_alloc(__n, __nobjs);
    __obj * volatile * __my_free_list;
    __obj * __result;
    __obj * __current_obj, * __next_obj;
    int __i;

    if (1 == __nobjs)  {
        return(__chunk);
    }
    __my_free_list = __free_list
		 + _Pthread_alloc_template<_Max_size>::_S_freelist_index(__n);

    /* Build free list in chunk */
      __result = (__obj *)__chunk;
      *__my_free_list = __next_obj = (__obj *)(__chunk + __n);
      for (__i = 1; ; __i++) {
        __current_obj = __next_obj;
        __next_obj = (__obj *)((char *)__next_obj + __n);
        if (__nobjs - 1 == __i) {
            __current_obj -> __free_list_link = 0;
            break;
        } else {
            __current_obj -> __free_list_link = __next_obj;
        }
      }
    return(__result);
}

template <size_t _Max_size>
void *_Pthread_alloc_template<_Max_size>
::reallocate(void *__p, size_t __old_sz, size_t __new_sz)
{
    void * __result;
    size_t __copy_sz;

    if (__old_sz > _Max_size
	&& __new_sz > _Max_size) {
        return(realloc(__p, __new_sz));
    }
    if (_S_round_up(__old_sz) == _S_round_up(__new_sz)) return(__p);
    __result = allocate(__new_sz);
    __copy_sz = __new_sz > __old_sz? __old_sz : __new_sz;
    memcpy(__result, __p, __copy_sz);
    deallocate(__p, __old_sz);
    return(__result);
}

template <size_t _Max_size>
_Pthread_alloc_per_thread_state<_Max_size> *
_Pthread_alloc_template<_Max_size>::_S_free_per_thread_states = 0;

template <size_t _Max_size>
pthread_key_t _Pthread_alloc_template<_Max_size>::_S_key;

template <size_t _Max_size>
bool _Pthread_alloc_template<_Max_size>::_S_key_initialized = false;

template <size_t _Max_size>
pthread_mutex_t _Pthread_alloc_template<_Max_size>::_S_chunk_allocator_lock
= PTHREAD_MUTEX_INITIALIZER;

template <size_t _Max_size>
char *_Pthread_alloc_template<_Max_size>
::_S_start_free = 0;

template <size_t _Max_size>
char *_Pthread_alloc_template<_Max_size>
::_S_end_free = 0;

template <size_t _Max_size>
size_t _Pthread_alloc_template<_Max_size>
::_S_heap_size = 0;

#ifdef __STL_USE_STD_ALLOCATORS

template <class _Tp>
class pthread_allocator {
  typedef pthread_alloc _S_Alloc;          // The underlying allocator.
public:
  typedef size_t     size_type;
  typedef ptrdiff_t  difference_type;
  typedef _Tp*       pointer;
  typedef const _Tp* const_pointer;
  typedef _Tp&       reference;
  typedef const _Tp& const_reference;
  typedef _Tp        value_type;

  template <class _NewType> struct rebind {
    typedef pthread_allocator<_NewType> other;
  };

  pthread_allocator() __STL_NOTHROW {}
  pthread_allocator(const pthread_allocator& a) __STL_NOTHROW {}
  template <class _OtherType>
	pthread_allocator(const pthread_allocator<_OtherType>&)
		__STL_NOTHROW {}
  ~pthread_allocator() __STL_NOTHROW {}

  pointer address(reference __x) const { return &__x; }
  const_pointer address(const_reference __x) const { return &__x; }

  // __n is permitted to be 0.  The C++ standard says nothing about what
  // the return value is when __n == 0.
  _Tp* allocate(size_type __n, const void* = 0) {
    return __n != 0 ? static_cast<_Tp*>(_S_Alloc::allocate(__n * sizeof(_Tp)))
                    : 0;
  }

  // p is not permitted to be a null pointer.
  void deallocate(pointer __p, size_type __n)
    { _S_Alloc::deallocate(__p, __n * sizeof(_Tp)); }

  size_type max_size() const __STL_NOTHROW 
    { return size_t(-1) / sizeof(_Tp); }

  void construct(pointer __p, const _Tp& __val) { new(__p) _Tp(__val); }
  void destroy(pointer _p) { _p->~_Tp(); }
};

template<>
class pthread_allocator<void> {
public:
  typedef size_t      size_type;
  typedef ptrdiff_t   difference_type;
  typedef void*       pointer;
  typedef const void* const_pointer;
  typedef void        value_type;

  template <class _NewType> struct rebind {
    typedef pthread_allocator<_NewType> other;
  };
};

template <size_t _Max_size>
inline bool operator==(const _Pthread_alloc_template<_Max_size>&,
                       const _Pthread_alloc_template<_Max_size>&)
{
  return true;
}

template <class _T1, class _T2>
inline bool operator==(const pthread_allocator<_T1>&,
                       const pthread_allocator<_T2>& a2) 
{
  return true;
}

template <class _T1, class _T2>
inline bool operator!=(const pthread_allocator<_T1>&,
                       const pthread_allocator<_T2>&)
{
  return false;
}

template <class _Tp, size_t _Max_size>
struct _Alloc_traits<_Tp, _Pthread_alloc_template<_Max_size> >
{
  static const bool _S_instanceless = true;
  typedef simple_alloc<_Tp, _Pthread_alloc_template<_Max_size> > _Alloc_type;
  typedef __allocator<_Tp, _Pthread_alloc_template<_Max_size> > 
          allocator_type;
};

template <class _Tp, class _Atype, size_t _Max>
struct _Alloc_traits<_Tp, __allocator<_Atype, _Pthread_alloc_template<_Max> > >
{
  static const bool _S_instanceless = true;
  typedef simple_alloc<_Tp, _Pthread_alloc_template<_Max> > _Alloc_type;
  typedef __allocator<_Tp, _Pthread_alloc_template<_Max> > allocator_type;
};

template <class _Tp, class _Atype>
struct _Alloc_traits<_Tp, pthread_allocator<_Atype> >
{
  static const bool _S_instanceless = true;
  typedef simple_alloc<_Tp, _Pthread_alloc_template<> > _Alloc_type;
  typedef pthread_allocator<_Tp> allocator_type;
};


#endif /* __STL_USE_STD_ALLOCATORS */

__STL_END_NAMESPACE

#endif /* __SGI_STL_PTHREAD_ALLOC */

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