// itself(to debug the allocator itself).
//#define _BALLOC_SANITY_CHECK
-// The constant in the expression below is the alignment required in
-// bytes.
+/** @brief The constant in the expression below is the alignment
+ * required in bytes.
+ */
#define _BALLOC_ALIGN_BYTES 8
#if defined _BALLOC_SANITY_CHECK
#if defined __GTHREADS
namespace
{
- // If true, then the application being compiled will be using
- // threads, so use mutexes as a synchronization primitive, else do
- // no use any synchronization primitives.
+ /** @brief If true, then the application being compiled will be
+ * using threads, so use mutexes as a synchronization primitive,
+ * else do no use any synchronization primitives.
+ */
bool const __threads_enabled = __gthread_active_p();
}
#endif
#if defined __GTHREADS
- // _Mutex is an OO-Wrapper for __gthread_mutex_t. It does not allow
- // you to copy or assign an already initialized mutex. This is used
- // merely as a convenience for the locking classes.
+ /** @class _Mutex bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief _Mutex is an OO-Wrapper for __gthread_mutex_t.
+ *
+ * It does not allow you to copy or assign an already initialized
+ * mutex. This is used merely as a convenience for the locking
+ * classes.
+ */
class _Mutex
{
__gthread_mutex_t _M_mut;
_M_get() { return &_M_mut; }
};
- // _Lock is a simple manual lokcing class which allows you to
- // manually lock and unlock a mutex associated with the lock. There
- // is not automatic locking or unlocking happening without the
- // programmer's explicit instructions. This class unlocks the mutex
- // ONLY if it has not been locked. However, this check does not
- // apply for lokcing, and wayward use may cause dead-locks.
+ /** @class _Lock bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief _Lock is a simple manual locking class which allows you to
+ * manually lock and unlock a mutex associated with the lock.
+ *
+ * There is no automatic locking or unlocking happening without the
+ * programmer's explicit instructions. This class unlocks the mutex
+ * ONLY if it has not been locked. However, this check does not
+ * apply for locking, and wayward use may cause dead-locks.
+ */
class _Lock
{
_Mutex* _M_pmt;
~_Lock() { }
};
- // _Auto_Lock locks the associated mutex on construction, and
- // unlocks on it's destruction. There are no checks performed, and
- // this calss follows the RAII principle.
+ /** @class _Auto_Lock bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief _Auto_Lock locks the associated mutex on construction, and
+ * unlocks on destruction.
+ *
+ * There are no checks performed, and this class follows the RAII
+ * principle.
+ */
class _Auto_Lock
{
_Mutex* _M_pmt;
namespace balloc
{
- // __mini_vector<> is to be used only for built-in types or
- // PODs. It is a stripped down version of the full-fledged
- // std::vector<>. Noteable differences are:
- //
- // 1. Not all accessor functions are present.
- // 2. Used ONLY for PODs.
- // 3. No Allocator template argument. Uses ::operator new() to get
- // memory, and ::operator delete() to free it.
+ /** @class __mini_vector bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief __mini_vector<> is a stripped down version of the
+ * full-fledged std::vector<>.
+ *
+ * It is to be used only for built-in types or PODs. Notable
+ * differences are:
+ *
+ * @detail
+ * 1. Not all accessor functions are present.
+ * 2. Used ONLY for PODs.
+ * 3. No Allocator template argument. Uses ::operator new() to get
+ * memory, and ::operator delete() to free it.
+ * Caveat: The dtor does NOT free the memory allocated, so this a
+ * memory-leaking vector!
+ */
template<typename _Tp>
class __mini_vector
{
return __first;
}
+ /** @brief The number of Blocks pointed to by the address pair
+ * passed to the function.
+ */
template<typename _AddrPair>
inline size_t
__num_blocks(_AddrPair __ap)
{ return (__ap.second - __ap.first) + 1; }
+ /** @brief The number of Bit-maps pointed to by the address pair
+ * passed to the function.
+ */
template<typename _AddrPair>
inline size_t
__num_bitmaps(_AddrPair __ap)
{ return _M_fref(__arg); }
};
+ /** @class _Ffit_finder bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The class which acts as a predicate for applying the
+ * first-fit memory allocation policy for the bitmap allocator.
+ */
// _Tp should be a pointer type, and _Alloc is the Allocator for
// the vector.
template<typename _Tp>
};
-
+ /** @class _Bitmap_counter bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The bitmap counter which acts as the bitmap
+ * manipulator, and manages the bit-manipulation functions and
+ * the searching and identification functions on the bit-map.
+ */
// _Tp should be a pointer type.
template<typename _Tp>
class _Bitmap_counter
{ return _M_curr_index; }
};
+ /** @brief Mark a memory address as allocated by re-setting the
+ * corresponding bit in the bit-map.
+ */
inline void
__bit_allocate(size_t* __pbmap, size_t __pos) throw()
{
*__pbmap &= __mask;
}
+ /** @brief Mark a memory address as free by setting the
+ * corresponding bit in the bit-map.
+ */
inline void
__bit_free(size_t* __pbmap, size_t __pos) throw()
{
}
} // namespace balloc
- // Generic Version of the bsf instruction.
+ /** @brief Generic Version of the bsf instruction.
+ */
inline size_t
_Bit_scan_forward(size_t __num)
{ return static_cast<size_t>(__builtin_ctzl(__num)); }
+ /** @class free_list bitmap_allocator.h bitmap_allocator.h
+ *
+ * @brief The free list class for managing chunks of memory to be
+ * given to and returned by the bitmap_allocator.
+ */
class free_list
{
typedef size_t* value_type;
static _Mutex _S_bfl_mutex;
#endif
static vector_type _S_free_list;
-
+
+ /** @brief Performs validation of memory based on their size.
+ *
+ * @param __addr The pointer to the memory block to be
+ * validated.
+ *
+ * @detail Validates the memory block passed to this function and
+ * appropriately performs the action of managing the free list of
+ * blocks by adding this block to the free list or deleting this
+ * or larger blocks from the free list.
+ */
void
_M_validate(size_t* __addr) throw()
{
_S_free_list.insert(__temp, __addr);
}
+ /** @brief Decides whether the wastage of memory is acceptable for
+ * the current memory request and returns accordingly.
+ *
+ * @param __block_size The size of the block available in the free
+ * list.
+ *
+ * @param __required_size The required size of the memory block.
+ *
+ * @return true if the wastage incurred is acceptable, else returns
+ * false.
+ */
bool
_M_should_i_give(size_t __block_size,
size_t __required_size) throw()
}
public:
+ /** @brief This function returns the block of memory to the
+ * internal free list.
+ *
+ * @param __addr The pointer to the memory block that was given
+ * by a call to the _M_get function.
+ */
inline void
_M_insert(size_t* __addr) throw()
{
// See discussion as to why this is 1!
}
+ /** @brief This function gets a block of memory of the specified
+ * size from the free list.
+ *
+ * @param __sz The size in bytes of the memory required.
+ *
+ * @return A pointer to the new memory block of size at least
+ * equal to that requested.
+ */
size_t*
_M_get(size_t __sz) throw(std::bad_alloc);
- // This function just clears the internal Free List, and gives back
- // all the memory to the OS.
+ /** @brief This function just clears the internal Free List, and
+ * gives back all the memory to the OS.
+ */
void
_M_clear();
};
}
#endif
- // Complexity: O(1), but internally depends upon the complexity
- // of the function free_list::_M_get. The
- // part where the bitmap headers are written is of worst case
- // complexity: O(X),where X is the number of blocks of size
- // sizeof(value_type) within the newly acquired block. Having a
- // tight bound.
+ /** @brief Responsible for exponentially growing the internal
+ * memory pool.
+ *
+ * @throw std::bad_alloc. If memory can not be allocated.
+ *
+ * @detail Complexity: O(1), but internally depends upon the
+ * complexity of the function free_list::_M_get. The part where
+ * the bitmap headers are written has complexity: O(X),where X
+ * is the number of blocks of size sizeof(value_type) within
+ * the newly acquired block. Having a tight bound.
+ */
void
_S_refill_pool() throw(std::bad_alloc)
{
public:
- // Complexity: Worst case complexity is O(N), but that is hardly
- // ever hit. if and when this particular case is encountered,
- // the next few cases are guaranteed to have a worst case
- // complexity of O(1)! That's why this function performs very
- // well on the average. you can consider this function to be
- // having a complexity referred to commonly as: Amortized
- // Constant time.
+ /** @brief Allocates memory for a single object of size
+ * sizeof(_Tp).
+ *
+ * @throw std::bad_alloc. If memory can not be allocated.
+ *
+ * @detail Complexity: Worst case complexity is O(N), but that
+ * is hardly ever hit. If and when this particular case is
+ * encountered, the next few cases are guaranteed to have a
+ * worst case complexity of O(1)! That's why this function
+ * performs very well on average. You can consider this
+ * function to have a complexity referred to commonly as:
+ * Amortized Constant time.
+ */
pointer
_M_allocate_single_object() throw(std::bad_alloc)
{
return __ret;
}
- // Complexity: O(lg(N)), but the worst case is hit quite often!
- // I need to do something about this. I'll be able to work on
- // it, only when I have some solid figures from a few real apps.
+ /** @brief Deallocates memory that belongs to a single object of
+ * size sizeof(_Tp).
+ *
+ * @detail Complexity: O(lg(N)), but the worst case is not hit
+ * often! This is because containers usually deallocate memory
+ * close to each other and this case is handled in O(1) time by
+ * the deallocate function.
+ */
void
_M_deallocate_single_object(pointer __p) throw()
{
~bitmap_allocator() throw()
{ }
- // Complexity: O(1), but internally the complexity depends upon the
- // complexity of the function(s) _S_allocate_single_object and
- // operator new.
pointer
allocate(size_type __n)
{
projects / thirdparty / gcc.git / commitdiff
