Classes | |
struct | Pool |
Public Member Functions | |
GrowingVectorMemory (const unsigned int initial_size=0, const bool log_statistics=false) | |
~GrowingVectorMemory () | |
virtual VECTOR * | alloc () |
virtual void | free (const VECTOR *const) |
unsigned int | memory_consumption () const |
Private Types | |
typedef std::pair< bool, VECTOR * > | entry_type |
Private Attributes | |
unsigned int | total_alloc |
unsigned int | current_alloc |
bool | log_statistics |
Static Private Attributes | |
static Pool | pool |
static Threads::ThreadMutex | mutex |
Each time a vector is requested from this class, it checks if it has one available and returns its address, or allocates a new one on the heap. If a vector is returned, through the free() member function, it doesn't return it to the operating system memory subsystem, but keeps it around unused for later use if alloc() is called again, or until the object is destroyed. The class therefore avoid the overhead of repeatedly allocating memory on the heap if temporary vectors are required and released frequently; on the other hand, it doesn't release once-allocated memory at the earliest possible time and may therefore lead to an increased overall memory consumption.
All GrowingVectorMemory objects of the same vector type use the same memory Pool. Therefore, functions can create such a VectorMemory object whenever needed without preformance penalty. A drawback of this policy might be that vectors once allocated are only released at the end of the program run. Nebertheless, the since they are reused, this should be of no concern. Additionally, the destructor of the Pool warns about memory leaks.
float
, double
, long double
, <std::complex<float>>
, <std::complex<double>>
and <std::complex<long double>>
. In order to generate additional instances, it is sufficient to define the Pool variable somewhere by #include <lac/vector_memory.h> template GrowingVectorMemory<MyVector>::Pool GrowingVectorMemory<MyVector>::pool;
typedef std::pair<bool, VECTOR*> GrowingVectorMemory< VECTOR >::entry_type [private] |
Type to enter into the array. First component will be a flag telling whether the vector is used, second the vector itself.
GrowingVectorMemory< VECTOR >::GrowingVectorMemory | ( | const unsigned int | initial_size = 0 , |
|
const bool | log_statistics = false | |||
) |
Constructor. The argument allows to preallocate a certain number of vectors. The default is not to do this.
GrowingVectorMemory< VECTOR >::~GrowingVectorMemory | ( | ) |
Destructor. Release all vectors. This destructor also offers some statistic on the number of allocated vectors.
The log file will also contain a warning message, if there are allocated vectors left.
virtual VECTOR* GrowingVectorMemory< VECTOR >::alloc | ( | ) | [virtual] |
Return a pointer to a new vector. The number of elements or their subdivision into blocks (if applicable) is unspecified and users of this function should reset vectors to their proper size. The same holds for the contents of vectors: they are unspecified.
Implements VectorMemory< VECTOR >.
virtual void GrowingVectorMemory< VECTOR >::free | ( | const VECTOR * | const | ) | [virtual] |
Return a vector and indicate that it is not going to be used any further by the instance that called alloc() to get a pointer to it.
For the present class, this means retaining the vector for later reuse by the alloc() method.
Implements VectorMemory< VECTOR >.
unsigned int GrowingVectorMemory< VECTOR >::memory_consumption | ( | ) | const |
Memory consumed by this class and all currently allocated vectors.
Pool GrowingVectorMemory< VECTOR >::pool [static, private] |
Array of allocated vectors.
unsigned int GrowingVectorMemory< VECTOR >::total_alloc [private] |
Overall number of allocations. Only used for bookkeeping and to generate output at the end of an object's lifetime.
unsigned int GrowingVectorMemory< VECTOR >::current_alloc [private] |
Number of vectors currently allocated in this object; used for detecting memory leaks.
bool GrowingVectorMemory< VECTOR >::log_statistics [private] |
A flag controlling the logging of statistics by the destructor.
Threads::ThreadMutex GrowingVectorMemory< VECTOR >::mutex [static, private] |
Mutex to synchronise access to internal data of this object from multiple threads.