JLANG::JRAM Class Reference

Memory management for small objects. More...

#include <JRAM.hh>

Inheritance diagram for JLANG::JRAM:

Public Member Functions
	JRAM (const std::size_t block_size, const std::size_t number_of_blocks=65536)
	Constructor. More...
	~JRAM ()
	Destructor. More...
long long int	getTotalRAM ()
	Get total used RAM. More...
long long int	getFreeRAM ()
	Get total free RAM. More...
void *	allocate ()
	Allocate memory. More...
void	free (void *p)
	Deallocate memory. More...
void	gc ()
	Run garbage collector. More...

Private Member Functions
void	addMemory ()
	Add memory. More...

Private Attributes
const std::size_t	BLOCK_SIZE
const std::size_t	numberOfBlocks
std::vector< unsigned char * >	memory

Detailed Description

Memory management for small objects.

This object allocator is optimised for speed at the cost of some memory overhead.

Definition at line 23 of file JRAM.hh.

Constructor & Destructor Documentation

JLANG::JRAM::JRAM ( const std::size_t  block_size, const std::size_t  number_of_blocks = 65536  )

inline

Constructor.

Parameters

block_size	number of bytes
number_of_blocks	number of blocks

Definition at line 66 of file JRAM.hh.

                                                   :
      std::vector<void*>(),
      BLOCK_SIZE    (block_size),
      numberOfBlocks(number_of_blocks)
    {
      addMemory();
    }

JLANG::JRAM::~JRAM ( )

inline

Destructor.

Definition at line 79 of file JRAM.hh.

    {
      for (std::vector<unsigned char*>::iterator i = memory.begin(); i != memory.end(); ++i) {
        delete [] (*i);
      }
    }

Member Function Documentation

void JLANG::JRAM::addMemory ( )

inlineprivate

Add memory.

Definition at line 36 of file JRAM.hh.

    {
      unsigned char* buffer = new unsigned char[BLOCK_SIZE * numberOfBlocks];
      
      if (buffer == NULL) {
        throw JException("JRAM::allocate(): not enough space in memory.");
      }
      
      memory.push_back(buffer);

      const std::size_t size = this->size();

      this->resize(size + numberOfBlocks);
      
      iterator q = this->begin();

      std::advance(q, size);

      for ( ; q != this->end(); buffer += BLOCK_SIZE, ++q) {
        *q = buffer;
      }
    }

long long int JLANG::JRAM::getTotalRAM ( )

inline

Get total used RAM.

Returns

number of bytes

Definition at line 92 of file JRAM.hh.

    {
      return this->size() * sizeof(void*)  +  memory.size() * BLOCK_SIZE * numberOfBlocks;
    }

long long int JLANG::JRAM::getFreeRAM ( )

inline

Get total free RAM.

Returns

number of bytes

Definition at line 103 of file JRAM.hh.

    {
      return this->size() * BLOCK_SIZE;
    }

void* JLANG::JRAM::allocate ( )

inline

Allocate memory.

Returns

pointer to avaible memory

Definition at line 114 of file JRAM.hh.

    {
      if (this->empty()) {
        addMemory();
      }

      this->pop_back();

      return *(this->end());
    }

void JLANG::JRAM::free ( void *  p )

inline

Deallocate memory.

Parameters

p	pointer to memory to be freed

Definition at line 131 of file JRAM.hh.

    {
      this->push_back(p);
    }

void JLANG::JRAM::gc ( )

inline

Run garbage collector.

Definition at line 140 of file JRAM.hh.

    {
      using namespace std;

      sort(this->begin(), this->end());

      vector<unsigned char*>::iterator __end = memory.end();
      
      for (vector<unsigned char*>::iterator i = memory.begin(); i != __end; ) {

        iterator p = lower_bound(this->begin(), this->end(), *i);
        iterator q = p  +  numberOfBlocks  -  1;

        if (*p == *i                      && 
            distance(q, this->end()) > 0  && 
            ((unsigned char*) (*q) - (unsigned char*) *p) == (int) (BLOCK_SIZE * (numberOfBlocks - 1))) {

          iter_swap(i, --__end);

          this->erase(p,++q);

        } else {
          ++i;
        }
      }

      for (std::vector<unsigned char*>::iterator i = __end; i != memory.end(); ++i) {
        delete [] (*i);
      }

      memory.erase(__end, memory.end());
    }

Member Data Documentation

const std::size_t JLANG::JRAM::BLOCK_SIZE

private

Definition at line 28 of file JRAM.hh.

const std::size_t JLANG::JRAM::numberOfBlocks

private

Definition at line 29 of file JRAM.hh.

std::vector<unsigned char*> JLANG::JRAM::memory

private

Definition at line 30 of file JRAM.hh.

---

The documentation for this class was generated from the following file:

• JRAM.hh