---

PsnDescriptorMemoryManager Class Reference

defines a memory manager that allocates memory for PsnMemoryElementDescriptors. More...

#include <PsnDescriptorMemoryManager.h>

Inheritance diagram for PsnDescriptorMemoryManager:

[legend]Collaboration diagram for PsnDescriptorMemoryManager:

[legend]List of all members.

Public Methods
virtual	~PsnDescriptorMemoryManager ()
	Desctructor.
	PsnDescriptorMemoryManager (PsnMemoryManager &rawMemoryProvider)
	Constructor.
virtual void *	allocateSizeRemembered (size_t size)
	alloc a memory zone that can be correctly freed by calling freeSizeRemembered with the resulting pointer
virtual void	freeSizeRemembered (void *ptr)
	free a memory zone allocated with allocateSizeRemembered
virtual bool	inAdressSpace (void *ptr) const
	find out if a given adress is managed by the current memory manager
bool	isFree (void *ptr)
	make sure a pointer is in the list of unused memory element descriptors
Protected Attributes
PsnMemoryManager &	_rawMemoryProvider
	if more memory is needed, get it from this memory manager
vector< void * >	_freeBlocks
	the list of available memory blocks.
int	_stackTop
	the vector is used a a stack
PsnMemoryElementDescriptor *	_managedMemoryZones
	head of the list of managed memory zones
size_t	_currentMemorySize
	the size of the managed memory

---

Detailed Description

defines a memory manager that allocates memory for PsnMemoryElementDescriptors.

Author:

David Margery

Version:

1.0

Definition at line 31 of file PsnDescriptorMemoryManager.h.

---

Constructor & Destructor Documentation

PsnDescriptorMemoryManager::~PsnDescriptorMemoryManager (    )  [virtual]

Desctructor. Definition at line 5 of file PsnDescriptorMemoryManager.cxx. { }

PsnDescriptorMemoryManager::PsnDescriptorMemoryManager (  PsnMemoryManager &    rawMemoryProvider )

Constructor. Parameters: rawMemoryProvider:  if more memory is needed, get it from this memory manager Definition at line 10 of file PsnDescriptorMemoryManager.cxx. References _currentMemorySize, _freeBlocks, _managedMemoryZones, _rawMemoryProvider, _stackTop, PsnMemoryManager::allocateSizeRemembered(), PsnMemoryElementDescriptor::base, PsnMemoryElementDescriptor::next, vector< void * >::push_back(), vector< void * >::reserve(), and PsnMemoryElementDescriptor::size. 00010 : 00011 PsnMemoryManager (), 00012 _rawMemoryProvider ( rawMemoryProvider ), 00013 _stackTop (-1) 00014 { 00015 // a bit less than a memory page 00016 _currentMemorySize = 85 * sizeof (PsnMemoryElementDescriptor) ; 00017 00018 _freeBlocks.reserve ( 85 ) ; 00019 00020 void * memory = _rawMemoryProvider.allocateSizeRemembered ( _currentMemorySize ) ; 00021 00022 for ( void * mem = memory; 00023 mem != (void *) ((unsigned int)memory + _currentMemorySize) ; 00024 mem = (void *) ((unsigned int)mem + sizeof (PsnMemoryElementDescriptor) ) ) 00025 { 00026 _freeBlocks.push_back(mem) ; 00027 ++_stackTop ; 00028 } 00029 00030 _managedMemoryZones = new (& _rawMemoryProvider) PsnMemoryElementDescriptor() ; 00031 _managedMemoryZones->base = (unsigned int)memory ; 00032 _managedMemoryZones->size = _currentMemorySize ; 00033 _managedMemoryZones->next = 0 ; 00034 00035 }

---

Member Function Documentation

void * PsnDescriptorMemoryManager::allocateSizeRemembered (  size_t    size )  [virtual]

alloc a memory zone that can be correctly freed by calling freeSizeRemembered with the resulting pointer Implements PsnMemoryManager. Definition at line 52 of file PsnDescriptorMemoryManager.cxx. References _currentMemorySize, _freeBlocks, _managedMemoryZones, _rawMemoryProvider, _stackTop, PsnMemoryManager::allocateSizeRemembered(), PsnMemoryElementDescriptor::base, vector< void * >::capacity(), isFree(), PsnMemoryElementDescriptor::next, vector< void * >::resize(), and PsnMemoryElementDescriptor::size. { // this memory manager only allocates memory for memoryElementDescriptors assert ( size == sizeof (PsnMemoryElementDescriptor) ) ; void * result ; if (_stackTop == -1) { // allocate an other memory zone for memory element decriptors size_t allocatedMemory = _currentMemorySize ; void * memory = _rawMemoryProvider.allocateSizeRemembered ( allocatedMemory ) ; _freeBlocks.resize (_freeBlocks.capacity() + allocatedMemory/sizeof (PsnMemoryElementDescriptor), NULL ) ; for ( void * mem = memory; mem != (void *) ((unsigned int)memory + allocatedMemory) ; mem = (void *) ((unsigned int)mem + sizeof (PsnMemoryElementDescriptor) ) ) { ++_stackTop ; _freeBlocks[_stackTop] = mem ; } PsnMemoryElementDescriptor * newMemoryZones = new (& _rawMemoryProvider) PsnMemoryElementDescriptor() ; newMemoryZones->base = (unsigned int)memory ; newMemoryZones->size = allocatedMemory ; newMemoryZones->next = (unsigned int) _managedMemoryZones ; _managedMemoryZones = newMemoryZones ; _currentMemorySize += allocatedMemory ; //recursive call result = allocateSizeRemembered (size) ; } else { result = _freeBlocks[_stackTop] ; --_stackTop ; } #ifdef _DEBUGMEMORYMANAGEMENT assert ( !isFree (result) ) ; #endif return result ; }

void PsnDescriptorMemoryManager::freeSizeRemembered (  void *    ptr )  [virtual]

free a memory zone allocated with allocateSizeRemembered Implements PsnMemoryManager. Definition at line 98 of file PsnDescriptorMemoryManager.cxx. References _freeBlocks, _stackTop, isFree(), and vector< void * >::size(). { #ifdef _DEBUGMEMORYMANAGEMENT // make sure no double free happens assert ( ! isFree (ptr) ) ; assert ( _stackTop < _freeBlocks.size() ) ; #endif ++_stackTop ; _freeBlocks[_stackTop] = ptr ; #ifdef _DEBUGMEMORYMANAGEMENT assert ( isFree ( ptr ) ) ; #endif }

bool PsnDescriptorMemoryManager::inAdressSpace (  void *    ptr )  const [virtual]

find out if a given adress is managed by the current memory manager Implements PsnMemoryManager. Definition at line 39 of file PsnDescriptorMemoryManager.cxx. References _managedMemoryZones, PsnMemoryElementDescriptor::inAdressSpace(), and PsnMemoryElementDescriptor::next. { bool result = false ; unsigned int adress = (unsigned int ) ptr ; PsnMemoryElementDescriptor * current = _managedMemoryZones ; while ( (! result) && ( current != NULL ) ) { result = current->inAdressSpace ( adress ) ; current = (PsnMemoryElementDescriptor *) current->next ; } return result ; }

bool PsnDescriptorMemoryManager::isFree (  void *    ptr )

make sure a pointer is in the list of unused memory element descriptors Definition at line 112 of file PsnDescriptorMemoryManager.cxx. References _freeBlocks, and _stackTop. Referenced by allocateSizeRemembered(), and freeSizeRemembered(). { #ifndef _DEBUGMEMORYMANAGEMENT // this should only be used when debugging assert ( false ) ; #endif bool found = false ; int i = 0 ; while ( (!found) && ( i != _stackTop+1 ) ) { found = ( ptr == _freeBlocks[i] ) ; ++i ; } return found ; }

---

Member Data Documentation

size_t PsnDescriptorMemoryManager::_currentMemorySize [protected]

the size of the managed memory Definition at line 70 of file PsnDescriptorMemoryManager.h. Referenced by allocateSizeRemembered(), and PsnDescriptorMemoryManager().

vector<void *> PsnDescriptorMemoryManager::_freeBlocks [protected]

the list of available memory blocks. a vector is used because allocation can be done by block, and there for only once for n descriptors here, Definition at line 61 of file PsnDescriptorMemoryManager.h. Referenced by allocateSizeRemembered(), freeSizeRemembered(), isFree(), and PsnDescriptorMemoryManager().

PsnMemoryElementDescriptor* PsnDescriptorMemoryManager::_managedMemoryZones [protected]

head of the list of managed memory zones Definition at line 67 of file PsnDescriptorMemoryManager.h. Referenced by allocateSizeRemembered(), inAdressSpace(), and PsnDescriptorMemoryManager().

PsnMemoryManager& PsnDescriptorMemoryManager::_rawMemoryProvider [protected]

if more memory is needed, get it from this memory manager Definition at line 56 of file PsnDescriptorMemoryManager.h. Referenced by allocateSizeRemembered(), and PsnDescriptorMemoryManager().

int PsnDescriptorMemoryManager::_stackTop [protected]

the vector is used a a stack Definition at line 64 of file PsnDescriptorMemoryManager.h. Referenced by allocateSizeRemembered(), freeSizeRemembered(), isFree(), and PsnDescriptorMemoryManager().

---

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

• PsnDescriptorMemoryManager.h
• PsnDescriptorMemoryManager.cxx

---