Share Library (C++)

/**
 * @file DefaultAllocator.cpp
 * @brief Allocator for blocks inside shared segment
 * @author Kamil Dudka, xdudka00@gmail.com
 * @date 2007-05-15
 * @ingroup backend
 */
 
#include "DefaultAllocator.h"
 
using namespace Share;
 
DefaultAllocator::DefaultAllocator(void *atAddr, size_t shareMangerSize, size_t dataSize) throw (ShareException):
  size_ (dataSize),
  available_ (dataSize)
{
  typedef TRelocPtr::pointer TAbsPtr;
  typedef TRelocPtr::relative_pointer TRelPtr;
 
  // Check alignment
  const TRelocPtr ptr (atAddr, 0);
  const TRelPtr rel = ptr.toRel();
  if (alignmenter (rel) != rel)
    throw ShareException ("DefaultAllocator: Address alignment assertion failed. Try to recompile Share library with lower value of BITS_ALIGNMENT macro defined.");
 
  current_ = TRelocPtr::fromRel (shareMangerSize);
}
 
DefaultAllocator::~DefaultAllocator()
{
}
 
size_t DefaultAllocator::sizeNeeded (size_t shareMangerSize, size_t dataSize)
{
  return
    alignmenter(shareMangerSize) +
    alignmenter(dataSize);
}
 
void* DefaultAllocator::alloc (size_t size) throw (ShareException)
{
  // Align size
  const size_t alignedSize = alignmenter (size);
  TRelocPtr tmp = current_;
  tmp += alignedSize;
 
  // Check available space
  if (tmp.toRel() > size_)
    throw ShareException ("DefaultAllocator: Not enough space inside shared segment - alloc() call failed");
 
  // Move next
  void *addr= current_;
  current_+= alignedSize;
  available_ -= alignedSize;
 
  return addr;
}
 
void DefaultAllocator::free (void *) throw ()
{
}
 
size_t DefaultAllocator::size()
{
  return size_;
}
 
size_t DefaultAllocator::available ()
{
  return available_;
}