allocator.h

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/*
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 *  Point Cloud Library (PCL) - www.pointclouds.org
 *  Copyright (c) 2009-2012, Willow Garage, Inc.
 *  Copyright (c) 2006, Michael Kazhdan and Matthew Bolitho,
 *                      Johns Hopkins University
 *
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 * $Id: allocator.h 5036 2012-03-12 08:54:15Z rusu $
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#ifndef PCL_POISSON_ALLOCATOR_H_
#define PCL_POISSON_ALLOCATOR_H_
#include <vector>

namespace pcl 
{
  namespace poisson 
  {
    class AllocatorState
    {
      public:
        int index,remains;
    };

    template<class T>
    class Allocator
    {
      int blockSize;
      int index, remains;
      std::vector<T*> memory;

      public:
        Allocator () : blockSize (0), index (0), remains (0), memory ()
        {
        }

        ~Allocator ()
        {
          reset ();
        }

        void 
        reset ()
        {
          for (size_t i = 0; i < memory.size (); i++)
            delete[] memory[i];

          memory.clear ();
          blockSize = index = remains = 0;
        }

        AllocatorState 
        getState () const
        {
          AllocatorState s;
          s.index = index;
          s.remains = remains;
          return (s);
        }

        void 
        rollBack ()
        {
          if(memory.size ())
          {
            for (size_t i = 0; i < memory.size (); i++)
            {
              for (int j = 0; j < blockSize; j++)
              {
                memory[i][j].~T();
                new(&memory[i][j]) T();
              }
            }
            index = 0;
            remains = blockSize;
          }
        }

        void 
        rollBack (const AllocatorState& state)
        {
          if (state.index < index || (state.index == index && state.remains < remains))
          {
            if (state.index < index)
            {
              for (int j = state.remains; j < blockSize; j++)
              {
                memory[state.index][j].~T ();
                new (&memory[state.index][j]) T();
              }

              for (int i = state.index + 1; i < index - 1; i++)
              {
                for (int j = 0; j < blockSize; j++)
                {
                  memory[i][j].~T();
                  new(&memory[i][j]) T();
                }
              }
              for (int j = 0; j < remains; j++)
              {
                memory[index][j].~T();
                new(&memory[index][j]) T();
              }
              index = state.index;
              remains = state.remains;
            }
            else
            {
              for (int j = 0; j < state.remains; j<remains)
              {
                memory[index][j].~T();
                new(&memory[index][j]) T();
              }
              remains = state.remains;
            }
          }
        }

        void 
        set (const int& blockSize)
        {
          reset ();
          this->blockSize = blockSize;
          index = -1;
          remains = 0;
        }

        T* 
        newElements (const int& elements = 1)
        {
          T* mem;
          if (!elements)
            return (NULL);
         
          if (elements>blockSize)
          {
            fprintf (stderr, "Allocator Error, elements bigger than block-size: %d>%d\n", elements,blockSize);
            return (NULL);
          }
          if (remains<elements)
          {
            if(index == static_cast<int>(memory.size() - 1))
            {
              mem = new T[blockSize];

              if (!mem)
                throw "Failed to allocate memory";
              memory.push_back (mem);
            }
            index++;
            remains = blockSize;
          }
          mem = &(memory[index][blockSize-remains]);
          remains -= elements;
          return (mem);
        }
    };
  }
}


#endif /* PCL_POISSON_ALLOCATOR_H_ */