Src/Common/Allocators/SimplePooledAlloc.h

   1 // SimplePooledAlloc.h
   2 //
   3 // Copyright (c) 2005 David Ward
   4
   5 #ifndef __SimplePooledAlloc_h__
   6 #define __SimplePooledAlloc_h__
   7
   8 // CSimplePooledAlloc allocates objects T in fixed-size blocks (specified)
   9 // Alloc returns a default-constructed T*
  10 // Memory is only freed on destruction of the allocator
  11
  12 #include <cstddef>
  13 #include <vector>
  14
  15 template<typename T>
  16 class CSimplePooledAlloc {
  17 public:
  18   // Construct with given block size
  19   CSimplePooledAlloc(std::size_t iBlockSize);
  20
  21   ~CSimplePooledAlloc();
  22
  23   // Return an uninitialized object
  24   T *Alloc();
  25
  26 private:
  27   class CPool {
  28   public:
  29     CPool(std::size_t iSize):m_iCurrent(0), m_iSize(iSize) {
  30       m_pData = new T[m_iSize];
  31     }
  32     ~CPool() {
  33       delete[]m_pData;
  34     }
  35     T *Alloc() const {
  36       if(m_iCurrent < m_iSize)
  37         return &m_pData[m_iCurrent++];
  38       return NULL;
  39     }
  40   private:
  41     mutable std::size_t m_iCurrent;
  42     std::size_t m_iSize;
  43     T *m_pData;
  44   };
  45
  46   std::vector < CPool * >m_vPool;
  47
  48   std::size_t m_iBlockSize;
  49   int m_iCurrent;
  50 };
  51
  52 template < typename T > CSimplePooledAlloc < T >::CSimplePooledAlloc(std::size_t iSize):m_iBlockSize(iSize), m_iCurrent(0) {
  53   m_vPool.push_back(new CPool(m_iBlockSize));
  54 }
  55
  56 template < typename T > CSimplePooledAlloc < T >::~CSimplePooledAlloc() {
  57   for(std::size_t i = 0; i < m_vPool.size(); i++)
  58     delete m_vPool[i];
  59 }
  60
  61 template < typename T > T * CSimplePooledAlloc < T >::Alloc() {
  62   T *p = m_vPool[m_iCurrent]->Alloc();
  63   if(p)
  64     return p;
  65   m_vPool.push_back(new CPool(m_iBlockSize));
  66   m_iCurrent++;
  67   return m_vPool.back()->Alloc();
  68 }
  69
  70 #endif // __include__