freelist.h

Conditional Random Fields的训练识别工具

/*
  CRF++ -- Yet Another CRF toolkit

  $Id: freelist.h 1528 2006-08-07 02:39:50Z taku $;

  Copyright(C) 2005 Taku Kudo <[e-mail]>

  This is free software with ABSOLUTELY NO WARRANTY.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or(at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#ifndef _CRFPP_FREELIST_H
#define _CRFPP_FREELIST_H

#include <vector>

namespace CRFPP
{
  template <class T>
    class Length { public: size_t operator()(const T *str) const { return 1; } };
  class charLength { public: size_t operator()(const char *str) const  { return strlen(str) + 1; } };

  template <class T, class LengthFunc = Length<T> >
    class FreeList
    {
      private:
      std::vector <T *> freeList;
      size_t pi;
      size_t li;
      size_t size;

      public:
      void free() { li = pi = 0; }

      T* alloc(size_t len = 1)
      {
        if ((pi + len) >= size) { li++; pi = 0; }
        if (li == freeList.size()) {
          freeList.push_back(new T [size]);
        }
        T* r = freeList[li] + pi;
        pi += len;
        return r;
      }

      T* dup(T *src, size_t len = 0)
      {
        if (! len) len = LengthFunc () (src);
        T *p = alloc(len);
        if (src == 0) memset (p, 0, len * sizeof (T));
        else        memcpy(p, src, len * sizeof(T));
        return p;
      }

      void set_size(size_t n) { size = n; }
      FreeList(size_t _size): pi(0), li(0), size(_size) {}
      FreeList(): pi(0), li(0), size(0) {};
      ~FreeList()
      {
        for (li = 0; li < freeList.size(); ++li) {
          delete [] freeList[li];
        }
      }
    };

  typedef FreeList<char, charLength> StrFreeList;
}
#endif