/*

 * Copyright (c) 2002

 * John Maddock

 *

 * Use, modification and distribution are subject to the 

 * Boost Software License, Version 1.0. (See accompanying file 

 * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

 *

 */

 /*

  *   LOCATION:    see http://www.boost.org for most recent version.

  *   FILE         mem_block_cache.hpp

  *   VERSION      see <boost/version.hpp>

  *   DESCRIPTION: memory block cache used by the non-recursive matcher.

  */

#ifndef BOOST_REGEX_V4_MEM_BLOCK_CACHE_HPP

#define BOOST_REGEX_V4_MEM_BLOCK_CACHE_HPP

#include <new>

#ifdef BOOST_HAS_THREADS

#include <boost/regex/pending/static_mutex.hpp>

#endif

#ifdef BOOST_HAS_ABI_HEADERS

#  include BOOST_ABI_PREFIX

#endif

namespace boost{

namespace re_detail{

struct mem_block_node

{

   mem_block_node* next;

};

struct mem_block_cache

{

   // this member has to be statically initialsed:

   mem_block_node* next;

   unsigned cached_blocks;

#ifdef BOOST_HAS_THREADS

   boost::static_mutex mut;

#endif

   ~mem_block_cache()

   {

      while(next)

      {

         mem_block_node* old = next;

         next = next->next;

         ::operator delete(old);

      }

   }

   void* get()

   {

#ifdef BOOST_HAS_THREADS

      boost::static_mutex::scoped_lock g(mut);

#endif

     if(next)

      {

         mem_block_node* result = next;

         next = next->next;

         --cached_blocks;

         return result;

      }

      return ::operator new(BOOST_REGEX_BLOCKSIZE);

   }

   void put(void* p)

   {

#ifdef BOOST_HAS_THREADS

      boost::static_mutex::scoped_lock g(mut);

#endif

      if(cached_blocks >= BOOST_REGEX_MAX_CACHE_BLOCKS)

      {

         ::operator delete(p);

      }

      else

      {

         mem_block_node* old = static_cast<mem_block_node*>(p);

         old->next = next;

         next = old;

         ++cached_blocks;

      }

   }

};

extern mem_block_cache block_cache;

}

} // namespace boost

#ifdef BOOST_HAS_ABI_HEADERS

#  include BOOST_ABI_SUFFIX

#endif

#endif