/*

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of JITCraft.

  *

  * JITCraft is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * Foobar 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 General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * JITCraft. If not, see http://www.gnu.org/licenses/.

  */

 #include <assert.h>

 #include <stdlib.h>

 #include <new>

 #include "PoolAllocator.h"

 #include "Zone.h"

 using namespace ke;

 PoolAllocator::PoolAllocator()

   : reserved_(NULL),

     last_(NULL)

 {

 }

 PoolAllocator::~PoolAllocator()

 {

     unwind(NULL);

     if (reserved_)

         free(reserved_);

 }

 char *

 PoolAllocator::enter()

 {

     if (!last_)

         return NULL;

     return last_->ptr;

 }

 void

 PoolAllocator::leave(char *pos)

 {

     unwind(pos);

 }

 void

 PoolAllocator::unwind(char *pos)

 {

     while (last_) {

         if (pos && pos >= last_->base && pos < last_->end)

             break;

         Pool *prev = last_->prev;

         {

             if (last_->size() <= kMaxReserveSize &&

                 (!reserved_ || reserved_->size() < last_->size()))

             {

                 if (reserved_)

                     free(reserved_);

                 reserved_ = last_;

             } else {

                 free(last_);

             }

         }

         last_ = prev;

     }

     if (!last_) {

         assert(!pos);

         return;

     }

     last_->ptr = pos;

 }

 void *

 PoolAllocator::slowAllocate(size_t actualBytes)

 {

     size_t bytesNeeded = actualBytes + sizeof(Pool);

     if (bytesNeeded < kDefaultPoolSize)

         bytesNeeded = kDefaultPoolSize;

     Pool *pool;

     if (reserved_ && reserved_->size() >= bytesNeeded) {

         pool = reserved_;

         reserved_ = NULL;

     } else {

         pool = (Pool *)malloc(bytesNeeded);

         if (!pool)

             throw std::bad_alloc();

         pool->base = (char *)(pool + 1);

         pool->end = (char *)pool + bytesNeeded;

     }

     pool->ptr = pool->base + actualBytes;

     pool->prev = last_;

     last_ = pool;

     return pool->base;

 }

 void

 PoolAllocationPolicy::reportOutOfMemory()

 {

     // :TODO: report

     assert(false);

 }

 void

 PoolAllocationPolicy::reportAllocationOverflow()

 {

     // :TODO: report

     assert(false);

 }

 void *

 PoolAllocationPolicy::malloc(size_t bytes)

 {

     void *ptr = ZONE()->pool().allocate(bytes);

     if (!ptr)

         reportOutOfMemory();

     return ptr;

 }

 void

 PoolAllocationPolicy::free(void *ptr)

 {

 }