text: /*
  * Copyright (c) 2015-2017, Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included
  * in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */
  //!
  //! \file      mhw_memory_pool.c  
  //! \brief         This modules implements simple memory pool infrastructure for MHW  
  //!
  #include "mhw_memory_pool.h"
  
  typedef struct _MHW_MEMORY_POOL_ENTRY
  {
      PMHW_MEMORY_POOL_ENTRY  pNext;              //!< Next pool entry (doubled linked list)
      PMHW_MEMORY_POOL_ENTRY  pPrev;              //!< Prev pool entry (doubled linked list)
      PMHW_MEMORY_POOL        pPool;              //!< Pool object
      void                    *pAllocation;        //!< Memory allocation from malloc (to be freed)
      uint32_t                dwSize;             //!< Memory size allocated from malloc
      void                    *pObjects;           //!< Pointer to first object in this pool entry
      uint32_t                dwCount;            //!< Number of objects in this pool allocation
  } MHW_MEMORY_POOL_ENTRY, *PMHW_MEMORY_POOL_ENTRY;
  
  MHW_MEMORY_POOL::MHW_MEMORY_POOL(uint32_t dwObjSize, uint32_t dwObjAlignment):
      m_pFirst(nullptr),
      m_pLast (nullptr),
      m_dwCount(0),
      m_dwSize(0),
      m_dwObjSize(dwObjSize),
      m_dwObjAlignment(dwObjAlignment),
      m_dwObjCount(0)
  {
      
  }
  
  
  MHW_MEMORY_POOL::~MHW_MEMORY_POOL()
  {
      PMHW_MEMORY_POOL_ENTRY pEntry;
      PMHW_MEMORY_POOL_ENTRY pNext;
  
      pEntry = m_pFirst;
      while (pEntry)
      {
          pNext = pEntry->pNext;
          if (pEntry->pAllocation)
          {
              MOS_FreeMemory(pEntry->pAllocation);
          }
          pEntry = pNext;
      }
  }
  
  // Allocate an array of objects to be added to the pool
  void  *MHW_MEMORY_POOL::Allocate(uint32_t dwObjCount)
  {   
      uint8_t                *pObjects  = nullptr;
      uint32_t               dwSize;
      PMHW_MEMORY_POOL_ENTRY pEntry = nullptr;
  
      if (dwObjCount == 0)
      {
          return nullptr;
      }
  
      // Calculate total size - pool entry + objects + alignments
      dwSize = sizeof(MHW_MEMORY_POOL_ENTRY);
      dwSize += m_dwObjSize * dwObjCount + m_dwObjAlignment;
  
      pEntry = (PMHW_MEMORY_POOL_ENTRY) MOS_AllocMemory(dwSize);
      if (!pEntry)
      {
          return nullptr;
      }
  
      pObjects  = ((uint8_t*) pEntry) + sizeof(MHW_MEMORY_POOL_ENTRY);
  
      // adjust alignment if necessary
      if ((uintptr_t(pObjects) % m_dwObjAlignment))
      {
          // clear out lower bits
          pObjects = (uint8_t*)((uintptr_t)pObjects & (~(uintptr_t)(m_dwObjAlignment - 1)));
          // add alignment
          pObjects += m_dwObjAlignment;
      }
  
      // Insert pool entry into linked list
      pEntry->pNext = nullptr;
      pEntry->pPrev = m_pLast;
      m_pLast = pEntry;
      
      if (pEntry->pPrev) pEntry->pPrev->pNext = pEntry;
      
      if (!m_pFirst) m_pFirst = pEntry;
  
      // Setup pool entry
      pEntry->pPool       = this;
      pEntry->pAllocation = (void *)pEntry;
      pEntry->dwSize      = dwSize;
      pEntry->pObjects    = pObjects;
      pEntry->dwCount     = dwObjCount;
  
      // Update pool object
      m_dwCount++;
      m_dwSize     += dwSize;
      m_dwObjCount += dwObjCount;
  
      return pObjects;
  }
  