/*
   Copyright (C) 2006, 2008 MySQL AB
    All rights reserved. Use is subject to license terms.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include <ndb_global.h>
#include "SuperPool.hpp"
#include "ndbd_malloc_impl.hpp"
#include "NdbdSuperPool.hpp"

#define PSI (1 << (BMW_2LOG + 2))

struct AllocArea
{
  AllocArea(AllocArea* next);

  Uint16 m_currPage;                        // 2
  Uint16 m_numPages;  // number of pages    // 2
  SuperPool::PtrI m_firstPageI;             // 4
  void* m_memory;     // page-aligned pages // 4/8
  struct AllocArea* m_nextArea;             // 4/8
  // tot 16/24
};

AllocArea::AllocArea(AllocArea* next)
{
  m_nextArea = next;
  m_firstPageI = RNIL;
  m_currPage = m_numPages = 0;
  m_memory = 0;
}

NdbdSuperPool::NdbdSuperPool(class Ndbd_mem_manager & mm,
			     Uint32 pageSize, Uint32 pageBits) :
  SuperPool(pageSize, pageBits),
  m_mm(mm),
  m_currArea(0), m_firstArea(0)
{
  m_memRoot = m_mm.get_memroot();
  
  m_shift = Ndbd_mem_manager::ndb_log2((1 << (BMW_2LOG + 2)) / pageSize) - 1;
  m_add = (1 << m_shift) - 1;
}

NdbdSuperPool::~NdbdSuperPool()
{
  Uint32 cnt = PSI / sizeof(AllocArea);
  AllocArea* ap = m_firstArea;
  while(ap != 0)
  {
    AllocArea * first = ap;
    for(Uint32 i = 0; i<cnt; i++)
    {
      if (ap->m_numPages)
      {
	m_mm.release(ap->m_memory, ap->m_numPages >> m_shift);
      }
      ap = ap->m_nextArea;
    }
    m_mm.release((void*)first, 1);
  }
}

bool
NdbdSuperPool::init_1()
{
  Uint32 pageCount = (1 << m_pageBits);
  if (m_pageEnt == 0) {
    // allocate page entry array
    Uint32 bytes = pageCount * sizeof(PageEnt);
    m_pageEnt = static_cast<PageEnt*>(malloc(bytes));
    if (m_pageEnt == 0)
      return false;
    for (Uint32 i = 0; i < pageCount; i++)
      new (&m_pageEnt[i]) PageEnt();
  }
  if (m_pageType == 0) {
    // allocate type check array
    Uint32 bytes = pageCount;
    m_pageType = static_cast<Uint8*>(malloc(bytes));
    if (m_pageType == 0)
      return false;
    memset(m_pageType, 0, bytes);
  }
  
  return true;
}

static
void
initAllocAreaPage(AllocArea * p1)
{
  AllocArea * ap = p1;
  Uint32 cnt = PSI / sizeof(AllocArea);
  for(Uint32 i = 0; i<cnt; i++, ap++)
  {
    new (ap) AllocArea(ap + 1);
  }

  (p1 + cnt - 1)->m_nextArea = 0;
}

bool
NdbdSuperPool::init_2()
{
  m_memRoot = m_mm.get_memroot();

  Uint32 cnt = 1;
  AllocArea* p1 = (AllocArea*)m_mm.alloc(&cnt, 1);
  if (p1 == 0)
    return false;

  initAllocAreaPage(p1);
  m_currArea = p1;
  m_firstArea = p1;
  return true;
}

SuperPool::PtrI
NdbdSuperPool::getNewPage()
{
  AllocArea* ap = m_currArea;
  Uint32 curr = ap->m_currPage;
  Uint32 cnt = ap->m_numPages;
  if (curr == cnt)
  {
    // area is used up
    if (! (ap = allocMem()))
    {
      abort();
      return RNIL;
    }
    curr = ap->m_currPage;
    cnt = ap->m_numPages;
  }

  assert(curr < cnt);
  PtrI pageI = ap->m_firstPageI;
  Uint32 recBits = m_recBits;
  Int32 ip = ((Int32)pageI >> recBits) + curr;
  pageI = ip << recBits;
  ap->m_currPage = curr + 1;
  return pageI;
}

Uint32
NdbdSuperPool::allocAreaMemory(AllocArea* ap, Uint32 tryPages)
{
  Uint32 cnt = (tryPages + m_add) >> m_shift;
  void* p1 = m_mm.alloc(&cnt, 1);
  if (p1 == 0)
  {
    abort();
    return 0;
  }
  Uint32 pageI = getPageI(p1);
  ap->m_firstPageI = pageI;
  ap->m_currPage = 0;
  ap->m_memory = p1;
  ap->m_numPages = cnt << m_shift;
  return cnt;
}

AllocArea*
NdbdSuperPool::allocArea()
{
  AllocArea * curr = m_currArea;
  AllocArea * next = curr->m_nextArea;
  if (next == 0)
  {
    Uint32 cnt = 1;
    AllocArea* p1 = (AllocArea*)m_mm.alloc(&cnt, 1);
    if (p1 == 0)
      return 0;
    
    initAllocAreaPage(p1);

    m_currArea->m_nextArea = p1;
    return m_currArea = p1;
  }
  else
  {
    m_currArea = m_currArea->m_nextArea;
    return m_currArea;
  }
}

AllocArea*
NdbdSuperPool::allocMem()
{
  // compute number of additional pages needed
  if (m_totPages >= m_maxPages)
  {
    abort();
    return 0;
  }
  Uint32 needPages = (m_totPages == 0 ? m_initPages : m_incrPages);
  
  // add new area
  AllocArea* ap = allocArea();
  if (ap == 0)
  {
    abort();
    return 0;
  }
  
  Uint32 numPages;
  if (!(numPages = allocAreaMemory(ap, needPages)))
  {
    abort();
    return 0;
  }
  
  // update counts
  m_totPages += numPages;
  return ap;
}
