/*
   Copyright (C) 2005, 2006 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"

#define SP_ALIGN(sz, al) (((sz) + (al) - 1) & ~((al) - 1))

// This is used for m_freeRecI when there is no record pool page.
#define NNIL    0xffffffff

// SuperPool

SuperPool::SuperPool(Uint32 pageSize, Uint32 pageBits) :
  m_pageSize(pageSize),
  m_pageBits(pageBits),
  m_recBits(32 - m_pageBits),
  m_recMask((1 << m_recBits) - 1),
  m_memRoot(0),
  m_pageEnt(0),
  m_pageType(0),
  m_freeList(),
  m_initPages(0),
  m_incrPages(0),
  m_maxPages(0),
  m_totPages(0),
  m_typeCount(0),
  m_groupMinPct(0),
  m_groupMinPages(0),
  m_groupTotPages(0)
{
  assert(m_pageSize != 0 && (m_pageSize & (m_pageSize - 1)) == 0);
  assert(m_pageBits <= 30);
}

SuperPool::~SuperPool()
{
}

SuperPool::PageEnt::PageEnt() :
  m_pageType(0),
  m_useCount(0),
  m_freeRecI(NNIL),
  m_nextPageI(RNIL),
  m_prevPageI(RNIL)
{
}

// page list routines

SuperPool::PageList::PageList() :
  m_headPageI(RNIL),
  m_tailPageI(RNIL),
  m_pageCount(0)
{
}

SuperPool::PageList::PageList(PtrI pageI) :
  m_headPageI(pageI),
  m_tailPageI(pageI),
  m_pageCount(1)
{
  assert(pageI != RNIL);
}

void
SuperPool::movePages(PageList& pl1, PageList& pl2)
{
  PtrI pageI1 = pl1.m_tailPageI;
  PtrI pageI2 = pl2.m_headPageI;
  if (pl1.m_pageCount != 0) {
    assert(pageI1 != RNIL);
    if (pl2.m_pageCount != 0) {
      assert(pageI2 != RNIL);
      PageEnt& pe1 = getPageEnt(pageI1);
      PageEnt& pe2 = getPageEnt(pageI2);
      pe1.m_nextPageI = pageI2;
      pe2.m_prevPageI = pageI1;
      pl1.m_tailPageI = pl2.m_tailPageI;
      pl1.m_pageCount += pl2.m_pageCount;
    } else {
      assert(pageI2 == RNIL);
    }
  } else {
    assert(pageI1 == RNIL);
    pl1 = pl2;
  }
  pl2.m_headPageI = pl2.m_tailPageI = RNIL;
  pl2.m_pageCount = 0;
}

void
SuperPool::addHeadPage(PageList& pl, PtrI pageI)
{
  assert(pageI != RNIL);
  PageEnt& pe = getPageEnt(pageI);
  assert(pe.m_nextPageI == RNIL & pe.m_prevPageI == RNIL);
  PageList pl2(pageI);
  movePages(pl2, pl);
  pl = pl2;
}

void
SuperPool::addTailPage(PageList& pl, PtrI pageI)
{
  assert(pageI != RNIL);
  PageEnt& pe = getPageEnt(pageI);
  assert(pe.m_nextPageI == RNIL & pe.m_prevPageI == RNIL);
  PageList pl2(pageI);
  movePages(pl, pl2);
}

void
SuperPool::removePage(PageList& pl, PtrI pageI)
{
  assert(pageI != RNIL);
  PageEnt& pe = getPageEnt(pageI);
  if (pe.m_nextPageI != RNIL) {
    assert(pl.m_tailPageI != pageI);
    PageEnt& nextPe = getPageEnt(pe.m_nextPageI);
    nextPe.m_prevPageI = pe.m_prevPageI;
  } else {
    assert(pl.m_tailPageI == pageI);
    pl.m_tailPageI = pe.m_prevPageI;
  }
  if (pe.m_prevPageI != RNIL) {
    assert(pl.m_headPageI != pageI);
    PageEnt& prevPe = getPageEnt(pe.m_prevPageI);
    prevPe.m_nextPageI = pe.m_nextPageI;
  } else {
    assert(pl.m_headPageI == pageI);
    pl.m_headPageI = pe.m_nextPageI;
  }
  pe.m_nextPageI = RNIL;
  pe.m_prevPageI = RNIL;
  assert(pl.m_pageCount != 0);
  pl.m_pageCount--;
}

// reverse mapping

SuperPool::PtrI
SuperPool::getPageI(void* pageP)
{
  Uint32 pageSize = m_pageSize;
  Uint32 pageBits = m_pageBits;
  Uint32 recBits = m_recBits;
  void* memRoot = m_memRoot;
  my_ptrdiff_t ipL = (Uint8*)pageP - (Uint8*)memRoot;
  assert(ipL % pageSize == 0);
  ipL /= (Int32)pageSize;
  Int32 ip = (Int32)ipL;
  Int32 lim = 1 << (pageBits - 1);
  if (! (ip == ipL && -lim <= ip && ip < lim && ip != -1)) {
    // page was too distant from memory root
    return RNIL;
  }
  PtrI pageI = ip << recBits;
  assert(pageP == getPageP(pageI));
  return pageI;
}

// record pool

SuperPool::RecInfo::RecInfo(GroupPool& gp, Uint32 recSize) :
  m_groupPool(gp),
  m_recSize(recSize),
  m_recType(0),
  m_maxPerPage(0),
  m_freeRecI(NNIL),
  m_useCount(0),
  m_pageList(),
  m_hyX(1),
  m_hyY(2)
{
  SuperPool& sp = gp.m_superPool;
  m_recType = (sp.m_typeCount++ << 1) | 1;
  assert(m_recSize == SP_ALIGN(m_recSize, sizeof(Uint32)));
  { // compute max records per page
    Uint32 n1 = sp.m_pageSize / m_recSize;
    Uint32 b2 = (sp.m_recBits < 16 ? sp.m_recBits : 16);
    Uint32 n2 = (1 << b2) - 1;  // last is reserved
    m_maxPerPage = (n1 < n2 ? n1 : n2);
    assert(m_maxPerPage != 0);
  }
}

Uint32
SuperPool::getFreeCount(RecInfo& ri, PtrI recI)
{
  Uint32 n = 0;
  Uint32 recMask = m_recMask;
  Uint32 loopRecI = recI;
  while ((loopRecI & recMask) != recMask) {
    n++;
    void* loopRecP = getRecP(loopRecI, ri);
    loopRecI = *(Uint32*)loopRecP;
  }
  assert(n == (Uint16)n);
  return n;
}

Uint32
SuperPool::getRecPageCount(RecInfo& ri)
{
  Uint32 n = 0;
  for (Uint32 k = 0; k <= 2; k++)
    n += ri.m_pageList[k].m_pageCount;
  if (ri.m_freeRecI != NNIL)
    n += 1;
  return n;
}

Uint32
SuperPool::getRecTotCount(RecInfo& ri)
{
  return ri.m_maxPerPage * getRecPageCount(ri);
}

Uint32
SuperPool::getRecUseCount(RecInfo& ri)
{
  Uint32 n = ri.m_useCount;
  // current page does not keep count
  if (ri.m_freeRecI != NNIL) {
    Uint32 maxPerPage = ri.m_maxPerPage;
    Uint32 freeCount = getFreeCount(ri, ri.m_freeRecI);
    assert(maxPerPage >= freeCount);
    n += maxPerPage - freeCount;
  }
  return n;
}

// current page

Uint32
SuperPool::getRecPageList(RecInfo& ri, PageEnt& pe)
{
  if (pe.m_useCount == 0)
    return 0;
  if (pe.m_useCount < ri.m_maxPerPage)
    return 1;
  if (pe.m_useCount == ri.m_maxPerPage)
    return 2;
  assert(false);
  return ~(Uint32)0;
}

void
SuperPool::addCurrPage(RecInfo& ri, PtrI pageI)
{
  PageEnt& pe = getPageEnt(pageI);
  ri.m_freeRecI = pe.m_freeRecI;
  // remove from right list
  Uint32 k = getRecPageList(ri, pe);
  assert(k != 2);
  removePage(ri.m_pageList[k], pageI);
  assert(ri.m_useCount >= pe.m_useCount);
  ri.m_useCount -= pe.m_useCount;
}

void
SuperPool::removeCurrPage(RecInfo& ri)
{
  Uint32 recMask = m_recMask;
  PtrI pageI = ri.m_freeRecI & ~ m_recMask;
  // update page entry
  PageEnt& pe = getPageEnt(pageI);
  pe.m_freeRecI = ri.m_freeRecI;
  Uint32 maxPerPage = ri.m_maxPerPage;
  Uint32 freeCount = getFreeCount(ri, pe.m_freeRecI);
  assert(maxPerPage >= freeCount);
  pe.m_useCount = maxPerPage - freeCount;
  // add to right list
  Uint32 k = getRecPageList(ri, pe);
  addHeadPage(ri.m_pageList[k], pageI);
  ri.m_useCount += pe.m_useCount;
  ri.m_freeRecI = NNIL;
  if (k == 0) {
    freeRecPages(ri);
  }
}

// page allocation

bool
SuperPool::getAvailPage(RecInfo& ri)
{
  PtrI pageI;
  if ((pageI = ri.m_pageList[1].m_headPageI) != RNIL ||
      (pageI = ri.m_pageList[0].m_headPageI) != RNIL ||
      (pageI = getFreePage(ri)) != RNIL) {
    // the page is in record pool now
    if (ri.m_freeRecI != NNIL)
      removeCurrPage(ri);
    addCurrPage(ri, pageI);
    return true;
  }
  return false;
}

SuperPool::PtrI
SuperPool::getFreePage(RecInfo& ri)
{
  GroupPool& gp = ri.m_groupPool;
  PtrI pageI;
  if ((pageI = getFreePage(gp)) != RNIL) {
    initFreePage(ri, pageI);
    addHeadPage(ri.m_pageList[0], pageI);
    return pageI;
  }
  return RNIL;
}

SuperPool::PtrI
SuperPool::getFreePage(GroupPool& gp)
{
  PtrI pageI;
  if ((pageI = gp.m_freeList.m_headPageI) != RNIL) {
    removePage(gp.m_freeList, pageI);
    return pageI;
  }
  if (gp.m_totPages < getMaxPages(gp) &&
      (pageI = getFreePage()) != RNIL) {
    gp.m_totPages++;
    return pageI;
  }
  return RNIL;
}

SuperPool::PtrI
SuperPool::getFreePage()
{
  PtrI pageI;
  if ((pageI = m_freeList.m_headPageI) != RNIL) {
    removePage(m_freeList, pageI);
    return pageI;
  }
  if ((pageI = getNewPage()) != RNIL) {
    return pageI;
  }
  return RNIL;
}

void
SuperPool::initFreePage(RecInfo& ri, PtrI pageI)
{
  void* pageP = getPageP(pageI);
  // set up free record list
  Uint32 num = ri.m_maxPerPage;
  Uint32 recSize = ri.m_recSize;
  void* recP = (Uint8*)pageP;
  Uint32 irNext = 1;
  while (irNext < num) {
    *(Uint32*)recP = pageI | irNext;
    recP = (Uint8*)recP + recSize;
    irNext++;
  }
  // terminator has all recBits set
  *(Uint32*)recP = pageI | m_recMask;
  // set up new page entry
  PageEnt& pe = getPageEnt(pageI);
  new (&pe) PageEnt();
  pe.m_pageType = ri.m_recType;
  pe.m_freeRecI = pageI | 0;
  pe.m_useCount = 0;
  // set type check byte
  Uint32 ip = pageI >> m_recBits;
  m_pageType[ip] = (ri.m_recType & 0xFF);
}

// release

void
SuperPool::releaseNotCurrent(RecInfo& ri, PtrI recI)
{
  PageEnt& pe = getPageEnt(recI);
  void* recP = getRecP(recI, ri);
  *(Uint32*)recP = pe.m_freeRecI;
  pe.m_freeRecI = recI;
  PtrI pageI = recI & ~ m_recMask;
  Uint32 maxPerPage = ri.m_maxPerPage;
  // move to right list
  Uint32 k1 = getRecPageList(ri, pe);
  assert(pe.m_useCount != 0);
  pe.m_useCount--;
  Uint32 k2 = getRecPageList(ri, pe);
  if (k1 != k2) {
    removePage(ri.m_pageList[k1], pageI);
    addHeadPage(ri.m_pageList[k2], pageI);
    if (k2 == 0) {
      freeRecPages(ri);
    }
  }
  assert(ri.m_useCount != 0);
  ri.m_useCount--;
}

void
SuperPool::freeRecPages(RecInfo& ri)
{
  // ignore current page
  Uint32 useCount = ri.m_useCount;
  Uint32 totCount = 0;
  for (uint32 k = 0; k <= 2; k++)
    totCount += ri.m_pageList[k].m_pageCount;
  totCount *= ri.m_maxPerPage;
  assert(totCount >= useCount);
  if ((totCount - useCount) * ri.m_hyY < useCount * ri.m_hyX)
    return;
  // free all free pages
  GroupPool& gp = ri.m_groupPool;
  Uint32 minPages = getMinPages(gp);
  PageList& pl = ri.m_pageList[0];
  while (pl.m_pageCount != 0) {
    PtrI pageI = pl.m_headPageI;
    removePage(pl, pageI);
    PageEnt& pe = getPageEnt(pageI);
    pe.m_pageType = 0;
    pe.m_freeRecI = NNIL;
    Uint32 ip = pageI >> m_recBits;
    m_pageType[ip] = 0;
    if (gp.m_totPages <= minPages) {
      addHeadPage(gp.m_freeList, pageI);
    } else {
      // return excess to super pool
     addHeadPage(m_freeList, pageI);
     assert(gp.m_totPages != 0);
     gp.m_totPages--;
    }
  }
}

void
SuperPool::freeAllRecPages(RecInfo& ri, bool force)
{
  GroupPool& gp = ri.m_groupPool;
  if (ri.m_freeRecI != NNIL)
    removeCurrPage(ri);
  assert(force || ri.m_useCount == 0);
  for (Uint32 k = 0; k <= 2; k++)
    movePages(gp.m_freeList, ri.m_pageList[k]);
}

// size parameters

void
SuperPool::setInitPages(Uint32 initPages)
{
  m_initPages = initPages;
}

void
SuperPool::setIncrPages(Uint32 incrPages)
{
  m_incrPages = incrPages;
}

void
SuperPool::setMaxPages(Uint32 maxPages)
{
  m_maxPages = maxPages;
}

Uint32
SuperPool::getGpMinPages()
{
  Uint32 minPages = (m_groupMinPct * m_totPages) / 100;
  if (minPages < m_groupMinPages)
    minPages = m_groupMinPages;
  return minPages;
}

Uint32
SuperPool::getMinPages(GroupPool& gp)
{
  Uint32 minPages = (gp.m_minPct * m_totPages) / 100;
  if (minPages < gp.m_minPages)
    minPages = gp.m_minPages;
  return minPages;
}

Uint32
SuperPool::getMaxPages(GroupPool& gp)
{
  Uint32 n1 = getGpMinPages();
  Uint32 n2 = getMinPages(gp);
  assert(n1 >= n2);
  // pages reserved by other groups
  Uint32 n3 = n1 - n2;
  // rest can be claimed
  Uint32 n4 = (m_totPages >= n3 ? m_totPages - n3 : 0);
  return n4;
}

// debug

void
SuperPool::verify(RecInfo& ri)
{
  GroupPool& gp = ri.m_groupPool;
  verifyPageList(m_freeList);
  verifyPageList(gp.m_freeList);
  for (Uint32 k = 0; k <= 2; k++) {
    PageList& pl = ri.m_pageList[k];
    verifyPageList(pl);
    PtrI pageI = pl.m_headPageI;
    while (pageI != RNIL) {
      PageEnt& pe = getPageEnt(pageI);
      assert(pe.m_pageType == ri.m_recType);
      Uint32 maxPerPage = ri.m_maxPerPage;
      Uint32 freeCount = getFreeCount(ri, pe.m_freeRecI);
      assert(maxPerPage >= freeCount);
      Uint32 useCount = maxPerPage - freeCount;
      assert(pe.m_useCount == useCount);
      assert(k != 0 || useCount == 0);
      assert(k != 1 || (useCount != 0 && freeCount != 0));
      assert(k != 2 || freeCount == 0);
      pageI = pe.m_nextPageI;
    }
  }
}

void
SuperPool::verifyPageList(PageList& pl)
{
  Uint32 count = 0;
  PtrI pageI = pl.m_headPageI;
  while (pageI != RNIL) {
    PageEnt& pe = getPageEnt(pageI);
    if (pe.m_prevPageI == RNIL) {
      assert(count == 0);
    } else {
      PageEnt& prevPe = getPageEnt(pe.m_prevPageI);
      assert(prevPe.m_nextPageI == pageI);
    }
    if (pe.m_nextPageI == RNIL) {
      assert(pl.m_tailPageI == pageI);
    } else {
      PageEnt& nextPe = getPageEnt(pe.m_nextPageI);
      assert(nextPe.m_prevPageI == pageI);
    }
    if (pe.m_pageType != 0) {
      assert(pe.m_freeRecI != NNIL);
      PageEnt& pe2 = getPageEnt(pe.m_freeRecI);
      assert(&pe == &pe2);
    } else {
      assert(pe.m_freeRecI == NNIL);
    }
    pageI = pe.m_nextPageI;
    count++;
  }
  assert(pl.m_pageCount == count);
}

// GroupPool

GroupPool::GroupPool(SuperPool& sp) :
  m_superPool(sp),
  m_minPct(0),
  m_minPages(0),
  m_totPages(0),
  m_freeList()
{
}

GroupPool::~GroupPool()
{
}

void
GroupPool::setMinPct(Uint32 minPct)
{
  SuperPool& sp = m_superPool;
  // subtract any previous value
  assert(sp.m_groupMinPct >= m_minPct);
  sp.m_groupMinPct -= m_minPct;
  // add new value
  sp.m_groupMinPct += minPct;
  m_minPct = minPct;
}

void
GroupPool::setMinPages(Uint32 minPages)
{
  SuperPool& sp = m_superPool;
  // subtract any previous value
  assert(sp.m_groupMinPages >= m_minPages);
  sp.m_groupMinPages -= m_minPages;
  // add new value
  sp.m_groupMinPages += minPages;
  m_minPages = minPages;
}

// HeapPool

HeapPool::HeapPool(Uint32 pageSize, Uint32 pageBits) :
  SuperPool(pageSize, pageBits),
  m_areaHead(),
  m_currArea(&m_areaHead),
  m_lastArea(&m_areaHead)
{
}

HeapPool::~HeapPool()
{
  free(m_pageEnt);
  free(m_pageType);
  Area* ap;
  while ((ap = m_areaHead.m_nextArea) != 0) {
    m_areaHead.m_nextArea = ap->m_nextArea;
    free(ap->m_memory);
    free(ap);
  }
}

HeapPool::Area::Area() :
  m_nextArea(0),
  m_firstPageI(RNIL),
  m_currPage(0),
  m_memory(0),
  m_pages(0),
  m_numPages(0)
{
}

SuperPool::PtrI
HeapPool::getNewPage()
{
  Area* ap = m_currArea;
  if (ap->m_currPage == ap->m_numPages) {
    // area is used up
    if (ap->m_nextArea == 0) {
      if (! allocMemoryImpl())
        return RNIL;
    }
    ap = m_currArea = ap->m_nextArea;
    assert(ap != 0);
  }
  assert(ap->m_currPage < ap->m_numPages);
  PtrI pageI = ap->m_firstPageI;
  Uint32 recBits = m_recBits;
  Int32 ip = (Int32)pageI >> recBits;
  ip += ap->m_currPage;
  pageI = ip << recBits;
  ap->m_currPage++;
  return pageI;
}

bool
HeapPool::allocInit()
{
  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;
}

bool
HeapPool::allocArea(Area* ap, Uint32 tryPages)
{
  Uint32 pageSize = m_pageSize;
  // one page is usually lost due to alignment
  Uint8* p1 = (Uint8*)malloc(pageSize * (tryPages + 1));
  if (p1 == 0)
    return false;
  // align
  UintPtr n1 = (UintPtr)p1;
  UintPtr n2 = SP_ALIGN(n1, (UintPtr)pageSize);
  Uint8* p2 = p1 + (n2 - n1);
  assert(p2 >= p1 && p2 - p1 < pageSize && (UintPtr)p2 % pageSize == 0);
  // set memory root to first allocated page
  if (m_memRoot == 0)
    m_memRoot = p2;
  // convert to i-value
  Uint32 pageI = getPageI(p2);
  ap->m_firstPageI = pageI;
  ap->m_currPage = 0;
  ap->m_memory = p1;
  ap->m_pages = p2;
  ap->m_numPages = tryPages + (p1 == p2);
  return true;
}

bool
HeapPool::allocMemoryImpl()
{
  if (! allocInit())
    return false;
  // compute number of additional pages needed
  if (m_maxPages <= m_totPages)
    return false;
  Uint32 needPages = (m_totPages == 0 ? m_initPages : m_incrPages);
  if (needPages > m_maxPages - m_totPages)
    needPages = m_maxPages - m_totPages;
  while (needPages != 0) {
    // add new area
    Area* ap = static_cast<Area*>(malloc(sizeof(Area)));
    if (ap == 0)
      return false;
    new (ap) Area();
    m_lastArea->m_nextArea = ap;
    m_lastArea = ap;
    // initial malloc is done in m_incrPages pieces
    Uint32 wantPages = needPages;
    if (m_incrPages != 0 && wantPages > m_incrPages)
      wantPages = m_incrPages;
    Uint32 tryPages = wantPages;
    while (tryPages != 0) {
      if (allocArea(ap, tryPages))
        break;
      tryPages /= 2;
    }
    if (tryPages == 0)
      return false;
    // update counts
    Uint32 numPages = ap->m_numPages;
    m_totPages += numPages;
    needPages = (needPages > numPages ? needPages - numPages : 0);
  }
  return true;
}
