static int SplitNode(
  Rtree *pRtree,
  RtreeNode *pNode,
  RtreeCell *pCell,
  int iHeight
){
  int i;
  int newCellIsRight = 0;

  int rc = SQLITE_OK;
  int nCell = NCELL(pNode);
  RtreeCell *aCell;
  int *aiUsed;

  RtreeNode *pLeft = 0;
  RtreeNode *pRight = 0;

  RtreeCell leftbbox;
  RtreeCell rightbbox;

  /* Allocate an array and populate it with a copy of pCell and 
  ** all cells from node pLeft. Then zero the original node.
  */
  aCell = sqlite3_malloc64((sizeof(RtreeCell)+sizeof(int))*(nCell+1));
  if( !aCell ){
    rc = SQLITE_NOMEM;
    goto splitnode_out;
  }
  aiUsed = (int *)&aCell[nCell+1];
  memset(aiUsed, 0, sizeof(int)*(nCell+1));
  for(i=0; i<nCell; i++){
    nodeGetCell(pRtree, pNode, i, &aCell[i]);
  }
  nodeZero(pRtree, pNode);
  memcpy(&aCell[nCell], pCell, sizeof(RtreeCell));
  nCell++;

  if( pNode->iNode==1 ){
    pRight = nodeNew(pRtree, pNode);
    pLeft = nodeNew(pRtree, pNode);
    pRtree->iDepth++;
    pNode->isDirty = 1;
    writeInt16(pNode->zData, pRtree->iDepth);
  }else{
    pLeft = pNode;
    pRight = nodeNew(pRtree, pLeft->pParent);
    pLeft->nRef++;
  }

  if( !pLeft || !pRight ){
    rc = SQLITE_NOMEM;
    goto splitnode_out;
  }

  memset(pLeft->zData, 0, pRtree->iNodeSize);
  memset(pRight->zData, 0, pRtree->iNodeSize);

  rc = splitNodeStartree(pRtree, aCell, nCell, pLeft, pRight,
                         &leftbbox, &rightbbox);
  if( rc!=SQLITE_OK ){
    goto splitnode_out;
  }

  /* Ensure both child nodes have node numbers assigned to them by calling
  ** nodeWrite(). Node pRight always needs a node number, as it was created
  ** by nodeNew() above. But node pLeft sometimes already has a node number.
  ** In this case avoid the all to nodeWrite().
  */
  if( SQLITE_OK!=(rc = nodeWrite(pRtree, pRight))
   || (0==pLeft->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pLeft)))
  ){
    goto splitnode_out;
  }

  rightbbox.iRowid = pRight->iNode;
  leftbbox.iRowid = pLeft->iNode;

  if( pNode->iNode==1 ){
    rc = rtreeInsertCell(pRtree, pLeft->pParent, &leftbbox, iHeight+1);
    if( rc!=SQLITE_OK ){
      goto splitnode_out;
    }
  }else{
    RtreeNode *pParent = pLeft->pParent;
    int iCell;
    rc = nodeParentIndex(pRtree, pLeft, &iCell);
    if( rc==SQLITE_OK ){
      nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
      rc = AdjustTree(pRtree, pParent, &leftbbox);
    }
    if( rc!=SQLITE_OK ){
      goto splitnode_out;
    }
  }
  if( (rc = rtreeInsertCell(pRtree, pRight->pParent, &rightbbox, iHeight+1)) ){
    goto splitnode_out;
  }

  for(i=0; i<NCELL(pRight); i++){
    i64 iRowid = nodeGetRowid(pRtree, pRight, i);
    rc = updateMapping(pRtree, iRowid, pRight, iHeight);
    if( iRowid==pCell->iRowid ){
      newCellIsRight = 1;
    }
    if( rc!=SQLITE_OK ){
      goto splitnode_out;
    }
  }
  if( pNode->iNode==1 ){
    for(i=0; i<NCELL(pLeft); i++){
      i64 iRowid = nodeGetRowid(pRtree, pLeft, i);
      rc = updateMapping(pRtree, iRowid, pLeft, iHeight);
      if( rc!=SQLITE_OK ){
        goto splitnode_out;
      }
    }
  }else if( newCellIsRight==0 ){
    rc = updateMapping(pRtree, pCell->iRowid, pLeft, iHeight);
  }

  if( rc==SQLITE_OK ){
    rc = nodeRelease(pRtree, pRight);
    pRight = 0;
  }
  if( rc==SQLITE_OK ){
    rc = nodeRelease(pRtree, pLeft);
    pLeft = 0;
  }

splitnode_out:
  nodeRelease(pRtree, pRight);
  nodeRelease(pRtree, pLeft);
  sqlite3_free(aCell);
  return rc;
}