rtree.c

最新的sqlite3.6.2源代码

  }

  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 = nodeParentIndex(pRtree, pLeft);
    nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
    AdjustTree(pRtree, pParent, &leftbbox);
  }
  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;
}

static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){
  int rc = SQLITE_OK;
  if( pLeaf->iNode!=1 && pLeaf->pParent==0 ){
    sqlite3_bind_int64(pRtree->pReadParent, 1, pLeaf->iNode);
    if( sqlite3_step(pRtree->pReadParent)==SQLITE_ROW ){
      i64 iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
      rc = nodeAcquire(pRtree, iNode, 0, &pLeaf->pParent);
    }else{
      rc = SQLITE_ERROR;
    }
    sqlite3_reset(pRtree->pReadParent);
    if( rc==SQLITE_OK ){
      rc = fixLeafParent(pRtree, pLeaf->pParent);
    }
  }
  return rc;
}

static int deleteCell(Rtree *, RtreeNode *, int, int);

static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
  int rc;
  RtreeNode *pParent;
  int iCell;

  assert( pNode->nRef==1 );

  /* Remove the entry in the parent cell. */
  iCell = nodeParentIndex(pRtree, pNode);
  pParent = pNode->pParent;
  pNode->pParent = 0;
  if( SQLITE_OK!=(rc = deleteCell(pRtree, pParent, iCell, iHeight+1)) 
   || SQLITE_OK!=(rc = nodeRelease(pRtree, pParent))
  ){
    return rc;
  }

  /* Remove the xxx_node entry. */
  sqlite3_bind_int64(pRtree->pDeleteNode, 1, pNode->iNode);
  sqlite3_step(pRtree->pDeleteNode);
  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteNode)) ){
    return rc;
  }

  /* Remove the xxx_parent entry. */
  sqlite3_bind_int64(pRtree->pDeleteParent, 1, pNode->iNode);
  sqlite3_step(pRtree->pDeleteParent);
  if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteParent)) ){
    return rc;
  }
  
  /* Remove the node from the in-memory hash table and link it into
  ** the Rtree.pDeleted list. Its contents will be re-inserted later on.
  */
  nodeHashDelete(pRtree, pNode);
  pNode->iNode = iHeight;
  pNode->pNext = pRtree->pDeleted;
  pNode->nRef++;
  pRtree->pDeleted = pNode;

  return SQLITE_OK;
}

static void fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
  RtreeNode *pParent = pNode->pParent;
  if( pParent ){
    int ii; 
    int nCell = NCELL(pNode);
    RtreeCell box;                            /* Bounding box for pNode */
    nodeGetCell(pRtree, pNode, 0, &box);
    for(ii=1; ii<nCell; ii++){
      RtreeCell cell;
      nodeGetCell(pRtree, pNode, ii, &cell);
      cellUnion(pRtree, &box, &cell);
    }
    box.iRowid = pNode->iNode;
    ii = nodeParentIndex(pRtree, pNode);
    nodeOverwriteCell(pRtree, pParent, &box, ii);
    fixBoundingBox(pRtree, pParent);
  }
}

/*
** Delete the cell at index iCell of node pNode. After removing the
** cell, adjust the r-tree data structure if required.
*/
static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
  int rc;

  if( SQLITE_OK!=(rc = fixLeafParent(pRtree, pNode)) ){
    return rc;
  }

  /* Remove the cell from the node. This call just moves bytes around
  ** the in-memory node image, so it cannot fail.
  */
  nodeDeleteCell(pRtree, pNode, iCell);

  /* If the node is not the tree root and now has less than the minimum
  ** number of cells, remove it from the tree. Otherwise, update the
  ** cell in the parent node so that it tightly contains the updated
  ** node.
  */
  if( pNode->iNode!=1 ){
    RtreeNode *pParent = pNode->pParent;
    if( (pParent->iNode!=1 || NCELL(pParent)!=1) 
     && (NCELL(pNode)<RTREE_MINCELLS(pRtree))
    ){
      rc = removeNode(pRtree, pNode, iHeight);
    }else{
      fixBoundingBox(pRtree, pNode);
    }
  }

  return rc;
}

static int Reinsert(
  Rtree *pRtree, 
  RtreeNode *pNode, 
  RtreeCell *pCell, 
  int iHeight
){
  int *aOrder;
  int *aSpare;
  RtreeCell *aCell;
  float *aDistance;
  int nCell;
  float aCenterCoord[RTREE_MAX_DIMENSIONS];
  int iDim;
  int ii;
  int rc = SQLITE_OK;

  memset(aCenterCoord, 0, sizeof(float)*RTREE_MAX_DIMENSIONS);

  nCell = NCELL(pNode)+1;

  /* Allocate the buffers used by this operation. The allocation is
  ** relinquished before this function returns.
  */
  aCell = (RtreeCell *)sqlite3_malloc(nCell * (
    sizeof(RtreeCell) +         /* aCell array */
    sizeof(int)       +         /* aOrder array */
    sizeof(int)       +         /* aSpare array */
    sizeof(float)               /* aDistance array */
  ));
  if( !aCell ){
    return SQLITE_NOMEM;
  }
  aOrder    = (int *)&aCell[nCell];
  aSpare    = (int *)&aOrder[nCell];
  aDistance = (float *)&aSpare[nCell];

  for(ii=0; ii<nCell; ii++){
    if( ii==(nCell-1) ){
      memcpy(&aCell[ii], pCell, sizeof(RtreeCell));
    }else{
      nodeGetCell(pRtree, pNode, ii, &aCell[ii]);
    }
    aOrder[ii] = ii;
    for(iDim=0; iDim<pRtree->nDim; iDim++){
      aCenterCoord[iDim] += DCOORD(aCell[ii].aCoord[iDim*2]);
      aCenterCoord[iDim] += DCOORD(aCell[ii].aCoord[iDim*2+1]);
    }
  }
  for(iDim=0; iDim<pRtree->nDim; iDim++){
    aCenterCoord[iDim] = aCenterCoord[iDim]/((float)nCell*2.0);
  }

  for(ii=0; ii<nCell; ii++){
    aDistance[ii] = 0.0;
    for(iDim=0; iDim<pRtree->nDim; iDim++){
      float coord = DCOORD(aCell[ii].aCoord[iDim*2+1]) - 
          DCOORD(aCell[ii].aCoord[iDim*2]);
      aDistance[ii] += (coord-aCenterCoord[iDim])*(coord-aCenterCoord[iDim]);
    }
  }

  SortByDistance(aOrder, nCell, aDistance, aSpare);
  nodeZero(pRtree, pNode);

  for(ii=0; rc==SQLITE_OK && ii<(nCell-(RTREE_MINCELLS(pRtree)+1)); ii++){
    RtreeCell *p = &aCell[aOrder[ii]];
    nodeInsertCell(pRtree, pNode, p);
    if( p->iRowid==pCell->iRowid ){
      if( iHeight==0 ){
        rc = rowidWrite(pRtree, p->iRowid, pNode->iNode);
      }else{
        rc = parentWrite(pRtree, p->iRowid, pNode->iNode);
      }
    }
  }
  if( rc==SQLITE_OK ){
    fixBoundingBox(pRtree, pNode);
  }
  for(; rc==SQLITE_OK && ii<nCell; ii++){
    /* Find a node to store this cell in. pNode->iNode currently contains
    ** the height of the sub-tree headed by the cell.
    */
    RtreeNode *pInsert;
    RtreeCell *p = &aCell[aOrder[ii]];
    rc = ChooseLeaf(pRtree, p, iHeight, &pInsert);
    if( rc==SQLITE_OK ){
      int rc2;
      rc = rtreeInsertCell(pRtree, pInsert, p, iHeight);
      rc2 = nodeRelease(pRtree, pInsert);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }
  }

  sqlite3_free(aCell);
  return rc;
}

/*
** Insert cell pCell into node pNode. Node pNode is the head of a 
** subtree iHeight high (leaf nodes have iHeight==0).
*/
static int rtreeInsertCell(
  Rtree *pRtree,
  RtreeNode *pNode,
  RtreeCell *pCell,
  int iHeight
){
  int rc = SQLITE_OK;
  if( iHeight>0 ){
    RtreeNode *pChild = nodeHashLookup(pRtree, pCell->iRowid);
    if( pChild ){
      nodeRelease(pRtree, pChild->pParent);
      nodeReference(pNode);
      pChild->pParent = pNode;
    }
  }
  if( nodeInsertCell(pRtree, pNode, pCell) ){
#if VARIANT_RSTARTREE_REINSERT
    if( iHeight<=pRtree->iReinsertHeight || pNode->iNode==1){
      rc = SplitNode(pRtree, pNode, pCell, iHeight);
    }else{
      pRtree->iReinsertHeight = iHeight;
      rc = Reinsert(pRtree, pNode, pCell, iHeight);
    }
#else
    rc = SplitNode(pRtree, pNode, pCell, iHeight);
#endif
  }else{
    AdjustTree(pRtree, pNode, pCell);
    if( iHeight==0 ){
      rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
    }else{
      rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
    }
  }
  return rc;
}

static int reinsertNodeContent(Rtree *pRtree, RtreeNode *pNode){
  int ii;
  int rc = SQLITE_OK;
  int nCell = NCELL(pNode);

  for(ii=0; rc==SQLITE_OK && ii<nCell; ii++){
    RtreeNode *pInsert;
    RtreeCell cell;
    nodeGetCell(pRtree, pNode, ii, &cell);

    /* Find a node to store this cell in. pNode->iNode currently contains
    ** the height of the sub-tree headed by the cell.
    */
    rc = ChooseLeaf(pRtree, &cell, pNode->iNode, &pInsert);
    if( rc==SQLITE_OK ){
      int rc2;
      rc = rtreeInsertCell(pRtree, pInsert, &cell, pNode->iNode);
      rc2 = nodeRelease(pRtree, pInsert);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }
  }
  return rc;
}

/*
** Select a currently unused rowid for a new r-tree record.
*/
static int newRowid(Rtree *pRtree, i64 *piRowid){
  int rc;
  sqlite3_bind_null(pRtree->pWriteRowid, 1);
  sqlite3_bind_null(pRtree->pWriteRowid, 2);
  sqlite3_step(pRtree->pWriteRowid);
  rc = sqlite3_reset(pRtree->pWriteRowid);
  *piRowid = sqlite3_last_insert_rowid(pRtree->db);
  return rc;
}

#ifndef NDEBUG
static int hashIsEmpty(Rtree *pRtree){
  int ii;
  for(ii=0; ii<HASHSIZE; ii++){
    assert( !pRtree->aHash[ii] );
  }
  return 1;
}
#endif

/*
** The xUpdate method for rtree module virtual tables.
*/
int rtreeUpdate(
  sqlite3_vtab *pVtab, 
  int nData, 
  sqlite3_value **azData, 
  sqlite_int64 *pRowid
){
  Rtree *pRtree = (Rtree *)pVtab;
  int rc = SQLITE_OK;

  rtreeReference(pRtree);

  assert(nData>=1);
  assert(hashIsEmpty(pRtree));

  /* If azData[0] is not an SQL NULL value, it is the rowid of a
  ** record to delete from the r-tree table. The following block does
  ** just that.
  */
  if( sqlite3_value_type(azData[0])!=SQLITE_NULL ){
    i64 iDelete;                /* The rowid to delete */
    RtreeNode *pLeaf;           /* Leaf node containing record iDelete */
    int iCell;                  /* Index of iDelete cell in pLeaf */
    RtreeNode *pRoot;

    /* Obtain a reference to the root node to initialise Rtree.iDepth */
    rc = nodeAcquire(pRtree, 1, 0, &pRoot);

    /* Obtain a reference to the leaf node that contains the entry 
    ** about to be deleted. 
    */
    if( rc==SQLITE_OK ){
      iDelete = sqlite3_value_int64(azData[0]);
      rc = findLeafNode(pRtree, iDelete, &pLeaf);
    }

    /* Delete the cell in question from the leaf node. */
    if( rc==SQLITE_OK ){
      int rc2;
      iCell = nodeRowidIndex(pRtree, pLeaf, iDelete);
      rc = deleteCell(pRtree, pLeaf, iCell, 0);
      rc2 = nodeRelease(pRtree, pLeaf);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }

    /* Delete the corresponding entry in the <rtree>_rowid table. */
    if( rc==SQLITE_OK ){
      sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
      sqlite3_step(pRtree->pDeleteRowid);
      rc = sqlite3_reset(pRtree->pDeleteRowid);
    }

    /* Check if the root node now has exactly one child. If so, remove
    ** it, schedule the contents of the child for reinsertion and 
    ** reduce the tree height by one.
    **
    ** This is equivalent to copying the contents of the child into
    ** the root node (the operation that Gutman's paper says to perform 
    ** in this scenario).
    */
    if( rc==SQLITE_OK && pRtree->iDepth>0 ){
      if( rc==SQLITE_OK && NCELL(pRoot)==1 ){
        RtreeNode *pChild;
        i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
        rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);
        if( rc==SQLITE_OK ){
          rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
        }
        if( rc==SQLITE_OK ){
          pRtree->iDepth--;
          writeInt16(pRoot->zData, pRtree->iDepth);
          pRoot->isDirty = 1;
        }
      }
    }

    /* Re-insert the contents of any underfull nodes removed from the tree. */
    for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
      if( rc==SQLITE_OK ){
        rc = reinsertNodeContent(pRtree, pLeaf);
      }
      pRtree->pDeleted = pLeaf->pNext;
      sqlite3_free(pLeaf);
    }

    /* Release the reference to the root node. */
    if( rc==SQLITE_OK ){
      rc = nodeRelease(pRtree, pRoot);
    }else{
      nodeRelease(pRtree, pRoot);
    }
  }

  /* If the azData[] array contains more than one element, elements
  ** (azData[2]..azData[argc-1]) contain a new record to insert into
  ** the r-tree structure.
  */
  if( rc==SQLITE_OK && nData>1 ){
    /* Insert a new record into the r-tree */
    RtreeCell cell;
    int ii;
    RtreeNode *pLeaf;

    /* Populate the cell.aCoord[] array. The first coordinate is azData[3]. */
    assert( nData==(pRtree->nDim*2 + 3) );
    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
      for(ii=0; ii<(pRtree->nDim*2); ii+=2){
        cell.aCoord[ii].f = (float)sqlite3_value_double(azData[ii+3]);
        cell.aCoord[ii+1].f = (float)sqlite3_value_double(azData[ii+4]);
        if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
          rc = SQLITE_CONSTRAINT;
          goto constraint;
        }
      }
    }else{
      for(ii=0; ii<(pRtree->nDim*2); ii+=2){
        cell.