SQLite

#define RTREE_GT    0x45
#define RTREE_MATCH 0x46

/* 
** An rtree structure node.
*/
struct RtreeNode {
  RtreeNode *pParent;         /* Parent node */
  i64 iNode;                  /* The node number */
  int nRef;                   /* Number of references to this node */
  int isDirty;                /* True if the node needs to be written to disk */
  u8 *zData;                  /* Content of the node, as should be on disk */
  RtreeNode *pNext;           /* Next node in this hash collision chain */
};

/* Return the number of cells in a node  */
#define NCELL(pNode) readInt16(&(pNode)->zData[2])

/* 
** A single cell from a node, deserialized
*/
struct RtreeCell {
  i64 iRowid;                                 /* Node or entry ID */
  RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];  /* Bounding box coordinates */
};


/*





** This object becomes the sqlite3_user_data() for the SQL functions







** that are created by sqlite3_rtree_geometry_callback() and
** sqlite3_rtree_query_callback() and which appear on the right of MATCH




** operators in order to constrain a search.
**
** xGeom and xQueryFunc are the callback functions.  Exactly one of 
** xGeom and xQueryFunc fields is non-NULL, depending on whether the
** SQL function was created using sqlite3_rtree_geometry_callback() or

** sqlite3_rtree_query_callback().
** 
** This object is deleted automatically by the destructor mechanism in
** sqlite3_create_function_v2().
*/
struct RtreeGeomCallback {
  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
  int (*xQueryFunc)(sqlite3_rtree_query_info*);
  void (*xDestructor)(void*);
  void *pContext;
};


/*
** Value for the first field of every RtreeMatchArg object. The MATCH
** operator tests that the first field of a blob operand matches this
** value to avoid operating on invalid blobs (which could cause a segfault).
*/
#define RTREE_GEOMETRY_MAGIC 0x891245AB

/*
** An instance of this structure (in the form of a BLOB) is returned by
** the SQL functions that sqlite3_rtree_geometry_callback() and
** sqlite3_rtree_query_callback() create, and is read as the right-hand
** operand to the MATCH operator of an R-Tree.
*/
struct RtreeMatchArg {
  u32 magic;                  /* Always RTREE_GEOMETRY_MAGIC */
  RtreeGeomCallback cb;       /* Info about the callback functions */
  int nParam;                 /* Number of parameters to the SQL function */
  RtreeDValue aParam[1];      /* Values for parameters to the SQL function */
};

#ifndef MAX
# define MAX(x,y) ((x) < (y) ? (y) : (x))
#endif
#ifndef MIN
# define MIN(x,y) ((x) > (y) ? (y) : (x))
#endif

  if( p->magic!=RTREE_GEOMETRY_MAGIC 
   || nBlob!=(int)(sizeof(RtreeMatchArg) + (p->nParam-1)*sizeof(RtreeDValue))
  ){
    sqlite3_free(pGeom);
    return SQLITE_ERROR;
  }

  pGeom->pContext = p->cb.pContext;
  pGeom->nParam = p->nParam;
  pGeom->aParam = p->aParam;

  pCons->xGeom = p->cb.xGeom;
  pCons->pGeom = pGeom;
  return SQLITE_OK;
}

/* 
** Rtree virtual table module xFilter method.
*/

    rc = sqlite3_create_module_v2(db, "rtree_i32", &rtreeModule, c, 0);
  }

  return rc;
}

/*
** This routine deletes the RtreeGeomCallback object that was attached
** one of the SQL functions create by sqlite3_rtree_geometry_callback()
** or sqlite3_rtree_query_callback().  In other words, this routine is the
** destructor for an RtreeGeomCallback objecct.  This routine is called when
** the corresponding SQL function is deleted.
*/
static void rtreeFreeCallback(void *p){
  RtreeGeomCallback *pGeom = (RtreeGeomCallback*)p;
  if( pGeom->xDestructor ) pGeom->xDestructor(pGeom->pContext);
  sqlite3_free(p);
}

/*
** Each call to sqlite3_rtree_geometry_callback() or
** sqlite3_rtree_query_callback() creates an ordinary SQLite
** scalar function that is implemented by this routine.
**
** All this function does is construct an RtreeMatchArg object that
** contains the geometry-checking callback routines and a list of
** parameters to this function, then return that RtreeMatchArg object
** as a BLOB.
**
** The R-Tree MATCH operator will read the returned BLOB, deserialize
** the RtreeMatchArg object, and use the RtreeMatchArg object to figure
** out which elements of the R-Tree should be returned by the query.
*/
static void geomCallback(sqlite3_context *ctx, int nArg, sqlite3_value **aArg){
  RtreeGeomCallback *pGeomCtx = (RtreeGeomCallback *)sqlite3_user_data(ctx);
  RtreeMatchArg *pBlob;
  int nBlob;

  nBlob = sizeof(RtreeMatchArg) + (nArg-1)*sizeof(RtreeDValue);
  pBlob = (RtreeMatchArg *)sqlite3_malloc(nBlob);
  if( !pBlob ){
    sqlite3_result_error_nomem(ctx);
  }else{
    int i;
    pBlob->magic = RTREE_GEOMETRY_MAGIC;
    pBlob->cb = pGeomCtx[0];

    pBlob->nParam = nArg;
    for(i=0; i<nArg; i++){
#ifdef SQLITE_RTREE_INT_ONLY
      pBlob->aParam[i] = sqlite3_value_int64(aArg[i]);
#else
      pBlob->aParam[i] = sqlite3_value_double(aArg[i]);
#endif
    }
    sqlite3_result_blob(ctx, pBlob, nBlob, sqlite3_free);
  }
}

/*
** Register a new geometry function for use with the r-tree MATCH operator.
*/
int sqlite3_rtree_geometry_callback(
  sqlite3 *db,                  /* Register SQL function on this connection */
  const char *zGeom,            /* Name of the new SQL function */
  int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*), /* Callback */
  void *pContext                /* Extra data associated with the callback */
){
  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */

  /* Allocate and populate the context object. */
  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
  if( !pGeomCtx ) return SQLITE_NOMEM;
  pGeomCtx->xGeom = xGeom;
  pGeomCtx->xQueryFunc = 0;
  pGeomCtx->xDestructor = 0;
  pGeomCtx->pContext = pContext;



  return sqlite3_create_function_v2(db, zGeom, -1, SQLITE_ANY, 
      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
  );
}

/*
** Register a new 2nd-generation geometry function for use with the
** r-tree MATCH operator.
*/
int sqlite3_rtree_query_callback(
  sqlite3 *db,                 /* Register SQL function on this connection */
  const char *zQueryFunc,      /* Name of new SQL function */
  int (*xQueryFunc)(sqlite3_rtree_query_info*), /* Callback */
  void *pContext,              /* Extra data passed into the callback */
  void (*xDestructor)(void*)   /* Destructor for the extra data */
){
  RtreeGeomCallback *pGeomCtx;      /* Context object for new user-function */

  /* Allocate and populate the context object. */
  pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback));
  if( !pGeomCtx ) return SQLITE_NOMEM;
  pGeomCtx->xGeom = 0;
  pGeomCtx->xQueryFunc = xQueryFunc;
  pGeomCtx->xDestructor = xDestructor;
  pGeomCtx->pContext = pContext;



  return sqlite3_create_function_v2(db, zQueryFunc, -1, SQLITE_ANY, 
      (void *)pGeomCtx, geomCallback, 0, 0, rtreeFreeCallback
  );
}

#if !SQLITE_CORE
#ifdef _WIN32

/*
** Implementation of "circle" r-tree geometry callback.
*/
static int circle_geom(
  sqlite3_rtree_geometry *p,
  int nCoord, 



  sqlite3_rtree_dbl *aCoord,

  int *pRes
){
  int i;                          /* Iterator variable */
  Circle *pCircle;                /* Structure defining circular region */
  double xmin, xmax;              /* X dimensions of box being tested */
  double ymin, ymax;              /* X dimensions of box being tested */

  }

  /* The specified bounding box does not intersect the circular region. Set
  ** the output variable to zero and return SQLITE_OK. */
  *pRes = 0;
  return SQLITE_OK;
}

/*
** Implementation of "circle" r-tree geometry callback using the 
** 2nd-generation interface that allows scoring.
*/
static int circle_query_func(sqlite3_rtree_query_info *p){
  int i;                          /* Iterator variable */
  Circle *pCircle;                /* Structure defining circular region */
  double xmin, xmax;              /* X dimensions of box being tested */
  double ymin, ymax;              /* X dimensions of box being tested */
  int nWithin = 0;                /* Number of corners inside the circle */

  if( p->pUser==0 ){
    /* If pUser is still 0, then the parameter values have not been tested
    ** for correctness or stored into a Circle structure yet. Do this now. */

    /* This geometry callback is for use with a 2-dimensional r-tree table.
    ** Return an error if the table does not have exactly 2 dimensions. */
    if( p->nCoord!=4 ) return SQLITE_ERROR;

    /* Test that the correct number of parameters (3) have been supplied,
    ** and that the parameters are in range (that the radius of the circle 
    ** radius is greater than zero). */
    if( p->nParam!=3 || p->aParam[2]<0.0 ) return SQLITE_ERROR;

    /* Allocate a structure to cache parameter data in. Return SQLITE_NOMEM
    ** if the allocation fails. */
    pCircle = (Circle *)(p->pUser = sqlite3_malloc(sizeof(Circle)));
    if( !pCircle ) return SQLITE_NOMEM;
    p->xDelUser = circle_del;

    /* Record the center and radius of the circular region. One way that
    ** tested bounding boxes that intersect the circular region are detected
    ** is by testing if each corner of the bounding box lies within radius
    ** units of the center of the circle. */
    pCircle->centerx = p->aParam[0];
    pCircle->centery = p->aParam[1];
    pCircle->radius = p->aParam[2];

    /* Define two bounding box regions. The first, aBox[0], extends to
    ** infinity in the X dimension. It covers the same range of the Y dimension
    ** as the circular region. The second, aBox[1], extends to infinity in
    ** the Y dimension and is constrained to the range of the circle in the
    ** X dimension.
    **
    ** Then imagine each box is split in half along its short axis by a line
    ** that intersects the center of the circular region. A bounding box
    ** being tested can be said to intersect the circular region if it contains
    ** points from each half of either of the two infinite bounding boxes.
    */
    pCircle->aBox[0].xmin = pCircle->centerx;
    pCircle->aBox[0].xmax = pCircle->centerx;
    pCircle->aBox[0].ymin = pCircle->centery + pCircle->radius;
    pCircle->aBox[0].ymax = pCircle->centery - pCircle->radius;
    pCircle->aBox[1].xmin = pCircle->centerx + pCircle->radius;
    pCircle->aBox[1].xmax = pCircle->centerx - pCircle->radius;
    pCircle->aBox[1].ymin = pCircle->centery;
    pCircle->aBox[1].ymax = pCircle->centery;
  }

  pCircle = (Circle *)p->pUser;
  xmin = p->aCoord[0];
  xmax = p->aCoord[1];
  ymin = p->aCoord[2];
  ymax = p->aCoord[3];

  /* Check if any of the 4 corners of the bounding-box being tested lie 
  ** inside the circular region. If they do, then the bounding-box does
  ** intersect the region of interest. Set the output variable to true and
  ** return SQLITE_OK in this case. */
  for(i=0; i<4; i++){
    double x = (i&0x01) ? xmax : xmin;
    double y = (i&0x02) ? ymax : ymin;
    double d2;
    
    d2  = (x-pCircle->centerx)*(x-pCircle->centerx);
    d2 += (y-pCircle->centery)*(y-pCircle->centery);
    if( d2<(pCircle->radius*pCircle->radius) ) nWithin++;
  }

  /* Check if the bounding box covers any other part of the circular region.
  ** See comments above for a description of how this test works. If it does
  ** cover part of the circular region, set the output variable to true
  ** and return SQLITE_OK. */
  if( nWithin==0 ){
    for(i=0; i<2; i++){
      if( xmin<=pCircle->aBox[i].xmin 
       && xmax>=pCircle->aBox[i].xmax 
       && ymin<=pCircle->aBox[i].ymin 
       && ymax>=pCircle->aBox[i].ymax 
      ){
        nWithin = 1;
        break;
      }
    }
  }

  p->rScore = p->iLevel;
  if( nWithin==0 ){
    p->eWithin = NOT_WITHIN;
  }else if( nWithin>=4 ){
    p->eWithin = FULLY_WITHIN;
  }else{
    p->eWithin = PARTLY_WITHIN;
  }
  return SQLITE_OK;
}

/* END of implementation of "circle" geometry callback.
**************************************************************************
*************************************************************************/

#include <assert.h>
#include "tcl.h"

**   cube(x, y, z, width, height, depth)
**
** The width, height and depth parameters must all be greater than zero.
*/
static int cube_geom(
  sqlite3_rtree_geometry *p,
  int nCoord,



  sqlite3_rtree_dbl *aCoord,

  int *piRes
){
  Cube *pCube = (Cube *)p->pUser;

  assert( p->pContext==(void *)&gHere );

  if( pCube==0 ){

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  rc = sqlite3_rtree_geometry_callback(db, "circle", circle_geom, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_rtree_query_callback(db, "Qcircle",
                                      circle_query_func, 0, 0);
  }
  Tcl_SetResult(interp, (char *)sqlite3ErrName(rc), TCL_STATIC);
#endif
  return TCL_OK;
}

int Sqlitetestrtree_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "register_cube_geom", register_cube_geom, 0, 0);
  Tcl_CreateObjCommand(interp, "register_circle_geom",register_circle_geom,0,0);
  return TCL_OK;
}