RTreeBuilder()

static int RTreeBuilder ( const LWGEOM *  lwgeom, GeomCache *  cache  )

static

Callback function sent into the GetGeomCache generic caching system.

Given a LWGEOM* this function builds and stores an RTREE_POLY_CACHE into the provided GeomCache object.

Definition at line 316 of file lwgeom_rtree.c.

{
        uint32_t i, p, r;
        LWMPOLY *mpoly;
        LWPOLY *poly;
        int nrings;
        RTreeGeomCache* rtree_cache = (RTreeGeomCache*)cache;
        RTREE_POLY_CACHE* currentCache;
 
        if ( ! cache )
                return LW_FAILURE;
 
        if ( rtree_cache->index )
        {
                lwpgerror("RTreeBuilder asked to build index where one already exists.");
                return LW_FAILURE;
        }
 
        if (lwgeom->type == MULTIPOLYGONTYPE)
        {
                POSTGIS_DEBUG(2, "RTreeBuilder MULTIPOLYGON");
                mpoly = (LWMPOLY *)lwgeom;
                nrings = 0;
                /*
                ** Count the total number of rings.
                */
                currentCache = RTreeCacheCreate();
                currentCache->polyCount = mpoly->ngeoms;
                currentCache->ringCounts = lwalloc(sizeof(int) * mpoly->ngeoms);
                for ( i = 0; i < mpoly->ngeoms; i++ )
                {
                        currentCache->ringCounts[i] = mpoly->geoms[i]->nrings;
                        nrings += mpoly->geoms[i]->nrings;
                }
                currentCache->ringIndices = lwalloc(sizeof(RTREE_NODE *) * nrings);
                /*
                ** Load the array in geometry order, each outer ring followed by the inner rings
                ** associated with that outer ring
                */
                i = 0;
                for ( p = 0; p < mpoly->ngeoms; p++ )
                {
                        for ( r = 0; r < mpoly->geoms[p]->nrings; r++ )
                        {
                                currentCache->ringIndices[i] = RTreeCreate(mpoly->geoms[p]->rings[r]);
                                i++;
                        }
                }
                rtree_cache->index = currentCache;
        }
        else if ( lwgeom->type == POLYGONTYPE )
        {
                POSTGIS_DEBUG(2, "RTreeBuilder POLYGON");
                poly = (LWPOLY *)lwgeom;
                currentCache = RTreeCacheCreate();
                currentCache->polyCount = 1;
                currentCache->ringCounts = lwalloc(sizeof(int));
                currentCache->ringCounts[0] = poly->nrings;
                /*
                ** Just load the rings on in order
                */
                currentCache->ringIndices = lwalloc(sizeof(RTREE_NODE *) * poly->nrings);
                for ( i = 0; i < poly->nrings; i++ )
                {
                        currentCache->ringIndices[i] = RTreeCreate(poly->rings[i]);
                }
                rtree_cache->index = currentCache;
        }
        else
        {
                /* Uh oh, shouldn't be here. */
                lwpgerror("RTreeBuilder got asked to build index on non-polygon");
                return LW_FAILURE;
        }
        return LW_SUCCESS;
}

References LWMPOLY::geoms, RTreeGeomCache::index, LW_FAILURE, LW_SUCCESS, lwalloc(), MULTIPOLYGONTYPE, LWMPOLY::ngeoms, LWPOLY::nrings, RTREE_POLY_CACHE::polyCount, POLYGONTYPE, r, RTREE_POLY_CACHE::ringCounts, RTREE_POLY_CACHE::ringIndices, LWPOLY::rings, RTreeCacheCreate(), RTreeCreate(), and LWGEOM::type.

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