circ_tree_new()

CIRC_NODE * circ_tree_new

(

const POINTARRAY *

pa

)

Build a tree of nodes from a point array, one node per edge.

Definition at line 354 of file lwgeodetic_tree.c.

{
        int num_edges;
        int i, j;
        CIRC_NODE **nodes;
        CIRC_NODE *node;
        CIRC_NODE *tree;
 
        /* Can't do anything with no points */
        if ( pa->npoints < 1 )
                return NULL;
 
        /* Special handling for a single point */
        if ( pa->npoints == 1 )
                return circ_node_leaf_point_new(pa);
 
        /* First create a flat list of nodes, one per edge. */
        num_edges = pa->npoints - 1;
        nodes = lwalloc(sizeof(CIRC_NODE*) * pa->npoints);
        j = 0;
        for ( i = 0; i < num_edges; i++ )
        {
                node = circ_node_leaf_new(pa, i);
                if ( node ) /* Not zero length? */
                        nodes[j++] = node;
        }
 
        /* Special case: only zero-length edges. Make a point node. */
        if ( j == 0 ) {
                lwfree(nodes);
                return circ_node_leaf_point_new(pa);
        }
 
        /* Merge the node list pairwise up into a tree */
        tree = circ_nodes_merge(nodes, j);
 
        /* Free the old list structure, leaving the tree in place */
        lwfree(nodes);
 
        return tree;
}

References circ_node_leaf_new(), circ_node_leaf_point_new(), circ_nodes_merge(), lwalloc(), lwfree(), and POINTARRAY::npoints.

Referenced by lwline_calculate_circ_tree(), lwpoint_calculate_circ_tree(), lwpoly_calculate_circ_tree(), test_tree_circ_create(), test_tree_circ_pip(), and test_tree_circ_pip2().

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