Make geographic point initialization slightly more efficient (avoid doing it twice...

git-svn-id: http://svn.osgeo.org/postgis/trunk@4629 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/liblwgeom/lwgeodetic.c b/liblwgeom/lwgeodetic.c
index d5fe5f5bc944be8010734e40aa2ada45fe9b1864..a0f60575b0a3c420f435ae392f651ce5c2e9a99e 100644 (file)
--- a/liblwgeom/lwgeodetic.c
+++ b/liblwgeom/lwgeodetic.c
@@ -1307,13 +1307,17 @@ double ptarray_area_sphere(POINTARRAY *pa, POINT2D pt_outside)
        
        geographic_point_init(pt_outside.x, pt_outside.y, &c);
 
+       /* Initialize first point */
+       getPoint2d_p(pa, 0, &p);
+       geographic_point_init(p.x, p.y, &a);
+
        for( i = 1; i < pa->npoints; i++ )
        {
-               getPoint2d_p(pa, i-1, &p);
-               geographic_point_init(p.x, p.y, &a);
                getPoint2d_p(pa, i, &p);
                geographic_point_init(p.x, p.y, &b);
                area += sphere_excess(a, b, c);
+               /* B gets incremented in the next loop, so we save the value here */
+               a = b;
        }
        return fabs(area);
 }
@@ -1426,12 +1430,14 @@ static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double t
                getPoint2d_p(pa_one, 0, &p);
                geographic_point_init(p.x, p.y, &g1);
 
+               /* Initialize start of line */
+               getPoint2d_p(pa_many, 0, &p);
+               geographic_point_init(p.x, p.y, &(e1.start));
+
                /* Iterate through the edges in our line */
                for( i = 1; i < pa_many->npoints; i++ )
                {
                        double d;
-                       getPoint2d_p(pa_many, i - 1, &p);
-                       geographic_point_init(p.x, p.y, &(e1.start));
                        getPoint2d_p(pa_many, i, &p);
                        geographic_point_init(p.x, p.y, &(e1.end));
                        d = edge_distance_to_point(e1, g1, 0);
@@ -1439,25 +1445,31 @@ static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double t
                                distance = d;
                        if( d < tolerance ) 
                                return distance;
+                       e1.start = e1.end;
                }
                return distance;                        
        }
+
+       /* Initialize start of line 1 */
+       getPoint2d_p(pa1, 0, &p);
+       geographic_point_init(p.x, p.y, &(e1.start));
+
        
        /* Handle line/line case */
        for( i = 1; i < pa1->npoints; i++ )
        {
-               getPoint2d_p(pa1, i - 1, &p);
-               geographic_point_init(p.x, p.y, &(e1.start));
                getPoint2d_p(pa1, i, &p);
                geographic_point_init(p.x, p.y, &(e1.end));
 
+               /* Initialize start of line 2 */
+               getPoint2d_p(pa2, 0, &p);
+               geographic_point_init(p.x, p.y, &(e2.start));
+
                for( j = 1; j < pa2->npoints; j++ )
                {
                        double d;
                        GEOGRAPHIC_POINT g;
 
-                       getPoint2d_p(pa2, j - 1, &p);
-                       geographic_point_init(p.x, p.y, &(e2.start));
                        getPoint2d_p(pa2, j, &p);
                        geographic_point_init(p.x, p.y, &(e2.end));
 
@@ -1473,11 +1485,19 @@ static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double t
                        }
                        d = edge_distance_to_edge(e1, e2, 0, 0);
                        LWDEBUGF(4,"got edge_distance_to_edge %.8g", d);
+                       
                        if( d < distance )
                                distance = d;
                        if( d < tolerance )
                                return distance;
+                               
+                       /* Copy end to start to allow a new end value in next iteration */
+                       e2.start = e2.end;
                }
+               
+               /* Copy end to start to allow a new end value in next iteration */
+               e1.start = e1.end;
+               
        }
        LWDEBUGF(4,"finished all loops, returning %.8g", distance);