[postgis-tickets] r16501 - ST_CPAWithin precision fix

[Darafei]

Author: komzpa
Date: 2018-03-27 10:38:18 -0700 (Tue, 27 Mar 2018)
New Revision: 16501

Modified:
   branches/2.3/NEWS
   branches/2.3/liblwgeom/lwlinearreferencing.c
Log:
ST_CPAWithin precision fix

Closes #4032


Modified: branches/2.3/NEWS
===================================================================
--- branches/2.3/NEWS	2018-03-27 17:36:47 UTC (rev 16500)
+++ branches/2.3/NEWS	2018-03-27 17:38:18 UTC (rev 16501)
@@ -7,7 +7,8 @@
   - #4003, lwpoly_construct_circle: Avoid division by zero (Raúl Marín Rodríguez)
   - #4020, Casting from box3d to geometry now returns correctly connected
            PolyhedralSurface (Matthias Bay)
-  - #4025, Incorrect answers for temporally "amost overlapping" ranges
+  - #4025, #4032 Incorrect answers for temporally "almost overlapping" ranges
+           (Paul Ramsey, Darafei Praliaskouski)
   - #4017, lwgeom lexer memory corruption (Peter E)
   - #4052, schema qualify several functions in geography
 

Modified: branches/2.3/liblwgeom/lwlinearreferencing.c
===================================================================
--- branches/2.3/liblwgeom/lwlinearreferencing.c	2018-03-27 17:36:47 UTC (rev 16500)
+++ branches/2.3/liblwgeom/lwlinearreferencing.c	2018-03-27 17:38:18 UTC (rev 16501)
@@ -23,7 +23,6 @@
  *
  **********************************************************************/
 
-
 #include "liblwgeom_internal.h"
 #include "lwgeom_log.h"
 #include "measures3d.h"
@@ -1239,7 +1238,7 @@
 {
 	LWLINE *l1, *l2;
 	int i;
-	const GBOX *gbox1, *gbox2;
+	GBOX gbox1, gbox2;
 	double tmin, tmax;
 	double *mvals;
 	int nmvals = 0;
@@ -1268,20 +1267,19 @@
 		return LW_FALSE;
 	}
 
-	/* WARNING: these ranges may be wider than real ones */
-	gbox1 = lwgeom_get_bbox(g1);
-	gbox2 = lwgeom_get_bbox(g2);
+	/* We use lwgeom_calculate_gbox() instead of lwgeom_get_gbox() */
+ 	/* because we cannot afford the float rounding inaccuracy when */
+ 	/* we compare the ranges for overlap below */
+ 	lwgeom_calculate_gbox(g1, &gbox1);
+ 	lwgeom_calculate_gbox(g2, &gbox2);
 
-	assert(gbox1); /* or the npoints check above would have failed */
-	assert(gbox2); /* or the npoints check above would have failed */
-
 	/*
 	 * Find overlapping M range
 	 * WARNING: may be larger than the real one
 	 */
 
-	tmin = FP_MAX(gbox1->mmin, gbox2->mmin);
-	tmax = FP_MIN(gbox1->mmax, gbox2->mmax);
+	tmin = FP_MAX(gbox1.mmin, gbox2.mmin);
+	tmax = FP_MIN(gbox1.mmax, gbox2.mmax);
 
 	if ( tmax < tmin )
 	{
@@ -1289,8 +1287,6 @@
 		return LW_FALSE;
 	}
 
-	// lwnotice("Min:%g, Max:%g", tmin, tmax);
-
 	/*
 	 * Collect M values in common time range from inputs
 	 */