From ebc424f290348d56fbd53c06438d18c69d55e120 Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Tue, 2 Mar 2010 21:32:09 +0000
Subject: [PATCH] ST_MakeValid : turn collapsed lines into points [RT-SIGTA]

git-svn-id: http://svn.osgeo.org/postgis/trunk@5363 b70326c6-7e19-0410-871a-916f4a2858ee
---
 postgis/lwgeom_geos_clean.c | 102 +++++++++++++++++++++++++++++++++++-
 regress/clean.sql           |   3 +-
 regress/clean_expected      |   1 +
 3 files changed, 102 insertions(+), 4 deletions(-)

diff --git a/postgis/lwgeom_geos_clean.c b/postgis/lwgeom_geos_clean.c
index 998a36157..2c8a613f2 100644
--- a/postgis/lwgeom_geos_clean.c
+++ b/postgis/lwgeom_geos_clean.c
@@ -581,6 +581,95 @@ LWGEOM_GEOS_makeValidLine(const GEOSGeometry* gin)
 	return noded;
 }
 
+static GEOSGeometry*
+LWGEOM_GEOS_makeValidMultiLine(const GEOSGeometry* gin)
+{
+	GEOSGeometry** lines;
+	GEOSGeometry** points;
+	GEOSGeometry* mline_out=0;
+	GEOSGeometry* mpoint_out=0;
+	GEOSGeometry* gout;
+	unsigned int nlines;
+	unsigned int npoints=0;
+	unsigned int ngeoms=0;
+	unsigned int i;
+
+	ngeoms = GEOSGetNumGeometries(gin);
+
+	lines = lwalloc(sizeof(GEOSGeometry*)*ngeoms);
+	points = lwalloc(sizeof(GEOSGeometry*)*ngeoms);
+
+	for (i=0; i<ngeoms; ++i)
+	{
+		const GEOSGeometry* g = GEOSGetGeometryN(gin, i);
+		GEOSGeometry* vg;
+		vg = LWGEOM_GEOS_makeValidLine(g);
+		if ( GEOSisEmpty(vg) ) {
+			/* we don't care about this one */
+			GEOSGeom_destroy(vg);
+		}
+		if ( GEOSGeomTypeId(vg) == GEOS_POINT )
+		{
+			points[npoints++] = vg;
+		}
+		else if ( GEOSGeomTypeId(vg) == GEOS_LINESTRING )
+		{
+			lines[nlines++] = vg;
+		}
+		else
+		{
+			/* NOTE: return from GEOSGeomType will leak
+			 * but we really don't expect this to happen */
+			lwerror("unexpected geom type returned "
+				"by LWGEOM_GEOS_makeValid: %s",
+				GEOSGeomType(vg));
+		}
+	}
+
+	if ( npoints )
+	{
+		if ( npoints > 1 ) {
+			mpoint_out = GEOSGeom_createCollection(GEOS_MULTIPOINT,
+				points, npoints);
+		} else {
+			mpoint_out = points[0];
+		}
+	}
+
+	if ( nlines )
+	{
+		if ( nlines > 1 ) {
+			mline_out = GEOSGeom_createCollection(
+				GEOS_MULTILINESTRING, lines, nlines);
+		} else {
+			mline_out = lines[0];
+		}
+	}
+
+	lwfree(lines);
+
+	if ( mline_out && mpoint_out )
+	{
+		points[0] = mline_out;
+		points[1] = mpoint_out;
+		gout = GEOSGeom_createCollection(GEOS_GEOMETRYCOLLECTION,
+			points, 2);
+	}
+	else if ( mline_out )
+	{
+		gout = mline_out;
+	}
+	else if ( mpoint_out )
+	{
+		gout = mpoint_out;
+	}
+
+	lwfree(points);
+
+	return gout;
+}
+
+
 static GEOSGeometry*
 LWGEOM_GEOS_makeValid(const GEOSGeometry* gin)
 {
@@ -631,7 +720,6 @@ LWGEOM_GEOS_makeValid(const GEOSGeometry* gin)
 		break;
 
 	case GEOS_LINESTRING:
-	case GEOS_MULTILINESTRING:
 		gout = LWGEOM_GEOS_makeValidLine(gin);
 		if ( ! gout )  /* an exception or something */
 		{
@@ -640,7 +728,16 @@ LWGEOM_GEOS_makeValid(const GEOSGeometry* gin)
 			return NULL;
 		}
 		break; /* we've done */
-		break;
+
+	case GEOS_MULTILINESTRING:
+		gout = LWGEOM_GEOS_makeValidMultiLine(gin);
+		if ( ! gout )  /* an exception or something */
+		{
+			/* cleanup and throw */
+			lwerror("%s", loggederror);
+			return NULL;
+		}
+		break; /* we've done */
 
 	case GEOS_POLYGON:
 	case GEOS_MULTIPOLYGON:
@@ -764,6 +861,7 @@ lwgeom_make_valid(LWGEOM* lwgeom_in)
 	if ( lwgeom_is_collection(TYPE_GETTYPE(lwgeom_in->type))
 		&& ! lwgeom_is_collection(TYPE_GETTYPE(lwgeom_out->type)) )
 	{
+		POSTGIS_DEBUG(3, "lwgeom_make_valid: forcing multi");
 		lwgeom_out = lwgeom_as_multi(lwgeom_out);
 	}
 
diff --git a/regress/clean.sql b/regress/clean.sql
index d4cd1bd14..83b301c92 100644
--- a/regress/clean.sql
+++ b/regress/clean.sql
@@ -27,12 +27,11 @@ RT	16.4	010600000002000000010300000001000000080000000000000000C05040000000000000
 RT	17.1	010300000003000000050000000000000000004E4000000000000014C0000000000000544000000000000014C0000000000000544000000000000034400000000000004E4000000000000034400000000000004E4000000000000014C0050000000000000000804B4000000000000000000000000000805140000000000000000000000000008051400000000000002E400000000000804B400000000000002E400000000000804B40000000000000000005000000000000000040504000000000000014400000000000C0524000000000000014400000000000C0524000000000000024400000000000405040000000000000244000000000004050400000000000001440	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
 PG	1	0103000000010000000100000000000000000000000000000000000000	POINT(0 0)
 PG	2	LINESTRING(0 0, 0 0)	POINT(0 0)
+PG	3	MULTILINESTRING((0 0, 10 0),(20 20, 20 20))	GEOMETRYCOLLECTION(LINESTRING(0 0, 10 0),POINT(20 20))
 \.
 
 -- PG.1 : polygon with single ring with single point in it
 --        to be converted to a POINT
--- PG.2 : linestring composed by two equal points to be converted
---        to a point
 --
 
 SELECT origin,caseno,
diff --git a/regress/clean_expected b/regress/clean_expected
index e73e7ce88..ba94b8c87 100644
--- a/regress/clean_expected
+++ b/regress/clean_expected
@@ -23,3 +23,4 @@ RT|16.4|t|t|f
 RT|17.1|t|t|f
 PG|1|t|t|f
 PG|2|t|t|f
+PG|3|t|t|f
-- 
2.40.0