From 3e181e60c94921a17635cdd6a23b8e30b5ebf5a3 Mon Sep 17 00:00:00 2001
From: David Blasby <dblasby@gmail.com>
Date: Wed, 18 Jul 2001 22:17:34 +0000
Subject: [PATCH] Added function: point_inside_circle(geometry, Px, Py, d)     
    - returns true if there is a point in geometry whose distance to 	
 (Px,Py) is < d

git-svn-id: http://svn.osgeo.org/postgis/trunk@18 b70326c6-7e19-0410-871a-916f4a2858ee
---
 postgis.h      |  2 ++
 postgis.sql.in |  6 ++++++
 postgis_fn.c   | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/postgis.h b/postgis.h
index 3d749f254..c034e77b9 100644
--- a/postgis.h
+++ b/postgis.h
@@ -371,6 +371,8 @@ Datum ellipsoid_in(PG_FUNCTION_ARGS);
 Datum length_ellipsoid(PG_FUNCTION_ARGS);
 Datum length3d_ellipsoid(PG_FUNCTION_ARGS);
 
+Datum point_inside_circle(PG_FUNCTION_ARGS);
+
 
 
 //for GIST index
diff --git a/postgis.sql.in b/postgis.sql.in
index ca3213f07..5b797d812 100644
--- a/postgis.sql.in
+++ b/postgis.sql.in
@@ -230,6 +230,12 @@ CREATE FUNCTION truly_inside(GEOMETRY,GEOMETRY)
    AS '@MODULE_FILENAME@'
    LANGUAGE 'c' with (isstrict);
 
+CREATE FUNCTION point_inside_circle(GEOMETRY,float8,float8,float8)
+   RETURNS bool
+   AS '@MODULE_FILENAME@'
+   LANGUAGE 'c' with (isstrict);
+
+
 ------- Aggregate
 
 CREATE FUNCTION combine_bbox(BOX3D,GEOMETRY)
diff --git a/postgis_fn.c b/postgis_fn.c
index 6e462f8f5..dbed0cc0c 100644
--- a/postgis_fn.c
+++ b/postgis_fn.c
@@ -1455,4 +1455,42 @@ Datum force_collection(PG_FUNCTION_ARGS)
 
 
 
+// point_inside_circle(geometry, Px, Py, d)
+// returns true if there is a point in geometry whose distance to (Px,Py) is < d
 
+PG_FUNCTION_INFO_V1(point_inside_circle);
+Datum point_inside_circle(PG_FUNCTION_ARGS)
+{
+
+	GEOMETRY		      *geom = (GEOMETRY *)  PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	char				*o;
+	int				type1,j;
+	int32				*offsets1;
+	POINT3D			*pt;
+	double			Px  = PG_GETARG_FLOAT8(1);
+	double			Py =  PG_GETARG_FLOAT8(2);
+	double			d =   PG_GETARG_FLOAT8(3);
+	double			dd = d*d; //d squared
+
+	offsets1 = (int32 *) ( ((char *) &(geom->objType[0] ))+ sizeof(int32) * geom->nobjs ) ;
+
+	//now have to do a scan of each object 
+
+	for (j=0; j< geom->nobjs; j++)		//for each object in geom
+	{
+		o = (char *) geom +offsets1[j] ;  
+		type1=  geom->objType[j];
+
+		if (type1 == POINTTYPE)	//point
+		{
+			//see if its within d of Px,Py
+			pt = (POINT3D *) o;
+			if  ( (   (pt->x - Px)*(pt->x - Px) + (pt->y - Py)*(pt->y - Py) ) < dd)
+			{
+				PG_RETURN_BOOL(TRUE);
+			}
+		}
+
+	}
+	PG_RETURN_BOOL(FALSE);	
+}
\ No newline at end of file
-- 
2.49.0