[ISSUE #16] Implemented a function and tests to extract vertices from…

… spoly by index

doc/functions.sgm

@@ -463,7 +463,7 @@
               Positions at a path
             </title>
             <para>
-              <application>pgSphere</application> provides two functions to
+              <application>pgSphere</application> provides three functions to
               get points at a path.
             </para>
             <funcsynopsis>
@@ -477,6 +477,10 @@
                   <paramdef>spath  <parameter>path</parameter></paramdef>
                   <paramdef>float8 <parameter>f</parameter></paramdef>
               </funcprototype>
+              <funcprototype>
+                <funcdef><function>spath_as_array</function></funcdef>
+                  <paramdef>spath  <parameter>path</parameter></paramdef>
+              </funcprototype>
             </funcsynopsis>
             <para>
                The first function returns the <parameter>i</parameter>-th
@@ -495,6 +499,36 @@
 <![CDATA[  spoint]]>
 <![CDATA[------------]]>
 <![CDATA[ (15d , 0d)]]>
+<![CDATA[(1 row)]]>
+              </programlisting>
+            </example>
+            <example>
+              <title>
+                Get i-th point of a path
+              </title>
+              <programlisting>
+<![CDATA[sql> SELECT spoint( spath '{(0, 0),(1, 1)}', 1 );]]>
+<![CDATA[   spoint  ]]>
+<![CDATA[------------]]>
+<![CDATA[  (0 , 0) ]]>
+<![CDATA[(1 row)]]>
+<![CDATA[]]>
+<![CDATA[sql> SELECT spoint( spath '{(0, 0),(1, 1)}', 2 );]]>
+<![CDATA[   spoint  ]]>
+<![CDATA[------------]]>
+<![CDATA[  (1 , 1) ]]>
+<![CDATA[(1 row)]]>
+              </programlisting>
+            </example>
+            <example>
+              <title>
+                Get array representation of points
+              </title>
+              <programlisting>
+<![CDATA[sql> SELECT spath_as_array( spath '{(0, 0),(1, 1)}');]]>
+<![CDATA[    spath_as_array     ]]>
+<![CDATA[-----------------------]]>
+<![CDATA[ {"(0 , 0)","(1 , 1)"}]]>
 <![CDATA[(1 row)]]>
               </programlisting>
             </example>
@@ -532,7 +566,58 @@
             </example>
 
           </sect3>
-
+          <sect3 id="funcs.spoly.pos">
+            <title>
+              Positions at a polygon
+            </title>
+            <para>
+              <application>pgSphere</application> provides two functions to
+              get points at a path.
+            </para>
+            <funcsynopsis>
+              <funcprototype>
+                <funcdef><function>spoint</function></funcdef>
+                  <paramdef>spoly <parameter>path</parameter></paramdef>
+                  <paramdef>int4 <parameter>i</parameter></paramdef>
+              </funcprototype>
+              <funcprototype>
+                <funcdef><function>spoly_as_array</function></funcdef>
+                  <paramdef>spath  <parameter>path</parameter></paramdef>
+              </funcprototype>
+              </funcsynopsis>
+              <example>
+              <title>Get by index</title>
+              <programlisting>
+<![CDATA[sql> SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 1 );]]>
+<![CDATA[ spoint  ]]>
+<![CDATA[---------]]>
+<![CDATA[ (0 , 0)]]>
+<![CDATA[ (1 row)]]>
+<![CDATA[]]>
+<![CDATA[sql> SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 2 );]]>
+<![CDATA[ spoint  ]]>
+<![CDATA[---------]]>
+<![CDATA[ (1 , 0)]]>
+<![CDATA[ (1 row)]]>
+<![CDATA[]]>
+<![CDATA[sql> SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 3 );]]>
+<![CDATA[ spoint  ]]>
+<![CDATA[---------]]>
+<![CDATA[ (1 , 1)]]>
+<![CDATA[ (1 row)]]>
+              </programlisting>
+            </example>
+                          <example>
+              <title>Represent points as array</title>
+              <programlisting>
+<![CDATA[sql> SELECT  spoly_as_array( spoly '{(0,0),(1,0),(1,1)}' );]]>
+<![CDATA[         spoly_as_array          ]]>
+<![CDATA[---------------------------------]]>
+<![CDATA[ {"(0 , 0)","(1 , 0)","(1 , 1)"}]]>
+<![CDATA[(1 row)]]>
+              </programlisting>
+            </example>
+            </sect3>
         </sect2>
 
         <sect2 id="funcs.sbox">

expected/init_test.out.in

@@ -24,12 +24,12 @@ psql:pg_sphere.test.sql:158: NOTICE:  argument type spath is only a shell
 psql:pg_sphere.test.sql:177: NOTICE:  type "sbox" is not yet defined
 DETAIL:  Creating a shell type definition.
 psql:pg_sphere.test.sql:184: NOTICE:  argument type sbox is only a shell
-psql:pg_sphere.test.sql:8568: NOTICE:  type "spherekey" is not yet defined
+psql:pg_sphere.test.sql:8594: NOTICE:  type "spherekey" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:pg_sphere.test.sql:8575: NOTICE:  argument type spherekey is only a shell
-psql:pg_sphere.test.sql:8589: NOTICE:  type "pointkey" is not yet defined
+psql:pg_sphere.test.sql:8601: NOTICE:  argument type spherekey is only a shell
+psql:pg_sphere.test.sql:8615: NOTICE:  type "pointkey" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:pg_sphere.test.sql:8596: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8602: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8608: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8614: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8622: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8628: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8634: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8640: NOTICE:  argument type pointkey is only a shell

expected/init_test_healpix.out.in

@@ -1,2 +1,2 @@
-psql:pg_sphere.test.sql:9181: NOTICE:  return type smoc is only a shell
-psql:pg_sphere.test.sql:9187: NOTICE:  argument type smoc is only a shell
+psql:pg_sphere.test.sql:9207: NOTICE:  return type smoc is only a shell
+psql:pg_sphere.test.sql:9213: NOTICE:  argument type smoc is only a shell

expected/path.out

@@ -468,3 +468,28 @@ SELECT spoint(p,2) FROM spheretmp6 WHERE id=2;
  (1d , -5d)
 (1 row)
 
+SELECT set_sphere_output( 'RAD' );
+ set_sphere_output 
+-------------------
+ SET RAD
+(1 row)
+
+-- get n-th point and array representation path points tests
+SELECT spoint( spath '{(0, 0),(1, 1)}', 1 );
+ spoint  
+---------
+ (0 , 0)
+(1 row)
+
+SELECT spoint( spath '{(0, 0),(1, 1)}', 2 );
+ spoint  
+---------
+ (1 , 1)
+(1 row)
+
+SELECT spath_as_array( spath '{(0, 0),(1, 1)}');
+    spath_as_array     
+-----------------------
+ {"(0 , 0)","(1 , 1)"}
+(1 row)
+

expected/poly.out

@@ -1760,3 +1760,33 @@ SELECT npoints( spoly '{
        4
 (1 row)
 
+SELECT set_sphere_output( 'RAD' );
+ set_sphere_output 
+-------------------
+ SET RAD
+(1 row)
+
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 1 );
+ spoint  
+---------
+ (0 , 0)
+(1 row)
+
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 2 );
+ spoint  
+---------
+ (1 , 0)
+(1 row)
+
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 3 );
+ spoint  
+---------
+ (1 , 1)
+(1 row)
+
+SELECT  spoly_as_array( spoly '{(0,0),(1,0),(1,1)}' );
+         spoly_as_array          
+---------------------------------
+ {"(0 , 0)","(1 , 0)","(1 , 1)"}
+(1 row)
+

pgs_path.sql.in

@@ -34,6 +34,14 @@ CREATE FUNCTION spoint(spath, float8)
 COMMENT ON FUNCTION  spoint(spath, float8) IS
   'returns n-th point of spherical path using linear interpolation';
 
+CREATE FUNCTION spath_as_array(spath)
+   RETURNS spoint[]
+   AS 'MODULE_PATHNAME', 'spherepath_get_array'
+   LANGUAGE 'c'
+   IMMUTABLE STRICT PARALLEL SAFE;
+
+COMMENT ON FUNCTION  spath_as_array(spath) IS
+  'returns spath as array of points';
 
 -- ******************************
 --

pgs_polygon.sql.in

@@ -11,6 +11,24 @@ CREATE FUNCTION npoints(spoly)
 COMMENT ON FUNCTION  npoints(spoly) IS
   'returns number of points of spherical polygon';
 
+CREATE FUNCTION spoint(spoly, int4)
+   RETURNS spoint
+   AS 'MODULE_PATHNAME', 'spherepoly_get_point'
+   LANGUAGE 'c'
+   IMMUTABLE STRICT PARALLEL SAFE;
+
+COMMENT ON FUNCTION  spoint(spoly, int4) IS
+  'returns n-th point of spherical polygon';
+
+CREATE FUNCTION spoly_as_array(spoly)
+   RETURNS spoint[]
+   AS 'MODULE_PATHNAME', 'spherepoly_get_array'
+   LANGUAGE 'c'
+   IMMUTABLE STRICT PARALLEL SAFE;
+
+COMMENT ON FUNCTION  spoly_as_array(spoly) IS
+  'returns spoly as array of points';
+
 CREATE FUNCTION area(spoly)
    RETURNS FLOAT8
    AS 'MODULE_PATHNAME', 'spherepoly_area'

sql/path.sql

@@ -104,3 +104,9 @@ SELECT set_sphere_output( 'DEG' );
 -- test stored data
 SELECT spoint(p,2) FROM spheretmp6 WHERE id=2;
 
+SELECT set_sphere_output( 'RAD' );
+
+-- get n-th point and array representation path points tests
+SELECT spoint( spath '{(0, 0),(1, 1)}', 1 );
+SELECT spoint( spath '{(0, 0),(1, 1)}', 2 );
+SELECT spath_as_array( spath '{(0, 0),(1, 1)}');

sql/poly.sql

@@ -603,3 +603,10 @@ SELECT npoints( spoly '{
   (1.5121581120647 , -1.93925472462553e-05),
   (1.51214841579108 , -1.93925472462553e-05)
 }');
+
+SELECT set_sphere_output( 'RAD' );
+
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 1 );
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 2 );
+SELECT  spoint( spoly '{(0,0),(1,0),(1,1)}', 3 );
+SELECT  spoly_as_array( spoly '{(0,0),(1,0),(1,1)}' );

src/path.c

@@ -1,4 +1,6 @@
 #include "path.h"
+#include "point.h"
+#include <catalog/namespace.h>
 
 /*
  *  Path functions
@@ -50,6 +52,7 @@ PG_FUNCTION_INFO_V1(spheretrans_path);
 PG_FUNCTION_INFO_V1(spheretrans_path_inverse);
 PG_FUNCTION_INFO_V1(spherepath_add_point);
 PG_FUNCTION_INFO_V1(spherepath_add_points_finalize);
+PG_FUNCTION_INFO_V1(spherepath_get_array);
 
 
 /*
@@ -555,6 +558,32 @@ spherepath_get_point(PG_FUNCTION_ARGS)
 	PG_RETURN_NULL();
 }
 
+Datum
+spherepath_get_array(PG_FUNCTION_ARGS)
+{
+    SPATH *path = PG_GETARG_SPATH(0);
+    Datum *datum_arr = (Datum *) palloc(sizeof(Datum) * path->npts);
+    ArrayType *res;
+	SPoint *p = (SPoint *) palloc(sizeof(SPoint) * path->npts);
+
+    for (size_t i = 0; i < path->npts; i++)
+    {
+        if (!spath_get_point(&p[i], path, i))
+        {
+            // Clean up and return NULL
+            for (size_t j = 0; j < i; j++)
+                pfree(DatumGetPointer(datum_arr[j]));
+            pfree(datum_arr);
+            PG_RETURN_NULL();
+        }
+        datum_arr[i] = PointerGetDatum(&p[i]);
+    }
+
+    res = construct_array(datum_arr, path->npts, get_spoint_type_oid(), sizeof(SPoint), false, 'd');
+
+    PG_RETURN_ARRAYTYPE_P(res);
+}
+
 Datum
 spherepath_point(PG_FUNCTION_ARGS)
 {

src/path.h

@@ -71,6 +71,11 @@ Datum	spherepath_in(PG_FUNCTION_ARGS);
  */
 Datum	spherepath_get_point(PG_FUNCTION_ARGS);
 
+/*
+* Returns spath as array of points
+*/
+Datum	spherepath_get_array(PG_FUNCTION_ARGS);
+
 /*
  * This function interpolates between points of path. Returns the
  * n-th point of a path where n is a float.

src/point.c

@@ -15,6 +15,17 @@ PG_FUNCTION_INFO_V1(spherepoint_z);
 PG_FUNCTION_INFO_V1(spherepoint_xyz);
 PG_FUNCTION_INFO_V1(spherepoint_equal);
 
+static Oid point_id = InvalidOid;
+
+Oid	get_spoint_type_oid(void)
+{
+	if (point_id == InvalidOid)
+	{
+		point_id = TypenameGetTypid("spoint");
+	}
+	return point_id;
+}
+
 bool
 spoint_eq(const SPoint *p1, const SPoint *p2)
 {

src/point.h

@@ -3,6 +3,7 @@
 
 #include "vector3d.h"
 #include "sbuffer.h"
+#include <catalog/namespace.h>
 
 /* This file contains declarations for spherical point and functions. */
 
@@ -15,6 +16,8 @@ typedef struct
 	float8	lat;	/* latitude value in radians */
 } SPoint;
 
+Oid	get_spoint_type_oid(void);
+
 /*
  * Calculate the distance between two spherical points in radians.
  */