Expose PC_Get(pcpoint) returning an array of float8 at the SQL level

Initial code by Remi-C, refactored to reduce code extent and equipped
with regress test.

README.md

@@ -225,6 +225,14 @@ Now that you have created two tables, you'll see entries for them in the `pointc
 >
 >     4
 
+**PC_Get(pt pcpoint)** returns **float8[]**  (from 2.0)
+
+> Return values of all dimensions in an array.
+>
+>     SELECT PC_Get('010100000064CEFFFF94110000703000000400'::pcpoint);
+>
+>     {-127,45,124,4}
+
 **PC_Patch(pts pcpoint[])** returns **pcpatch**
 
 > Aggregate function that collects a result set of `pcpoint` values into a `pcpatch`.

pgsql/expected/pointcloud.out

@@ -126,6 +126,14 @@ SELECT Sum(PC_Get(pt, 'y')) FROM pt_test;
  0.09
 (1 row)
 
+SELECT PC_Get(pt) FROM pt_test;
+       pc_get       
+--------------------
+ {0.01,0.02,0.03,4}
+ {0.02,0.03,0.03,5}
+ {0.03,0.04,0.03,6}
+(3 rows)
+
 SELECT PC_AsText(pt) FROM pt_test;
              pc_astext              
 ------------------------------------

pgsql/pc_access.c

@@ -15,6 +15,7 @@
 
 /* General SQL functions */
 Datum pcpoint_get_value(PG_FUNCTION_ARGS);
+Datum pcpoint_get_values(PG_FUNCTION_ARGS);
 Datum pcpatch_from_pcpoint_array(PG_FUNCTION_ARGS);
 Datum pcpatch_from_pcpatch_array(PG_FUNCTION_ARGS);
 Datum pcpatch_uncompress(PG_FUNCTION_ARGS);
@@ -71,6 +72,39 @@ Datum pcpoint_get_value(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(DirectFunctionCall1(float8_numeric, Float8GetDatum(double_result)));
 }
 
+/**
+* Returns all the values of a point as a double precision array
+* PC_Get(point pcpoint) returns Float8[]
+*/
+PG_FUNCTION_INFO_V1(pcpoint_get_values);
+Datum pcpoint_get_values(PG_FUNCTION_ARGS)
+{
+	SERIALIZED_POINT *serpt;
+	ArrayType  *result;
+	PCSCHEMA *schema;
+	PCPOINT *pt;
+	Datum *elems;
+	int i;
+	double *vals;
+
+	serpt = PG_GETARG_SERPOINT_P(0);
+	schema = pc_schema_from_pcid(serpt->pcid, fcinfo);
+	pt = pc_point_deserialize(serpt, schema);
+	if ( ! pt ) PG_RETURN_NULL();
+
+  elems = (Datum * )palloc(schema->ndims * sizeof(Datum) );
+  vals = pc_point_to_double_array(pt);
+  i = schema->ndims;
+  while (i--) elems[i] = Float8GetDatum(vals[i]);
+  pcfree(vals);
+  result = construct_array(elems, schema->ndims, FLOAT8OID,
+	                         sizeof(float8), FLOAT8PASSBYVAL, 'd');
+
+	pc_point_free(pt);
+	PG_RETURN_ARRAYTYPE_P(result);
+}
+
+
 static inline bool
 array_get_isnull(const bits8 *nullbitmap, int offset)
 {

pgsql/pointcloud--1.0.sql

@@ -81,6 +81,11 @@ CREATE OR REPLACE FUNCTION PC_Get(pt pcpoint, dimname text)
 	RETURNS numeric AS 'MODULE_PATHNAME', 'pcpoint_get_value'
     LANGUAGE 'c' IMMUTABLE STRICT;
 
+-- Availability: 2.0
+CREATE OR REPLACE FUNCTION PC_Get(pt pcpoint)
+	RETURNS float8[] AS 'MODULE_PATHNAME', 'pcpoint_get_values'
+	LANGUAGE 'c' IMMUTABLE STRICT;
+
 CREATE OR REPLACE FUNCTION PC_MakePoint(pcid integer, vals float8[])
 	RETURNS pcpoint AS 'MODULE_PATHNAME', 'pcpoint_from_double_array'
 	LANGUAGE 'c' IMMUTABLE STRICT;

pgsql/sql/pointcloud.sql

@@ -109,6 +109,8 @@ INSERT INTO pt_test (pt) VALUES ('00000000010000000300000004000000030006');
 SELECT PC_Get(pt, 'Intensity') FROM pt_test;
 SELECT Sum(PC_Get(pt, 'y')) FROM pt_test;
 
+SELECT PC_Get(pt) FROM pt_test;
+
 SELECT PC_AsText(pt) FROM pt_test;
 
 SELECT PC_AsText(PC_Patch(pt)) FROM pt_test;