Add SP-GiST support for range types.

The implementation is a quad-tree, largely copied from the quad-tree
implementation for points. The lower and upper bound of ranges are the 2d
coordinates, with some extra code to handle empty ranges.

I left out the support for adjacent operator, -|-, from the original patch.
Not because there was necessarily anything wrong with it, but it was more
complicated than the other operators, and I only have limited time for
reviewing. That will follow as a separate patch.

Alexander Korotkov, reviewed by Jeff Davis and me.

Author: hlinnaka

src/backend/utils/adt/Makefile

@@ -30,7 +30,7 @@ OBJS = acl.o arrayfuncs.o array_selfuncs.o array_typanalyze.o \
 	tsginidx.o tsgistidx.o tsquery.o tsquery_cleanup.o tsquery_gist.o \
 	tsquery_op.o tsquery_rewrite.o tsquery_util.o tsrank.o \
 	tsvector.o tsvector_op.o tsvector_parser.o \
-	txid.o uuid.o windowfuncs.o xml.o
+	txid.o uuid.o windowfuncs.o xml.o rangetypes_spgist.o
 
 like.o: like.c like_match.c
 

src/backend/utils/adt/rangetypes_gist.c

@@ -21,19 +21,6 @@
 #include "utils/rangetypes.h"
 
 
-/* Operator strategy numbers used in the GiST range opclass */
-/* Numbers are chosen to match up operator names with existing usages */
-#define RANGESTRAT_BEFORE				1
-#define RANGESTRAT_OVERLEFT				2
-#define RANGESTRAT_OVERLAPS				3
-#define RANGESTRAT_OVERRIGHT			4
-#define RANGESTRAT_AFTER				5
-#define RANGESTRAT_ADJACENT				6
-#define RANGESTRAT_CONTAINS				7
-#define RANGESTRAT_CONTAINED_BY			8
-#define RANGESTRAT_CONTAINS_ELEM		16
-#define RANGESTRAT_EQ					18
-
 /*
  * Range class properties used to segregate different classes of ranges in
  * GiST.  Each unique combination of properties is a class.  CLS_EMPTY cannot