WIP: GiST support

CHANGELOG.md

@@ -27,6 +27,7 @@ avoid adding features or APIs which do not map onto the
   </summary>
 
 - Add distance operator `<->`
+- Add `gist` operator class (see [#42], thanks [@abelvm])
 
 </details>
 
@@ -162,6 +163,7 @@ avoid adding features or APIs which do not map onto the
 [#26]: https://github.com/bytesandbrains/h3-pg/pull/26
 [#37]: https://github.com/bytesandbrains/h3-pg/issues/37
 [#38]: https://github.com/bytesandbrains/h3-pg/issues/38
+[#42]: https://github.com/bytesandbrains/h3-pg/issues/42
 [@abelvm]: https://github.com/AbelVM
 [@komzpa]: https://github.com/Komzpa
 [@kmacdough]: https://github.com/kmacdough

sql/install/13-opclass_gist.sql

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2019-2020 Bytes & Brains
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- ---------- ---------- ---------- ---------- ---------- ---------- ----------
+-- GiST Operator Class (opclass_gist.c)
+-- ---------- ---------- ---------- ---------- ---------- ---------- ----------
+
+CREATE OR REPLACE FUNCTION h3index_gist_consistent(internal, h3index, smallint, oid, internal) RETURNS boolean
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_union(internal, internal) RETURNS h3index
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_compress(internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_decompress(internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_penalty(internal, internal, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_picksplit(internal, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_same(h3index, h3index, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_distance(internal, h3index, smallint, oid, internal) RETURNS float8
+    AS 'h3' LANGUAGE C STRICT;
+
+CREATE OPERATOR CLASS gist_h3index_ops DEFAULT FOR TYPE h3index USING gist AS
+    OPERATOR  3   &&  ,
+    OPERATOR  6   =   ,
+    OPERATOR  7   @>  ,
+    OPERATOR  8   <@  ,
+    OPERATOR  15  <-> (h3index, h3index) FOR ORDER BY integer_ops,
+
+    FUNCTION  1  h3index_gist_consistent(internal, h3index, smallint, oid, internal),
+    FUNCTION  2  h3index_gist_union(internal, internal),
+    FUNCTION  3  h3index_gist_compress(internal),
+    FUNCTION  4  h3index_gist_decompress(internal),
+    FUNCTION  5  h3index_gist_penalty(internal, internal, internal),
+    FUNCTION  6  h3index_gist_picksplit(internal, internal),
+    FUNCTION  7  h3index_gist_same(h3index, h3index, internal),
+    FUNCTION  8  (h3index, h3index) h3index_gist_distance(internal, h3index, smallint, oid, internal);

sql/updates/h3--3.6.5--unreleased.sql

@@ -23,3 +23,40 @@ CREATE OPERATOR <-> (
   PROCEDURE = h3_distance,
   COMMUTATOR = <->
 );
+
+-- ---------- ---------- ---------- ---------- ---------- ---------- ----------
+-- GiST Operator Class (opclass_gist.c)
+-- ---------- ---------- ---------- ---------- ---------- ---------- ----------
+
+CREATE OR REPLACE FUNCTION h3index_gist_consistent(internal, h3index, smallint, oid, internal) RETURNS boolean
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_union(internal, internal) RETURNS h3index
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_compress(internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_decompress(internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_penalty(internal, internal, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_picksplit(internal, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_same(h3index, h3index, internal) RETURNS internal
+    AS 'h3' LANGUAGE C STRICT;
+CREATE OR REPLACE FUNCTION h3index_gist_distance(internal, h3index, smallint, oid, internal) RETURNS float8
+    AS 'h3' LANGUAGE C STRICT;
+
+CREATE OPERATOR CLASS gist_h3index_ops DEFAULT FOR TYPE h3index USING gist AS
+    OPERATOR  3   &&  ,
+    OPERATOR  6   =   ,
+    OPERATOR  7   @>  ,
+    OPERATOR  8   <@  ,
+    OPERATOR  15  <-> (h3index, h3index) FOR ORDER BY integer_ops,
+
+    FUNCTION  1  h3index_gist_consistent(internal, h3index, smallint, oid, internal),
+    FUNCTION  2  h3index_gist_union(internal, internal),
+    FUNCTION  3  h3index_gist_compress(internal),
+    FUNCTION  4  h3index_gist_decompress(internal),
+    FUNCTION  5  h3index_gist_penalty(internal, internal, internal),
+    FUNCTION  6  h3index_gist_picksplit(internal, internal),
+    FUNCTION  7  h3index_gist_same(h3index, h3index, internal),
+    FUNCTION  8  (h3index, h3index) h3index_gist_distance(internal, h3index, smallint, oid, internal);