1 files changed, 52 insertions, 1 deletions

diff --git a/contrib/btree_gist/btree_oid.c b/contrib/btree_gist/btree_oid.c
index 4927448258f..c81dd31799e 100644
--- a/contrib/btree_gist/btree_oid.c
+++ b/contrib/btree_gist/btree_oid.c
@@ -17,6 +17,7 @@ PG_FUNCTION_INFO_V1(gbt_oid_compress);
 PG_FUNCTION_INFO_V1(gbt_oid_union);
 PG_FUNCTION_INFO_V1(gbt_oid_picksplit);
 PG_FUNCTION_INFO_V1(gbt_oid_consistent);
+PG_FUNCTION_INFO_V1(gbt_oid_distance);
 PG_FUNCTION_INFO_V1(gbt_oid_penalty);
 PG_FUNCTION_INFO_V1(gbt_oid_same);
 
@@ -24,6 +25,7 @@ Datum		gbt_oid_compress(PG_FUNCTION_ARGS);
 Datum		gbt_oid_union(PG_FUNCTION_ARGS);
 Datum		gbt_oid_picksplit(PG_FUNCTION_ARGS);
 Datum		gbt_oid_consistent(PG_FUNCTION_ARGS);
+Datum		gbt_oid_distance(PG_FUNCTION_ARGS);
 Datum		gbt_oid_penalty(PG_FUNCTION_ARGS);
 Datum		gbt_oid_same(PG_FUNCTION_ARGS);
 
@@ -71,6 +73,18 @@ gbt_oidkey_cmp(const void *a, const void *b)
 	return (ia->lower > ib->lower) ? 1 : -1;
 }
 
+static float8
+gbt_oid_dist(const void *a, const void *b)
+{
+	Oid			aa = *(const Oid *) a;
+	Oid			bb = *(const Oid *) b;
+
+	if (aa < bb)
+		return (float8) (bb - aa);
+	else
+		return (float8) (aa - bb);
+}
+
 
 static const gbtree_ninfo tinfo =
 {
@@ -81,10 +95,28 @@ static const gbtree_ninfo tinfo =
 	gbt_oideq,
 	gbt_oidle,
 	gbt_oidlt,
-	gbt_oidkey_cmp
+	gbt_oidkey_cmp,
+	gbt_oid_dist
 };
 
 
+PG_FUNCTION_INFO_V1(oid_dist);
+Datum       oid_dist(PG_FUNCTION_ARGS);
+Datum
+oid_dist(PG_FUNCTION_ARGS)
+{
+    Oid        	a = PG_GETARG_OID(0);
+	Oid        	b = PG_GETARG_OID(1);
+	Oid 		res;
+
+	if (a < b)
+		res = b - a;
+	else
+		res = a - b;
+	PG_RETURN_OID(res);
+}
+
+
 /**************************************************
  * Oid ops
  **************************************************/
@@ -125,6 +157,25 @@ gbt_oid_consistent(PG_FUNCTION_ARGS)
 
 
 Datum
+gbt_oid_distance(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	Oid			query = PG_GETARG_OID(1);
+
+	/* Oid		subtype = PG_GETARG_OID(3); */
+	oidKEY	   *kkk = (oidKEY *) DatumGetPointer(entry->key);
+	GBT_NUMKEY_R key;
+
+	key.lower = (GBT_NUMKEY *) &kkk->lower;
+	key.upper = (GBT_NUMKEY *) &kkk->upper;
+
+	PG_RETURN_FLOAT8(
+				   gbt_num_distance(&key, (void *) &query, GIST_LEAF(entry), &tinfo)
+		);
+}
+
+
+Datum
 gbt_oid_union(PG_FUNCTION_ARGS)
 {
 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);