Implement = and <> on smoc

Author: df7cb

expected/moc.out

@@ -42,6 +42,30 @@ SELECT '(0.78, 0.81)'::spoint <@ '7/123-456,1000-2000'::smoc;
  f
 (1 row)
 
+SELECT '0/'::smoc = '1/'::smoc AS eq;
+ eq 
+----
+ t
+(1 row)
+
+SELECT '0/1,3,7'::smoc = '0/1,3,7' AS eq;
+ eq 
+----
+ t
+(1 row)
+
+SELECT '0/1,4,7'::smoc = '0/1,3,7' AS eq;
+ eq 
+----
+ f
+(1 row)
+
+SELECT '0/1,2,3'::smoc <> '0/1-3'::smoc AS neq;
+ neq 
+-----
+ f
+(1 row)
+
 SELECT 1 <@ (smoc('29/2-5,20-29,123,444,17-21,33-39,332-339,0-1'));
  ?column? 
 ----------

moc.c

@@ -9,6 +9,8 @@ PG_FUNCTION_INFO_V1(smoc_out);
 PG_FUNCTION_INFO_V1(moc_debug);
 PG_FUNCTION_INFO_V1(set_smoc_output_type);
 PG_FUNCTION_INFO_V1(smoc_order);
+PG_FUNCTION_INFO_V1(smoc_eq);
+PG_FUNCTION_INFO_V1(smoc_neq);
 
 PG_FUNCTION_INFO_V1(healpix_subset_smoc);
 PG_FUNCTION_INFO_V1(healpix_not_subset_smoc);
@@ -413,6 +415,55 @@ moc_debug(PG_FUNCTION_ARGS)
 	PG_RETURN_TEXT_P(cstring_to_text(x));
 }
 
+static bool
+smoc_eq_impl(Smoc* moc_a, Smoc* moc_b)
+{
+	int32	a = moc_a->data_begin;
+	int32	b = moc_b->data_begin;
+	int32	entry_size = MOC_INTERVAL_SIZE;
+	int32	moc_a_end = VARSIZE(moc_a) - VARHDRSZ;
+	int32	moc_b_end = VARSIZE(moc_b) - VARHDRSZ;
+	char*	moc_a_base = MOC_BASE(moc_a);
+	char*	moc_b_base = MOC_BASE(moc_b);
+
+	if (moc_a->data_begin != moc_b->data_begin || moc_a_end != moc_b_end) /* this needs to be reconsidered if the MOC version is updated */
+		return false;
+
+	if (moc_a->order != moc_b->order || moc_a->first != moc_b->first || moc_a->last != moc_b->last || moc_a->area != moc_b->area)
+		return false;
+
+	for (int j = moc_a->data_begin; j < moc_a_end; j += entry_size) // iterate over both in parallel
+	{
+		// page bumps
+		int32 mod = (j + entry_size) % PG_TOAST_PAGE_FRAGMENT;
+		if (mod > 0 && mod < entry_size)
+			j += entry_size - mod;
+		moc_interval *x = MOC_INTERVAL(moc_a_base, j);
+		moc_interval *y = MOC_INTERVAL(moc_b_base, j);
+
+		if (x->first != y->first || x->second != y->second)
+			return false;
+	}
+
+	return true;
+}
+
+Datum
+smoc_eq(PG_FUNCTION_ARGS)
+{
+	Smoc*	moc_a = (Smoc *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	Smoc*	moc_b = (Smoc *) PG_DETOAST_DATUM(PG_GETARG_DATUM(1));
+	PG_RETURN_BOOL(smoc_eq_impl(moc_a, moc_b));
+}
+
+Datum
+smoc_neq(PG_FUNCTION_ARGS)
+{
+	Smoc*	moc_a = (Smoc *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	Smoc*	moc_b = (Smoc *) PG_DETOAST_DATUM(PG_GETARG_DATUM(1));
+	PG_RETURN_BOOL(! smoc_eq_impl(moc_a, moc_b));
+}
+
 static bool
 entry_equal(moc_tree_entry *a, hpint64 y)
 {

pgs_moc_ops.sql.in

@@ -1,3 +1,35 @@
+CREATE FUNCTION smoc_eq (smoc, smoc)
+	RETURNS boolean
+	AS 'MODULE_PATHNAME'
+	LANGUAGE C
+	STRICT;
+
+CREATE OPERATOR = (
+	LEFTARG    = smoc,
+	RIGHTARG   = smoc,
+	PROCEDURE  = smoc_eq,
+	COMMUTATOR = '=',
+	NEGATOR    = '<>',
+	RESTRICT   = eqsel,
+	JOIN       = eqjoinsel
+);
+
+CREATE FUNCTION smoc_neq (smoc, smoc)
+	RETURNS boolean
+	AS 'MODULE_PATHNAME'
+	LANGUAGE C
+	STRICT;
+
+CREATE OPERATOR <> (
+	LEFTARG    = smoc,
+	RIGHTARG   = smoc,
+	PROCEDURE  = smoc_neq,
+	COMMUTATOR = '<>',
+	NEGATOR    = '=',
+	RESTRICT   = neqsel,
+	JOIN       = neqjoinsel
+);
+
 CREATE FUNCTION smoc_union (smoc, smoc)
 	RETURNS smoc
 	AS 'MODULE_PATHNAME'

sql/moc.sql

@@ -9,6 +9,11 @@ SELECT '0/0,1,2,3,7'::smoc; -- expected: '0/0-3,7'
 SELECT '(0.78, 0.81)'::spoint <@ '7/123-456,10000-20000'::smoc;
 SELECT '(0.78, 0.81)'::spoint <@ '7/123-456,1000-2000'::smoc;
 
+SELECT '0/'::smoc = '1/'::smoc AS eq;
+SELECT '0/1,3,7'::smoc = '0/1,3,7' AS eq;
+SELECT '0/1,4,7'::smoc = '0/1,3,7' AS eq;
+SELECT '0/1,2,3'::smoc <> '0/1-3'::smoc AS neq;
+
 SELECT 1 <@ (smoc('29/2-5,20-29,123,444,17-21,33-39,332-339,0-1'));
 SELECT 1 <@ (smoc('29/2-5,20-29,123,444,17-21,33-39,332-339'));
 SELECT 2 <@ (smoc('29/2-5,20-29,123,444,17-21,33-39,332-339'));