Fix up hash functions for datetime datatypes so that they don't take

unwarranted liberties with int8 vs float8 values for these types.
Specifically, be sure to apply either hashint8 or hashfloat8 depending
on HAVE_INT64_TIMESTAMP.  Per my gripe of even date.

1 files changed, 26 insertions, 8 deletions

diff --git a/src/backend/utils/adt/date.c b/src/backend/utils/adt/date.c
index a66680f4772..efc965ae4c3 100644
--- a/src/backend/utils/adt/date.c
+++ b/src/backend/utils/adt/date.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.133 2007/06/15 20:56:50 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.134 2007/07/06 04:15:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1198,6 +1198,17 @@ time_cmp(PG_FUNCTION_ARGS)
 }
 
 Datum
+time_hash(PG_FUNCTION_ARGS)
+{
+	/* We can use either hashint8 or hashfloat8 directly */
+#ifdef HAVE_INT64_TIMESTAMP
+	return hashint8(fcinfo);
+#else
+	return hashfloat8(fcinfo);
+#endif
+}
+
+Datum
 time_larger(PG_FUNCTION_ARGS)
 {
 	TimeADT		time1 = PG_GETARG_TIMEADT(0);
@@ -1960,20 +1971,27 @@ timetz_cmp(PG_FUNCTION_ARGS)
 	PG_RETURN_INT32(timetz_cmp_internal(time1, time2));
 }
 
-/*
- * timetz, being an unusual size, needs a specialized hash function.
- */
 Datum
 timetz_hash(PG_FUNCTION_ARGS)
 {
 	TimeTzADT  *key = PG_GETARG_TIMETZADT_P(0);
+	uint32		thash;
 
 	/*
-	 * Specify hash length as sizeof(double) + sizeof(int4), not as
-	 * sizeof(TimeTzADT), so that any garbage pad bytes in the structure won't
-	 * be included in the hash!
+	 * To avoid any problems with padding bytes in the struct,
+	 * we figure the field hashes separately and XOR them.  This also
+	 * provides a convenient framework for dealing with the fact that
+	 * the time field might be either double or int64.
 	 */
-	return hash_any((unsigned char *) key, sizeof(key->time) + sizeof(key->zone));
+#ifdef HAVE_INT64_TIMESTAMP
+	thash = DatumGetUInt32(DirectFunctionCall1(hashint8,
+											   Int64GetDatumFast(key->time)));
+#else
+	thash = DatumGetUInt32(DirectFunctionCall1(hashfloat8,
+											   Float8GetDatumFast(key->time)));
+#endif
+	thash ^= DatumGetUInt32(hash_uint32(key->zone));
+	PG_RETURN_UINT32(thash);
 }
 
 Datum