Get rid of a bunch of #ifdef HAVE_INT64_TIMESTAMP conditionals by inventing

a new typedef TimeOffset to represent an intermediate time value.  It's
either int64 or double as appropriate, and in most usages will be measured
in microseconds or seconds the same as Timestamp.  We don't call it
Timestamp, though, since the value doesn't necessarily represent an absolute
time instant.

Warren Turkal

1 files changed, 27 insertions, 22 deletions

diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h
index cc224aa147a..8950979b945 100644
--- a/src/include/utils/timestamp.h
+++ b/src/include/utils/timestamp.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.75 2008/02/17 02:09:31 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.76 2008/03/21 01:31:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -25,31 +25,42 @@
 
 /*
  * Timestamp represents absolute time.
+ *
  * Interval represents delta time. Keep track of months (and years), days,
- *	and time separately since the elapsed time spanned is unknown until
- *	instantiated relative to an absolute time.
+ * and hours/minutes/seconds separately since the elapsed time spanned is
+ * unknown until instantiated relative to an absolute time.
  *
  * Note that Postgres uses "time interval" to mean a bounded interval,
  * consisting of a beginning and ending time, not a time span - thomas 97/03/20
+ *
+ * We have two implementations, one that uses int64 values with units of
+ * microseconds, and one that uses double values with units of seconds.
+ *
+ * TimeOffset and fsec_t are convenience typedefs for temporary variables
+ * that are of different types in the two cases.  Do not use fsec_t in values
+ * stored on-disk, since it is not the same size in both implementations.
  */
 
 #ifdef HAVE_INT64_TIMESTAMP
+
 typedef int64 Timestamp;
 typedef int64 TimestampTz;
+typedef int64 TimeOffset;
+typedef int32 fsec_t;			/* fractional seconds (in microseconds) */
+
 #else
+
 typedef double Timestamp;
 typedef double TimestampTz;
+typedef double TimeOffset;
+typedef double fsec_t;			/* fractional seconds (in seconds) */
+
 #endif
 
 typedef struct
 {
-#ifdef HAVE_INT64_TIMESTAMP
-	int64		time;			/* all time units other than days, months and
-								 * years */
-#else
-	double		time;			/* all time units other than days, months and
+	TimeOffset	time;			/* all time units other than days, months and
 								 * years */
-#endif
 	int32		day;			/* days, after time for alignment */
 	int32		month;			/* months and years, after time for alignment */
 } Interval;
@@ -106,17 +117,18 @@ typedef struct
 #define TimestampTzGetDatum(X) Int64GetDatum(X)
 #define IntervalPGetDatum(X) PointerGetDatum(X)
 
-#define PG_GETARG_TIMESTAMP(n) PG_GETARG_INT64(n)
-#define PG_GETARG_TIMESTAMPTZ(n) PG_GETARG_INT64(n)
+#define PG_GETARG_TIMESTAMP(n) DatumGetTimestamp(PG_GETARG_DATUM(n))
+#define PG_GETARG_TIMESTAMPTZ(n) DatumGetTimestampTz(PG_GETARG_DATUM(n))
 #define PG_GETARG_INTERVAL_P(n) DatumGetIntervalP(PG_GETARG_DATUM(n))
 
-#define PG_RETURN_TIMESTAMP(x) PG_RETURN_INT64(x)
-#define PG_RETURN_TIMESTAMPTZ(x) PG_RETURN_INT64(x)
+#define PG_RETURN_TIMESTAMP(x) return TimestampGetDatum(x)
+#define PG_RETURN_TIMESTAMPTZ(x) return TimestampTzGetDatum(x)
 #define PG_RETURN_INTERVAL_P(x) return IntervalPGetDatum(x)
 
 #define DT_NOBEGIN		(-INT64CONST(0x7fffffffffffffff) - 1)
 #define DT_NOEND		(INT64CONST(0x7fffffffffffffff))
-#else
+
+#else  /* !HAVE_INT64_TIMESTAMP */
 
 #define DatumGetTimestamp(X)  ((Timestamp) DatumGetFloat8(X))
 #define DatumGetTimestampTz(X)	((TimestampTz) DatumGetFloat8(X))
@@ -141,6 +153,7 @@ typedef struct
 #define DT_NOBEGIN		(-DBL_MAX)
 #define DT_NOEND		(DBL_MAX)
 #endif
+
 #endif   /* HAVE_INT64_TIMESTAMP */
 
 
@@ -154,14 +167,6 @@ typedef struct
 
 #define TIMESTAMP_NOT_FINITE(j) (TIMESTAMP_IS_NOBEGIN(j) || TIMESTAMP_IS_NOEND(j))
 
-#ifdef HAVE_INT64_TIMESTAMP
-
-typedef int32 fsec_t;
-#else
-
-typedef double fsec_t;
-#endif
-
 /*
  *	Round off to MAX_TIMESTAMP_PRECISION decimal places.
  *	Note: this is also used for rounding off intervals.