Refactor code so that to_date() does not call to_timestamp() and then

perform a timestamp-to-date coercion.  Instead both routines share a
subroutine that delivers the parsing result as a struct tm.  This avoids
problems with timezone dependency of to_date's result, and should be
at least marginally faster too.

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 1e9b49ea8d2396c16d7b8b15f6ebf692aaf26ad6..cc31115fa6c371f160abca078522d8305699fbca 100644 (file)
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------
  * formatting.c
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.66 2003/08/04 23:59:38 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v 1.67 2003/08/25 16:13:27 tgl Exp $
  *
  *
  *      Portions Copyright (c) 1999-2003, PostgreSQL Global Development Group
@@ -880,6 +880,8 @@ static int  seq_search(char *name, char **array, int type, int max, int *len);
 static int     dch_global(int arg, char *inout, int suf, int flag, FormatNode *node, void *data);
 static int     dch_time(int arg, char *inout, int suf, int flag, FormatNode *node, void *data);
 static int     dch_date(int arg, char *inout, int suf, int flag, FormatNode *node, void *data);
+static void do_to_timestamp(text *date_txt, text *fmt,
+                                                       struct tm *tm, fsec_t *fsec);
 static char *fill_str(char *str, int c, int max);
 static FormatNode *NUM_cache(int len, NUMDesc *Num, char *pars_str, bool *shouldFree);
 static char *int_to_roman(int number);
@@ -2901,21 +2903,65 @@ to_timestamp(PG_FUNCTION_ARGS)
 {
        text       *date_txt = PG_GETARG_TEXT_P(0);
        text       *fmt = PG_GETARG_TEXT_P(1);
-
        Timestamp       result;
+       int                     tz;
+       struct tm       tm;
+       fsec_t          fsec;
+
+       do_to_timestamp(date_txt, fmt, &tm, &fsec);
+
+       tz = DetermineLocalTimeZone(&tm);
+
+       if (tm2timestamp(&tm, fsec, &tz, &result) != 0)
+               ereport(ERROR,
+                               (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+                                errmsg("timestamp out of range")));
+
+       PG_RETURN_TIMESTAMP(result);
+}
+
+/* ----------
+ * TO_DATE
+ *     Make Date from date_str which is formated at argument 'fmt'
+ * ----------
+ */
+Datum
+to_date(PG_FUNCTION_ARGS)
+{
+       text       *date_txt = PG_GETARG_TEXT_P(0);
+       text       *fmt = PG_GETARG_TEXT_P(1);
+       DateADT         result;
+       struct tm       tm;
+       fsec_t          fsec;
+
+       do_to_timestamp(date_txt, fmt, &tm, &fsec);
+
+       result = date2j(tm.tm_year, tm.tm_mon, tm.tm_mday) - POSTGRES_EPOCH_JDATE;
+
+       PG_RETURN_DATEADT(result);
+}
+
+/*
+ * do_to_timestamp: shared code for to_timestamp and to_date
+ *
+ * Parse the 'date_txt' according to 'fmt', return results as a struct tm
+ * and fractional seconds.
+ */
+static void
+do_to_timestamp(text *date_txt, text *fmt,
+                               struct tm *tm, fsec_t *fsec)
+{
        FormatNode *format;
        TmFromChar      tmfc;
-
        bool            incache;
        char       *str;
        char       *date_str;
        int                     len,
-                               date_len,
-                               tz = 0;
-       struct tm       tm;
-       fsec_t          fsec = 0;
+                               date_len;
+
+       ZERO_tm(tm);
+       *fsec = 0;
 
-       ZERO_tm(&tm);
        ZERO_tmfc(&tmfc);
 
        len = VARSIZE(fmt) - VARHDRSZ;
@@ -3004,15 +3050,15 @@ to_timestamp(PG_FUNCTION_ARGS)
        {
                int                     x = tmfc.ssss;
 
-               tm.tm_hour = x / 3600;
+               tm->tm_hour = x / 3600;
                x %= 3600;
-               tm.tm_min = x / 60;
+               tm->tm_min = x / 60;
                x %= 60;
-               tm.tm_sec = x;
+               tm->tm_sec = x;
        }
 
        if (tmfc.cc)
-               tm.tm_year = (tmfc.cc - 1) * 100;
+               tm->tm_year = (tmfc.cc - 1) * 100;
 
        if (tmfc.ww)
                tmfc.ddd = (tmfc.ww - 1) * 7 + 1;
@@ -3021,79 +3067,79 @@ to_timestamp(PG_FUNCTION_ARGS)
                tmfc.dd = (tmfc.w - 1) * 7 + 1;
 
        if (tmfc.ss)
-               tm.tm_sec = tmfc.ss;
+               tm->tm_sec = tmfc.ss;
        if (tmfc.mi)
-               tm.tm_min = tmfc.mi;
+               tm->tm_min = tmfc.mi;
        if (tmfc.hh)
-               tm.tm_hour = tmfc.hh;
+               tm->tm_hour = tmfc.hh;
 
        if (tmfc.pm || tmfc.am)
        {
-               if (tm.tm_hour < 1 || tm.tm_hour > 12)
+               if (tm->tm_hour < 1 || tm->tm_hour > 12)
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_DATETIME_FORMAT),
                                         errmsg("AM/PM hour must be between 1 and 12")));
 
-               if (tmfc.pm && tm.tm_hour < 12)
-                       tm.tm_hour += 12;
+               if (tmfc.pm && tm->tm_hour < 12)
+                       tm->tm_hour += 12;
 
-               else if (tmfc.am && tm.tm_hour == 12)
-                       tm.tm_hour = 0;
+               else if (tmfc.am && tm->tm_hour == 12)
+                       tm->tm_hour = 0;
        }
 
        switch (tmfc.q)
        {
                case 1:
-                       tm.tm_mday = 1;
-                       tm.tm_mon = 1;
+                       tm->tm_mday = 1;
+                       tm->tm_mon = 1;
                        break;
                case 2:
-                       tm.tm_mday = 1;
-                       tm.tm_mon = 4;
+                       tm->tm_mday = 1;
+                       tm->tm_mon = 4;
                        break;
                case 3:
-                       tm.tm_mday = 1;
-                       tm.tm_mon = 7;
+                       tm->tm_mday = 1;
+                       tm->tm_mon = 7;
                        break;
                case 4:
-                       tm.tm_mday = 1;
-                       tm.tm_mon = 10;
+                       tm->tm_mday = 1;
+                       tm->tm_mon = 10;
                        break;
        }
 
        if (tmfc.year)
-               tm.tm_year = tmfc.year;
+               tm->tm_year = tmfc.year;
 
        if (tmfc.bc)
        {
-               if (tm.tm_year > 0)
-                       tm.tm_year = -(tm.tm_year - 1);
+               if (tm->tm_year > 0)
+                       tm->tm_year = -(tm->tm_year - 1);
                else
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_DATETIME_FORMAT),
                                         errmsg("inconsistent use of year %04d and \"BC\"",
-                                                       tm.tm_year)));
+                                                       tm->tm_year)));
        }
 
        if (tmfc.j)
-               j2date(tmfc.j, &tm.tm_year, &tm.tm_mon, &tm.tm_mday);
+               j2date(tmfc.j, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 
        if (tmfc.iw)
-               isoweek2date(tmfc.iw, &tm.tm_year, &tm.tm_mon, &tm.tm_mday);
+               isoweek2date(tmfc.iw, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 
        if (tmfc.d)
-               tm.tm_wday = tmfc.d;
+               tm->tm_wday = tmfc.d;
        if (tmfc.dd)
-               tm.tm_mday = tmfc.dd;
+               tm->tm_mday = tmfc.dd;
        if (tmfc.ddd)
-               tm.tm_yday = tmfc.ddd;
+               tm->tm_yday = tmfc.ddd;
        if (tmfc.mm)
-               tm.tm_mon = tmfc.mm;
+               tm->tm_mon = tmfc.mm;
 
        /*
         * we don't ignore DDD
         */
-       if (tmfc.ddd && (tm.tm_mon <= 1 || tm.tm_mday <= 1))
+       if (tmfc.ddd && (tm->tm_mon <= 1 || tm->tm_mday <= 1))
        {
                /* count mday and mon from yday */
                int                *y,
@@ -3103,65 +3149,41 @@ to_timestamp(PG_FUNCTION_ARGS)
                        {31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365, 0},
                {31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366, 0}};
 
-               if (!tm.tm_year)
+               if (!tm->tm_year)
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_DATETIME_FORMAT),
                                errmsg("cannot convert yday without year information")));
 
-               y = ysum[isleap(tm.tm_year)];
+               y = ysum[isleap(tm->tm_year)];
 
                for (i = 0; i <= 11; i++)
                {
-                       if (tm.tm_yday < y[i])
+                       if (tm->tm_yday < y[i])
                                break;
                }
-               if (tm.tm_mon <= 1)
-                       tm.tm_mon = i + 1;
+               if (tm->tm_mon <= 1)
+                       tm->tm_mon = i + 1;
 
-               if (tm.tm_mday <= 1)
-                       tm.tm_mday = i == 0 ? tm.tm_yday :
-                               tm.tm_yday - y[i - 1];
+               if (tm->tm_mday <= 1)
+                       tm->tm_mday = i == 0 ? tm->tm_yday :
+                               tm->tm_yday - y[i - 1];
        }
 
 #ifdef HAVE_INT64_TIMESTAMP
        if (tmfc.ms)
-               fsec += tmfc.ms * 1000;
+               *fsec += tmfc.ms * 1000;
        if (tmfc.us)
-               fsec += tmfc.us;
+               *fsec += tmfc.us;
 #else
        if (tmfc.ms)
-               fsec += (double) tmfc.ms / 1000;
+               *fsec += (double) tmfc.ms / 1000;
        if (tmfc.us)
-               fsec += (double) tmfc.us / 1000000;
+               *fsec += (double) tmfc.us / 1000000;
 #endif
 
-       /* -------------------------------------------------------------- */
-
-       DEBUG_TM(&tm);
-       tz = DetermineLocalTimeZone(&tm);
-
-       if (tm2timestamp(&tm, fsec, &tz, &result) != 0)
-               ereport(ERROR,
-                               (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-                                errmsg("timestamp out of range")));
-
-       PG_RETURN_TIMESTAMP(result);
+       DEBUG_TM(tm);
 }
 
-/* ----------
- * TO_DATE
- *     Make Date from date_str which is formated at argument 'fmt'
- * ----------
- */
-Datum
-to_date(PG_FUNCTION_ARGS)
-{
-       /*
-        * Quick hack: since our inputs are just like to_timestamp, hand over
-        * the whole input info struct...
-        */
-       return DirectFunctionCall1(timestamptz_date, to_timestamp(fcinfo));
-}
 
 /**********************************************************************
  *     the NUMBER version part