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