[gnumeric] Number match: support ISO 8602 date/time UTC values.

[Morten Welinder <mortenw src gnome org>]

commit c1dd1b23e33c80d25c5439a963f76cb2c4f7ef38
Author: Morten Welinder <terra gnome org>
Date:   Thu Jan 3 14:36:26 2019 -0500

    Number match: support ISO 8602 date/time UTC values.
    
    This is not meant to be perfect support, but to catch the saner 99% of
    the possible strings.

 NEWS               |  1 +
 src/number-match.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 53 insertions(+), 9 deletions(-)
---
diff --git a/NEWS b/NEWS
index 02d03f562..1e7957ac5 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,7 @@ Gnumeric 1.12.45
 
 Morten:
        * Add DIGAMMA function.
+       * Support ISO-8601 UTC date/time input.  Mostly.  [#371]
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.44
diff --git a/src/number-match.c b/src/number-match.c
index f0cf15b19..193d0389d 100644
--- a/src/number-match.c
+++ b/src/number-match.c
@@ -108,6 +108,7 @@ static struct {
        GORegexp re_ddMMMMyyyy;
        GORegexp re_yyyymmdd1;
        GORegexp re_yyyymmdd2;
+       GORegexp re_yyyymmdd3;
        GORegexp re_mmddyyyy;
        GORegexp re_mmdd;
        GORegexp re_hhmmss1;
@@ -125,6 +126,7 @@ datetime_locale_clear (void)
        go_regfree (&datetime_locale.re_ddMMMMyyyy);
        go_regfree (&datetime_locale.re_yyyymmdd1);
        go_regfree (&datetime_locale.re_yyyymmdd2);
+       go_regfree (&datetime_locale.re_yyyymmdd3);
        go_regfree (&datetime_locale.re_mmddyyyy);
        go_regfree (&datetime_locale.re_mmdd);
        go_regfree (&datetime_locale.re_hhmmss1);
@@ -241,11 +243,24 @@ datetime_locale_setup (char const *lc_time)
        datetime_locale_setup1 (&datetime_locale.re_yyyymmdd1, s);
        g_free (s);
 
+       /*
+        * ISO 8601 UTC date+time (date + "T" + time + "Z")
+        * Date: "2000-12-31" or without dashes.
+        * Time: "12:34:56.123" or without colons or with fewer parts.
+        */
+       s = g_strconcat ("^(\\d\\d\\d\\d)(-?)(\\d\\d)\\2(\\d\\d)T"
+                        "\\d+(:?)\\d+(\\5\\d+(",
+                        p_decimal->str,
+                        "\\d*)?)?(Z)\\s*$",
+                        NULL);
+       datetime_locale_setup1 (&datetime_locale.re_yyyymmdd2, s);
+       g_free (s);
+
        /*
         * "1900/01/01"
         * "1900-1-1"
         */
-       datetime_locale_setup1 (&datetime_locale.re_yyyymmdd2,
+       datetime_locale_setup1 (&datetime_locale.re_yyyymmdd3,
                                "^(\\d\\d\\d\\d)[-/.](\\d+)[-/.](\\d+)\\b");
 
        /*
@@ -653,6 +668,8 @@ format_match_datetime (char const *text,
        char *date_format = NULL;
        GnmValue *res = NULL;
        char *time_format = NULL;
+       int timeend = 0;
+       const char *format_sep = " ";
 
        if (lc_time != datetime_locale.lc_time &&
            (lc_time == NULL ||
@@ -722,10 +739,27 @@ format_match_datetime (char const *text,
                }
        }
 
+       // ^(\d\d\d\d)(-?)(\d\d)\2(\d\d)T\d+(:?)\d+(\5\d+(.\d*)?)?(Z)\s*$
+       //  1         2   3       4         5      6     7        8
+       if (dig1 > 0 &&  /* Exclude zero.  */
+           go_regexec (&datetime_locale.re_yyyymmdd2, text, G_N_ELEMENTS (match), match, 0) == 0) {
+               year = handle_year (text, match + 1);
+               month = handle_month (text, match + 3);
+               day = handle_day (text, match + 4);
+               if (valid_dmy (day, month, year)) {
+                       date_format = g_strdup ("yyyy-mm-dd");
+                       time_format = g_strdup ("hh:mm:ss\"Z\"");
+                       format_sep = "\"T\"";
+                       text += match[4].rm_eo + 1;
+                       timeend = match[8].rm_so - (match[4].rm_eo + 1);
+                       goto got_date;
+               }
+       }
+
        /* ^(\d\d\d\d)[-/.](\d\d)[-/.](\d\d)\b */
        /*  1              2          3        */
        if (dig1 > 0 &&  /* Exclude zero.  */
-           go_regexec (&datetime_locale.re_yyyymmdd2, text, G_N_ELEMENTS (match), match, 0) == 0) {
+           go_regexec (&datetime_locale.re_yyyymmdd3, text, G_N_ELEMENTS (match), match, 0) == 0) {
                year = handle_year (text, match + 1);
                month = handle_month (text, match + 2);
                day = handle_day (text, match + 3);
@@ -809,15 +843,24 @@ format_match_datetime (char const *text,
        SKIP_SPACES (text);
 
        if (*text) {
-               GnmValue *v = format_match_time (text, FALSE,
-                                                TRUE, add_format);
-               GOFormat const *fmt;
+               GnmValue *v;
+               const char *subtext = text;
+               char *textcopy = NULL;
+
+               if (timeend)
+                       subtext = textcopy = g_strndup (text, timeend);
+
+               v = format_match_time (subtext, FALSE,
+                                      TRUE, add_format);
+               g_free (textcopy);
                if (!v)
                        goto out;
                time_val = value_get_as_float (v);
-               fmt = VALUE_FMT (v);
-               if (fmt)
-                       time_format = g_strdup (go_format_as_XL (fmt));
+               if (!time_format) {
+                       GOFormat const *fmt = VALUE_FMT (v);
+                       if (fmt)
+                               time_format = g_strdup (go_format_as_XL (fmt));
+               }
                value_release (v);
        } else
                time_val = 0;
@@ -827,7 +870,7 @@ format_match_datetime (char const *text,
                GOFormat *fmt;
                if (time_format) {
                        char *format = g_strconcat (date_format,
-                                                   " ",
+                                                   format_sep,
                                                    time_format,
                                                    NULL);
                        fmt = go_format_new_from_XL (format);