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GDateTime: Support parsing ISO 8601 strings
This supports a subset of ISO 8601 since that is a commonly used standard for storing date and time information. We support only ISO 8601 strings that contain full date and time information as this would otherwise not map to GDateTime. This subset includes all of RFC 3339 which is commonly used on the Internet and the week and ordinal day formats as these are supported in the GDateTime APIs. (Minor modification by Philip Withnall to change API versions from 2.54 to 2.56.) https://bugzilla.gnome.org/show_bug.cgi?id=753459
This commit is contained in:
Robert Ancell
committed by
Philip Withnall
Philip Withnall
parent
d5933142c8
commit
491f835c17
337
glib/gdatetime.c
337
glib/gdatetime.c
@@ -22,6 +22,7 @@
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* Thiago Santos <thiago.sousa.santos@collabora.co.uk>
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* Emmanuele Bassi <ebassi@linux.intel.com>
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* Ryan Lortie <desrt@desrt.ca>
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* Robert Ancell <robert.ancell@canonical.com>
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*/
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/* Algorithms within this file are based on the Calendar FAQ by
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@@ -902,6 +903,342 @@ g_date_time_new_from_timeval_utc (const GTimeVal *tv)
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return datetime;
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}
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/* Parse integers in the form d (week days), dd (hours etc), ddd (ordinal days) or dddd (years) */
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static gboolean
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get_iso8601_int (const gchar *text, gsize length, gint *value)
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{
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gint i, v = 0;
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if (length < 1 || length > 4)
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return FALSE;
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for (i = 0; i < length; i++)
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{
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const gchar c = text[i];
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if (c < '0' || c > '9')
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return FALSE;
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v = v * 10 + (c - '0');
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}
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*value = v;
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return TRUE;
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}
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/* Parse seconds in the form ss or ss.sss (variable length decimal) */
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static gboolean
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get_iso8601_seconds (const gchar *text, gsize length, gdouble *value)
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{
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gint i;
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gdouble multiplier = 0.1, v = 0;
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if (length < 2)
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return FALSE;
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for (i = 0; i < 2; i++)
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{
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const gchar c = text[i];
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if (c < '0' || c > '9')
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return FALSE;
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v = v * 10 + (c - '0');
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}
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if (length > 2 && !(text[i] == '.' || text[i] == ','))
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return FALSE;
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i++;
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if (i == length)
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return FALSE;
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for (; i < length; i++)
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{
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const gchar c = text[i];
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if (c < '0' || c > '9')
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return FALSE;
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v += (c - '0') * multiplier;
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multiplier *= 0.1;
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}
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*value = v;
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return TRUE;
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}
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static GDateTime *
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g_date_time_new_ordinal (GTimeZone *tz, gint year, gint ordinal_day, gint hour, gint minute, gdouble seconds)
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{
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GDateTime *dt;
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if (ordinal_day < 1 || ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
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return NULL;
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dt = g_date_time_new (tz, year, 1, 1, hour, minute, seconds);
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dt->days += ordinal_day - 1;
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return dt;
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}
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static GDateTime *
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g_date_time_new_week (GTimeZone *tz, gint year, gint week, gint week_day, gint hour, gint minute, gdouble seconds)
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{
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gint64 p;
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gint max_week, jan4_week_day, ordinal_day;
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GDateTime *dt;
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p = (year * 365 + (year / 4) - (year / 100) + (year / 400)) % 7;
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max_week = p == 4 ? 53 : 52;
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if (week < 1 || week > max_week || week_day < 1 || week_day > 7)
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return NULL;
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dt = g_date_time_new (tz, year, 1, 4, 0, 0, 0);
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g_date_time_get_week_number (dt, NULL, &jan4_week_day, NULL);
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ordinal_day = (week * 7) + week_day - (jan4_week_day + 3);
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if (ordinal_day < 0)
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{
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year--;
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ordinal_day += GREGORIAN_LEAP (year) ? 366 : 365;
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}
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else if (ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
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{
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ordinal_day -= (GREGORIAN_LEAP (year) ? 366 : 365);
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year++;
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}
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return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
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}
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static GDateTime *
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parse_iso8601_date (const gchar *text, gsize length,
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gint hour, gint minute, gdouble seconds, GTimeZone *tz)
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{
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/* YYYY-MM-DD */
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if (length == 10 && text[4] == '-' && text[7] == '-')
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{
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int year, month, day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 5, 2, &month) ||
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!get_iso8601_int (text + 8, 2, &day))
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return NULL;
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return g_date_time_new (tz, year, month, day, hour, minute, seconds);
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}
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/* YYYY-DDD */
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else if (length == 8 && text[4] == '-')
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{
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gint year, ordinal_day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 5, 3, &ordinal_day))
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return NULL;
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return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
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}
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/* YYYY-Www-D */
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else if (length == 10 && text[4] == '-' && text[5] == 'W' && text[8] == '-')
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{
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gint year, week, week_day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 6, 2, &week) ||
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!get_iso8601_int (text + 9, 1, &week_day))
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return NULL;
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return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
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}
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/* YYYYWwwD */
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else if (length == 8 && text[4] == 'W')
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{
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gint year, week, week_day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 5, 2, &week) ||
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!get_iso8601_int (text + 7, 1, &week_day))
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return NULL;
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return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
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}
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/* YYYYMMDD */
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else if (length == 8)
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{
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int year, month, day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 4, 2, &month) ||
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!get_iso8601_int (text + 6, 2, &day))
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return NULL;
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return g_date_time_new (tz, year, month, day, hour, minute, seconds);
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}
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/* YYYYDDD */
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else if (length == 7)
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{
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gint year, ordinal_day;
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if (!get_iso8601_int (text, 4, &year) ||
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!get_iso8601_int (text + 4, 3, &ordinal_day))
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return NULL;
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return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
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}
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else
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return FALSE;
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}
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static GTimeZone *
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parse_iso8601_timezone (const gchar *text, gsize length, gssize *tz_offset)
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{
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gint i, tz_length, offset_sign = 1, offset_hours, offset_minutes;
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GTimeZone *tz;
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/* UTC uses Z suffix */
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if (length > 0 && text[length - 1] == 'Z')
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{
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*tz_offset = length - 1;
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return g_time_zone_new_utc ();
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}
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/* Look for '+' or '-' of offset */
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for (i = length - 1; i >= 0; i--)
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if (text[i] == '+' || text[i] == '-')
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{
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offset_sign = text[i] == '-' ? -1 : 1;
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break;
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}
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if (i < 0)
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return NULL;
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tz_length = length - i;
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/* +hh:mm or -hh:mm */
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if (tz_length == 6 && text[i+3] == ':')
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{
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if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
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!get_iso8601_int (text + i + 4, 2, &offset_minutes))
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return NULL;
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}
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/* +hhmm or -hhmm */
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else if (tz_length == 5)
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{
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if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
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!get_iso8601_int (text + i + 3, 2, &offset_minutes))
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return NULL;
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}
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/* +hh or -hh */
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else if (tz_length == 3)
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{
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if (!get_iso8601_int (text + i + 1, 2, &offset_hours))
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return NULL;
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offset_minutes = 0;
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}
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else
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return NULL;
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*tz_offset = i;
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tz = g_time_zone_new (text + i);
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/* Double-check that the GTimeZone matches our interpretation of the timezone.
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* Failure would indicate a bug either here of in the GTimeZone code. */
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g_assert (g_time_zone_get_offset (tz, 0) == offset_sign * (offset_hours * 3600 + offset_minutes * 60));
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return tz;
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}
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static gboolean
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parse_iso8601_time (const gchar *text, gsize length,
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gint *hour, gint *minute, gdouble *seconds, GTimeZone **tz)
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{
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gssize tz_offset = -1;
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/* Check for timezone suffix */
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*tz = parse_iso8601_timezone (text, length, &tz_offset);
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if (tz_offset >= 0)
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length = tz_offset;
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/* hh:mm:ss(.sss) */
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if (length >= 8 && text[2] == ':' && text[5] == ':')
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{
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return get_iso8601_int (text, 2, hour) &&
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get_iso8601_int (text + 3, 2, minute) &&
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get_iso8601_seconds (text + 6, length - 6, seconds);
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}
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/* hhmmss(.sss) */
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else if (length >= 6)
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{
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return get_iso8601_int (text, 2, hour) &&
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get_iso8601_int (text + 2, 2, minute) &&
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get_iso8601_seconds (text + 4, length - 4, seconds);
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}
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else
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return FALSE;
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}
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/**
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* g_date_time_new_from_iso8601:
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* @text: an ISO 8601 formatted time string.
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* @default_tz: (nullable): a #GTimeZone to use if the text doesn't contain a
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* timezone, or %NULL.
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*
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* Creates a #GDateTime corresponding to the given
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* [ISO 8601 formatted string](https://en.wikipedia.org/wiki/ISO_8601)
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* @text. ISO 8601 strings of the form <date><sep><time><tz> are supported.
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*
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* <sep> is the separator and can be either 'T', 't' or ' '.
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*
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* <date> is in the form:
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*
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* - `YYYY-MM-DD` - Year/month/day, e.g. 2016-08-24.
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* - `YYYYMMDD` - Same as above without dividers.
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* - `YYYY-DDD` - Ordinal day where DDD is from 001 to 366, e.g. 2016-237.
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* - `YYYYDDD` - Same as above without dividers.
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* - `YYYY-Www-D` - Week day where ww is from 01 to 52 and D from 1-7,
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* e.g. 2016-W34-3.
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* - `YYYYWwwD` - Same as above without dividers.
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*
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* <time> is in the form:
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*
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* - `hh:mm:ss(.sss)` - Hours, minutes, seconds (subseconds), e.g. 22:10:42.123.
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* - `hhmmss(.sss)` - Same as above without dividers.
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*
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* <tz> is an optional timezone suffix of the form:
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*
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* - `Z` - UTC.
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* - `+hh:mm` or `-hh:mm` - Offset from UTC in hours and minutes, e.g. +12:00.
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* - `+hh` or `-hh` - Offset from UTC in hours, e.g. +12.
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*
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* If the timezone is not provided in @text it must be provided in @default_tz
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* (this field is otherwise ignored).
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*
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* This call can fail (returning %NULL) if @text is not a valid ISO 8601
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* formatted string.
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*
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* You should release the return value by calling g_date_time_unref()
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* when you are done with it.
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*
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* Returns: (transfer full) (nullable): a new #GDateTime, or %NULL
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*
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* Since: 2.56
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*/
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GDateTime *
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g_date_time_new_from_iso8601 (const gchar *text, GTimeZone *default_tz)
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{
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gint length, date_length = -1;
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gint hour = 0, minute = 0;
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gdouble seconds = 0.0;
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GTimeZone *tz = NULL;
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GDateTime *datetime = NULL;
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g_return_val_if_fail (text != NULL, NULL);
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/* Count length of string and find date / time separator ('T', 't', or ' ') */
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for (length = 0; text[length] != '\0'; length++)
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{
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if (date_length < 0 && (text[length] == 'T' || text[length] == 't' || text[length] == ' '))
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date_length = length;
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}
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if (date_length < 0)
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return NULL;
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if (!parse_iso8601_time (text + date_length + 1, length - (date_length + 1),
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&hour, &minute, &seconds, &tz))
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goto out;
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if (tz == NULL && default_tz == NULL)
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return NULL;
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datetime = parse_iso8601_date (text, date_length, hour, minute, seconds, tz ? tz : default_tz);
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out:
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if (tz != NULL)
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g_time_zone_unref (tz);
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return datetime;
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}
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/* full new functions {{{1 */
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/**
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