@@ -342,51 +342,103 @@ namespace std::chrono
friend istream& operator>>(istream&, on_day&);
};
- // Wrapper for chrono::year that reads a year, or one of the keywords
- // "minimum" or "maximum", or an unambiguous prefix of a keyword.
- struct minmax_year
+ // Wrapper for two chrono::year values, which reads the FROM and TO
+ // fields of a Rule line. The FROM field is a year and TO is a year or
+ // one of the keywords "maximum" or "only" (or an abbreviation of those).
+ // For backwards compatibility, the keyword "minimum" is recognized
+ // for FROM and interpreted as 1900.
+ struct years_from_to
{
- year& y;
+ year& from;
+ year& to;
- friend istream& operator>>(istream& in, minmax_year&& y)
+ friend istream& operator>>(istream& in, years_from_to&& yy)
{
- if (ws(in).peek() == 'm') // keywords "minimum" or "maximum"
+ string s;
+ auto c = ws(in).peek();
+ if (c == 'm') [[unlikely]] // keyword "minimum"
{
- string s;
- in >> s; // extract the rest of the word, but only look at s[1]
- if (s[1] == 'a')
- y.y = year::max();
- else if (s[1] == 'i')
- y.y = year::min();
- else
- in.setstate(ios::failbit);
+ in >> s; // extract the rest of the word
+ yy.from = year(1900);
+ }
+ else if (int num = 0; in >> num) [[likely]]
+ yy.from = year{num};
+
+ c = ws(in).peek();
+ if (c == 'm') // keyword "maximum"
+ {
+ in >> s; // extract the rest of the word
+ yy.to = year::max();
+ }
+ else if (c == 'o') // keyword "only"
+ {
+ in >> s; // extract the rest of the word
+ yy.to = yy.from;
}
else if (int num = 0; in >> num)
- y.y = year{num};
+ yy.to = year{num};
+
return in;
}
};
- // As above for minmax_year, but also supports the keyword "only",
- // meaning that the TO year is the same as the FROM year.
- struct minmax_year2
+ bool
+ select_std_or_dst_abbrev(string& abbrev, minutes save)
{
- minmax_year to;
- year from;
+ if (size_t pos = abbrev.find('/'); pos != string::npos)
+ {
+ // Select one of "STD/DST" for standard or daylight.
+ if (save == 0min)
+ abbrev.erase(pos);
+ else
+ abbrev.erase(0, pos + 1);
+ return true;
+ }
+ return false;
+ }
- friend istream& operator>>(istream& in, minmax_year2&& y)
- {
- if (ws(in).peek() == 'o') // keyword "only"
- {
- string s;
- in >> s; // extract the whole keyword
- y.to.y = y.from;
- }
- else
- in >> std::move(y.to);
- return in;
- }
- };
+ // Set the sys_info::abbrev string by expanding any placeholders.
+ void
+ format_abbrev_str(sys_info& info, string_view letters = {})
+ {
+ if (size_t pos = info.abbrev.find('%'); pos != string::npos)
+ {
+ if (info.abbrev[pos + 1] == 's')
+ {
+ // Expand "%s" to the variable part, given by Rule::letters.
+ if (letters == "-")
+ info.abbrev.erase(pos, 2);
+ else
+ info.abbrev.replace(pos, 2, letters);
+ }
+ else if (info.abbrev[pos + 1] == 'z')
+ {
+ // Expand "%z" to the UT offset as +/-hh, +/-hhmm, or +/-hhmmss.
+ hh_mm_ss<seconds> t(info.offset);
+ string z(1, "+-"[t.is_negative()]);
+ long val = t.hours().count();
+ int digits = 2;
+ if (int m = t.minutes().count())
+ {
+ digits = 4;
+ val *= 100;
+ val += m;
+ if (int s = t.seconds().count())
+ {
+ digits = 6;
+ val *= 100;
+ val += s;
+ }
+ }
+ auto sval = std::to_string(val);
+ z += string(digits - sval.size(), '0');
+ z += sval;
+ info.abbrev.replace(pos, 2, z);
+ }
+ }
+ else
+ select_std_or_dst_abbrev(info.abbrev, info.save);
+ }
// A time zone information record.
// Zone NAME STDOFF RULES FORMAT [UNTIL]
@@ -462,6 +514,7 @@ namespace std::chrono
info.offset = offset();
info.save = minutes(m_save);
info.abbrev = format();
+ format_abbrev_str(info); // expand %z
return true;
}
@@ -469,12 +522,9 @@ namespace std::chrono
friend class time_zone;
void
- set_abbrev(const string& abbrev)
+ set_abbrev(string abbrev)
{
- // In practice, the FORMAT field never needs expanding here.
- if (abbrev.find_first_of("/%") != abbrev.npos)
- __throw_runtime_error("std::chrono::time_zone: invalid data");
- m_buf = abbrev;
+ m_buf = std::move(abbrev);
m_pos = 0;
m_expanded = true;
}
@@ -544,9 +594,7 @@ namespace std::chrono
// Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
- in >> quoted(rule.name)
- >> minmax_year{rule.from}
- >> minmax_year2{rule.to, rule.from};
+ in >> quoted(rule.name) >> years_from_to{rule.from, rule.to};
if (char type; in >> type && type != '-')
in.setstate(ios::failbit);
@@ -557,7 +605,7 @@ namespace std::chrono
if (save_time.indicator != at_time::Wall)
{
// We don't actually store the save_time.indicator, because we
- // assume that it's always deducable from the actual offset value.
+ // assume that it's always deducable from the offset value.
auto expected = save_time.time == 0s
? at_time::Standard
: at_time::Daylight;
@@ -567,8 +615,6 @@ namespace std::chrono
rule.save = save_time.time;
in >> rule.letters;
- if (rule.letters == "-")
- rule.letters.clear();
return in;
}
@@ -719,58 +765,6 @@ namespace std::chrono
#endif // TZDB_DISABLED
};
-#ifndef TZDB_DISABLED
- namespace
- {
- bool
- select_std_or_dst_abbrev(string& abbrev, minutes save)
- {
- if (size_t pos = abbrev.find('/'); pos != string::npos)
- {
- // Select one of "STD/DST" for standard or daylight.
- if (save == 0min)
- abbrev.erase(pos);
- else
- abbrev.erase(0, pos + 1);
- return true;
- }
- return false;
- }
-
- // Set the sys_info::abbrev string by expanding any placeholders.
- void
- format_abbrev_str(sys_info& info, string_view letters = {})
- {
- if (size_t pos = info.abbrev.find("%s"); pos != string::npos)
- {
- // Expand "%s" to the variable part, given by Rule::letters.
- info.abbrev.replace(pos, 2, letters);
- }
- else if (size_t pos = info.abbrev.find("%z"); pos != string::npos)
- {
- // Expand "%z" to the UT offset as +/-hh, +/-hhmm, or +/-hhmmss.
- hh_mm_ss<seconds> t(info.offset);
- string z(1, "+-"[t.is_negative()]);
- long val = t.hours().count();
- if (minutes m = t.minutes(); m != m.zero())
- {
- val *= 100;
- val += m.count();
- if (seconds s = t.seconds(); s != s.zero())
- {
- val *= 100;
- val += s.count();
- }
- }
- z += std::to_string(val);
- info.abbrev.replace(pos, 2, z);
- }
- else
- select_std_or_dst_abbrev(info.abbrev, info.save);
- }
- }
-#endif // TZDB_DISABLED
-
// Implementation of std::chrono::time_zone::get_info(const sys_time<D>&)
sys_info
time_zone::_M_get_sys_info(sys_seconds tp) const
@@ -839,12 +833,72 @@ namespace std::chrono
info.abbrev = ri.format();
string_view letters;
- if (i != infos.begin())
+ if (i != infos.begin() && i[-1].expanded())
+ letters = i[-1].next_letters();
+
+ if (letters.empty())
{
- if (i[-1].expanded())
- letters = i[-1].next_letters();
- // XXX else need to find Rule active before this time and use it
- // to know the initial offset, save, and letters.
+ sys_seconds t = info.begin - seconds(1);
+ const year_month_day date(chrono::floor<days>(t));
+
+ // Try to find a Rule active before this time, to get initial
+ // SAVE and LETTERS values. There may not be a Rule for the period
+ // before the first DST transition, so find the earliest DST->STD
+ // transition and use the LETTERS from that.
+ const Rule* active_rule = nullptr;
+ sys_seconds active_rule_start = sys_seconds::min();
+ const Rule* first_std = nullptr;
+ for (const auto& rule : rules)
+ {
+ if (rule.save == minutes(0))
+ {
+ if (!first_std)
+ first_std = &rule;
+ else if (rule.from < first_std->from)
+ first_std = &rule;
+ else if (rule.from == first_std->from)
+ {
+ if (rule.start_time(rule.from, {})
+ < first_std->start_time(first_std->from, {}))
+ first_std = &rule;
+ }
+ }
+
+ year y = date.year();
+
+ if (y > rule.to) // rule no longer applies at time t
+ continue;
+ if (y < rule.from) // rule doesn't apply yet at time t
+ continue;
+
+ sys_seconds rule_start;
+
+ seconds offset{}; // appropriate for at_time::Universal
+ if (rule.when.indicator == at_time::Wall)
+ offset = info.offset;
+ else if (rule.when.indicator == at_time::Standard)
+ offset = ri.offset();
+
+ // Time the rule takes effect this year:
+ rule_start = rule.start_time(y, offset);
+
+ if (rule_start >= t && rule.from < y)
+ {
+ // Try this rule in the previous year.
+ rule_start = rule.start_time(--y, offset);
+ }
+
+ if (active_rule_start < rule_start && rule_start < t)
+ {
+ active_rule_start = rule_start;
+ active_rule = &rule;
+ }
+ }
+
+ if (active_rule)
+ letters = active_rule->letters;
+ else if (first_std)
+ letters = first_std->letters;
}
const Rule* curr_rule = nullptr;
@@ -2069,9 +2123,11 @@ namespace std::chrono
istringstream in2(std::move(rules));
in2 >> rules_time;
inf.m_save = duration_cast<minutes>(rules_time.time);
+ // If the FORMAT is "STD/DST" then we can choose the right one
+ // now, so that we store a shorter string.
select_std_or_dst_abbrev(fmt, inf.m_save);
}
- inf.set_abbrev(fmt);
+ inf.set_abbrev(std::move(fmt));
}
// YEAR [MONTH [DAY [TIME]]]
@@ -2082,7 +2138,12 @@ namespace std::chrono
abbrev_month m{January};
int d = 1;
at_time t{};
+ // XXX DAY should support ON format, e.g. lastSun or Sun>=8
in >> m >> d >> t;
+ // XXX UNTIL field should be interpreted
+ // "using the rules in effect just before the transition"
+ // so might need to store as year_month_day and hh_mm_ss and only
+ // convert to a sys_time once we know the offset in effect.
inf.m_until = sys_days(year(y)/m.m/day(d)) + seconds(t.time);
}
else
new file mode 100644
@@ -0,0 +1,106 @@
+// { dg-do run { target c++20 } }
+// { dg-require-effective-target tzdb }
+// { dg-require-effective-target cxx11_abi }
+// { dg-xfail-run-if "no weak override on AIX" { powerpc-ibm-aix* } }
+
+#include <chrono>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+static bool override_used = false;
+
+namespace __gnu_cxx
+{
+ const char* zoneinfo_dir_override() {
+ override_used = true;
+ return "./";
+ }
+}
+
+using namespace std::chrono;
+
+void
+test_format()
+{
+ std::ofstream("tzdata.zi") << R"(# version test_1
+Zone Africa/Bissau -1:2:20 - LMT 1912 Ja 1 1u
+ -1 - %z 1975
+ 0 - GMT
+Zon Some/Zone 1:2:3 - %z 1900
+ 1:23:45 - %z 1950
+Zo Another/Zone 1:2:3 - AZ0 1901
+ 1 Roolz A%sZ 2000
+ 1 Roolz SAZ/DAZ 2005
+ 1 Roolz %z
+Rule Roolz 1950 max - April 1 2 1 D
+Rul Roolz 1950 max - Oct 1 1 0 S
+Z Strange/Zone 1 - X%sX 1980
+ 1 - FOO/BAR 1990
+ 2:00 - %zzz 1995
+ 0:9 - %zzz 1996
+ 0:8:7 - %zzz 1997
+ 0:6:5.5 - %zzz 1998
+)";
+
+ const auto& db = reload_tzdb();
+ VERIFY( override_used ); // If this fails then XFAIL for the target.
+ VERIFY( db.version == "test_1" );
+
+ // Test formatting %z as
+ auto tz = locate_zone("Africa/Bissau");
+ auto inf = tz->get_info(sys_days(1974y/1/1));
+ VERIFY( inf.abbrev == "-01" );
+
+ tz = locate_zone("Some/Zone");
+ inf = tz->get_info(sys_days(1899y/1/1));
+ VERIFY( inf.abbrev == "+010203" );
+ inf = tz->get_info(sys_days(1955y/1/1));
+ VERIFY( inf.abbrev == "+012345" );
+
+ tz = locate_zone("Another/Zone");
+ // Test formatting %s as the LETTER/S field from the active Rule.
+ inf = tz->get_info(sys_days(1910y/January/1));
+ VERIFY( inf.abbrev == "ASZ" );
+ inf = tz->get_info(sys_days(1950y/January/1));
+ VERIFY( inf.abbrev == "ASZ" );
+ inf = tz->get_info(sys_days(1950y/June/1));
+ VERIFY( inf.abbrev == "ADZ" );
+ inf = tz->get_info(sys_days(1999y/January/1));
+ VERIFY( inf.abbrev == "ASZ" );
+ inf = tz->get_info(sys_days(1999y/July/1));
+ VERIFY( inf.abbrev == "ADZ" );
+ // Test formatting STD/DST according to the active Rule.
+ inf = tz->get_info(sys_days(2000y/January/2));
+ VERIFY( inf.abbrev == "SAZ" );
+ inf = tz->get_info(sys_days(2001y/January/1));
+ VERIFY( inf.abbrev == "SAZ" );
+ inf = tz->get_info(sys_days(2001y/July/1));
+ VERIFY( inf.abbrev == "DAZ" );
+ // Test formatting %z as the offset determined by the active Rule.
+ inf = tz->get_info(sys_days(2005y/January/2));
+ VERIFY( inf.abbrev == "+01" );
+ inf = tz->get_info(sys_days(2006y/January/1));
+ VERIFY( inf.abbrev == "+01" );
+ inf = tz->get_info(sys_days(2006y/July/1));
+ VERIFY( inf.abbrev == "+02" );
+
+ // Test formatting %z, %s and S/D for a Zone with no associated Rules.
+ tz = locate_zone("Strange/Zone");
+ inf = tz->get_info(sys_days(1979y/January/1));
+ VERIFY( inf.abbrev == "XX" ); // No Rule means nothing to use for %s.
+ inf = tz->get_info(sys_days(1981y/July/1));
+ VERIFY( inf.abbrev == "FOO" ); // Always standard time means first string.
+ inf = tz->get_info(sys_days(1994y/July/1));
+ VERIFY( inf.abbrev == "+02zz" );
+ inf = tz->get_info(sys_days(1995y/July/1));
+ VERIFY( inf.abbrev == "+0009zz" );
+ inf = tz->get_info(sys_days(1996y/July/1));
+ VERIFY( inf.abbrev == "+000807zz" );
+ inf = tz->get_info(sys_days(1997y/July/1));
+ VERIFY( inf.abbrev == "+000606zz" );
+}
+
+int main()
+{
+ test_format();
+}
@@ -39,11 +39,15 @@ test_locate()
const tzdb& db = get_tzdb();
const time_zone* tz = db.locate_zone("GMT");
VERIFY( tz != nullptr );
- VERIFY( tz->name() == "Etc/GMT" );
VERIFY( tz == std::chrono::locate_zone("GMT") );
VERIFY( tz == db.locate_zone("Etc/GMT") );
VERIFY( tz == db.locate_zone("Etc/GMT+0") );
+ // Since 2022f GMT is now a Zone and Etc/GMT a link instead of vice versa,
+ // but only when using the vanguard format. As of 2024a, the main and
+ // rearguard formats still have Etc/GMT as a Zone and GMT as a link.
+ VERIFY( tz->name() == "GMT" || tz->name() == "Etc/GMT" );
+
VERIFY( db.locate_zone(db.current_zone()->name()) == db.current_zone() );
}