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WIP: Add glibc extensions (fmtlib#2959)
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* support `-` for no padding
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@jayache80
jayache80 committed Jul 31, 2022
1 parent 756822b commit 112a927
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Showing 2 changed files with 173 additions and 38 deletions.
128 changes: 90 additions & 38 deletions include/fmt/chrono.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -605,6 +605,8 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
const Char* end,
Handler&& handler) {
auto ptr = begin;
bool pad = true;

while (ptr != end) {
auto c = *ptr;
if (c == '}') break;
Expand All @@ -613,7 +615,11 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
continue;
}
if (begin != ptr) handler.on_text(begin, ptr);
++ptr; // consume '%'
c = *++ptr; // consume '%'
if (c == '-') {
pad = false;
++ptr;
}
if (ptr == end) FMT_THROW(format_error("invalid format"));
c = *ptr++;
switch (c) {
Expand Down Expand Up @@ -691,16 +697,16 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
break;
// Hour, minute, second:
case 'H':
handler.on_24_hour(numeric_system::standard);
handler.on_24_hour(numeric_system::standard, pad);
break;
case 'I':
handler.on_12_hour(numeric_system::standard);
handler.on_12_hour(numeric_system::standard, pad);
break;
case 'M':
handler.on_minute(numeric_system::standard);
handler.on_minute(numeric_system::standard, pad);
break;
case 'S':
handler.on_second(numeric_system::standard);
handler.on_second(numeric_system::standard, pad);
break;
// Other:
case 'c':
Expand Down Expand Up @@ -802,16 +808,16 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
handler.on_dec1_weekday(numeric_system::alternative);
break;
case 'H':
handler.on_24_hour(numeric_system::alternative);
handler.on_24_hour(numeric_system::alternative, pad);
break;
case 'I':
handler.on_12_hour(numeric_system::alternative);
handler.on_12_hour(numeric_system::alternative, pad);
break;
case 'M':
handler.on_minute(numeric_system::alternative);
handler.on_minute(numeric_system::alternative, pad);
break;
case 'S':
handler.on_second(numeric_system::alternative);
handler.on_second(numeric_system::alternative, pad);
break;
default:
FMT_THROW(format_error("invalid format"));
Expand Down Expand Up @@ -892,10 +898,10 @@ struct tm_format_checker : null_chrono_spec_handler<tm_format_checker> {
FMT_CONSTEXPR void on_day_of_year() {}
FMT_CONSTEXPR void on_day_of_month(numeric_system) {}
FMT_CONSTEXPR void on_day_of_month_space(numeric_system) {}
FMT_CONSTEXPR void on_24_hour(numeric_system) {}
FMT_CONSTEXPR void on_12_hour(numeric_system) {}
FMT_CONSTEXPR void on_minute(numeric_system) {}
FMT_CONSTEXPR void on_second(numeric_system) {}
FMT_CONSTEXPR void on_24_hour(numeric_system, bool) {}
FMT_CONSTEXPR void on_12_hour(numeric_system, bool) {}
FMT_CONSTEXPR void on_minute(numeric_system, bool) {}
FMT_CONSTEXPR void on_second(numeric_system, bool) {}
FMT_CONSTEXPR void on_datetime(numeric_system) {}
FMT_CONSTEXPR void on_loc_date(numeric_system) {}
FMT_CONSTEXPR void on_loc_time(numeric_system) {}
Expand Down Expand Up @@ -1315,21 +1321,44 @@ template <typename OutputIt, typename Char> class tm_writer {
}
}

void on_24_hour(numeric_system ns) {
if (is_classic_ || ns == numeric_system::standard) return write2(tm_hour());
void on_24_hour(numeric_system ns, bool pad = true) {
if (is_classic_ || ns == numeric_system::standard) {
int hour24 = tm_hour();
if (hour24 < 10 && !pad) {
return write1(hour24);
}
return write2(hour24);
}
format_localized('H', 'O');
}
void on_12_hour(numeric_system ns) {
if (is_classic_ || ns == numeric_system::standard)
return write2(tm_hour12());
void on_12_hour(numeric_system ns, bool pad = true) {
if (is_classic_ || ns == numeric_system::standard) {
int hour12 = tm_hour12();
if (hour12 < 10 && !pad) {
return write1(hour12);
}
return write2(hour12);
}
format_localized('I', 'O');
}
void on_minute(numeric_system ns) {
if (is_classic_ || ns == numeric_system::standard) return write2(tm_min());
void on_minute(numeric_system ns, bool pad = true) {
if (is_classic_ || ns == numeric_system::standard) {
int min = tm_min();
if (min < 10 && !pad) {
return write1(min);
}
return write2(min);
}
format_localized('M', 'O');
}
void on_second(numeric_system ns) {
if (is_classic_ || ns == numeric_system::standard) return write2(tm_sec());
void on_second(numeric_system ns, bool pad = true) {
if (is_classic_ || ns == numeric_system::standard) {
int sec = tm_sec();
if (sec < 10 && !pad) {
return write1(sec);
}
return write2(sec);
}
format_localized('S', 'O');
}

Expand Down Expand Up @@ -1376,10 +1405,10 @@ struct chrono_format_checker : null_chrono_spec_handler<chrono_format_checker> {

template <typename Char>
FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
FMT_CONSTEXPR void on_24_hour(numeric_system) {}
FMT_CONSTEXPR void on_12_hour(numeric_system) {}
FMT_CONSTEXPR void on_minute(numeric_system) {}
FMT_CONSTEXPR void on_second(numeric_system) {}
FMT_CONSTEXPR void on_24_hour(numeric_system, bool) {}
FMT_CONSTEXPR void on_12_hour(numeric_system, bool) {}
FMT_CONSTEXPR void on_minute(numeric_system, bool) {}
FMT_CONSTEXPR void on_second(numeric_system, bool) {}
FMT_CONSTEXPR void on_12_hour_time() {}
FMT_CONSTEXPR void on_24_hour_time() {}
FMT_CONSTEXPR void on_iso_time() {}
Expand Down Expand Up @@ -1739,34 +1768,52 @@ struct chrono_formatter {
void on_day_of_month(numeric_system) {}
void on_day_of_month_space(numeric_system) {}

void on_24_hour(numeric_system ns) {
void on_24_hour(numeric_system ns, bool pad = true) {
if (handle_nan_inf()) return;

if (ns == numeric_system::standard) return write(hour(), 2);
if (ns == numeric_system::standard) {
int hour24 = hour();
if (hour24 < 10 && !pad) {
return write(hour24, 1);
}
return write(hour24, 2);
}
auto time = tm();
time.tm_hour = to_nonnegative_int(hour(), 24);
format_tm(time, &tm_writer_type::on_24_hour, ns);
format_tm(time, &tm_writer_type::on_24_hour, ns, pad);
}

void on_12_hour(numeric_system ns) {
void on_12_hour(numeric_system ns, bool pad = true) {
if (handle_nan_inf()) return;

if (ns == numeric_system::standard) return write(hour12(), 2);
if (ns == numeric_system::standard) {
Rep hour12_ = hour12();
if (hour12_ < 10 && !pad) {
return write(hour12_, 1);
}
return write(hour12_, 2);
}
auto time = tm();
time.tm_hour = to_nonnegative_int(hour12(), 12);
format_tm(time, &tm_writer_type::on_12_hour, ns);
format_tm(time, &tm_writer_type::on_12_hour, ns, pad);
}

void on_minute(numeric_system ns) {
void on_minute(numeric_system ns, bool pad = true) {
if (handle_nan_inf()) return;

if (ns == numeric_system::standard) return write(minute(), 2);
if (ns == numeric_system::standard) {
int min = minute();
if (min < 10 && !pad) {
return write(min, 1);
}
return write(min, 2);
}
auto time = tm();
time.tm_min = to_nonnegative_int(minute(), 60);
format_tm(time, &tm_writer_type::on_minute, ns);
format_tm(time, &tm_writer_type::on_minute, ns, pad);
}

void on_second(numeric_system ns) {
void on_second(numeric_system ns, bool pad = true) {
if (handle_nan_inf()) return;

if (ns == numeric_system::standard) {
Expand All @@ -1783,14 +1830,19 @@ struct chrono_formatter {
if (buf.size() < 2 || buf[1] == '.') *out++ = '0';
out = std::copy(buf.begin(), buf.end(), out);
} else {
write(second(), 2);
int sec = second();
if (sec < 10 && !pad) {
write(sec, 1);
} else {
write(sec, 2);
}
write_fractional_seconds(std::chrono::duration<rep, Period>(val));
}
return;
}
auto time = tm();
time.tm_sec = to_nonnegative_int(second(), 60);
format_tm(time, &tm_writer_type::on_second, ns);
format_tm(time, &tm_writer_type::on_second, ns, pad);
}

void on_12_hour_time() {
Expand Down
83 changes: 83 additions & 0 deletions test/chrono-test.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -629,4 +629,87 @@ TEST(chrono_test, cpp20_duration_subsecond_support) {
"00.142857");
}

TEST(chrono_test, glibc_extensions) {
// Glibc provides some extensions for conversion specifications. (These extensions are not specified in POSIX.1-2001, but a few other
// systems provide similar features.) Between the '%' character and the conversion specifier character, an optional flag and field
// width may be specified. (These precede the E or O modifiers, if present.)

// The following flag characters are permitted:

// _ (underscore) Pad a numeric result string with spaces.

// - (dash) Do not pad a numeric result string.

// 0 Pad a numeric result string with zeros even if the conversion specifier character uses space-padding by default.

// ^ Convert alphabetic characters in result string to uppercase.

// # Swap the case of the result string. (This flag works only with certain conversion specifier characters, and of these, it is
// only really useful with %Z.)

// An optional decimal width specifier may follow the (possibly absent) flag. If the natural size of the field is smaller than this
// width, then the result string is padded (on the left) to the specified width.

// Do not pad a numeric result string

// chrono_formatter, numeric_system::standard
auto dur = std::chrono::milliseconds{97445678};
auto formatted_dur_pad_12 = fmt::format("{:%I:%M:%S}", dur);
auto formatted_dur_no_pad_12 = fmt::format("{:%-I:%-M:%-S}", dur);
auto formatted_dur_pad_24 = fmt::format("{:%H:%M:%S}", dur);
auto formatted_dur_no_pad_24 = fmt::format("{:%-H:%-M:%-S}", dur);
auto expected_pad_12 = "03:04:05.678";
auto expected_no_pad_12 = "3:4:5.678";
auto expected_pad_24 = expected_pad_12;
auto expected_no_pad_24 = expected_no_pad_12;
EXPECT_EQ(formatted_dur_pad_12, expected_pad_12);
EXPECT_EQ(formatted_dur_no_pad_12, expected_no_pad_12);
EXPECT_EQ(formatted_dur_pad_24, expected_pad_24);
EXPECT_EQ(formatted_dur_no_pad_24, expected_no_pad_24);

// chrono_formatter -> tm_writer, numeric_system::alternative
formatted_dur_pad_12 = fmt::format("{:%OI:%OM:%OS}", dur);
formatted_dur_no_pad_12 = fmt::format("{:%-OI:%-OM:%-OS}", dur);
formatted_dur_pad_24 = fmt::format("{:%OH:%M:%OS}", dur);
formatted_dur_no_pad_24 = fmt::format("{:%-OH:%-OM:%-OS}", dur);
// TODO: %OS causes fractional seconds to be dropped. Is this intended?
expected_pad_12 = "03:04:05";
expected_no_pad_12 = "3:4:5";
expected_pad_24 = expected_pad_12;
expected_no_pad_24 = expected_no_pad_12;
EXPECT_EQ(formatted_dur_pad_12, expected_pad_12);
EXPECT_EQ(formatted_dur_no_pad_12, expected_no_pad_12);
EXPECT_EQ(formatted_dur_pad_24, expected_pad_24);
EXPECT_EQ(formatted_dur_no_pad_24, expected_no_pad_24);

// tm_writer, numeric_system::standard
std::tm tm = make_tm(1970, 1, 2, 3, 4, 5);
auto formatted_tm_pad_12 = fmt::format("{:%I:%M:%S}", tm);
auto formatted_tm_no_pad_12 = fmt::format("{:%-I:%-M:%-S}", tm);
auto formatted_tm_pad_24 = fmt::format("{:%H:%M:%S}", tm);
auto formatted_tm_no_pad_24 = fmt::format("{:%-H:%-M:%-S}", tm);
EXPECT_EQ(formatted_tm_pad_12, expected_pad_12);
EXPECT_EQ(formatted_tm_no_pad_12, expected_no_pad_12);
EXPECT_EQ(formatted_tm_pad_24, expected_pad_24);
EXPECT_EQ(formatted_tm_no_pad_24, expected_no_pad_24);

// tm_writer, numeric_system::alternative (localized)
auto loc = get_locale("ja_JP.utf8");
if (loc == std::locale::classic()) return;
formatted_tm_pad_12 = fmt::format(loc, "{:%OI:%OM:%OS}", tm);
formatted_tm_no_pad_12 = fmt::format(loc, "{:%-OI:%-OM:%-OS}", tm);
formatted_tm_pad_24 = fmt::format(loc, "{:%OH:%OM:%OS}", tm);
formatted_tm_no_pad_24 = fmt::format(loc, "{:%-OH:%-OM:%-OS}", tm);
// TODO: For localized, there is no concept of 0-padding so padded and not
// padded should be the same. If this is incorrect, please let me know.
expected_pad_12 = "三:四:五";
expected_no_pad_12 = expected_pad_12;
expected_pad_24 = expected_pad_12;
expected_no_pad_24 = expected_pad_12;
EXPECT_EQ(formatted_tm_pad_12, expected_pad_12);
EXPECT_EQ(formatted_tm_no_pad_12, expected_no_pad_12);
EXPECT_EQ(formatted_tm_pad_24, expected_pad_24);
EXPECT_EQ(formatted_tm_no_pad_24, expected_no_pad_24);
}

#endif // FMT_STATIC_THOUSANDS_SEPARATOR

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