JezK
Edit File: Piece.pm
package Time::Piece; use strict; use XSLoader (); use Time::Seconds; use Carp; use Time::Local; use Exporter (); our @EXPORT = qw( localtime gmtime ); our %EXPORT_TAGS = ( ':override' => 'internal', ); our $VERSION = '1.3204'; XSLoader::load( 'Time::Piece', $VERSION ); my $DATE_SEP = '-'; my $TIME_SEP = ':'; my @MON_LIST = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec); my @FULLMON_LIST = qw(January February March April May June July August September October November December); my @DAY_LIST = qw(Sun Mon Tue Wed Thu Fri Sat); my @FULLDAY_LIST = qw(Sunday Monday Tuesday Wednesday Thursday Friday Saturday); my $IS_WIN32 = ($^O =~ /Win32/); my $LOCALE; use constant { 'c_sec' => 0, 'c_min' => 1, 'c_hour' => 2, 'c_mday' => 3, 'c_mon' => 4, 'c_year' => 5, 'c_wday' => 6, 'c_yday' => 7, 'c_isdst' => 8, 'c_epoch' => 9, 'c_islocal' => 10, }; sub localtime { unshift @_, __PACKAGE__ unless eval { $_[0]->isa('Time::Piece') }; my $class = shift; my $time = shift; $time = time if (!defined $time); $class->_mktime($time, 1); } sub gmtime { unshift @_, __PACKAGE__ unless eval { $_[0]->isa('Time::Piece') }; my $class = shift; my $time = shift; $time = time if (!defined $time); $class->_mktime($time, 0); } sub new { my $class = shift; my ($time) = @_; my $self; if (ref($time)) { $self = $time->[c_islocal] ? $class->localtime($time) : $class->gmtime($time); } elsif (defined($time)) { $self = $class->localtime($time); } elsif (ref($class) && $class->isa(__PACKAGE__)) { $self = $class->_mktime($class->epoch, $class->[c_islocal]); } else { $self = $class->localtime(); } return bless $self, ref($class) || $class; } sub parse { my $proto = shift; my $class = ref($proto) || $proto; my @components; warnings::warnif("deprecated", "parse() is deprecated, use strptime() instead."); if (@_ > 1) { @components = @_; } else { @components = shift =~ /(\d+)$DATE_SEP(\d+)$DATE_SEP(\d+)(?:(?:T|\s+)(\d+)$TIME_SEP(\d+)(?:$TIME_SEP(\d+)))/; @components = reverse(@components[0..5]); } return $class->new( timelocal(@components )); } sub _mktime { my ($class, $time, $islocal) = @_; $class = eval { (ref $class) && (ref $class)->isa('Time::Piece') } ? ref $class : $class; if (ref($time)) { my @new_time = @$time; my @tm_parts = (@new_time[c_sec .. c_mon], $new_time[c_year]+1900); $new_time[c_epoch] = $islocal ? timelocal(@tm_parts) : timegm(@tm_parts); return wantarray ? @new_time : bless [@new_time[0..9], $islocal], $class; } _tzset(); my @time = $islocal ? CORE::localtime($time) : CORE::gmtime($time); wantarray ? @time : bless [@time, $time, $islocal], $class; } my %_special_exports = ( localtime => sub { my $c = $_[0]; sub { $c->localtime(@_) } }, gmtime => sub { my $c = $_[0]; sub { $c->gmtime(@_) } }, ); sub export { my ($class, $to, @methods) = @_; for my $method (@methods) { if (exists $_special_exports{$method}) { no strict 'refs'; no warnings 'redefine'; *{$to . "::$method"} = $_special_exports{$method}->($class); } else { $class->Exporter::export($to, $method); } } } sub import { # replace CORE::GLOBAL localtime and gmtime if passed :override my $class = shift; my %params; map($params{$_}++,@_,@EXPORT); if (delete $params{':override'}) { $class->export('CORE::GLOBAL', keys %params); } else { $class->export(scalar caller, keys %params); } } ## Methods ## sub sec { my $time = shift; $time->[c_sec]; } *second = \&sec; sub min { my $time = shift; $time->[c_min]; } *minute = \&min; sub hour { my $time = shift; $time->[c_hour]; } sub mday { my $time = shift; $time->[c_mday]; } *day_of_month = \&mday; sub mon { my $time = shift; $time->[c_mon] + 1; } sub _mon { my $time = shift; $time->[c_mon]; } sub month { my $time = shift; if (@_) { return $_[$time->[c_mon]]; } elsif (@MON_LIST) { return $MON_LIST[$time->[c_mon]]; } else { return $time->strftime('%b'); } } *monname = \&month; sub fullmonth { my $time = shift; if (@_) { return $_[$time->[c_mon]]; } elsif (@FULLMON_LIST) { return $FULLMON_LIST[$time->[c_mon]]; } else { return $time->strftime('%B'); } } sub year { my $time = shift; $time->[c_year] + 1900; } sub _year { my $time = shift; $time->[c_year]; } sub yy { my $time = shift; my $res = $time->[c_year] % 100; return $res > 9 ? $res : "0$res"; } sub wday { my $time = shift; $time->[c_wday] + 1; } sub _wday { my $time = shift; $time->[c_wday]; } *day_of_week = \&_wday; sub wdayname { my $time = shift; if (@_) { return $_[$time->[c_wday]]; } elsif (@DAY_LIST) { return $DAY_LIST[$time->[c_wday]]; } else { return $time->strftime('%a'); } } *day = \&wdayname; sub fullday { my $time = shift; if (@_) { return $_[$time->[c_wday]]; } elsif (@FULLDAY_LIST) { return $FULLDAY_LIST[$time->[c_wday]]; } else { return $time->strftime('%A'); } } sub yday { my $time = shift; $time->[c_yday]; } *day_of_year = \&yday; sub isdst { my $time = shift; $time->[c_isdst]; } *daylight_savings = \&isdst; # Thanks to Tony Olekshy <olekshy@cs.ualberta.ca> for this algorithm sub tzoffset { my $time = shift; return Time::Seconds->new(0) unless $time->[c_islocal]; my $epoch = $time->epoch; my $j = sub { my ($s,$n,$h,$d,$m,$y) = @_; $m += 1; $y += 1900; $time->_jd($y, $m, $d, $h, $n, $s); }; # Compute floating offset in hours. # # Note use of crt methods so the tz is properly set... # See: http://perlmonks.org/?node_id=820347 my $delta = 24 * ($j->(_crt_localtime($epoch)) - $j->(_crt_gmtime($epoch))); # Return value in seconds rounded to nearest minute. return Time::Seconds->new( int($delta * 60 + ($delta >= 0 ? 0.5 : -0.5)) * 60 ); } sub epoch { my $time = shift; if (defined($time->[c_epoch])) { return $time->[c_epoch]; } else { my $epoch = $time->[c_islocal] ? timelocal(@{$time}[c_sec .. c_mon], $time->[c_year]+1900) : timegm(@{$time}[c_sec .. c_mon], $time->[c_year]+1900); $time->[c_epoch] = $epoch; return $epoch; } } sub hms { my $time = shift; my $sep = @_ ? shift(@_) : $TIME_SEP; sprintf("%02d$sep%02d$sep%02d", $time->[c_hour], $time->[c_min], $time->[c_sec]); } *time = \&hms; sub ymd { my $time = shift; my $sep = @_ ? shift(@_) : $DATE_SEP; sprintf("%d$sep%02d$sep%02d", $time->year, $time->mon, $time->[c_mday]); } *date = \&ymd; sub mdy { my $time = shift; my $sep = @_ ? shift(@_) : $DATE_SEP; sprintf("%02d$sep%02d$sep%d", $time->mon, $time->[c_mday], $time->year); } sub dmy { my $time = shift; my $sep = @_ ? shift(@_) : $DATE_SEP; sprintf("%02d$sep%02d$sep%d", $time->[c_mday], $time->mon, $time->year); } sub datetime { my $time = shift; my %seps = (date => $DATE_SEP, T => 'T', time => $TIME_SEP, @_); return join($seps{T}, $time->date($seps{date}), $time->time($seps{time})); } # Julian Day is always calculated for UT regardless # of local time sub julian_day { my $time = shift; # Correct for localtime $time = $time->gmtime( $time->epoch ) if $time->[c_islocal]; # Calculate the Julian day itself my $jd = $time->_jd( $time->year, $time->mon, $time->mday, $time->hour, $time->min, $time->sec); return $jd; } # MJD is defined as JD - 2400000.5 days sub mjd { return shift->julian_day - 2_400_000.5; } # Internal calculation of Julian date. Needed here so that # both tzoffset and mjd/jd methods can share the code # Algorithm from Hatcher 1984 (QJRAS 25, 53-55), and # Hughes et al, 1989, MNRAS, 238, 15 # See: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1989MNRAS.238.1529H&db_key=AST # for more details sub _jd { my $self = shift; my ($y, $m, $d, $h, $n, $s) = @_; # Adjust input parameters according to the month $y = ( $m > 2 ? $y : $y - 1); $m = ( $m > 2 ? $m - 3 : $m + 9); # Calculate the Julian Date (assuming Julian calendar) my $J = int( 365.25 *( $y + 4712) ) + int( (30.6 * $m) + 0.5) + 59 + $d - 0.5; # Calculate the Gregorian Correction (since we have Gregorian dates) my $G = 38 - int( 0.75 * int(49+($y/100))); # Calculate the actual Julian Date my $JD = $J + $G; # Modify to include hours/mins/secs in floating portion. return $JD + ($h + ($n + $s / 60) / 60) / 24; } sub week { my $self = shift; my $J = $self->julian_day; # Julian day is independent of time zone so add on tzoffset # if we are using local time here since we want the week day # to reflect the local time rather than UTC $J += ($self->tzoffset/(24*3600)) if $self->[c_islocal]; # Now that we have the Julian day including fractions # convert it to an integer Julian Day Number using nearest # int (since the day changes at midday we convert all Julian # dates to following midnight). $J = int($J+0.5); use integer; my $d4 = ((($J + 31741 - ($J % 7)) % 146097) % 36524) % 1461; my $L = $d4 / 1460; my $d1 = (($d4 - $L) % 365) + $L; return $d1 / 7 + 1; } sub _is_leap_year { my $year = shift; return (($year %4 == 0) && !($year % 100 == 0)) || ($year % 400 == 0) ? 1 : 0; } sub is_leap_year { my $time = shift; my $year = $time->year; return _is_leap_year($year); } my @MON_LAST = qw(31 28 31 30 31 30 31 31 30 31 30 31); sub month_last_day { my $time = shift; my $year = $time->year; my $_mon = $time->_mon; return $MON_LAST[$_mon] + ($_mon == 1 ? _is_leap_year($year) : 0); } my $trans_map_common = { 'c' => sub { my ( $format ) = @_; if($LOCALE->{PM} && $LOCALE->{AM}){ $format =~ s/%c/%a %d %b %Y %I:%M:%S %p/; } else{ $format =~ s/%c/%a %d %b %Y %H:%M:%S/; } return $format; }, 'r' => sub { my ( $format ) = @_; if($LOCALE->{PM} && $LOCALE->{AM}){ $format =~ s/%r/%I:%M:%S %p/; } else{ $format =~ s/%r/%H:%M:%S/; } return $format; }, 'X' => sub { my ( $format ) = @_; if($LOCALE->{PM} && $LOCALE->{AM}){ $format =~ s/%X/%I:%M:%S %p/; } else{ $format =~ s/%X/%H:%M:%S/; } return $format; }, }; my $strftime_trans_map = { %{$trans_map_common}, 'e' => sub { my ( $format, $time ) = @_; $format =~ s/%e/%d/ if $IS_WIN32; return $format; }, 'D' => sub { my ( $format, $time ) = @_; $format =~ s/%D/%m\/%d\/%y/; return $format; }, 'F' => sub { my ( $format, $time ) = @_; $format =~ s/%F/%Y-%m-%d/; return $format; }, 'R' => sub { my ( $format, $time ) = @_; $format =~ s/%R/%H:%M/; return $format; }, 's' => sub { #%s not portable if time parts are from gmtime since %s will #cause a call to native mktime (and thus uses local TZ) my ( $format, $time ) = @_; $format =~ s/%s/$time->[c_epoch]/; return $format; }, 'T' => sub { my ( $format, $time ) = @_; $format =~ s/%T/%H:%M:%S/ if $IS_WIN32; return $format; }, 'u' => sub { my ( $format, $time ) = @_; $format =~ s/%u/%w/ if $IS_WIN32; return $format; }, 'V' => sub { my ( $format, $time ) = @_; my $week = sprintf( "%02d", $time->week() ); $format =~ s/%V/$week/ if $IS_WIN32; return $format; }, 'x' => sub { my ( $format, $time ) = @_; $format =~ s/%x/%a %d %b %Y/; return $format; }, 'z' => sub { #%[zZ] not portable if time parts are from gmtime my ( $format, $time ) = @_; $format =~ s/%z/+0000/ if not $time->[c_islocal]; return $format; }, 'Z' => sub { my ( $format, $time ) = @_; $format =~ s/%Z/UTC/ if not $time->[c_islocal]; return $format; }, }; sub strftime { my $time = shift; my $format = @_ ? shift(@_) : '%a, %d %b %Y %H:%M:%S %Z'; $format = _translate_format($format, $strftime_trans_map, $time); return $format unless $format =~ /%/; #if translate removes everything return _strftime($format, $time->epoch, $time->[c_islocal]); } my $strptime_trans_map = { %{$trans_map_common}, }; sub strptime { my $time = shift; my $string = shift; my $format = @_ ? shift(@_) : "%a, %d %b %Y %H:%M:%S %Z"; my $islocal = (ref($time) ? $time->[c_islocal] : 0); my $locales = $LOCALE || &Time::Piece::_default_locale(); $format = _translate_format($format, $strptime_trans_map); my @vals = _strptime($string, $format, $islocal, $locales); # warn(sprintf("got vals: %d-%d-%d %d:%d:%d\n", reverse(@vals[c_sec..c_year]))); return scalar $time->_mktime(\@vals, $islocal); } sub day_list { shift if ref($_[0]) && $_[0]->isa(__PACKAGE__); # strip first if called as a method my @old = @DAY_LIST; if (@_) { @DAY_LIST = @_; &Time::Piece::_default_locale(); } return @old; } sub mon_list { shift if ref($_[0]) && $_[0]->isa(__PACKAGE__); # strip first if called as a method my @old = @MON_LIST; if (@_) { @MON_LIST = @_; &Time::Piece::_default_locale(); } return @old; } sub time_separator { shift if ref($_[0]) && $_[0]->isa(__PACKAGE__); my $old = $TIME_SEP; if (@_) { $TIME_SEP = $_[0]; } return $old; } sub date_separator { shift if ref($_[0]) && $_[0]->isa(__PACKAGE__); my $old = $DATE_SEP; if (@_) { $DATE_SEP = $_[0]; } return $old; } use overload '""' => \&cdate, 'cmp' => \&str_compare, 'fallback' => undef; sub cdate { my $time = shift; if ($time->[c_islocal]) { return scalar(CORE::localtime($time->epoch)); } else { return scalar(CORE::gmtime($time->epoch)); } } sub str_compare { my ($lhs, $rhs, $reverse) = @_; if (UNIVERSAL::isa($rhs, 'Time::Piece')) { $rhs = "$rhs"; } return $reverse ? $rhs cmp $lhs->cdate : $lhs->cdate cmp $rhs; } use overload '-' => \&subtract, '+' => \&add; sub subtract { my $time = shift; my $rhs = shift; if (UNIVERSAL::isa($rhs, 'Time::Seconds')) { $rhs = $rhs->seconds; } if (shift) { # SWAPED is set (so someone tried an expression like NOTDATE - DATE). # Imitate Perl's standard behavior and return the result as if the # string $time resolves to was subtracted from NOTDATE. This way, # classes which override this one and which have a stringify function # that resolves to something that looks more like a number don't need # to override this function. return $rhs - "$time"; } if (UNIVERSAL::isa($rhs, 'Time::Piece')) { return Time::Seconds->new($time->epoch - $rhs->epoch); } else { # rhs is seconds. return $time->_mktime(($time->epoch - $rhs), $time->[c_islocal]); } } sub add { my $time = shift; my $rhs = shift; if (UNIVERSAL::isa($rhs, 'Time::Seconds')) { $rhs = $rhs->seconds; } croak "Invalid rhs of addition: $rhs" if ref($rhs); return $time->_mktime(($time->epoch + $rhs), $time->[c_islocal]); } use overload '<=>' => \&compare; sub get_epochs { my ($lhs, $rhs, $reverse) = @_; if (!UNIVERSAL::isa($rhs, 'Time::Piece')) { $rhs = $lhs->new($rhs); } if ($reverse) { return $rhs->epoch, $lhs->epoch; } return $lhs->epoch, $rhs->epoch; } sub compare { my ($lhs, $rhs) = get_epochs(@_); return $lhs <=> $rhs; } sub add_months { my ($time, $num_months) = @_; croak("add_months requires a number of months") unless defined($num_months); my $final_month = $time->_mon + $num_months; my $num_years = 0; if ($final_month > 11 || $final_month < 0) { # these two ops required because we have no POSIX::floor and don't # want to load POSIX.pm if ($final_month < 0 && $final_month % 12 == 0) { $num_years = int($final_month / 12) + 1; } else { $num_years = int($final_month / 12); } $num_years-- if ($final_month < 0); $final_month = $final_month % 12; } my @vals = _mini_mktime($time->sec, $time->min, $time->hour, $time->mday, $final_month, $time->year - 1900 + $num_years); # warn(sprintf("got %d vals: %d-%d-%d %d:%d:%d [%d]\n", scalar(@vals), reverse(@vals), $time->[c_islocal])); return scalar $time->_mktime(\@vals, $time->[c_islocal]); } sub add_years { my ($time, $years) = @_; $time->add_months($years * 12); } sub truncate { my ($time, %params) = @_; return $time unless exists $params{to}; #if ($params{to} eq 'week') { return $time->_truncate_week; } my %units = ( second => 0, minute => 1, hour => 2, day => 3, month => 4, quarter => 5, year => 5 ); my $to = $units{$params{to}}; croak "Invalid value of 'to' parameter: $params{to}" unless defined $to; my $start_month = 0; if ($params{to} eq 'quarter') { $start_month = int( $time->_mon / 3 ) * 3; } my @down_to = (0, 0, 0, 1, $start_month, $time->year); return $time->_mktime([@down_to[0..$to-1], @$time[$to..c_isdst]], $time->[c_islocal]); } #Given a format and a translate map, replace format flags in #accordance with the logic from the translation map subroutines sub _translate_format { my ( $format, $trans_map, $time ) = @_; $format =~ s/%%/\e\e/g; #escape the escape my $lexer = _build_format_lexer($format); while(my $flag = $lexer->() ){ next unless exists $trans_map->{$flag}; $format = $trans_map->{$flag}($format, $time); } $format =~ s/\e\e/%%/g; return $format; } sub _build_format_lexer { my $format = shift(); #Higher Order Perl p.359 (or thereabouts) return sub { LABEL: { return $1 if $format =~ m/\G%([a-zA-Z])/gc; #return single char flags redo LABEL if $format =~ m/\G(.)/gc; return; #return at empty string } }; } sub use_locale { #get locale month/day names from posix strftime (from Piece.xs) my $locales = _get_localization(); $locales->{PM} ||= ''; $locales->{AM} ||= ''; $locales->{pm} = lc $locales->{PM}; $locales->{am} = lc $locales->{AM}; #should probably figure out how to get a #region specific format for %c someday $locales->{c_fmt} = ''; #Set globals. If anything is #weird just use original if( @{$locales->{weekday}} < 7 ){ @{$locales->{weekday}} = @FULLDAY_LIST; } else { @FULLDAY_LIST = @{$locales->{weekday}}; } if( @{$locales->{wday}} < 7 ){ @{$locales->{wday}} = @DAY_LIST; } else { @DAY_LIST = @{$locales->{wday}}; } if( @{$locales->{month}} < 12 ){ @{$locales->{month}} = @FULLMON_LIST; }else { @FULLMON_LIST = @{$locales->{month}}; } if( @{$locales->{mon}} < 12 ){ @{$locales->{mon}} = @MON_LIST; } else{ @MON_LIST= @{$locales->{mon}}; } $LOCALE = $locales; } #$Time::Piece::LOCALE is used by strptime and thus needs to be #in sync with what ever users change to via day_list() and mon_list(). #Should probably deprecate this use of gloabl state, but oh well... sub _default_locale { my $locales = {}; @{ $locales->{weekday} } = @FULLDAY_LIST; @{ $locales->{wday} } = @DAY_LIST; @{ $locales->{month} } = @FULLMON_LIST; @{ $locales->{mon} } = @MON_LIST; $locales->{alt_month} = $locales->{month}; $locales->{PM} = 'PM'; $locales->{AM} = 'AM'; $locales->{pm} = 'pm'; $locales->{am} = 'am'; $locales->{c_fmt} = ''; $LOCALE = $locales; } sub _locale { return $LOCALE; } 1; __END__ =head1 NAME Time::Piece - Object Oriented time objects =head1 SYNOPSIS use Time::Piece; my $t = localtime; print "Time is $t\n"; print "Year is ", $t->year, "\n"; =head1 DESCRIPTION This module replaces the standard C<localtime> and C<gmtime> functions with implementations that return objects. It does so in a backwards compatible manner, so that using localtime/gmtime in the way documented in perlfunc will still return what you expect. The module actually implements most of an interface described by Larry Wall on the perl5-porters mailing list here: L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2000-01/msg00241.html> =head1 USAGE After importing this module, when you use localtime or gmtime in a scalar context, rather than getting an ordinary scalar string representing the date and time, you get a Time::Piece object, whose stringification happens to produce the same effect as the localtime and gmtime functions. There is also a new() constructor provided, which is the same as localtime(), except when passed a Time::Piece object, in which case it's a copy constructor. The following methods are available on the object: $t->sec # also available as $t->second $t->min # also available as $t->minute $t->hour # 24 hour $t->mday # also available as $t->day_of_month $t->mon # 1 = January $t->_mon # 0 = January $t->monname # Feb $t->month # same as $t->monname $t->fullmonth # February $t->year # based at 0 (year 0 AD is, of course 1 BC) $t->_year # year minus 1900 $t->yy # 2 digit year $t->wday # 1 = Sunday $t->_wday # 0 = Sunday $t->day_of_week # 0 = Sunday $t->wdayname # Tue $t->day # same as wdayname $t->fullday # Tuesday $t->yday # also available as $t->day_of_year, 0 = Jan 01 $t->isdst # also available as $t->daylight_savings $t->hms # 12:34:56 $t->hms(".") # 12.34.56 $t->time # same as $t->hms $t->ymd # 2000-02-29 $t->date # same as $t->ymd $t->mdy # 02-29-2000 $t->mdy("/") # 02/29/2000 $t->dmy # 29-02-2000 $t->dmy(".") # 29.02.2000 $t->datetime # 2000-02-29T12:34:56 (ISO 8601) $t->cdate # Tue Feb 29 12:34:56 2000 "$t" # same as $t->cdate $t->epoch # seconds since the epoch $t->tzoffset # timezone offset in a Time::Seconds object $t->julian_day # number of days since Julian period began $t->mjd # modified Julian date (JD-2400000.5 days) $t->week # week number (ISO 8601) $t->is_leap_year # true if it's a leap year $t->month_last_day # 28-31 $t->time_separator($s) # set the default separator (default ":") $t->date_separator($s) # set the default separator (default "-") $t->day_list(@days) # set the default weekdays $t->mon_list(@days) # set the default months $t->strftime(FORMAT) # same as POSIX::strftime (without the overhead # of the full POSIX extension) $t->strftime() # "Tue, 29 Feb 2000 12:34:56 GMT" Time::Piece->strptime(STRING, FORMAT) # see strptime man page. Creates a new # Time::Piece object Note that C<localtime> and C<gmtime> are not listed above. If called as methods on a Time::Piece object, they act as constructors, returning a new Time::Piece object for the current time. In other words: they're not useful as methods. =head2 Local Locales Both wdayname (day) and monname (month) allow passing in a list to use to index the name of the days against. This can be useful if you need to implement some form of localisation without actually installing or using locales. Note that this is a global override and will affect all Time::Piece instances. my @days = qw( Dimanche Lundi Merdi Mercredi Jeudi Vendredi Samedi ); my $french_day = localtime->day(@days); These settings can be overridden globally too: Time::Piece::day_list(@days); Or for months: Time::Piece::mon_list(@months); And locally for months: print localtime->month(@months); Or to populate with your current system locale call: Time::Piece->use_locale(); =head2 Date Calculations It's possible to use simple addition and subtraction of objects: use Time::Seconds; my $seconds = $t1 - $t2; $t1 += ONE_DAY; # add 1 day (constant from Time::Seconds) The following are valid ($t1 and $t2 are Time::Piece objects): $t1 - $t2; # returns Time::Seconds object $t1 - 42; # returns Time::Piece object $t1 + 533; # returns Time::Piece object However adding a Time::Piece object to another Time::Piece object will cause a runtime error. Note that the first of the above returns a Time::Seconds object, so while examining the object will print the number of seconds (because of the overloading), you can also get the number of minutes, hours, days, weeks and years in that delta, using the Time::Seconds API. In addition to adding seconds, there are two APIs for adding months and years: $t = $t->add_months(6); $t = $t->add_years(5); The months and years can be negative for subtractions. Note that there is some "strange" behaviour when adding and subtracting months at the ends of months. Generally when the resulting month is shorter than the starting month then the number of overlap days is added. For example subtracting a month from 2008-03-31 will not result in 2008-02-31 as this is an impossible date. Instead you will get 2008-03-02. This appears to be consistent with other date manipulation tools. =head2 Truncation Calling the C<truncate> method returns a copy of the object but with the time truncated to the start of the supplied unit. $t = $t->truncate(to => 'day'); This example will set the time to midnight on the same date which C<$t> had previously. Allowed values for the "to" parameter are: "year", "quarter", "month", "day", "hour", "minute" and "second". =head2 Date Comparisons Date comparisons are also possible, using the full suite of "<", ">", "<=", ">=", "<=>", "==" and "!=". =head2 Date Parsing Time::Piece has a built-in strptime() function (from FreeBSD), allowing you incredibly flexible date parsing routines. For example: my $t = Time::Piece->strptime("Sunday 3rd Nov, 1943", "%A %drd %b, %Y"); print $t->strftime("%a, %d %b %Y"); Outputs: Wed, 03 Nov 1943 (see, it's even smart enough to fix my obvious date bug) For more information see "man strptime", which should be on all unix systems. Alternatively look here: L<http://www.unix.com/man-page/FreeBSD/3/strftime/> =head3 CAVEAT %A, %a, %B, %b, and friends Time::Piece::strptime by default can only parse American English date names. Meanwhile, Time::Piece->strftime() will return date names that use the current configured system locale. This means dates returned by strftime might not be able to be parsed by strptime. This is the default behavior and can be overridden by calling Time::Piece->use_locale(). This builds a list of the current locale's day and month names which strptime will use to parse with. Note this is a global override and will affect all Time::Piece instances. For instance with a German locale: localtime->day_list(); Returns ( 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat' ) While: Time::Piece->use_locale(); localtime->day_list(); Returns ( 'So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa' ) =head2 YYYY-MM-DDThh:mm:ss The ISO 8601 standard defines the date format to be YYYY-MM-DD, and the time format to be hh:mm:ss (24 hour clock), and if combined, they should be concatenated with date first and with a capital 'T' in front of the time. =head2 Week Number The I<week number> may be an unknown concept to some readers. The ISO 8601 standard defines that weeks begin on a Monday and week 1 of the year is the week that includes both January 4th and the first Thursday of the year. In other words, if the first Monday of January is the 2nd, 3rd, or 4th, the preceding days of the January are part of the last week of the preceding year. Week numbers range from 1 to 53. =head2 Global Overriding Finally, it's possible to override localtime and gmtime everywhere, by including the ':override' tag in the import list: use Time::Piece ':override'; =head1 CAVEATS =head2 Setting $ENV{TZ} in Threads on Win32 Note that when using perl in the default build configuration on Win32 (specifically, when perl is built with PERL_IMPLICIT_SYS), each perl interpreter maintains its own copy of the environment and only the main interpreter will update the process environment seen by strftime. Therefore, if you make changes to $ENV{TZ} from inside a thread other than the main thread then those changes will not be seen by strftime if you subsequently call that with the %Z formatting code. You must change $ENV{TZ} in the main thread to have the desired effect in this case (and you must also call _tzset() in the main thread to register the environment change). Furthermore, remember that this caveat also applies to fork(), which is emulated by threads on Win32. =head2 Use of epoch seconds This module internally uses the epoch seconds system that is provided via the perl C<time()> function and supported by C<gmtime()> and C<localtime()>. If your perl does not support times larger than C<2^31> seconds then this module is likely to fail at processing dates beyond the year 2038. There are moves afoot to fix that in perl. Alternatively use 64 bit perl. Or if none of those are options, use the L<DateTime> module which has support for years well into the future and past. =head1 AUTHOR Matt Sergeant, matt@sergeant.org Jarkko Hietaniemi, jhi@iki.fi (while creating Time::Piece for core perl) =head1 COPYRIGHT AND LICENSE Copyright 2001, Larry Wall. This module is free software, you may distribute it under the same terms as Perl. =head1 SEE ALSO The excellent Calendar FAQ at L<http://www.tondering.dk/claus/calendar.html> =head1 BUGS The test harness leaves much to be desired. Patches welcome. =cut