NAME

Time::Normalize - Convert time and date values into standardized components.

VERSION

This is version 0.05 of Normalize.pm, November 15, 2006.

SYNOPSIS

use Time::Normalize;

$hashref = normalize_ymd ($in_yr, $in_mo, $in_d);
($year, $mon, $day,
 $dow, $dow_name, $dow_abbr,
 $mon_name, $mon_abbr) = normalize_ymd ($in_yr, $in_mo, $in_dy);

$hashref = normalize_ym ($in_yr, $in_mo);
@same_values_as_for_normalize_ymd = normalize_ym ($in_yr, $in_mo);

$hashref = normalize_hms ($in_h, $in_m, $in_s, $in_ampm);
($hour, $min, $sec,
 $h12, $ampm, $since_midnight)
         = normalize_hms ($in_h, $in_m, $in_s, $in_ampm);

$hashref = normalize_time ($time_epoch);
($sec, $min, $hour,
 $day, $mon, $year,
 $dow, $yday, $isdst,
 $h12, $ampm, $since_midnight,
 $dow_name, $dow_abbr,
 $mon_name, $mon_abbr) = normalize_time ($time_epoch);

$hashref = normalize_gmtime ($time_epoch);
@same_values_as_for_normalize_time = normalize_gmtime ($time_epoch);

$year  = normalize_year($input_year);

$month = normalize_month($input_month);

Utility functions (not exported by default):

use Time::Normalize qw(mon_name  mon_abbr  day_name  day_abbr
                       days_in   is_leap );

$name = mon_name($month_number);    # input: 1 to 12
$abbr = mon_abbr($month_number);    # input: 1 to 12
$name = day_name($weekday_number);  # input: 0(Sunday) to 6
$abbr = day_abbr($weekday_number);  # input: 0(Sunday) to 6
$num  = days_in($month, $year);
$bool = is_leap($year);

DESCRIPTION

Splitting a date into its component pieces is just the beginning.

Human date conventions are quirky (and I'm not just talking about the dates I've had!) Despite the Y2K near-disaster, some people continue to use two-digit year numbers. Months are sometimes specified as a number from 1-12, sometimes as a spelled-out name, sometimes as a abbreviation. Some months have more days than others. Humans sometimes use a 12-hour clock, and sometimes a 24-hour clock.

This module performs simple but tedious (and error-prone) checks on its inputs, and returns the time and/or date components in a sanitized, standardized manner, suitable for use in the remainder of your program.

Even when you get your values from a time-tested library function, such as localtime or gmtime, you need to do routine transformations on the returned values. The year returned is off by 1900 (for historical reasons); the month is in the range 0-11; you may want the month name or day of week name instead of numbers. The "normalize_time" function decodes localtime's values into commonly-needed formats.

FUNCTIONS

normalize_ymd

$hashref = normalize_ymd ($in_yr, $in_mo, $in_d);

($year, $mon, $day,
 $dow, $dow_name, $dow_abbr,
 $mon_name, $mon_abbr) = normalize_ymd ($in_yr, $in_mo, $in_dy);

Takes an arbitrary year, month, and day as input, and returns various data elements in a standard, consistent format. The output may be a hash reference or a list of values. If a hash reference is desired, the keys of that hash will be the same as the variable names given in the above synopsis; that is, day, dow, dow_abbr, dow_name, mon, mon_abbr, mon_name, and year.

Input:

The input year may be either two digits or four digits. If two digits, the century is chosen so that the resulting four-digit year is closest to the current calendar year (i.e., within 50 years).

The input month may either be a number from 1 to 12, or a full month name as defined by the current locale, or a month abbreviation as defined by the current locale. If it's a name or abbreviation, case is not significant.

The input day must be a number from 1 to the number of days in the specified month and year.

If any of the input values do not meet the above criteria, an exception will be thrown. See "DIAGNOSTICS".

Output:

year will always be four digits.

month will always be two digits, 01-12.

day will always be two digits 01-31.

dow will be a number from 0 (Sunday) to 6 (Saturday).

dow_name will be the name of the day of the week, as defined by the current locale, in the locale's preferred case.

dow_abbr will be the standard weekday name abbreviation, as defined by the current locale, in the locale's preferred case.

mon_name will be the month name, as defined by the current locale, in the locale's preferred case.

mon_abbr will be the standard month name abbreviation, as defined by the current locale, in the locale's preferred case.

normalize_ym

$hashref = normalize_ym ($in_yr, $in_mo);

($year, $mon, $day,
 $dow, $dow_name, $dow_abbr,
 $mon_name, $mon_abbr) = normalize_ym ($in_yr, $in_mo);

Works exactly like normalize_ymd, except that it does not take an input day. Instead, it computes the last day of the specified year and month, and returns the values associated with that date.

This is equivalent to the following sequence:

normalize_ymd ($in_yr, $in_mo, days_in ($in_mo, $in_yr));

normalize_year

$year = normalize_year ($in_yr);

This takes a two-digit or four-digit year, and returns the four-digit year.

normalize_month

$month = normalize_month ($in_mo);

This takes a numeric month (1-12), alphabetic spelled-out month, or alphabetic month abbreviation, and returns the two-digit month number (01-12).

normalize_hms

$hashref = normalize_hms ($in_h, $in_m, $in_s, $in_ampm);

($hour, $min, $sec,
 $h12, $ampm, $since_midnight)
         = normalize_hms ($in_h, $in_m, $in_s, $in_ampm);

Like "normalize_ymd", normalize_hms takes a variety of possible inputs and returns standardized values. As above, the output may be a hash reference or a list of values. If a hash reference is desired, the keys of that hash will be the same as the variable names given in the above synopsis; that is, ampm, h12, hour, min, sec, and since_midnight. Also, a h24 key is provided as a synonym for hour.

Input:

The input hour may either be a 12-hour or a 24-hour time value. If $in_ampm is specified, $in_h is assumed to be on a 12-hour clock, and if $in_ampm is absent, $in_h is assumed to be on a 24-hour clock.

The input minute must be numeric, and must be in the range 0 to 59.

The input second $in_s is optional. If omitted, it defaults to 0. If specified, it must be in the range 0 to 59.

The AM/PM indicator $in_ampm is optional. If specified, it may be any of the following:

a   am   a.m.  p   pm   p.m.  A   AM   A.M.  P   PM   P.M.

If any of the input values do not meet the above criteria, an exception will be thrown. See "DIAGNOSTICS".

Output:

hour The first output hour will always be on a 24-hour clock, and will always be two digits, 00-23.

min will always be two digits, 00-59.

sec will always be two digits, 00-59.

h12 is the 12-hour clock equivalent of $hour. It is not zero-padded.

ampm will always be either a lowercase 'a' or a lowercase 'p', no matter what format the input AM/PM indicator was, or even if it was omitted.

since_midnight is the number of seconds since midnight represented by this time.

h24 is a key created if you request a hashref as the output; it's a synonym for hour.

normalize_time

$hashref = normalize_time($time_epoch);

($sec, $min, $hour,
 $day, $mon, $year,
 $dow, $yday, $isdst,
 $h12, $ampm, $since_midnight,
 $dow_name, $dow_abbr,
 $mon_name, $mon_abbr) = normalize_time($time_epoch);

Takes a number in the usual perl epoch, passes it to localtime, and transforms the results. If $time_epoch is omitted, the current time is used instead.

The output values (or hash values) are exactly as for "normalize_ymd" and "normalize_hms", above.

normalize_gmtime

Exactly the same as normalize_time, but uses gmtime internally instead of localtime.

mon_name

$name = mon_name($m);

Returns the full name of the specified month $m; $m ranges from 1 (January) to 12 (December). The name is returned in the language and case appropriate for the current locale.

mon_abbr

$abbr = mon_abbr($m);

Returns the abbreviated name of the specified month $m; $m ranges from 1 (Jan) to 12 (Dec). The name is returned in the language and case appropriate for the current locale.

day_name

$name = day_name($d);

Returns the full name of the specified day of the week $d; $d ranges from 0 (Sunday) to 6 (Saturday). The name is returned in the language and case appropriate for the current locale.

day_abbr

$abbr = day_abbr($d);

Returns the abbreviated name of the specified day of the week $d; $d ranges from 0 (Sun) to 6 (Sat). The name is returned in the language and case appropriate for the current locale.

days_in

$num = days_in ($month, $year);

Returns the number of days in the specified month and year. If the month is not 2 (February), $year isn't even examined.

is_leap

$boolean = is_leap ($year);

Returns true if the given year is a leap year, according to the usual Gregorian rules.

DIAGNOSTICS

The functions in this module throw exceptions (that is, they croak) whenever invalid arguments are passed to them. Therefore, it is generally a Good Idea to trap these exceptions with an eval block.

The error messages are meant to be easy to parse, if you need to. There are two kinds of errors thrown: data errors, and programming errors.

Data errors are caused by invalid data values; that is, values that do not conform to the expectations listed above. These messages all look like:

Time::Normalize: Invalid thing: "value"

Programming errors are caused by you--passing the wrong number of parameters to a function. These messages look like one of the following::

Too {many|few} arguments to function_name Non-integer month "month" for mon_name

EXAMPLES

$h = normalize_ymd (2005, 'january', 4);
#
# Returns:
#         $h->{day}        "04"
#         $h->{dow}        2
#         $h->{dow_abbr}   "Tue"
#         $h->{dow_name}   "Tuesday"
#         $h->{mon}        "01"
#         $h->{mon_abbr}   "Jan"
#         $h->{mon_name}   "January"
#         $h->{year}       2005
# ------------------------------------------------

$h = normalize_ymd ('05', 12, 31);
#
# Returns:
#         $h->{day}        31
#         $h->{dow}        6
#         $h->{dow_abbr}   "Sat"
#         $h->{dow_name}   "Saturday"
#         $h->{mon}        12
#         $h->{mon_abbr}   "Dec"
#         $h->{mon_name}   "December"
#         $h->{year}       2005
# ------------------------------------------------

$h = normalize_ymd (2005, 2, 29);
#
# Throws an exception:
#         Time::Normalize: Invalid day: "29"
# ------------------------------------------------

$h = normalize_hms (9, 10, 0, 'AM');
#
# Returns:
#         $h->{ampm}       "a"
#         $h->{h12}        9
#         $h->{h24}        "09"
#         $h->{hour}       "09"
#         $h->{min}        10
#         $h->{sec}        "00"
#         $h->{since_midnight}    33000
# ------------------------------------------------

$h = normalize_hms (9, 10, undef, 'p.m.');
#
# Returns:
#         $h->{ampm}       "p"
#         $h->{h12}        9
#         $h->{h24}        21
#         $h->{hour}       21
#         $h->{min}        10
#         $h->{sec}        "00"
#         $h->{since_midnight}    76200
# ------------------------------------------------

$h = normalize_hms (1, 10);
#
# Returns:
#         $h->{ampm}       "a"
#         $h->{h12}        1
#         $h->{h24}        "01"
#         $h->{hour}       "01"
#         $h->{min}        10
#         $h->{sec}        "00"
#         $h->{since_midnight}    4200
# ------------------------------------------------

$h = normalize_hms (13, 10);
#
# Returns:
#         $h->{ampm}       "p"
#         $h->{h12}        1
#         $h->{h24}        13
#         $h->{hour}       13
#         $h->{min}        10
#         $h->{sec}        "00"
#         $h->{since_midnight}    47400
# ------------------------------------------------

$h = normalize_hms (13, 10, undef, 'pm');
#
# Throws an exception:
#         Time::Normalize: Invalid hour: "13"
# ------------------------------------------------

$h = normalize_gmtime(1131725587);
#
# Returns:
#         $h->{ampm}       "p"
#         $h->{sec}        "07",
#         $h->{min}        13,
#         $h->{hour}       16,
#         $h->{day}        11,
#         $h->{mon}        11,
#         $h->{year}       2005,
#         $h->{dow}        5,
#         $h->{yday}       314,
#         $h->{isdst}      0,
#         $h->{h12}        4
#         $h->{ampm}       "p"
#         $h->{since_midnight}        58_387,
#         $h->{dow_name}   "Friday",
#         $h->{dow_abbr}   "Fri",
#         $h->{mon_name}   "November",
#         $h->{mon_abbr}   "Nov",
# ------------------------------------------------

EXPORTS

This module exports the following symbols into the caller's namespace:

normalize_ymd
normalize_hms
normalize_time
normalize_gmtime
normalize_month
normalize_year
normalize_ym

The following symbols are available for export:

mon_name
mon_abbr
day_name
day_abbr
is_leap
days_in

You may use the export tag "all" to get all of the above symbols:

use Time::Normalize ':all';

REQUIREMENTS

If POSIX and I18N::Langinfo is available, this module will use them; otherwise, it will use hardcoded English values for month and weekday names.

Test::More is required for the test suite.

BUGS

Uses Gregorian rules for computing whether a year is a leap year, no matter how long ago the year was.

NOT A BUG

By convention, noon is 12:00 pm; midnight is 12:00 am.

AUTHOR / COPYRIGHT

Eric J. Roode, roode@cpan.org

To avoid my spam filter, please include "Perl", "module", or this module's name in the message's subject line, and/or GPG-sign your message.

To install Time::Normalize, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Time::Normalize

CPAN shell

perl -MCPAN -e shell
install Time::Normalize

For more information on module installation, please visit the detailed CPAN module installation guide.

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