Perl convert YYYYMMDD to 16digit epoch time - perl

Question

Is there a perl function that converts YYYYMMDD to a 16digit epoch time?
I'm currently calling the date command:
date -d 20160219 +%s%6N
for the conversion but my script takes a long time to go through the millions of dates in my data set.
By "16digit epoch time", I mean a 16-digit decimal integer representing microseconds since the epoch. For example, 2016-02-19 00:00:00 UTC is 1455840000 seconds after the epoch, so the result I want is "1455840000000000".

Answer 1

You can also use Time::Moment. In the interest of full disclosure, I am the author of Time::Moment.
use v5.10;
use Time::Moment;
say Time::Moment->from_string('20160219' . 'T00Z')
->strftime('%s%6N');
Output:
1455840000000000

Answer 2

Time::Piece can do all the things you want. After that just right pad 0's to epoch, so that it becomes 16 digits.
#!/usr/bin/perl
use strict;
use warnings;
use Time::Piece;
my $t = Time::Piece -> strptime("20160219",
"%Y%m%d");
my $epoch = $t -> epoch;
# make $epoch 16 digits
$epoch .= "0" x (16 - length($epoch));
print "$epoch\n";

Answer 3

You can use the Time::Local core module:
use Time::Local 'timelocal';
$date = "20160218";
($year, $month, $day) = unpack "A4A2A2", $date;
$time = timelocal(0, 0, 0, $day, $month-1, $year);
$time .= '000000';

Answer 4

Wow, I just actually wrote a script to take the timestamp where it takes a timestamp where it's in seconds since epoch and convert it to human readable format. Not what you asked, but perhaps you can reverse what I wrote.
my $ts = $ARGV[0]; #2012-09-04-20:24:19.870 1030825460
my $newTs = toTimeString($ts);
print "\n".$newTs."\n";
## Convert from time since epoch in seconds to string YYYY-MM-DD-HH:mm:ss.sss
sub toTimeString{
my $ts=shift;
$ts += 432000; # Add 5 days to make computation easy.
my $sec = $ts-int($ts/60)*60; # Seconds
$ts = int($ts/60); # Convert to minutes
my $min = $ts%60; # minutes
$ts = int($ts/60); # Convert to hours.
my $hr = $ts%24; # hours;
$ts = int($ts/24); # Convert to days.
my $yr;
my $mo;
my $day;
my $days = [ [31,28,31,30,31,30,31,31,30,31,30,31],
[31,29,31,30,31,30,31,31,30,31,30,31]
];
our $cumDays = [ [0,31,59,90,120,151,181,212,243,273,304,334],
[0,31,60,91,121,152,182,213,244,274,305,335]
];
if($ts<366){$yr=1980;}
else{
$yr = 1981 + int(($ts-366)/1461)*4;
$ts = $ts - 366 - int(($ts-366)/1461)*1461;
if($ts < 1095){$yr += int($ts/365); $ts = $ts - int($ts/365)*365;}
else{$yr = $yr+3; $ts=$ts-1095;}
}
my $leap=0;
my $i;
if($yr%4 == 0){$leap=1;}
for($i=0;$i<12;$i++){
if($ts > $cumDays->[$leap]->[$i]){
$mo=$i+1;
}
}
$day=$ts-$cumDays->[$leap]->[$mo-1]+1;
my $ret;
$ret = sprintf("%04d",$yr)."-".sprintf("%02d",$mo)."-".sprintf("%02d",$day)."-";
$ret = $ret.sprintf("%02d",$hr).":".sprintf("%02d",$min).":".sprintf("%02d",int($sec));
$ret = $ret."\.".sprintf("%03d",int($sec*1000)%1000);
return ($ret)
}