123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596 |
- #------------------------------------------------------------------------------
- # File: Shift.pl
- #
- # Description: ExifTool time shifting routines
- #
- # Revisions: 10/28/2005 - P. Harvey Created
- #------------------------------------------------------------------------------
- package Image::ExifTool;
- use strict;
- sub ShiftTime($$;$$);
- #------------------------------------------------------------------------------
- # apply shift to value in new value hash
- # Inputs: 0) ExifTool ref, 1) shift type, 2) shift string, 3) raw date/time value,
- # 4) new value hash ref
- # Returns: error string or undef on success and updates value in new value hash
- sub ApplyShift($$$$;$)
- {
- my ($self, $func, $shift, $val, $nvHash) = @_;
- # get shift direction from first character in shift string
- my $pre = ($shift =~ s/^(\+|-)//) ? $1 : '+';
- my $dir = ($pre eq '+') ? 1 : -1;
- my $tagInfo = $$nvHash{TagInfo};
- my $tag = $$tagInfo{Name};
- my $shiftOffset;
- if ($$nvHash{ShiftOffset}) {
- $shiftOffset = $$nvHash{ShiftOffset};
- } else {
- $shiftOffset = $$nvHash{ShiftOffset} = { };
- }
- # initialize handler for eval warnings
- local $SIG{'__WARN__'} = \&SetWarning;
- SetWarning(undef);
- # shift is applied to ValueConv value, so we must ValueConv-Shift-ValueConvInv
- my ($type, $err);
- foreach $type ('ValueConv','Shift','ValueConvInv') {
- if ($type eq 'Shift') {
- #### eval ShiftXxx function
- $err = eval "Shift$func(\$val, \$shift, \$dir, \$shiftOffset)";
- } elsif ($$tagInfo{$type}) {
- my $conv = $$tagInfo{$type};
- if (ref $conv eq 'CODE') {
- $val = &$conv($val, $self);
- } else {
- return "Can't handle $type for $tag in ApplyShift()" if ref $$tagInfo{$type};
- #### eval ValueConv/ValueConvInv ($val, $self)
- $val = eval $$tagInfo{$type};
- }
- } else {
- next;
- }
- # handle errors
- $err and return $err;
- $@ and SetWarning($@);
- GetWarning() and return CleanWarning();
- }
- # update value in new value hash
- $nvHash->{Value} = [ $val ];
- return undef; # success
- }
- #------------------------------------------------------------------------------
- # Check date/time shift
- # Inputs: 0) shift type, 1) shift string (without sign)
- # Returns: updated shift string, or undef on error (and may update shift)
- sub CheckShift($$)
- {
- my ($type, $shift) = @_;
- my $err;
- if ($type eq 'Time') {
- return "No shift direction" unless $shift =~ s/^(\+|-)//;
- # do a test shift to validate the shift string
- my $testTime = '2005:11:02 09:00:13.25-04:00';
- $err = ShiftTime($testTime, $shift, $1 eq '+' ? 1 : -1);
- } else {
- $err = "Unknown shift type ($type)";
- }
- return $err;
- }
- #------------------------------------------------------------------------------
- # return the number of days in a month
- # Inputs: 0) month number (Jan=1, may be outside range), 1) year
- # Returns: number of days in month
- sub DaysInMonth($$)
- {
- my ($mon, $year) = @_;
- my @days = (31,28,31,30,31,30,31,31,30,31,30,31);
- # adjust to the range [0,11]
- while ($mon < 1) { $mon += 12; --$year; }
- while ($mon > 12) { $mon -= 12; ++$year; }
- # return standard number of days unless february on a leap year
- return $days[$mon-1] unless $mon == 2 and not $year % 4;
- # leap years don't occur on even centuries except every 400 years
- return 29 if $year % 100 or not $year % 400;
- return 28;
- }
- #------------------------------------------------------------------------------
- # split times into corresponding components: YYYY mm dd HH MM SS tzh tzm
- # Inputs: 0) date/time or shift string 1) reference to list for returned components
- # 2) optional reference to list of time components (if shift string)
- # Returns: true on success
- # Returned components are 0-Y, 1-M, 2-D, 3-hr, 4-min, 5-sec, 6-tzhr, 7-tzmin
- sub SplitTime($$;$)
- {
- my ($val, $vals, $time) = @_;
- # insert zeros if missing in shift string
- if ($time) {
- $val =~ s/(^|[-+:\s]):/${1}0:/g;
- $val =~ s/:([:\s]|$)/:0$1/g;
- }
- # change dashes to colons in date (for XMP dates)
- if ($val =~ s/^(\d{4})-(\d{2})-(\d{2})/$1:$2:$3/) {
- $val =~ tr/T/ /; # change 'T' separator to ' '
- }
- # add space before timezone to split it into a separate word
- $val =~ s/(\+|-)/ $1/;
- my @words = split ' ', $val;
- my $err = 1;
- my @v;
- for (;;) {
- my $word = shift @words;
- last unless defined $word;
- # split word into separate numbers (allow decimal points but no signs)
- my @vals = $word =~ /(?=\d|\.\d)\d*(?:\.\d*)?/g or last;
- if ($word =~ /^(\+|-)/) {
- # this is the timezone
- (defined $v[6] or @vals > 2) and $err = 1, last;
- my $sign = ($1 ne '-') ? 1 : -1;
- # apply sign to both minutes and seconds
- $v[6] = $sign * shift(@vals);
- $v[7] = $sign * (shift(@vals) || 0);
- } elsif ((@words and $words[0] =~ /^\d+/) or # there is a time word to follow
- (not $time and $vals[0] =~ /^\d{3}/) or # first value is year (3 or more digits)
- ($time and not defined $$time[3] and not defined $v[0])) # we don't have a time
- {
- # this is a date (must come first)
- (@v or @vals > 3) and $err = 1, last;
- not $time and @vals != 3 and $err = 1, last;
- $v[2] = pop(@vals); # take day first if only one specified
- $v[1] = pop(@vals) || 0;
- $v[0] = pop(@vals) || 0;
- } else {
- # this is a time (can't come after timezone)
- (defined $v[3] or defined $v[6] or @vals > 3) and $err = 1, last;
- not $time and @vals != 3 and @vals != 2 and $err = 1, last;
- $v[3] = shift(@vals); # take hour first if only one specified
- $v[4] = shift(@vals) || 0;
- $v[5] = shift(@vals) || 0;
- }
- $err = 0;
- }
- return 0 if $err or not @v;
- if ($time) {
- # zero any required shift entries which aren't yet defined
- $v[0] = $v[1] = $v[2] = 0 if defined $$time[0] and not defined $v[0];
- $v[3] = $v[4] = $v[5] = 0 if defined $$time[3] and not defined $v[3];
- $v[6] = $v[7] = 0 if defined $$time[6] and not defined $v[6];
- }
- @$vals = @v; # return split time components
- return 1;
- }
- #------------------------------------------------------------------------------
- # shift date/time by components
- # Inputs: 0) split date/time list ref, 1) split shift list ref,
- # 2) shift direction, 3) reference to output list of shifted components
- # 4) number of decimal points in seconds
- # 5) reference to return time difference due to rounding
- # Returns: error string or undef on success
- sub ShiftComponents($$$$$;$)
- {
- my ($time, $shift, $dir, $toTime, $dec, $rndPt) = @_;
- # min/max for Y, M, D, h, m, s
- my @min = ( 0, 1, 1, 0, 0, 0);
- my @max = (10000,12,28,24,60,60);
- my $i;
- #
- # apply the shift
- #
- my $c = 0;
- for ($i=0; $i<@$time; ++$i) {
- my $v = ($$time[$i] || 0) + $dir * ($$shift[$i] || 0) + $c;
- # handle fractional values by propagating remainders downwards
- if ($v != int($v) and $i < 5) {
- my $iv = int($v);
- $c = ($v - $iv) * $max[$i+1];
- $v = $iv;
- } else {
- $c = 0;
- }
- $$toTime[$i] = $v;
- }
- # round off seconds to the required number of decimal points
- my $sec = $$toTime[5];
- if (defined $sec and $sec != int($sec)) {
- my $mult = 10 ** $dec;
- my $rndSec = int($sec * $mult + 0.5 * ($sec <=> 0)) / $mult;
- $rndPt and $$rndPt = $sec - $rndSec;
- $$toTime[5] = $rndSec;
- }
- #
- # handle overflows, starting with least significant number first (seconds)
- #
- $c = 0;
- for ($i=5; $i>=0; $i--) {
- defined $$time[$i] or $c = 0, next;
- # apply shift and adjust for previous overflow
- my $v = $$toTime[$i] + $c;
- $c = 0; # set carry to zero
- # adjust for over/underflow
- my ($min, $max) = ($min[$i], $max[$i]);
- if ($v < $min) {
- if ($i == 2) { # 2 = day of month
- do {
- # add number of days in previous month
- --$c;
- my $mon = $$toTime[$i-1] + $c;
- $v += DaysInMonth($mon, $$toTime[$i-2]);
- } while ($v < 1);
- } else {
- my $fc = ($v - $min) / $max;
- # carry ($c) must be largest integer equal to or less than $fc
- $c = int($fc);
- --$c if $c > $fc;
- $v -= $c * $max;
- }
- } elsif ($v >= $max + $min) {
- if ($i == 2) {
- for (;;) {
- # test against number of days in current month
- my $mon = $$toTime[$i-1] + $c;
- my $days = DaysInMonth($mon, $$toTime[$i-2]);
- last if $v <= $days;
- $v -= $days;
- ++$c;
- last if $v <= 28;
- }
- } else {
- my $fc = ($v - $max - $min) / $max;
- # carry ($c) must be smallest integer greater than $fc
- $c = int($fc);
- ++$c if $c <= $fc;
- $v -= $c * $max;
- }
- }
- $$toTime[$i] = $v; # save the new value
- }
- # handle overflows in timezone
- if (defined $$toTime[6]) {
- my $m = $$toTime[6] * 60 + $$toTime[7];
- $m += 0.5 * ($m <=> 0); # avoid round-off errors
- $$toTime[6] = int($m / 60);
- $$toTime[7] = int($m - $$toTime[6] * 60);
- }
- return undef; # success
- }
- #------------------------------------------------------------------------------
- # Shift an integer or floating-point number
- # Inputs: 0) date/time string, 1) shift string, 2) shift direction (+1 or -1)
- # 3) (unused)
- # Returns: undef and updates input value
- sub ShiftNumber($$$;$)
- {
- my ($val, $shift, $dir) = @_;
- $_[0] = $val + $shift * $dir; # return shifted value
- return undef; # success!
- }
- #------------------------------------------------------------------------------
- # Shift date/time string
- # Inputs: 0) date/time string, 1) shift string, 2) shift direction (+1 or -1),
- # or 0 or undef to take shift direction from sign of shift,
- # 3) reference to ShiftOffset hash (with Date, DateTime, Time, Timezone keys)
- # Returns: error string or undef on success and date/time string is updated
- sub ShiftTime($$;$$)
- {
- local $_;
- my ($val, $shift, $dir, $shiftOffset) = @_;
- my (@time, @shift, @toTime, $mode, $needShiftOffset, $dec);
- $dir or $dir = ($shift =~ s/^(\+|-)// and $1 eq '-') ? -1 : 1;
- #
- # figure out what we are dealing with (time, date or date/time)
- #
- SplitTime($val, \@time) or return "Invalid time string ($val)";
- if (defined $time[0]) {
- $mode = defined $time[3] ? 'DateTime' : 'Date';
- } elsif (defined $time[3]) {
- $mode = 'Time';
- }
- # get number of digits after the seconds decimal point
- if (defined $time[5] and $time[5] =~ /\.(\d+)/) {
- $dec = length($1);
- } else {
- $dec = 0;
- }
- if ($shiftOffset) {
- $needShiftOffset = 1 unless defined $$shiftOffset{$mode};
- $needShiftOffset = 1 if defined $time[6] and not defined $$shiftOffset{Timezone};
- } else {
- $needShiftOffset = 1;
- }
- if ($needShiftOffset) {
- #
- # apply date/time shift the hard way
- #
- SplitTime($shift, \@shift, \@time) or return "Invalid shift string ($shift)";
- # change 'Z' timezone to '+00:00' only if necessary
- if (@shift > 6 and @time <= 6) {
- $time[6] = $time[7] = 0 if $val =~ s/Z$/\+00:00/;
- }
- my $rndDiff;
- my $err = ShiftComponents(\@time, \@shift, $dir, \@toTime, $dec, \$rndDiff);
- $err and return $err;
- #
- # calculate and save the shift offsets for next time
- #
- if ($shiftOffset) {
- if (defined $time[0] or defined $time[3]) {
- my @tm1 = (0, 0, 0, 1, 0, 2000);
- my @tm2 = (0, 0, 0, 1, 0, 2000);
- if (defined $time[0]) {
- @tm1[3..5] = reverse @time[0..2];
- @tm2[3..5] = reverse @toTime[0..2];
- --$tm1[4]; # month should start from 0
- --$tm2[4];
- }
- my $diff = 0;
- if (defined $time[3]) {
- @tm1[0..2] = reverse @time[3..5];
- @tm2[0..2] = reverse @toTime[3..5];
- # handle fractional seconds separately
- $diff = $tm2[0] - int($tm2[0]) - ($tm1[0] - int($tm1[0]));
- $diff += $rndDiff if defined $rndDiff; # un-do rounding
- $tm1[0] = int($tm1[0]);
- $tm2[0] = int($tm2[0]);
- }
- eval q{
- require Time::Local;
- $diff += Time::Local::timegm(@tm2) - Time::Local::timegm(@tm1);
- };
- # not a problem if we failed here since we'll just try again next time,
- # so don't return error message
- unless (@$) {
- my $mode;
- if (defined $time[0]) {
- $mode = defined $time[3] ? 'DateTime' : 'Date';
- } else {
- $mode = 'Time';
- }
- $$shiftOffset{$mode} = $diff;
- }
- }
- if (defined $time[6]) {
- $$shiftOffset{Timezone} = ($toTime[6] - $time[6]) * 60 +
- $toTime[7] - $time[7];
- }
- }
- } else {
- #
- # apply shift from previously calculated offsets
- #
- if ($$shiftOffset{Timezone} and @time <= 6) {
- # change 'Z' timezone to '+00:00' only if necessary
- $time[6] = $time[7] = 0 if $val =~ s/Z$/\+00:00/;
- }
- # apply the previous date/time shift if necessary
- if ($mode) {
- my @tm = (0, 0, 0, 1, 0, 2000);
- if (defined $time[0]) {
- @tm[3..5] = reverse @time[0..2];
- --$tm[4]; # month should start from 0
- }
- @tm[0..2] = reverse @time[3..5] if defined $time[3];
- # save fractional seconds
- my $frac = $tm[0] - int($tm[0]);
- $tm[0] = int($tm[0]);
- my $tm;
- eval q{
- require Time::Local;
- $tm = Time::Local::timegm(@tm) + $frac;
- };
- $@ and return CleanWarning($@);
- $tm += $$shiftOffset{$mode}; # apply the shift
- $tm < 0 and return 'Shift results in negative time';
- # save fractional seconds in shifted time
- $frac = $tm - int($tm);
- if ($frac) {
- $tm = int($tm);
- # must account for any rounding that could occur
- $frac + 0.5 * 10 ** (-$dec) >= 1 and ++$tm, $frac = 0;
- }
- @tm = gmtime($tm);
- @toTime = reverse @tm[0..5];
- $toTime[0] += 1900;
- ++$toTime[1];
- $toTime[5] += $frac; # add the fractional seconds back in
- }
- # apply the previous timezone shift if necessary
- if (defined $time[6]) {
- my $m = $time[6] * 60 + $time[7];
- $m += $$shiftOffset{Timezone};
- $m += 0.5 * ($m <=> 0); # avoid round-off errors
- $toTime[6] = int($m / 60);
- $toTime[7] = int($m - $toTime[6] * 60);
- }
- }
- #
- # insert shifted time components back into original string
- #
- my ($i, $err);
- for ($i=0; $i<@toTime; ++$i) {
- next unless defined $time[$i] and defined $toTime[$i];
- my ($v, $d, $s);
- if ($i != 6) { # not timezone hours
- last unless $val =~ /((?=\d|\.\d)\d*(\.\d*)?)/g;
- next if $toTime[$i] == $time[$i];
- $v = $1; # value
- $d = $2; # decimal part of value
- $s = ''; # no sign
- } else {
- last if $time[$i] == $toTime[$i] and $time[$i+1] == $toTime[$i+1];
- last unless $val =~ /((?:\+|-)(?=\d|\.\d)\d*(\.\d*)?)/g;
- $v = $1;
- $d = $2;
- if ($toTime[6] >= 0 and $toTime[7] >= 0) {
- $s = '+';
- } else {
- $s = '-';
- $toTime[6] = -$toTime[6];
- $toTime[7] = -$toTime[7];
- }
- }
- my $nv = $toTime[$i];
- my $pos = pos $val;
- my $len = length $v;
- my $sig = $len - length $s;
- my $dec = $d ? length($d) - 1 : 0;
- my $newNum = sprintf($dec ? "$s%0$sig.${dec}f" : "$s%0${sig}d", $nv);
- length($newNum) != $len and $err = 1;
- substr($val, $pos - $len, $len) = $newNum;
- pos($val) = $pos;
- }
- $err and return "Error packing shifted time ($val)";
- $_[0] = $val; # return shifted value
- return undef; # success!
- }
- 1; # end
- __END__
- =head1 NAME
- Image::ExifTool::Shift.pl - ExifTool time shifting routines
- =head1 DESCRIPTION
- This module contains routines used by ExifTool to shift date and time
- values.
- =head1 DETAILS
- Time shifts are applied to standard EXIF-formatted date/time values (eg.
- C<2005:03:14 18:55:00>). Date-only and time-only values may also be
- shifted, and an optional timezone (eg. C<-05:00>) is also supported. Here
- are some general rules and examples to explain how shift strings are
- interpreted:
- Date-only values are shifted using the following formats:
- 'Y:M:D' - shift date by 'Y' years, 'M' months and 'D' days
- 'M:D' - shift months and days only
- 'D' - shift specified number of days
- Time-only values are shifted using the following formats:
- 'h:m:s' - shift time by 'h' hours, 'm' minutes and 's' seconds
- 'h:m' - shift hours and minutes only
- 'h' - shift specified number of hours
- Timezone shifts are specified in the following formats:
- '+h:m' - shift timezone by 'h' hours and 'm' minutes
- '-h:m' - negative shift of timezone hours and minutes
- '+h' - shift timezone hours only
- '-h' - negative shift of timezone hours only
- A valid shift value consists of one or two arguments, separated by a space.
- If only one is provided, it is assumed to be a time shift when applied to a
- time-only or a date/time value, or a date shift when applied to a date-only
- value. For example:
- '1' - shift by 1 hour if applied to a time or date/time
- value, or by one day if applied to a date value
- '2:0' - shift 2 hours (time, date/time), or 2 months (date)
- '5:0:0' - shift 5 hours (time, date/time), or 5 years (date)
- '0:0:1' - shift 1 s (time, date/time), or 1 day (date)
- If two arguments are given, the date shift is first, followed by the time
- shift:
- '3:0:0 0' - shift date by 3 years
- '0 15:30' - shift time by 15 hours and 30 minutes
- '1:0:0 0:0:0+5:0' - shift date by 1 year and timezone by 5 hours
- A date shift is simply ignored if applied to a time value or visa versa.
- Numbers specified in shift fields may contain a decimal point:
- '1.5' - 1 hour 30 minutes (time, date/time), or 1 day (date)
- '2.5 0' - 2 days 12 hours (date/time), 12 hours (time) or
- 2 days (date)
- And to save typing, a zero is assumed for any missing numbers:
- '1::' - shift by 1 hour (time, date/time) or 1 year (date)
- '26:: 0' - shift date by 26 years
- '+:30 - shift timezone by 30 minutes
- Below are some specific examples applied to real date and/or time values
- ('Dir' is the applied shift direction: '+' is positive, '-' is negative):
- Original Value Shift Dir Shifted Value
- --------------------- ------- --- ---------------------
- '20:30:00' '5' + '01:30:00'
- '2005:01:27' '5' + '2005:02:01'
- '2005:01:27 20:30:00' '5' + '2005:01:28 01:30:00'
- '11:54:00' '2.5 0' - '23:54:00'
- '2005:11:02' '2.5 0' - '2005:10:31'
- '2005:11:02 11:54:00' '2.5 0' - '2005:10:30 23:54:00'
- '2004:02:28 08:00:00' '1 1.3' + '2004:02:29 09:18:00'
- '07:00:00' '-5' + '07:00:00'
- '07:00:00+01:00' '-5' + '07:00:00-04:00'
- '07:00:00Z' '+2:30' - '07:00:00-02:30'
- '1970:01:01' '35::' + '2005:01:01'
- '2005:01:01' '400' + '2006:02:05'
- '10:00:00.00' '::1.33' - '09:59:58.67'
- =head1 NOTES
- The format of the original date/time value is not changed when the time
- shift is applied. This means that the length of the date/time string will
- not change, and only the numbers in the string will be modified. The only
- exception to this rule is that a 'Z' timezone is changed to '+00:00'
- notation if a timezone shift is applied. A timezone will not be added to
- the date/time string.
- =head1 TRICKY
- This module is perhaps more complicated than it needs to be because it is
- designed to be very flexible in the way time shifts are specified and
- applied...
- The ability to shift dates by Y years, M months, etc, conflicts with the
- design goal of maintaining a constant shift for all time values when
- applying a batch shift. This is because shifting by 1 month can be
- equivalent to anything from 28 to 31 days, and 1 year can be 365 or 366
- days, depending on the starting date.
- The inconsistency is handled by shifting the first tag found with the actual
- specified shift, then calculating the equivalent time difference in seconds
- for this shift and applying this difference to subsequent tags in a batch
- conversion. So if it works as designed, the behaviour should be both
- intuitive and mathematically correct, and the user shouldn't have to worry
- about details such as this (in keeping with Perl's "do the right thing"
- philosophy).
- =head1 BUGS
- Due to the use of the standard time library functions, dates are typically
- limited to the range 1970 to 2038 on 32-bit systems.
- =head1 AUTHOR
- Copyright 2003-2016, Phil Harvey (phil at owl.phy.queensu.ca)
- This library is free software; you can redistribute it and/or modify it
- under the same terms as Perl itself.
- =head1 SEE ALSO
- L<Image::ExifTool(3pm)|Image::ExifTool>
- =cut
|