[Git][reproducible-builds/strip-nondeterminism][master] Support timestamp clamping of "tIME" chunks in .png files. (Closes: #7)

[Chris Lamb]

Chris Lamb pushed to branch master at Reproducible Builds / strip-nondeterminism


Commits:
849f8516 by Chris Lamb at 2019-06-27T09:55:46Z
Support timestamp clamping of "tIME" chunks in .png files. (Closes: #7)

- - - - -


3 changed files:

- lib/File/StripNondeterminism/handlers/png.pm
- + t/fixtures/png/bug_931039.png.in
- + t/fixtures/png/bug_931039.png.out


Changes:

=====================================
lib/File/StripNondeterminism/handlers/png.pm
=====================================
@@ -29,6 +29,7 @@ use File::StripNondeterminism::Common qw(copy_data);
 use File::Basename qw/dirname/;
 use POSIX qw/strftime/;
 use List::Util qw/min/;
+use Time::Local qw/timegm/;
 
 sub crc($) {
 	my ($data) = @_;
@@ -47,6 +48,12 @@ sub time_chunk($) {
 		pack('nCCCCC', 1900+$year, $mon+1, $mday, $hour, $min, $sec));
 }
 
+sub parse_time_chunk($) {
+	my ($data) = @_;
+	my ($year, $mon, $mday, $hour, $min, $sec) = unpack('nCCCCC', $data);
+	return timegm($sec, $min, $hour, $mday, $mon, $year);
+}
+
 sub text_chunk($$) {
 	my ($keyword, $data) = @_;
 	return chunk('tEXt', pack('Z*a*', $keyword, $data));
@@ -103,9 +110,12 @@ sub _normalize {
 			}
 
 			if ($type eq "tIME") {
-				print $tempfile time_chunk($canonical_time)
-				  if defined($canonical_time);
 				$modified = 1;
+				next if not defined $canonical_time;
+				my $timestamp = $canonical_time;
+				$timestamp = min($timestamp, parse_time_chunk($data))
+					if $File::StripNondeterminism::clamp_time;
+				print $tempfile time_chunk($timestamp);
 				next;
 			} elsif (($type =~ /[tiz]EXt/)
 				&& ($data =~ /^(date:[^\0]+|Creation Time)\0/)) {


=====================================
t/fixtures/png/bug_931039.png.in
=====================================
Binary files /dev/null and b/t/fixtures/png/bug_931039.png.in differ


=====================================
t/fixtures/png/bug_931039.png.out
=====================================
Binary files /dev/null and b/t/fixtures/png/bug_931039.png.out differ



View it on GitLab: https://salsa.debian.org/reproducible-builds/strip-nondeterminism/commit/849f8516fc6e3b6da86290d4dd08d3dd2ddbd04c

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View it on GitLab: https://salsa.debian.org/reproducible-builds/strip-nondeterminism/commit/849f8516fc6e3b6da86290d4dd08d3dd2ddbd04c
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