Description:
- if the file is shorter than blocksize_0, the seek/read returns an empty $buf later
- check for blocksize_0 is we are interested in blocksize_0
- seek (sic!) harder if OGGHEADERFLAG is not within $len
Origin: vendor
Bug:
https://rt.cpan.org/Public/Bug/Display.html?id=43693
Forwarded:
https://rt.cpan.org/Public/Bug/Display.html?id=43693
Bug-Debian:
https://bugs.debian.org/522075
Author: gregor herrmann <gregoa@debian.org>
Damyan Ivanov <dmn@debian.org>
Last-Update: 2020-07-19
--- a/lib/Ogg/Vorbis/Header/PurePerl.pm
+++ b/lib/Ogg/Vorbis/Header/PurePerl.pm
@@ -420,30 +420,44 @@ sub _calculate_track_length {
if (($data->{'filesize'} - $data->{'INFO'}{'offset'}) > ($data->{'INFO'}{'blocksize_0'} * 2)) {
$len = $data->{'INFO'}{'blocksize_0'} * 2;
+ } elsif ($data->{'filesize'} < $data->{'INFO'}{'blocksize_0'}) {
+ $len = $data->{'filesize'};
} else {
$len = $data->{'INFO'}{'blocksize_0'};
}
- if ($len == 0) {
+ if ($data->{'INFO'}{'blocksize_0'} == 0) {
print "Ogg::Vorbis::Header::PurePerl:\n";
warn "blocksize_0 is 0! Should be a power of 2!
http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-ref.html\n";
return;
}
seek($fh, -$len, 2);
- read($fh, my $buf, $len);
+ my $buf = '';
my $found_header = 0;
+ my $block = $len;
- for (my $i = 0; $i < $len; $i++) {
+ SEEK:
+ while ($found_header == 0 && read($fh, $buf, $len)) {
+ # search the last read $block bytes for Ogg header flag
+ # the search is conducted backwards so that the last flag
+ # is found first
+ for (my $i = $block; $i >= 0; $i--) {
+ if (substr($buf, $i, 4) eq OGGHEADERFLAG) {
+ substr($buf, 0, ($i+4), '');
+ $found_header = 1;
+ last SEEK;
+ }
+ }
- last if length($buf) < 4;
+ # already read the whole file?
+ last if $len == $data->{'filesize'};
- if (substr($buf, $i, 4) eq OGGHEADERFLAG) {
- substr($buf, 0, ($i+4), '');
- $found_header = 1;
- last;
- }
+ $len += $block;
+ $len = $data->{'filesize'} if $len > $data->{'filesize'};
+
+ seek($fh, -$len, 2);
}
unless ($found_header) {
RT for rt.cpan.org