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- #------------------------------------------------------------------------------
- # File: Torrent.pm
- #
- # Description: Read information from BitTorrent file
- #
- # Revisions: 2013/08/27 - P. Harvey Created
- #
- # References: 1) https://wiki.theory.org/BitTorrentSpecification
- #------------------------------------------------------------------------------
- package Image::ExifTool::Torrent;
- use strict;
- use vars qw($VERSION);
- use Image::ExifTool qw(:DataAccess :Utils);
- $VERSION = '1.03';
- sub ReadBencode($$);
- sub ExtractTags($$$;$$@);
- # tags extracted from BitTorrent files
- %Image::ExifTool::Torrent::Main = (
- GROUPS => { 2 => 'Document' },
- NOTES => q{
- Below are tags commonly found in BitTorrent files. As well as these tags,
- any other existing tags will be extracted. For convenience, list items are
- expanded into individual tags with an index in the tag name, but only the
- tags with index "1" are listed in the tables below. See
- L<https://wiki.theory.org/BitTorrentSpecification> for the BitTorrent
- specification.
- },
- 'announce' => { },
- 'announce-list' => { Name => 'AnnounceList1' },
- 'comment' => { },
- 'created by' => { Name => 'Creator' }, # software used to create the torrent
- 'creation date' => {
- Name => 'CreateDate',
- Groups => { 2 => 'Time' },
- ValueConv => 'ConvertUnixTime($val,1)',
- PrintConv => '$self->ConvertDateTime($val)',
- },
- 'encoding' => { },
- 'info' => { SubDirectory => { TagTable => 'Image::ExifTool::Torrent::Info' } },
- 'url-list' => { Name => 'URLList1' },
- );
- %Image::ExifTool::Torrent::Info = (
- GROUPS => { 2 => 'Document' },
- 'file-duration' => { Name => 'File1Duration' },
- 'file-media' => { Name => 'File1Media' },
- 'files' => { SubDirectory => { TagTable => 'Image::ExifTool::Torrent::Files' } },
- 'length' => { },
- 'md5sum' => { Name => 'MD5Sum' },
- 'name' => { },
- 'name.utf-8' => { Name => 'NameUTF-8' },
- 'piece length' => { Name => 'PieceLength' },
- 'pieces' => {
- Name => 'Pieces',
- Notes => 'concatenation of 20-byte SHA-1 digests for each piece',
- },
- 'private' => { },
- 'profiles' => { SubDirectory => { TagTable => 'Image::ExifTool::Torrent::Profiles' } },
- );
- %Image::ExifTool::Torrent::Profiles = (
- GROUPS => { 2 => 'Document' },
- 'width' => { Name => 'Profile1Width' },
- 'height' => { Name => 'Profile1Height' },
- 'acodec' => { Name => 'Profile1AudioCodec' },
- 'vcodec' => { Name => 'Profile1VideoCodec' },
- );
- %Image::ExifTool::Torrent::Files = (
- GROUPS => { 2 => 'Document' },
- 'length' => { Name => 'File1Length', PrintConv => 'ConvertFileSize($val)' },
- 'md5sum' => { Name => 'File1MD5Sum' },
- 'path' => { Name => 'File1Path', JoinPath => 1 },
- 'path.utf-8' => { Name => 'File1PathUTF-8', JoinPath => 1 },
- );
- #------------------------------------------------------------------------------
- # Read 64kB more data into buffer
- # Inputs: 0) RAF ref, 1) buffer ref
- # Returns: number of bytes read
- # Notes: Sets BencodeEOF element of RAF on end of file
- sub ReadMore($$)
- {
- my ($raf, $dataPt) = @_;
- my $buf2;
- my $n = $raf->Read($buf2, 65536);
- $$raf{BencodeEOF} = 1 if $n != 65536;
- $$dataPt = substr($$dataPt, pos($$dataPt)) . $buf2 if $n;
- return $n;
- }
- #------------------------------------------------------------------------------
- # Read bencoded value
- # Inputs: 0) input file, 1) buffer (pos must be set to current position)
- # Returns: HASH ref, ARRAY ref, SCALAR ref, SCALAR, or undef on error or end of data
- # Notes: Sets BencodeError element of RAF on any error
- sub ReadBencode($$)
- {
- my ($raf, $dataPt) = @_;
- # read more if necessary (keep a minimum of 64 bytes in the buffer)
- my $pos = pos($$dataPt);
- return undef unless defined $pos;
- my $remaining = length($$dataPt) - $pos;
- ReadMore($raf, $dataPt) if $remaining < 64 and not $$raf{BencodeEOF};
- # read next token
- $$dataPt =~ /(.)/sg or return undef;
- my $val;
- my $tok = $1;
- if ($tok eq 'i') { # integer
- $$dataPt =~ /\G(-?\d+)e/g or return $val;
- $val = $1;
- } elsif ($tok eq 'd') { # dictionary
- $val = { };
- for (;;) {
- my $k = ReadBencode($raf, $dataPt);
- last unless defined $k;
- # the key must be a byte string
- if (ref $k) {
- ref $k ne 'SCALAR' and $$raf{BencodeError} = 'Bad dictionary key', last;
- $k = $$k;
- }
- my $v = ReadBencode($raf, $dataPt);
- last unless defined $v;
- $$val{$k} = $v;
- }
- } elsif ($tok eq 'l') { # list
- $val = [ ];
- for (;;) {
- my $v = ReadBencode($raf, $dataPt);
- last unless defined $v;
- push @$val, $v;
- }
- } elsif ($tok eq 'e') { # end of dictionary or list
- # return undef (no error)
- } elsif ($tok =~ /^\d$/ and $$dataPt =~ /\G(\d*):/g) { # byte string
- my $len = $tok . $1;
- my $more = $len - (length($$dataPt) - pos($$dataPt));
- my $value;
- if ($more <= 0) {
- $value = substr($$dataPt,pos($$dataPt),$len);
- pos($$dataPt) = pos($$dataPt) + $len;
- } elsif ($more > 10000000) {
- # just skip over really long values
- $val = \ "(Binary data $len bytes)" if $raf->Seek($more, 1);
- } else {
- # need to read more from file
- my $buff;
- my $n = $raf->Read($buff, $more);
- if ($n == $more) {
- $value = substr($$dataPt,pos($$dataPt)) . $buff;
- $$dataPt = '';
- pos($$dataPt) = 0;
- }
- }
- if (defined $value) {
- # return as binary data unless it is a reasonable-length ASCII string
- if (length($value) > 256 or $value =~ /[^\t\x20-\x7e]/) {
- $val = \$value;
- } else {
- $val = $value;
- }
- } elsif (not defined $val) {
- $$raf{BencodeError} = 'Truncated byte string';
- }
- } else {
- $$raf{BencodeError} = 'Bad format';
- }
- return $val;
- }
- #------------------------------------------------------------------------------
- # Extract tags from dictionary hash
- # Inputs: 0) ExifTool ref, 1) dictionary hash reference, 2) tag table ref,
- # 3) parent hash ID, 4) parent hash name, 5-N) list indices
- # Returns: number of tags extracted
- sub ExtractTags($$$;$$@)
- {
- my ($et, $hashPtr, $tagTablePtr, $baseID, $baseName, @index) = @_;
- my $count = 0;
- my $tag;
- foreach $tag (sort keys %$hashPtr) {
- my $val = $$hashPtr{$tag};
- my ($i, $j, @more);
- for (; defined $val; $val = shift @more) {
- my $id = defined $baseID ? "$baseID/$tag" : $tag;
- unless ($$tagTablePtr{$id}) {
- my $name = ucfirst $tag;
- # capitalize all words in tag name and remove illegal characters
- $name =~ s/[^-_a-zA-Z0-9]+(.?)/\U$1/g;
- $name = "Tag$name" if length($name) < 2 or $name !~ /^[A-Z]/;
- $name = $baseName . $name if defined $baseName; # add base name if necessary
- AddTagToTable($tagTablePtr, $id, { Name => $name });
- $et->VPrint(0, " [adding $id '$name']\n");
- }
- my $tagInfo = $et->GetTagInfo($tagTablePtr, $id) or next;
- if (ref $val eq 'ARRAY') {
- if ($$tagInfo{JoinPath}) {
- $val = join '/', @$val;
- } else {
- push @more, @$val;
- next if ref $more[0] eq 'ARRAY'; # continue expanding nested lists
- $val = shift @more;
- $i or $i = 0, push(@index, $i);
- }
- }
- $index[-1] = ++$i if defined $i;
- if (@index) {
- $id .= join '_', @index; # add instance number(s) to tag ID
- unless ($$tagTablePtr{$id}) {
- my $name = $$tagInfo{Name};
- # embed indices at position of '1' in tag name
- my $n = ($name =~ tr/1/#/);
- for ($j=0; $j<$n; ++$j) {
- my $idx = $index[$j] || '';
- $name =~ s/#/$idx/;
- }
- # put remaining indices at end of tag name
- for (; $j<@index; ++$j) {
- $name .= '_' if $name =~ /\d$/;
- $name .= $index[$j];
- }
- AddTagToTable($tagTablePtr, $id, { %$tagInfo, Name => $name });
- }
- $tagInfo = $et->GetTagInfo($tagTablePtr, $id) or next;
- }
- if (ref $val eq 'HASH') {
- # extract tags from this dictionary
- my ($table, $rootID, $rootName);
- if ($$tagInfo{SubDirectory}) {
- $table = GetTagTable($$tagInfo{SubDirectory}{TagTable});
- } else {
- $table = $tagTablePtr;
- # use hash ID and Name as base for contained tags to avoid conflicts
- $rootID = $id;
- $rootName = $$tagInfo{Name};
- }
- $count += ExtractTags($et, $val, $table, $rootID, $rootName, @index);
- } else {
- # handle this simple tag value
- $et->HandleTag($tagTablePtr, $id, $val);
- ++$count;
- }
- }
- pop @index if defined $i;
- }
- return $count;
- }
- #------------------------------------------------------------------------------
- # Process BitTorrent file
- # Inputs: 0) ExifTool object reference, 1) dirInfo reference (with RAF set)
- # Returns: 1 on success, 0 if this wasn't a valid BitTorrent file
- sub ProcessTorrent($$)
- {
- my ($et, $dirInfo) = @_;
- my $success = 0;
- my $raf = $$dirInfo{RAF};
- my $buff = '';
- pos($buff) = 0;
- my $dict = ReadBencode($raf, \$buff);
- my $err = $$raf{BencodeError};
- $et->Warn("Bencode error: $err") if $err;
- if (ref $dict eq 'HASH' and $$dict{announce}) {
- $et->SetFileType();
- my $tagTablePtr = GetTagTable('Image::ExifTool::Torrent::Main');
- ExtractTags($et, $dict, $tagTablePtr) and $success = 1;
- }
- return $success;
- }
- 1; # end
- __END__
- =head1 NAME
- Image::ExifTool::Torrent - Read information from BitTorrent file
- =head1 SYNOPSIS
- This module is used by Image::ExifTool
- =head1 DESCRIPTION
- This module contains definitions required by Image::ExifTool to read
- bencoded information from BitTorrent files.
- =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 REFERENCES
- =over 4
- =item L<https://wiki.theory.org/BitTorrentSpecification>
- =back
- =head1 SEE ALSO
- L<Image::ExifTool::TagNames/Torrent Tags>,
- L<Image::ExifTool(3pm)|Image::ExifTool>
- =cut
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