/usr/share/perl5/IO/InnerFile.pm is in libio-stringy-perl 2.110-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 | package IO::InnerFile;
=head1 NAME
IO::InnerFile - define a file inside another file
=head1 SYNOPSIS
### Read a subset of a file:
$inner = IO::InnerFile->new($fh, $start, $length);
while (<$inner>) {
...
}
=head1 DESCRIPTION
If you have a filehandle that can seek() and tell(), then you
can open an IO::InnerFile on a range of the underlying file.
=head1 PUBLIC INTERFACE
=over
=cut
use Symbol;
# The package version, both in 1.23 style *and* usable by MakeMaker:
$VERSION = "2.110";
#------------------------------
=item new FILEHANDLE, [START, [LENGTH]]
I<Class method, constructor.>
Create a new inner-file opened on the given FILEHANDLE,
from bytes START to START+LENGTH. Both START and LENGTH
default to 0; negative values are silently coerced to zero.
Note that FILEHANDLE must be able to seek() and tell(), in addition
to whatever other methods you may desire for reading it.
=cut
sub new {
my ($class, $fh, $start, $lg) = @_;
$start = 0 if (!$start or ($start < 0));
$lg = 0 if (!$lg or ($lg < 0));
### Create the underlying "object":
my $a = {
FH => $fh,
CRPOS => 0,
START => $start,
LG => $lg,
};
### Create a new filehandle tied to this object:
$fh = gensym;
tie(*$fh, $class, $a);
return bless($fh, $class);
}
sub TIEHANDLE {
my ($class, $data) = @_;
return bless($data, $class);
}
sub DESTROY {
my ($self) = @_;
$self->close() if (ref($self) eq 'SCALAR');
}
#------------------------------
=item set_length LENGTH
=item get_length
=item add_length NBYTES
I<Instance methods.>
Get/set the virtual length of the inner file.
=cut
sub set_length { tied(${$_[0]})->{LG} = $_[1]; }
sub get_length { tied(${$_[0]})->{LG}; }
sub add_length { tied(${$_[0]})->{LG} += $_[1]; }
#------------------------------
=item set_start START
=item get_start
=item add_start NBYTES
I<Instance methods.>
Get/set the virtual start position of the inner file.
=cut
sub set_start { tied(${$_[0]})->{START} = $_[1]; }
sub get_start { tied(${$_[0]})->{START}; }
sub set_end { tied(${$_[0]})->{LG} = $_[1] - tied(${$_[0]})->{START}; }
sub get_end { tied(${$_[0]})->{LG} + tied(${$_[0]})->{START}; }
#------------------------------
=item binmode
=item close
=item flush
=item getc
=item getline
=item print LIST
=item printf LIST
=item read BUF, NBYTES
=item readline
=item seek OFFFSET, WHENCE
=item tell
=item write ARGS...
I<Instance methods.>
Standard filehandle methods.
=cut
sub write { shift->WRITE(@_) }
sub print { shift->PRINT(@_) }
sub printf { shift->PRINTF(@_) }
sub flush { "0 but true"; }
sub binmode { 1; }
sub getc { return GETC(tied(${$_[0]}) ); }
sub read { return READ( tied(${$_[0]}), @_[1,2,3] ); }
sub readline { return READLINE( tied(${$_[0]}) ); }
sub getline { return READLINE( tied(${$_[0]}) ); }
sub close { return CLOSE(tied(${$_[0]}) ); }
sub seek {
my ($self, $ofs, $whence) = @_;
$self = tied( $$self );
$self->{CRPOS} = $ofs if ($whence == 0);
$self->{CRPOS}+= $ofs if ($whence == 1);
$self->{CRPOS} = $self->{LG} + $ofs if ($whence == 2);
$self->{CRPOS} = 0 if ($self->{CRPOS} < 0);
$self->{CRPOS} = $self->{LG} if ($self->{CRPOS} > $self->{LG});
return 1;
}
sub tell {
return tied(${$_[0]})->{CRPOS};
}
sub WRITE {
die "inner files can only open for reading\n";
}
sub PRINT {
die "inner files can only open for reading\n";
}
sub PRINTF {
die "inner files can only open for reading\n";
}
sub GETC {
my ($self) = @_;
return 0 if ($self->{CRPOS} >= $self->{LG});
my $data;
### Save and seek...
my $old_pos = $self->{FH}->tell;
$self->{FH}->seek($self->{CRPOS}+$self->{START}, 0);
### ...read...
my $lg = $self->{FH}->read($data, 1);
$self->{CRPOS} += $lg;
### ...and restore:
$self->{FH}->seek($old_pos, 0);
$self->{LG} = $self->{CRPOS} unless ($lg);
return ($lg ? $data : undef);
}
sub READ {
my ($self, $undefined, $lg, $ofs) = @_;
$undefined = undef;
return 0 if ($self->{CRPOS} >= $self->{LG});
$lg = $self->{LG} - $self->{CRPOS} if ($self->{CRPOS} + $lg > $self->{LG});
return 0 unless ($lg);
### Save and seek...
my $old_pos = $self->{FH}->tell;
$self->{FH}->seek($self->{CRPOS}+$self->{START}, 0);
### ...read...
$lg = $self->{FH}->read($_[1], $lg, $_[3] );
$self->{CRPOS} += $lg;
### ...and restore:
$self->{FH}->seek($old_pos, 0);
$self->{LG} = $self->{CRPOS} unless ($lg);
return $lg;
}
sub READLINE {
my ($self) = @_;
return undef if ($self->{CRPOS} >= $self->{LG});
### Save and seek...
my $old_pos = $self->{FH}->tell;
$self->{FH}->seek($self->{CRPOS}+$self->{START}, 0);
### ...read...
my $text = $self->{FH}->getline;
### ...and restore:
$self->{FH}->seek($old_pos, 0);
#### If we detected a new EOF ...
unless (defined $text) {
$self->{LG} = $self->{CRPOS};
return undef;
}
my $lg=length($text);
$lg = $self->{LG} - $self->{CRPOS} if ($self->{CRPOS} + $lg > $self->{LG});
$self->{CRPOS} += $lg;
return substr($text, 0,$lg);
}
sub CLOSE { %{$_[0]}=(); }
1;
__END__
=back
=head1 VERSION
$Id: InnerFile.pm,v 1.4 2005/02/10 21:21:53 dfs Exp $
=head1 AUTHOR
Original version by Doru Petrescu (pdoru@kappa.ro).
Documentation and by Eryq (eryq@zeegee.com).
Currently maintained by David F. Skoll (dfs@roaringpenguin.com).
=cut
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