| 1 | # NOTE: Derived from lib/Image/Size.pm.
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| 2 | # Changes made here will be lost when autosplit is run again.
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| 3 | # See AutoSplit.pm.
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| 4 | package Image::Size;
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| 5 |
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| 6 | #line 979 "lib/Image/Size.pm (autosplit into blib/lib/auto/Image/Size/tiffsize.al)"
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| 7 | # tiffsize: size a TIFF image
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| 8 | #
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| 9 | # Contributed by Cloyce Spradling <[email protected]>
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| 10 | sub tiffsize {
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| 11 | my $stream = shift;
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| 12 |
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| 13 | my ($x, $y, $id) = (undef, undef, "Unable to determine size of TIFF data");
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| 14 |
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| 15 | my $endian = 'n'; # Default to big-endian; I like it better
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| 16 | my $header = &$read_in($stream, 4);
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| 17 | $endian = 'v' if ($header =~ /II\x2a\x00/o); # little-endian
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| 18 |
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| 19 | # Set up an association between data types and their corresponding
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| 20 | # pack/unpack specification. Don't take any special pains to deal with
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| 21 | # signed numbers; treat them as unsigned because none of the image
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| 22 | # dimensions should ever be negative. (I hope.)
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| 23 | my @packspec = ( undef, # nothing (shouldn't happen)
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| 24 | 'C', # BYTE (8-bit unsigned integer)
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| 25 | undef, # ASCII
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| 26 | $endian, # SHORT (16-bit unsigned integer)
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| 27 | uc($endian), # LONG (32-bit unsigned integer)
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| 28 | undef, # RATIONAL
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| 29 | 'c', # SBYTE (8-bit signed integer)
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| 30 | undef, # UNDEFINED
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| 31 | $endian, # SSHORT (16-bit unsigned integer)
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| 32 | uc($endian), # SLONG (32-bit unsigned integer)
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| 33 | );
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| 34 |
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| 35 | my $offset = &$read_in($stream, 4, 4); # Get offset to IFD
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| 36 | $offset = unpack(uc($endian), $offset); # Fix it so we can use it
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| 37 |
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| 38 | my $ifd = &$read_in($stream, 2, $offset); # Get number of directory entries
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| 39 | my $num_dirent = unpack($endian, $ifd); # Make it useful
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| 40 | $offset += 2;
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| 41 | $num_dirent = $offset + ($num_dirent * 12); # Calc. maximum offset of IFD
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| 42 |
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| 43 | # Do all the work
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| 44 | $ifd = '';
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| 45 | my $tag = 0;
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| 46 | my $type = 0;
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| 47 | while (!defined($x) || !defined($y)) {
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| 48 | $ifd = &$read_in($stream, 12, $offset); # Get first directory entry
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| 49 | last if (($ifd eq '') || ($offset > $num_dirent));
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| 50 | $offset += 12;
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| 51 | $tag = unpack($endian, $ifd); # ...and decode its tag
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| 52 | $type = unpack($endian, substr($ifd, 2, 2)); # ...and the data type
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| 53 | # Check the type for sanity.
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| 54 | next if (($type > @packspec+0) || (!defined($packspec[$type])));
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| 55 | if ($tag == 0x0100) { # ImageWidth (x)
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| 56 | # Decode the value
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| 57 | $x = unpack($packspec[$type], substr($ifd, 8, 4));
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| 58 | } elsif ($tag == 0x0101) { # ImageLength (y)
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| 59 | # Decode the value
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| 60 | $y = unpack($packspec[$type], substr($ifd, 8, 4));
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| 61 | }
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| 62 | }
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| 63 |
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| 64 | # Decide if we were successful or not
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| 65 | if (defined($x) && defined($y)) {
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| 66 | $id = 'TIF';
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| 67 | } else {
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| 68 | $id = '';
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| 69 | $id = 'ImageWidth ' if (!defined($x));
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| 70 | if (!defined ($y)) {
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| 71 | $id .= 'and ' if ($id ne '');
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| 72 | $id .= 'ImageLength ';
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| 73 | }
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| 74 | $id .= 'tag(s) could not be found';
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| 75 | }
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| 76 |
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| 77 | ($x, $y, $id);
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| 78 | }
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| 79 |
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| 80 | # end of Image::Size::tiffsize
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| 81 | 1;
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