# NOTE: Derived from blib/lib/Image/Size.pm.
# Changes made here will be lost when autosplit is run again.
# See AutoSplit.pm.
package Image::Size;

#line 1081 "blib/lib/Image/Size.pm (autosplit into blib/lib/auto/Image/Size/jpegsize.al)"
# jpegsize: gets the width and height (in pixels) of a jpeg file
# Andrew Tong, werdna@ugcs.caltech.edu           February 14, 1995
# modified slightly by alex@ed.ac.uk
# and further still by rjray@blackperl.com
# optimization and general re-write from tmetro@vl.com
sub jpegsize
{
    my $stream = shift;

    my $MARKER     = chr 0xff; # Section marker

    my $SIZE_FIRST = 0xC0;   # Range of segment identifier codes
    my $SIZE_LAST  = 0xC3;   #  that hold size info.

    my ($x, $y, $id) = (undef, undef, 'Could not determine JPEG size');

    my ($marker, $code, $length);
    my $segheader;

    # Dummy read to skip header ID
    $READ_IN->($stream, 2);
    while (1)
    {
        $length = 4;
        $segheader = $READ_IN->($stream, $length);

        # Extract the segment header.
        ($marker, $code, $length) = unpack 'a a n', $segheader;

        # Verify that it's a valid segment.
        if ($marker ne $MARKER)
        {
            # Was it there?
            $id = 'JPEG marker not found';
            last;
        }
        elsif ((ord($code) >= $SIZE_FIRST) && (ord($code) <= $SIZE_LAST))
        {
            # Segments that contain size info
            $length = 5;
            ($y, $x) = unpack 'xnn', $READ_IN->($stream, $length);
            $id = 'JPG';
            last;
        }
        else
        {
            # Dummy read to skip over data
            $READ_IN->($stream, ($length - 2));
        }
    }

    return ($x, $y, $id);
}

# end of Image::Size::jpegsize
1;