def self.new_from_stream(stream)
data = stream.read(512)
fields = data.unpack("A100" +
"A8A8A8" +
"A12A12" +
"A8A" +
"A100" +
"A6A2" +
"A32" +
"A32" +
"A8A8" +
"A155")
name = fields.shift
mode = fields.shift.oct
uid = fields.shift.oct
gid = fields.shift.oct
size = fields.shift.oct
mtime = fields.shift.oct
checksum = fields.shift.oct
typeflag = fields.shift
linkname = fields.shift
magic = fields.shift
version = fields.shift.oct
uname = fields.shift
gname = fields.shift
devmajor = fields.shift.oct
devminor = fields.shift.oct
prefix = fields.shift
empty = (data == "\0" * 512)
new(:name=>name, :mode=>mode, :uid=>uid, :gid=>gid, :size=>size,
:mtime=>mtime, :checksum=>checksum, :typeflag=>typeflag,
:magic=>magic, :version=>version, :uname=>uname, :gname=>gname,
:devmajor=>devmajor, :devminor=>devminor, :prefix=>prefix,
:empty => empty )
end