class TarReader::Entry

An entry in tar

Attributes

devmajor[R]

devminor[R]

gid[R]

linkname[R]

magic[R]

mode[R]

mtime[R]

name[R]

pos[R]

prefix[R]

size[R]

typeflag[R]

uid[R]

Public Class Methods

new(tar) click to toggle source

# File lib/tarreader.rb, line 20
def initialize tar
  @tar = tar
  @pos = @tar.pos
  buf = @tar.read(512)
  if buf.unpack('A512').first.empty? then
    @pos = @tar.pos
    buf = @tar.read(512)
    throw(:TarReaderEof) if buf.nil?
    throw(:TarReaderEof) if buf.unpack('A512').first.empty?
  end
  throw(:TarReaderEof) if buf.nil?
  @name = buf.unpack('A100').first
  @mode = buf[100, 8].to_i(8)
  @uid = buf[108, 8].to_i(8)
  @gid = buf[116, 8].to_i(8)
  @size = buf[124, 12].to_i(8)
  @mtime = buf[136, 12].to_i(8)
  cksum = buf[148, 8].to_i(8)
  xbuf = buf.dup
  xbuf[148, 8] = ' ' * 8
  s = 0
  xbuf.each_byte{|c| s += c}
  raise Errno::EBADF, "checksum #{s} != #{cksum}" unless s == cksum
  @typeflag = buf[156, 1]
  @linkname = buf[157, 100].unpack('A100').first
  @magic = buf[257, 6]
  if /^ustar/ === @magic
    @uname, @gname = buf[265, 64].unpack('A32 A32')
    @devmajor = buf[329, 8].to_i(8)
    @devminor = buf[337, 8].to_i(8)
    @prefix = buf[345, 155].unpack('A155').first
  else
    @uname = @gname = @devmajor = @devminor = @prefix = nil
  end
  @blocksize = @size - 1
  @blocksize -= @blocksize % 512
  @blocksize += 512
end

Public Instance Methods

end_entry() click to toggle source

# File lib/tarreader.rb, line 85
def end_entry
  @tar.pos = @pos + 512 + @blocksize
end

gname() click to toggle source

# File lib/tarreader.rb, line 66
def gname
  @gname || @gid.to_s
end

mode_symbolic() click to toggle source

# File lib/tarreader.rb, line 70
def mode_symbolic
  [
    case @typeflag when '0', '1' then '-' when '2' then 'l' when '5' then 'd' else @typeflag end,
    (@mode & 0400).zero? ? '-' : 'r',
    (@mode & 0200).zero? ? '-' : 'w',
    (@mode & 0100).zero? ? '-' : 'x',
    (@mode & 0040).zero? ? '-' : 'r',
    (@mode & 0020).zero? ? '-' : 'w',
    (@mode & 0010).zero? ? '-' : 'x',
    (@mode & 0004).zero? ? '-' : 'r',
    (@mode & 0002).zero? ? '-' : 'w',
    (@mode & 0001).zero? ? '-' : 'x'
  ].join
end

read() click to toggle source

# File lib/tarreader.rb, line 89
def read
  # rewind to data head
  @tar.pos = @pos + 512
  buf = @tar.read(@size)
  end_entry
  return buf
end

uname() click to toggle source

# File lib/tarreader.rb, line 62
def uname
  @uname || @uid.to_s
end