A header for a tar file
Fields in the tar header
Pack format for a tar header
Unpack format for a tar header
Creates a tar header from IO stream
# File lib/rubygems/package/tar_header.rb, line 98 def self.from(stream) header = stream.read 512 empty = (header == "\00"" * 512) fields = header.unpack UNPACK_FORMAT new :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 => empty end
Creates a new TarHeader using
vals
# File lib/rubygems/package/tar_header.rb, line 127 def initialize(vals) unless vals[:name] && vals[:size] && vals[:prefix] && vals[:mode] then raise ArgumentError, ":name, :size, :prefix and :mode required" end vals[:uid] ||= 0 vals[:gid] ||= 0 vals[:mtime] ||= 0 vals[:checksum] ||= "" vals[:typeflag] ||= "0" vals[:magic] ||= "ustar" vals[:version] ||= "00" vals[:uname] ||= "wheel" vals[:gname] ||= "wheel" vals[:devmajor] ||= 0 vals[:devminor] ||= 0 FIELDS.each do |name| instance_variable_set "@#{name}", vals[name] end @empty = vals[:empty] end
Is the tar entry empty?
# File lib/rubygems/package/tar_header.rb, line 154 def empty? @empty end
Updates the TarHeader's checksum
# File lib/rubygems/package/tar_header.rb, line 186 def update_checksum header = header " " * 8 @checksum = oct calculate_checksum(header), 6 end
# File lib/rubygems/package/tar_header.rb, line 193 def calculate_checksum(header) header.unpack("C*").inject { |a, b| a + b } end
# File lib/rubygems/package/tar_header.rb, line 197 def header(checksum = @checksum) header = [ name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11), oct(mtime, 11), checksum, " ", typeflag, linkname, magic, oct(version, 2), uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix ] header = header.pack PACK_FORMAT header << ("\00"" * ((512 - header.size) % 512)) end
# File lib/rubygems/package/tar_header.rb, line 223 def oct(num, len) "%0#{len}o" % num end