JezK
Edit File: tar_header.rb
# -*- coding: utf-8 -*- #-- # Copyright (C) 2004 Mauricio Julio Fernández Pradier # See LICENSE.txt for additional licensing information. #++ ## #-- # struct tarfile_entry_posix { # char name[100]; # ASCII + (Z unless filled) # char mode[8]; # 0 padded, octal, null # char uid[8]; # ditto # char gid[8]; # ditto # char size[12]; # 0 padded, octal, null # char mtime[12]; # 0 padded, octal, null # char checksum[8]; # 0 padded, octal, null, space # char typeflag[1]; # file: "0" dir: "5" # char linkname[100]; # ASCII + (Z unless filled) # char magic[6]; # "ustar\0" # char version[2]; # "00" # char uname[32]; # ASCIIZ # char gname[32]; # ASCIIZ # char devmajor[8]; # 0 padded, octal, null # char devminor[8]; # o padded, octal, null # char prefix[155]; # ASCII + (Z unless filled) # }; #++ # A header for a tar file class Gem::Package::TarHeader ## # Fields in the tar header FIELDS = [ :checksum, :devmajor, :devminor, :gid, :gname, :linkname, :magic, :mode, :mtime, :name, :prefix, :size, :typeflag, :uid, :uname, :version, ] ## # Pack format for a tar header PACK_FORMAT = 'a100' + # name 'a8' + # mode 'a8' + # uid 'a8' + # gid 'a12' + # size 'a12' + # mtime 'a7a' + # chksum 'a' + # typeflag 'a100' + # linkname 'a6' + # magic 'a2' + # version 'a32' + # uname 'a32' + # gname 'a8' + # devmajor 'a8' + # devminor 'a155' # prefix ## # Unpack format for a tar header UNPACK_FORMAT = 'A100' + # name 'A8' + # mode 'A8' + # uid 'A8' + # gid 'A12' + # size 'A12' + # mtime 'A8' + # checksum 'A' + # typeflag 'A100' + # linkname 'A6' + # magic 'A2' + # version 'A32' + # uname 'A32' + # gname 'A8' + # devmajor 'A8' + # devminor 'A155' # prefix attr_reader(*FIELDS) ## # Creates a tar header from IO +stream+ def self.from(stream) header = stream.read 512 empty = (header == "\0" * 512) fields = header.unpack UNPACK_FORMAT 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 new :name => name, :mode => mode, :uid => uid, :gid => gid, :size => size, :mtime => mtime, :checksum => checksum, :typeflag => typeflag, :linkname => linkname, :magic => magic, :version => version, :uname => uname, :gname => gname, :devmajor => devmajor, :devminor => devminor, :prefix => prefix, :empty => empty # HACK unfactor for Rubinius #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+ 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? def empty? @empty end def ==(other) # :nodoc: self.class === other and @checksum == other.checksum and @devmajor == other.devmajor and @devminor == other.devminor and @gid == other.gid and @gname == other.gname and @linkname == other.linkname and @magic == other.magic and @mode == other.mode and @mtime == other.mtime and @name == other.name and @prefix == other.prefix and @size == other.size and @typeflag == other.typeflag and @uid == other.uid and @uname == other.uname and @version == other.version end def to_s # :nodoc: update_checksum header end ## # Updates the TarHeader's checksum def update_checksum header = header " " * 8 @checksum = oct calculate_checksum(header), 6 end private def calculate_checksum(header) header.unpack("C*").inject { |a, b| a + b } end 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 << ("\0" * ((512 - header.size) % 512)) end def oct(num, len) "%0#{len}o" % num end end