Initial Commit

gxg/todo/uuidtools/uuidtools.rb

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+# encoding:utf-8
+#--
+# Copyright (C) 2005-2014 Bob Aman
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#++
+
+require 'uri'
+require 'time'
+require 'thread'
+require 'digest/sha1'
+require 'digest/md5'
+
+#require 'uuidtools/version'
+unless defined? UUIDTools::VERSION
+  module UUIDTools
+    module VERSION #:nodoc:
+      MAJOR = 2
+      MINOR = 1
+      TINY  = 5
+
+      STRING = [MAJOR, MINOR, TINY].join('.')
+    end
+  end
+end
+
+#begin
+#  require 'securerandom'
+#rescue LoadError
+#  require File.join(File.dirname(__FILE__), 'compat', 'securerandom')
+#end
+
+module UUIDTools
+  ##
+  # UUIDTools was designed to be a simple library for generating any
+  # of the various types of UUIDs.  It conforms to RFC 4122 whenever
+  # possible.
+  #
+  # @example
+  #   UUID.md5_create(UUID_DNS_NAMESPACE, "www.widgets.com")
+  #   # => #<UUID:0x287576 UUID:3d813cbb-47fb-32ba-91df-831e1593ac29>
+  #   UUID.sha1_create(UUID_DNS_NAMESPACE, "www.widgets.com")
+  #   # => #<UUID:0x2a0116 UUID:21f7f8de-8051-5b89-8680-0195ef798b6a>
+  #   UUID.timestamp_create
+  #   # => #<UUID:0x2adfdc UUID:64a5189c-25b3-11da-a97b-00c04fd430c8>
+  #   UUID.random_create
+  #   # => #<UUID:0x19013a UUID:984265dc-4200-4f02-ae70-fe4f48964159>
+  class UUID
+    include Comparable
+
+    ##
+    # @api private
+    @@last_timestamp = nil
+
+    ##
+    # @api private
+    @@last_node_id = nil
+
+    ##
+    # @api private
+    @@last_clock_sequence = nil
+
+    ##
+    # @api private
+    @@state_file = nil
+
+    ##
+    # @api private
+    @@mutex = Mutex.new
+
+    ##
+    # Creates a new UUID structure from its component values.
+    # @see UUID.md5_create
+    # @see UUID.sha1_create
+    # @see UUID.timestamp_create
+    # @see UUID.random_create
+    # @api private
+    def initialize(time_low, time_mid, time_hi_and_version,
+        clock_seq_hi_and_reserved, clock_seq_low, nodes)
+      unless time_low >= 0 && time_low < 4294967296
+        raise ArgumentError,
+          "Expected unsigned 32-bit number for time_low, got #{time_low}."
+      end
+      unless time_mid >= 0 && time_mid < 65536
+        raise ArgumentError,
+          "Expected unsigned 16-bit number for time_mid, got #{time_mid}."
+      end
+      unless time_hi_and_version >= 0 && time_hi_and_version < 65536
+        raise ArgumentError,
+          "Expected unsigned 16-bit number for time_hi_and_version, " +
+          "got #{time_hi_and_version}."
+      end
+      unless clock_seq_hi_and_reserved >= 0 && clock_seq_hi_and_reserved < 256
+        raise ArgumentError,
+          "Expected unsigned 8-bit number for clock_seq_hi_and_reserved, " +
+          "got #{clock_seq_hi_and_reserved}."
+      end
+      unless clock_seq_low >= 0 && clock_seq_low < 256
+        raise ArgumentError,
+          "Expected unsigned 8-bit number for clock_seq_low, " +
+          "got #{clock_seq_low}."
+      end
+      unless nodes.kind_of?(Enumerable)
+        raise TypeError,
+          "Expected Enumerable, got #{nodes.class.name}."
+      end
+      unless nodes.size == 6
+        raise ArgumentError,
+          "Expected nodes to have size of 6."
+      end
+      for node in nodes
+        unless node >= 0 && node < 256
+          raise ArgumentError,
+            "Expected unsigned 8-bit number for each node, " +
+            "got #{node}."
+        end
+      end
+      @time_low = time_low
+      @time_mid = time_mid
+      @time_hi_and_version = time_hi_and_version
+      @clock_seq_hi_and_reserved = clock_seq_hi_and_reserved
+      @clock_seq_low = clock_seq_low
+      @nodes = nodes
+    end
+
+    ##
+    # Returns the value of attribute `time_low`
+    attr_accessor :time_low
+
+    ##
+    # Returns the value of attribute `time_mid`
+    attr_accessor :time_mid
+
+    ##
+    # Returns the value of attribute `time_hi_and_version`
+    attr_accessor :time_hi_and_version
+
+    ##
+    # Returns the value of attribute `clock_seq_hi_and_reserved`
+    attr_accessor :clock_seq_hi_and_reserved
+
+    ##
+    # Returns the value of attribute `clock_seq_low`
+    attr_accessor :clock_seq_low
+
+    ##
+    # Returns the value of attribute `nodes`
+    attr_accessor :nodes
+
+    ##
+    # Parses a UUID from a string.
+    def self.parse(uuid_string)
+      unless uuid_string.kind_of? String
+        raise TypeError,
+          "Expected String, got #{uuid_string.class.name} instead."
+      end
+      uuid_components = uuid_string.downcase.scan(UUIDTools::UUID_REGEXP).first
+      raise ArgumentError, "Invalid UUID format." if uuid_components.nil?
+      time_low = uuid_components[0].to_i(16)
+      time_mid = uuid_components[1].to_i(16)
+      time_hi_and_version = uuid_components[2].to_i(16)
+      clock_seq_hi_and_reserved = uuid_components[3].to_i(16)
+      clock_seq_low = uuid_components[4].to_i(16)
+      nodes = []
+      for i in 0..5
+        nodes << uuid_components[5][(i * 2)..(i * 2) + 1].to_i(16)
+      end
+      return self.new(time_low, time_mid, time_hi_and_version,
+        clock_seq_hi_and_reserved, clock_seq_low, nodes)
+    end
+
+    ##
+    # Parses a UUID from a raw byte string.
+    def self.parse_raw(raw_string)
+      unless raw_string.kind_of? String
+        raise TypeError,
+          "Expected String, got #{raw_string.class.name} instead."
+      end
+      integer = self.convert_byte_string_to_int(raw_string)
+
+      time_low = (integer >> 96) & 0xFFFFFFFF
+      time_mid = (integer >> 80) & 0xFFFF
+      time_hi_and_version = (integer >> 64) & 0xFFFF
+      clock_seq_hi_and_reserved = (integer >> 56) & 0xFF
+      clock_seq_low = (integer >> 48) & 0xFF
+      nodes = []
+      for i in 0..5
+        nodes << ((integer >> (40 - (i * 8))) & 0xFF)
+      end
+      return self.new(time_low, time_mid, time_hi_and_version,
+        clock_seq_hi_and_reserved, clock_seq_low, nodes)
+    end
+
+    ##
+    # Parses a UUID from an Integer.
+    def self.parse_int(uuid_int)
+      unless uuid_int.kind_of?(Integer)
+        raise ArgumentError,
+          "Expected Integer, got #{uuid_int.class.name} instead."
+      end
+      return self.parse_raw(self.convert_int_to_byte_string(uuid_int, 16))
+    end
+
+    ##
+    # Parse a UUID from a hexdigest String.
+    def self.parse_hexdigest(uuid_hexdigest)
+      unless uuid_hexdigest.kind_of?(String)
+        raise ArgumentError,
+          "Expected String, got #{uuid_hexdigest.class.name} instead."
+      end
+      return self.parse_int(uuid_hexdigest.to_i(16))
+    end
+
+    ##
+    # Creates a UUID from a random value.
+    def self.random_create()
+      new_uuid = self.parse_raw(SecureRandom.random_bytes(16))
+      new_uuid.time_hi_and_version &= 0x0FFF
+      new_uuid.time_hi_and_version |= (4 << 12)
+      new_uuid.clock_seq_hi_and_reserved &= 0x3F
+      new_uuid.clock_seq_hi_and_reserved |= 0x80
+      return new_uuid
+    end
+
+    ##
+    # Creates a UUID from a timestamp.
+    def self.timestamp_create(timestamp=nil)
+      # We need a lock here to prevent two threads from ever
+      # getting the same timestamp.
+      @@mutex.synchronize do
+        # Always use GMT to generate UUIDs.
+        if timestamp.nil?
+          gmt_timestamp = Time.now.gmtime
+        else
+          gmt_timestamp = timestamp.gmtime
+        end
+        # Convert to 100 nanosecond blocks
+        gmt_timestamp_100_nanoseconds = (gmt_timestamp.tv_sec * 10000000) +
+          (gmt_timestamp.tv_usec * 10) + 0x01B21DD213814000
+        mac_address = self.mac_address
+        node_id = 0
+        if mac_address != nil
+          nodes = mac_address.split(":").collect do |octet|
+            octet.to_i(16)
+          end
+        else
+          nodes = SecureRandom.random_bytes(6).unpack("C*")
+          nodes[0] |= 0b00000001
+        end
+        for i in 0..5
+          node_id += (nodes[i] << (40 - (i * 8)))
+        end
+        clock_sequence = @@last_clock_sequence
+        if clock_sequence.nil?
+          clock_sequence = self.convert_byte_string_to_int(
+            SecureRandom.random_bytes(16)
+          )
+        end
+        if @@last_node_id != nil && @@last_node_id != node_id
+          # The node id has changed.  Change the clock id.
+          clock_sequence = self.convert_byte_string_to_int(
+            SecureRandom.random_bytes(16)
+          )
+        elsif @@last_timestamp != nil &&
+            gmt_timestamp_100_nanoseconds <= @@last_timestamp
+          clock_sequence = clock_sequence + 1
+        end
+        @@last_timestamp = gmt_timestamp_100_nanoseconds
+        @@last_node_id = node_id
+        @@last_clock_sequence = clock_sequence
+
+        time_low = gmt_timestamp_100_nanoseconds & 0xFFFFFFFF
+        time_mid = ((gmt_timestamp_100_nanoseconds >> 32) & 0xFFFF)
+        time_hi_and_version = ((gmt_timestamp_100_nanoseconds >> 48) & 0x0FFF)
+        time_hi_and_version |= (1 << 12)
+        clock_seq_low = clock_sequence & 0xFF;
+        clock_seq_hi_and_reserved = (clock_sequence & 0x3F00) >> 8
+        clock_seq_hi_and_reserved |= 0x80
+
+        return self.new(time_low, time_mid, time_hi_and_version,
+          clock_seq_hi_and_reserved, clock_seq_low, nodes)
+      end
+    end
+
+    ##
+    # Creates a UUID using the MD5 hash.  (Version 3)
+    def self.md5_create(namespace, name)
+      return self.create_from_hash(Digest::MD5, namespace, name)
+    end
+
+    ##
+    # Creates a UUID using the SHA1 hash.  (Version 5)
+    def self.sha1_create(namespace, name)
+      return self.create_from_hash(Digest::SHA1, namespace, name)
+    end
+
+    ##
+    # This method applies only to version 1 UUIDs.
+    # Checks if the node ID was generated from a random number
+    # or from an IEEE 802 address (MAC address).
+    # Always returns false for UUIDs that aren't version 1.
+    # This should not be confused with version 4 UUIDs where
+    # more than just the node id is random.
+    def random_node_id?
+      return false if self.version != 1
+      return ((self.nodes.first & 0x01) == 1)
+    end
+
+    ##
+    # Returns true if this UUID is the
+    # nil UUID (00000000-0000-0000-0000-000000000000).
+    def nil_uuid?
+      return false if self.time_low != 0
+      return false if self.time_mid != 0
+      return false if self.time_hi_and_version != 0
+      return false if self.clock_seq_hi_and_reserved != 0
+      return false if self.clock_seq_low != 0
+      self.nodes.each do |node|
+        return false if node != 0
+      end
+      return true
+    end
+
+    ##
+    # Returns the UUID version type.
+    # Possible values:
+    # 1 - Time-based with unique or random host identifier
+    # 2 - DCE Security version (with POSIX UIDs)
+    # 3 - Name-based (MD5 hash)
+    # 4 - Random
+    # 5 - Name-based (SHA-1 hash)
+    def version
+      return (time_hi_and_version >> 12)
+    end
+
+    ##
+    # Returns the UUID variant.
+    # Possible values:
+    # 0b000 - Reserved, NCS backward compatibility.
+    # 0b100 - The variant specified in this document.
+    # 0b110 - Reserved, Microsoft Corporation backward compatibility.
+    # 0b111 - Reserved for future definition.
+    def variant
+      variant_raw = (clock_seq_hi_and_reserved >> 5)
+      result = nil
+      if (variant_raw >> 2) == 0
+        result = 0x000
+      elsif (variant_raw >> 1) == 2
+        result = 0x100
+      else
+        result = variant_raw
+      end
+      return (result >> 6)
+    end
+
+    ##
+    # Returns true if this UUID is valid.
+    def valid?
+      if [0b000, 0b100, 0b110, 0b111].include?(self.variant) &&
+        (1..5).include?(self.version)
+        return true
+      else
+        return false
+      end
+    end
+
+    ##
+    # Returns the IEEE 802 address used to generate this UUID or
+    # nil if a MAC address was not used.
+    def mac_address
+      return nil if self.version != 1
+      return nil if self.random_node_id?
+      return (self.nodes.collect do |node|
+        sprintf("%2.2x", node)
+      end).join(":")
+    end
+
+    ##
+    # Returns the timestamp used to generate this UUID
+    def timestamp
+      return nil if self.version != 1
+      gmt_timestamp_100_nanoseconds = 0
+      gmt_timestamp_100_nanoseconds +=
+        ((self.time_hi_and_version  & 0x0FFF) << 48)
+      gmt_timestamp_100_nanoseconds += (self.time_mid << 32)
+      gmt_timestamp_100_nanoseconds += self.time_low
+      return Time.at(
+        (gmt_timestamp_100_nanoseconds - 0x01B21DD213814000) / 10000000.0)
+    end
+
+    ##
+    # Compares two UUIDs lexically
+    def <=>(other_uuid)
+      return nil unless other_uuid.is_a?(UUIDTools::UUID)
+      check = self.time_low <=> other_uuid.time_low
+      return check if check != 0
+      check = self.time_mid <=> other_uuid.time_mid
+      return check if check != 0
+      check = self.time_hi_and_version <=> other_uuid.time_hi_and_version
+      return check if check != 0
+      check = self.clock_seq_hi_and_reserved <=>
+        other_uuid.clock_seq_hi_and_reserved
+      return check if check != 0
+      check = self.clock_seq_low <=> other_uuid.clock_seq_low
+      return check if check != 0
+      for i in 0..5
+        if (self.nodes[i] < other_uuid.nodes[i])
+          return -1
+        end
+        if (self.nodes[i] > other_uuid.nodes[i])
+          return 1
+        end
+      end
+      return 0
+    end
+
+    ##
+    # Returns a representation of the object's state
+    def inspect
+      return "#<UUID:0x#{self.object_id.to_s(16)} UUID:#{self.to_s}>"
+    end
+
+    ##
+    # Returns the hex digest of the UUID object.
+    def hexdigest
+      (self.frozen? ?
+        generate_hexdigest : (@hexdigest ||= generate_hexdigest)
+      ).dup
+    end
+
+    ##
+    # Returns the raw bytes that represent this UUID.
+    def raw
+      (self.frozen? ? generate_raw : (@raw ||= generate_raw)).dup
+    end
+
+    ##
+    # Returns a string representation for this UUID.
+    def to_s
+      (self.frozen? ? generate_s : (@string ||= generate_s)).dup
+    end
+    alias_method :to_str, :to_s
+
+    ##
+    # Returns an integer representation for this UUID.
+    def to_i
+      self.frozen? ? generate_i : (@integer ||= generate_i)
+    end
+
+    ##
+    # Returns a URI string for this UUID.
+    def to_uri
+      return "urn:uuid:#{self.to_s}"
+    end
+
+    ##
+    # Returns an integer hash value.
+    def hash
+      self.frozen? ? generate_hash : (@hash ||= generate_hash)
+    end
+
+  protected
+    ##
+    # Generates the hex digest of the UUID object.
+    #
+    # @api private
+    def generate_hexdigest
+      return self.to_i.to_s(16).rjust(32, "0")
+    end
+
+    # Generates an integer hash value.
+    #
+    # @api private
+    def generate_hash
+      return self.to_i % 0x3fffffff
+    end
+
+    ##
+    # Generates an integer representation for this UUID.
+    #
+    # @api private
+    def generate_i
+      return (begin
+        bytes = (time_low << 96) + (time_mid << 80) +
+          (time_hi_and_version << 64) + (clock_seq_hi_and_reserved << 56) +
+          (clock_seq_low << 48)
+        for i in 0..5
+          bytes += (nodes[i] << (40 - (i * 8)))
+        end
+        bytes
+      end)
+    end
+
+    ##
+    # Generates a string representation for this UUID.
+    #
+    # @api private
+    def generate_s
+      result = sprintf("%8.8x-%4.4x-%4.4x-%2.2x%2.2x-", @time_low, @time_mid,
+        @time_hi_and_version, @clock_seq_hi_and_reserved, @clock_seq_low);
+      for i in 0..5
+        result << sprintf("%2.2x", @nodes[i])
+      end
+      return result.downcase
+    end
+
+    ##
+    # Generates the raw bytes that represent this UUID.
+    #
+    # @api private
+    def generate_raw
+      return self.class.convert_int_to_byte_string(self.to_i, 16)
+    end
+
+  public
+    ##
+    # Returns true if this UUID is exactly equal to the other UUID.
+    def eql?(other)
+      return self == other
+    end
+
+    #
+    # Determine what OS we're running on.  Helps decide how to find the MAC
+    #
+    def self.os_class
+      require 'rbconfig'
+      os_platform = RbConfig::CONFIG['target_os']
+      os_class = nil
+      if (os_platform =~ /win/i && !(os_platform =~ /darwin/i)) ||
+          os_platform =~ /w32/i
+        os_class = :windows
+      elsif os_platform =~ /solaris/i
+        os_class = :solaris
+      elsif os_platform =~ /netbsd/i
+        os_class = :netbsd
+      elsif os_platform =~ /openbsd/i
+        os_class = :openbsd
+      end
+    end
+
+    # making these class variables helps with testing
+    @ifconfig_command = "ifconfig"
+    @ifconfig_path_default = "/sbin/ifconfig"
+    @ip_command = "ip"
+    @ip_path_default = "/sbin/ip"
+
+    class << self
+      attr_accessor :ifconfig_command, :ifconfig_path_default
+      attr_accessor :ip_command, :ip_path_default
+    end
+
+    #
+    # Find the path of the ifconfig(8) command if it is present
+    #
+    def self.ifconfig_path
+      path = `which #{UUID.ifconfig_command} 2>/dev/null`.strip
+      path = UUID.ifconfig_path_default if (path == "" && File.exist?(UUID.ifconfig_path_default))
+      return (path === "" ? nil : path)
+    end
+
+    #
+    # Find the path of the ip(8) command if it is present
+    #
+    def self.ip_path
+      path = `which #{UUID.ip_command} 2>/dev/null`.strip
+      path = UUID.ip_path_default if (path == "" && File.exist?(UUID.ip_path_default))
+      return (path === "" ? nil : path)
+    end
+
+    #
+    # Call the ifconfig or ip command that is found
+    #
+    def self.ifconfig(all=nil)
+      # find the path of the ifconfig command
+      ifconfig_path = UUID.ifconfig_path
+
+      # if it does not exist, try the ip command
+      if ifconfig_path == nil
+        ifconfig_path = "#{UUID.ip_path} addr list"
+        # all makes no sense when using ip(1)
+        all = nil
+      end
+
+      all_switch = all == nil ? "" : "-a"
+      return `#{ifconfig_path} #{all_switch}` if not ifconfig_path == nil
+    end
+
+    # Match and return the first Mac address found
+    def self.first_mac(instring)
+      mac_regexps = [
+        Regexp.new("address:? (#{(["[0-9a-fA-F]{2}"] * 6).join(":")})"),
+        Regexp.new("addr:? (#{(["[0-9a-fA-F]{2}"] * 6).join(":")})"),
+        Regexp.new("ether:? (#{(["[0-9a-fA-F]{1,2}"] * 6).join(":")})"),
+        Regexp.new("HWaddr:? (#{(["[0-9a-fA-F]{2}"] * 6).join(":")})"),
+        Regexp.new("link/ether? (#{(["[0-9a-fA-F]{2}"] * 6).join(":")})"),
+        Regexp.new("(#{(["[0-9a-fA-F]{2}"] * 6).join(":")})"),
+        Regexp.new("(#{(["[0-9a-fA-F]{2}"] * 6).join("-")})")
+      ]
+      parse_mac = lambda do |output|
+        (mac_regexps.map do |regexp|
+           result = output[regexp, 1]
+           result.downcase.gsub(/-/, ":") if result != nil
+        end).compact.first
+      end
+
+      mac = parse_mac.call(instring)
+      if mac
+        # expand octets that were compressed (solaris)
+        return (mac.split(':').map do |octet|
+          (octet.length == 1 ? "0#{octet}" : octet)
+        end).join(':')
+      else
+        return nil
+      end
+    end
+
+    ##
+    # Returns the MAC address of the current computer's network card.
+    # Returns nil if a MAC address could not be found.
+    def self.mac_address
+      if !defined?(@@mac_address)
+        require 'rbconfig'
+
+        os_class = UUID.os_class
+
+        if os_class == :windows
+          begin
+            @@mac_address = UUID.first_mac `ipconfig /all`
+          rescue
+          end
+        else # linux, bsd, macos, solaris
+          @@mac_address = UUID.first_mac(UUID.ifconfig(:all))
+        end
+
+        if @@mac_address != nil
+          if @@mac_address.respond_to?(:to_str)
+            @@mac_address = @@mac_address.to_str
+          else
+            @@mac_address = @@mac_address.to_s
+          end
+          @@mac_address.downcase!
+          @@mac_address.strip!
+        end
+
+        # Verify that the MAC address is in the right format.
+        # Nil it out if it isn't.
+        unless @@mac_address.respond_to?(:scan) &&
+            @@mac_address.scan(/#{(["[0-9a-f]{2}"] * 6).join(":")}/)
+          @@mac_address = nil
+        end
+      end
+      return @@mac_address
+    end
+
+    ##
+    # Allows users to set the MAC address manually in cases where the MAC
+    # address cannot be obtained programatically.
+    def self.mac_address=(new_mac_address)
+      @@mac_address = new_mac_address
+    end
+
+    # The following methods are not part of the public API,
+    # and generally should not be called directly.
+
+
+    ##
+    # Creates a new UUID from a SHA1 or MD5 hash
+    #
+    # @api private
+    def self.create_from_hash(hash_class, namespace, name)
+      if hash_class == Digest::MD5
+        version = 3
+      elsif hash_class == Digest::SHA1
+        version = 5
+      else
+        raise ArgumentError,
+          "Expected Digest::SHA1 or Digest::MD5, got #{hash_class.name}."
+      end
+      hash = hash_class.new
+      hash.update(namespace.raw)
+      hash.update(name)
+      hash_string = hash.to_s[0..31]
+      new_uuid = self.parse("#{hash_string[0..7]}-#{hash_string[8..11]}-" +
+        "#{hash_string[12..15]}-#{hash_string[16..19]}-#{hash_string[20..31]}")
+
+      new_uuid.time_hi_and_version &= 0x0FFF
+      new_uuid.time_hi_and_version |= (version << 12)
+      new_uuid.clock_seq_hi_and_reserved &= 0x3F
+      new_uuid.clock_seq_hi_and_reserved |= 0x80
+      return new_uuid
+    end
+
+    ##
+    # @api private
+    def self.convert_int_to_byte_string(integer, size)
+      byte_string = ""
+      if byte_string.respond_to?(:force_encoding)
+        byte_string.force_encoding(Encoding::ASCII_8BIT)
+      end
+      for i in 0..(size - 1)
+        byte_string << ((integer >> (((size - 1) - i) * 8)) & 0xFF)
+      end
+      return byte_string
+    end
+
+    ##
+    # @api private
+    def self.convert_byte_string_to_int(byte_string)
+      if byte_string.respond_to?(:force_encoding)
+        byte_string.force_encoding(Encoding::ASCII_8BIT)
+      end
+      integer = 0
+      size = byte_string.size
+      for i in 0..(size - 1)
+        ordinal = (byte_string[i].respond_to?(:ord) ?
+          byte_string[i].ord : byte_string[i])
+        integer += (ordinal << (((size - 1) - i) * 8))
+      end
+      return integer
+    end
+  end
+
+  ##
+  # Constant Regexp that matches a UUID and captures its components.
+  UUID_REGEXP = Regexp.new("^([0-9a-f]{8})-([0-9a-f]{4})-([0-9a-f]{4})-" +
+                          "([0-9a-f]{2})([0-9a-f]{2})-([0-9a-f]{12})$")
+
+  ##
+  # Constant that represents the DNS namespace.
+  UUID_DNS_NAMESPACE = UUID.parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+
+  ##
+  # Constant that represents the URL namespace.
+  UUID_URL_NAMESPACE = UUID.parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8")
+
+  ##
+  # Constant that represents the OID namespace.
+  UUID_OID_NAMESPACE = UUID.parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8")
+
+  ##
+  # Constant that represents the X500 namespace.
+  UUID_X500_NAMESPACE = UUID.parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8")
+end