uuidtools.rb

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#--
# Copyright (c) 2005 Robert Aman
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#++

UUID_TOOLS_VERSION = "0.1.1"

$:.unshift(File.dirname(__FILE__))

require 'uri'
require 'time'
require 'thread'
require 'digest/sha1'
require 'digest/md5'

#  Because it's impossible to hype a UUID generator on its genuine merits,
#  I give you... Really bad ASCII art in the comments:
#
#                                                                  
#                \                                                 
#                /                                                   
#               +                                                  
#              ]                                                   
#              ]                                                   
#              |                                                    
#             /                                                     
#           Mp___                                                  
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#             g0M~"`                                               
#            ]0M*-                                                 
#                                                                  
#                    ___                                           
#                _g000M00g,                                        
#              j0M~      ~M&                                       
#            j0M"          ~N,                                     
#           j0P              M&                                    
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#        0M                     ]0L                                
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#        M0NN0M00MMM~"'M          0&                               
#          `~          ~0         ]0,                              
#                       ]M        ]0&                              
#                        M&        M0,                             
#               ____gp_   M&        M0_                            
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#           gN"`       M0N_j0,         MM&__                       
#         _gF           `~M0P`   __      M00g                      
#        g0'                    gM0&,     ~M0&                     
#      _pM`                     0, ]M1     "00&                    
#     _00                    /g1MMgj01      ]0MI                   
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#   g0'                  _   N&j&            40'                   
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#  0'              _g0000000g__              ~M@MMM000g            
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# ]M          _M00F              "00MM`                ~#&         
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#                                        `~~~M00000000000000       
#                                              `M0000000000f       
#                                                  ~@@@MF~`        
#                                                                  
#                                                                  

#= uuidtools.rb
#
# 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
  @@last_timestamp = nil
  @@last_node_id = nil
  @@last_clock_sequence = nil
  @@state_file = nil
  @@mutex = Mutex.new
  
  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.respond_to? :size
      raise ArgumentError,
        "Expected nodes to respond to :size."
    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
  
  attr_accessor :time_low
  attr_accessor :time_mid
  attr_accessor :time_hi_and_version
  attr_accessor :clock_seq_hi_and_reserved
  attr_accessor :clock_seq_low
  attr_accessor :nodes
  
  # Parses a UUID from a string.
  def UUID.parse(uuid_string)
    unless uuid_string.kind_of? String
      raise ArgumentError,
        "Expected String, got #{uuid_string.class.name} instead."
    end
    uuid_components = uuid_string.downcase.scan(
      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})$")).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 UUID.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 UUID.parse_raw(raw_string)
    unless raw_string.kind_of? String
      raise ArgumentError,
        "Expected String, got #{raw_string.class.name} instead."
    end
    integer = UUID.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 UUID.new(time_low, time_mid, time_hi_and_version,
      clock_seq_hi_and_reserved, clock_seq_low, nodes)
  end

  # Creates a UUID from a random value.
  def UUID.random_create()
    new_uuid = UUID.parse_raw(UUID.true_random)
    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 UUID.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.
      gmt_timestamp = Time.now.gmtime
      # Convert to 100 nanosecond blocks
      gmt_timestamp_100_nanoseconds = (gmt_timestamp.tv_sec * 10000000) +
        (gmt_timestamp.tv_usec * 10) + 0x01B21DD213814000
      nodes = UUID.get_mac_address.split(":").collect do |octet|
        octet.to_i(16)
      end
      node_id = 0
      for i in 0..5
        node_id += (nodes[i] << (40 - (i * 8)))
      end
      clock_sequence = @@last_clock_sequence
      if clock_sequence.nil?
        clock_sequence = UUID.convert_byte_string_to_int(UUID.true_random)
      end
      if @@last_node_id != nil && @@last_node_id != node_id
        # The node id has changed.  Change the clock id.
        clock_sequence = UUID.convert_byte_string_to_int(UUID.true_random)
      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 UUID.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 UUID.md5_create(namespace, name)
    return UUID.create_from_hash(Digest::MD5, namespace, name)
  end
  
  # Creates a UUID using the SHA1 hash.  (Version 5)
  def UUID.sha1_create(namespace, name)
    return UUID.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).