Class: UUID

Inherits:
Object
  • Object
show all
Defined in:
lib/uuidtools.rb

Overview

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>

Constant Summary collapse

@@last_timestamp = 
nil
@@last_node_id = 
nil
@@last_clock_sequence = 
nil
@@state_file = 
nil
@@mutex = 
Mutex.new

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(time_low, time_mid, time_hi_and_version, clock_seq_hi_and_reserved, clock_seq_low, nodes) ⇒ UUID

Returns a new instance of UUID.



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# File 'lib/uuidtools.rb', line 112

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

Instance Attribute Details

#clock_seq_hi_and_reserved ⇒ Object

Returns the value of attribute clock_seq_hi_and_reserved.



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# File 'lib/uuidtools.rb', line 163

def clock_seq_hi_and_reserved
  @clock_seq_hi_and_reserved
end

#clock_seq_low ⇒ Object

Returns the value of attribute clock_seq_low.



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# File 'lib/uuidtools.rb', line 164

def clock_seq_low
  @clock_seq_low
end

#nodes ⇒ Object

Returns the value of attribute nodes.



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# File 'lib/uuidtools.rb', line 165

def nodes
  @nodes
end

#time_hi_and_version ⇒ Object

Returns the value of attribute time_hi_and_version.



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# File 'lib/uuidtools.rb', line 162

def time_hi_and_version
  @time_hi_and_version
end

#time_low ⇒ Object

Returns the value of attribute time_low.



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# File 'lib/uuidtools.rb', line 160

def time_low
  @time_low
end

#time_mid ⇒ Object

Returns the value of attribute time_mid.



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# File 'lib/uuidtools.rb', line 161

def time_mid
  @time_mid
end

Class Method Details

.convert_byte_string_to_int(byte_string) ⇒ Object

:nodoc:



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# File 'lib/uuidtools.rb', line 548

def UUID.convert_byte_string_to_int(byte_string) #:nodoc:
  integer = 0
  size = byte_string.size
  for i in 0..(size - 1)
    integer += (byte_string[i] << (((size - 1) - i) * 8))
  end
  return integer
end

.convert_int_to_byte_string(integer, size) ⇒ Object

:nodoc:



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# File 'lib/uuidtools.rb', line 540

def UUID.convert_int_to_byte_string(integer, size) #:nodoc:
  byte_string = ""
  for i in 0..(size - 1)
    byte_string << ((integer >> (((size - 1) - i) * 8)) & 0xFF)
  end
  return byte_string
end

.create_from_hash(hash_class, namespace, name) ⇒ Object

:nodoc:



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# File 'lib/uuidtools.rb', line 437

def UUID.create_from_hash(hash_class, namespace, name) #:nodoc:
  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 = UUID.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

.get_mac_address ⇒ Object

Returns the MAC address of the current computer’s network card. Returns nil if a MAC address could not be found.



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# File 'lib/uuidtools.rb', line 462

def UUID.get_mac_address #:nodoc:
  if RUBY_PLATFORM =~ /win/ && !(RUBY_PLATFORM =~ /darwin/)
    begin
      ifconfig_output = `ipconfig /all`
      mac_addresses = ifconfig_output.scan(
        Regexp.new("(#{(["[0-9A-F]{2}"] * 6).join("-")})"))
      if mac_addresses.size > 0
        return mac_addresses.first.first.downcase.gsub(/-/, ":")
      end
    rescue
    end
  else
    begin
      ifconfig_output = `ifconfig`
      mac_addresses = ifconfig_output.scan(
        Regexp.new("ether (#{(["[0-9a-f]{2}"] * 6).join(":")})"))
      if mac_addresses.size == 0
        ifconfig_output = `ifconfig | grep HWaddr | cut -c39-`
        mac_addresses = ifconfig_output.scan(
          Regexp.new("(#{(["[0-9a-f]{2}"] * 6).join(":")})"))
      end
      if mac_addresses.size == 0
        ifconfig_output = `/sbin/ifconfig`
        mac_addresses = ifconfig_output.scan(
          Regexp.new("ether (#{(["[0-9a-f]{2}"] * 6).join(":")})"))
      end
      if mac_addresses.size == 0
        ifconfig_output = `/sbin/ifconfig | grep HWaddr | cut -c39-`
        mac_addresses = ifconfig_output.scan(
          Regexp.new("(#{(["[0-9a-f]{2}"] * 6).join(":")})"))
      end
      if mac_addresses.size > 0
        return mac_addresses.first.first
      end
    rescue
    end
  end
end

.md5_create(namespace, name) ⇒ Object

Creates a UUID using the MD5 hash. (Version 3)



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# File 'lib/uuidtools.rb', line 271

def UUID.md5_create(namespace, name)
  return UUID.create_from_hash(Digest::MD5, namespace, name)
end

.parse(uuid_string) ⇒ Object

Parses a UUID from a string.

Raises:

  • (ArgumentError) 


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# File 'lib/uuidtools.rb', line 168

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

.parse_raw(raw_string) ⇒ Object

Parses a UUID from a raw byte string.



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# File 'lib/uuidtools.rb', line 191

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

.random_create ⇒ Object

Creates a UUID from a random value.



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# File 'lib/uuidtools.rb', line 212

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

.sha1_create(namespace, name) ⇒ Object

Creates a UUID using the SHA1 hash. (Version 5)



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# File 'lib/uuidtools.rb', line 276

def UUID.sha1_create(namespace, name)
  return UUID.create_from_hash(Digest::SHA1, namespace, name)
end

.timestamp_create(timestamp = nil) ⇒ Object

Creates a UUID from a timestamp.



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# File 'lib/uuidtools.rb', line 222

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.
    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
    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

.true_random ⇒ Object

Returns 128 bits of highly unpredictable data. The random number generator isn’t perfect, but it’s much, much better than the built-in pseudorandom number generators.



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# File 'lib/uuidtools.rb', line 504

def UUID.true_random #:nodoc:
  require 'benchmark'
  hash = Digest::SHA1.new
  performance = Benchmark.measure do
    hash.update(rand.to_s)
    hash.update(srand.to_s)
    hash.update(rand.to_s)
    hash.update(srand.to_s)
    hash.update(Time.now.to_s)
    hash.update(rand.to_s)
    hash.update(self.object_id.to_s)
    hash.update(rand.to_s)
    hash.update(hash.object_id.to_s)
    hash.update(self.methods.inspect)
    begin
      random_device = nil
      if File.exists? "/dev/urandom"
        random_device = File.open "/dev/urandom", "r"
      elsif File.exists? "/dev/random"
        random_device = File.open "/dev/random", "r"
      end
      hash.update(random_device.read(20)) if random_device != nil
    rescue
    end
    begin
      srand(hash.to_s.to_i(16) >> 128)
    rescue
    end
    hash.update(rand.to_s)
    hash.update(UUID.true_random) if (rand(2) == 0)
  end
  hash.update(performance.real.to_s)
  hash.update(performance.inspect)
  return UUID.convert_int_to_byte_string(hash.to_s[4..35].to_i(16), 16)
end

Instance Method Details

#<=>(other_uuid) ⇒ Object

Compares two UUIDs lexically



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# File 'lib/uuidtools.rb', line 368

def <=>(other_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

#hexdigest ⇒ Object

Returns the hex digest of the UUID object.



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# File 'lib/uuidtools.rb', line 397

def hexdigest
  return self.to_i.to_s(16)
end

#inspect ⇒ Object

Returns a representation of the object’s state



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# File 'lib/uuidtools.rb', line 392

def inspect
  return "#<UUID:0x#{self.object_id.to_s(16)} UUID:#{self.to_s}>"
end

#mac_address ⇒ Object

Returns the IEEE 802 address used to generate this UUID or nil if a MAC address was not used.



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# File 'lib/uuidtools.rb', line 347

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

#nil_uuid? ⇒ Boolean

Returns true if this UUID is the nil UUID (00000000-0000-0000-0000-000000000000).

Returns:

  • (Boolean) 


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# File 'lib/uuidtools.rb', line 293

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

#random_node_id? ⇒ Boolean

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.

Returns:

  • (Boolean) 


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# File 'lib/uuidtools.rb', line 286

def random_node_id?
  return false if self.version != 1
  return ((self.nodes.first & 0x01) == 1)
end

#raw ⇒ Object

Returns the raw bytes that represent this UUID.



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# File 'lib/uuidtools.rb', line 402

def raw
  return UUID.convert_int_to_byte_string(self.to_i, 16)
end

#timestamp ⇒ Object

Returns the timestamp used to generate this UUID



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# File 'lib/uuidtools.rb', line 356

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

#to_i ⇒ Object

Returns an integer representation for this UUID.



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# File 'lib/uuidtools.rb', line 417

def to_i
  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
  return bytes
end

#to_s ⇒ Object

Returns a string representation for this UUID.



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# File 'lib/uuidtools.rb', line 407

def to_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
end

#to_uri ⇒ Object

Returns a URI for this UUID.



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# File 'lib/uuidtools.rb', line 428

def to_uri
  return URI.parse(self.to_uri_string)
end

#to_uri_string ⇒ Object

Returns a URI string for this UUID.



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# File 'lib/uuidtools.rb', line 433

def to_uri_string
  return "urn:uuid:#{self.to_s}"
end

#valid? ⇒ Boolean

Returns true if this UUID is valid.

Returns:

  • (Boolean) 


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# File 'lib/uuidtools.rb', line 336

def valid?
  if [0b000, 0b100, 0b110, 0b111].include?(self.variant) &&
    (1..5).include?(self.version)
    return true
  else
    return false
  end
end

#variant ⇒ Object

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.



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# File 'lib/uuidtools.rb', line 322

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

#version ⇒ Object

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)



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# File 'lib/uuidtools.rb', line 312

def version
  return (time_hi_and_version >> 12)
end