class UUID

require 'uuidtools'

Copyright © 2008 Intuit Written by Brian Morearty MIT License

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>

Constants

BUCKET_SIZE

Attributes

clock_seq_hi_and_reserved[RW]
clock_seq_low[RW]
nodes[RW]
time_hi_and_version[RW]
time_low[RW]
time_mid[RW]

Public Class Methods

md5_create(namespace, name) click to toggle source

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

# File lib/usesguid/uuidtools.rb, line 271
def UUID.md5_create(namespace, name)
  return UUID.create_from_hash(Digest::MD5, namespace, name)
end
mysql2_create(connection=ActiveRecord::Base.connection) click to toggle source
# File lib/usesguid/uuid_mysql.rb, line 26
def self.mysql2_create(connection=ActiveRecord::Base.connection)
  mysql_create connection
end
mysql_create(connection=ActiveRecord::Base.connection) click to toggle source

We'll retrieve a bunch of guids at a time to reduce the # of DB round-trips. If the guid bucket is empty, re-fill it by calling MySQL. Then return a guid.

# File lib/usesguid/uuid_mysql.rb, line 13
def self.mysql_create(connection=ActiveRecord::Base.connection)
  raise "UUID.mysql_create only works with MySQL" unless connection.adapter_name.downcase =~ /mysql/

  @@guid_bucket_mutex.synchronize do
    if @@guid_bucket.blank?
      uuid_functions = Array.new(BUCKET_SIZE, "UUID()")
      @@guid_bucket = connection.execute("SELECT #{uuid_functions.join(',')}").first
    end
    # My tests show shift is much faster than slice!(0), pop, or delete_at(0)
    parse @@guid_bucket.shift
  end
end
new(time_low, time_mid, time_hi_and_version, clock_seq_hi_and_reserved, clock_seq_low, nodes) click to toggle source
# File lib/usesguid/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
parse(uuid_string) click to toggle source

Parses a UUID from a string.

# File lib/usesguid/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
parse22(s) click to toggle source

Create a new UUID from a 22char string

# File lib/usesguid/uuid22.rb, line 24
def self.parse22(s)
      # get the integer representation
  integer=0
  s.each_byte {|c|
      integer = integer << 6
    pos=@@chars64.index(c.chr)
    integer+=pos
  }

  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 do
    nodes << ((integer >> (40 - (i * 8))) & 0xFF)
  end
  return new(time_low, time_mid, time_hi_and_version,
    clock_seq_hi_and_reserved, clock_seq_low, nodes)
end
parse_raw(raw_string) click to toggle source

Parses a UUID from a raw byte string.

# File lib/usesguid/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() click to toggle source

Creates a UUID from a random value.

# File lib/usesguid/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) click to toggle source

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

# File lib/usesguid/uuidtools.rb, line 276
def UUID.sha1_create(namespace, name)
  return UUID.create_from_hash(Digest::SHA1, namespace, name)
end
sqlserver_create(connection=ActiveRecord::Base.connection) click to toggle source
# File lib/usesguid/uuid_sqlserver.rb, line 3
def self.sqlserver_create(connection=ActiveRecord::Base.connection)
  raise "UUID.sql_server_create only works with SQL Server" unless connection.adapter_name.downcase =~ /sqlserver/
  parse connection.newid_function
end
timestamp_create(timestamp=nil) click to toggle source

Creates a UUID from a timestamp.

# File lib/usesguid/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

Public Instance Methods

<=>(other_uuid) click to toggle source

Compares two UUIDs lexically

# File lib/usesguid/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() click to toggle source

Returns the hex digest of the UUID object.

# File lib/usesguid/uuidtools.rb, line 397
def hexdigest
  return self.to_i.to_s(16)
end
inspect() click to toggle source

Returns a representation of the object's state

# File lib/usesguid/uuidtools.rb, line 392
def inspect
  return "#<UUID:0x#{self.object_id.to_s(16)} UUID:#{self.to_s}>"
end
mac_address() click to toggle source

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

# File lib/usesguid/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?() click to toggle source

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

# File lib/usesguid/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?() click to toggle source

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.

# File lib/usesguid/uuidtools.rb, line 286
def random_node_id?
  return false if self.version != 1
  return ((self.nodes.first & 0x01) == 1)
end
raw() click to toggle source

Returns the raw bytes that represent this UUID.

# File lib/usesguid/uuidtools.rb, line 402
def raw
  return UUID.convert_int_to_byte_string(self.to_i, 16)
end
timestamp() click to toggle source

Returns the timestamp used to generate this UUID

# File lib/usesguid/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() click to toggle source

Returns an integer representation for this UUID.

# File lib/usesguid/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() click to toggle source

Returns a string representation for this UUID.

# File lib/usesguid/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_s22() click to toggle source

return a 22 byte URL-safe string, encoded six bits at a time using 64 characters

# File lib/usesguid/uuid22.rb, line 12
def to_s22
      integer=self.to_i
      rval=''
  22.times do
    c=(integer & 0x3F)
    rval+=@@chars64[c]
    integer =integer >> 6
  end
  return rval.reverse
end
to_uri() click to toggle source

Returns a URI for this UUID.

# File lib/usesguid/uuidtools.rb, line 428
def to_uri
  return URI.parse(self.to_uri_string)
end
to_uri_string() click to toggle source

Returns a URI string for this UUID.

# File lib/usesguid/uuidtools.rb, line 433
def to_uri_string
  return "urn:uuid:#{self.to_s}"
end
valid?() click to toggle source

Returns true if this UUID is valid.

# File lib/usesguid/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() click to toggle source

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.

# File lib/usesguid/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() click to toggle source

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)

# File lib/usesguid/uuidtools.rb, line 312
def version
  return (time_hi_and_version >> 12)
end