Class: Cassandra::UUID

Inherits:
Comparable show all
Defined in:
lib/cassandra/uuid.rb

Overview

UUID format version 1, as specified in RFC 4122, with jitter in place of the mac address and sequence counter.

Defined Under Namespace

Classes: InvalidVersion

Constant Summary collapse

GREGORIAN_EPOCH_OFFSET =

Oct 15, 1582

0x01B2_1DD2_1381_4000
VARIANT = 
0b1000_0000_0000_0000

Instance Method Summary collapse

Methods inherited from Comparable

#==, #eql?, #hash, #to_s

Constructor Details

#initialize(bytes = nil) ⇒ UUID

Returns a new instance of UUID.



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# File 'lib/cassandra/uuid.rb', line 14

def initialize(bytes = nil)
  case bytes
  when self.class # UUID
    @bytes = bytes.to_s
  when String
    case bytes.size
    when 16 # Raw byte array
      @bytes = bytes
    when 36 # Human-readable UUID representation; inverse of #to_guid
      elements = bytes.split("-")
      raise TypeError, "Expected #{bytes.inspect} to cast to a #{self.class} (malformed UUID representation)" if elements.size != 5
      @bytes = elements.join.to_a.pack('H32')
    else
      raise TypeError, "Expected #{bytes.inspect} to cast to a #{self.class} (invalid bytecount)"
    end

  when Integer
    raise TypeError, "Expected #{bytes.inspect} to cast to a #{self.class} (integer out of range)" if bytes < 0 or bytes > 2**128
    @bytes = [
      (bytes >> 96) & 0xFFFF_FFFF,
      (bytes >> 64) & 0xFFFF_FFFF,
      (bytes >> 32) & 0xFFFF_FFFF,
      bytes & 0xFFFF_FFFF
    ].pack("NNNN")

  when NilClass, Time
    time = (bytes || Time).stamp * 10 + GREGORIAN_EPOCH_OFFSET
    # See http://github.com/spectra/ruby-uuid/
    @bytes = [
      time & 0xFFFF_FFFF,
      time >> 32,
      ((time >> 48) & 0x0FFF) | 0x1000,
      # Top 3 bytes reserved
      rand(2**13) | VARIANT,
      rand(2**16),
      rand(2**32)
    ].pack("NnnnnN")

  else
    raise TypeError, "Expected #{bytes.inspect} to cast to a #{self.class} (unknown source class)"
  end
end

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 90

def <=>(other)
  total_usecs <=> other.send(:total_usecs)
end

#inspect(long = false) ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 94

def inspect(long = false)
  "<Cassandra::UUID##{object_id} time: #{
    Time.at(seconds).inspect
  }, usecs: #{
    usecs
  } jitter: #{
    @bytes.unpack('QQ')[1]
  }" + (long ? ", version: #{version}, variant: #{variant}, guid: #{to_guid}>" :  ">")
end

#seconds ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 82

def seconds
  total_usecs / 1_000_000
end

#to_guid ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 75

def to_guid
  elements = @bytes.unpack("NnnCCa6")
  node = elements[-1].unpack('C*')
  elements[-1] = '%02x%02x%02x%02x%02x%02x' % node
  "%08x-%04x-%04x-%02x%02x-%s" % elements
end

#to_i ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 57

def to_i
  ints = @bytes.unpack("NNNN")
  (ints[0] << 96) +
  (ints[1] << 64) +
  (ints[2] << 32) +
  ints[3]
end

#usecs ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 86

def usecs
  total_usecs % 1_000_000
end

#variant ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 71

def variant
  @bytes.unpack('QnnN')[1] >> 13
end

#version ⇒ Object 



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# File 'lib/cassandra/uuid.rb', line 65

def version
  time_high = @bytes.unpack("NnnQ")[2]
  version = (time_high & 0xF000).to_s(16)[0].chr.to_i
  version > 0 and version < 6 ? version : -1
end