uuid_convertable.rb in bson-objectid-to-uuid-0.1.3

- old
+ new
@@ -1,54 +1,33 @@
 # frozen_string_literal: true
 
 module BSON::ObjectId::UUIDConvertable
-  GREGORIAN_EPOCH_OFFSET = 0x01B2_1DD2_1381_4000 # Oct 15, 1582
+  UUID_PREFIX = '0bdaea'
+  UUID_REGEX = /\A0bdaea[0-9a-f]{2}-[0-9a-f]{4}-4[0-9a-f]{3}-[ab][0-9a-f]{3}-[0-9a-f]{12}\z/i
+  UUID_VERSION = '4'
+  UUID_VARIANT = 'a'
 
-  UUID_REGEX = /\A[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\z/i
-  UUID_VERSION = 0x1000
-  UUID_VARIANT = 0b1000_0000_0000_0000
-
-  def to_uuid # rubocop:disable Metrics/AbcSize,Metrics/MethodLength
-    timestamp = to_s[0..7].to_i(16) * 10_000_000 + GREGORIAN_EPOCH_OFFSET
-    machine_pid = to_s[8..17].to_i(16)
-
-    high_counter = to_s[18..19].to_i(16)
-    mid_counter = to_s[20..21].to_i(16)
-    low_counter = to_s[22..23].to_i(16)
-
-    bytes = [
-      (timestamp + low_counter) & 0xFFFF_FFFF,
-      (timestamp >> 32) & 0xFFFF,
-      ((timestamp >> 48) & 0x0FFF) | UUID_VERSION,
-      mid_counter | UUID_VARIANT,
-      (high_counter << 40) + machine_pid
-    ]
-
-    format('%08x-%04x-%04x-%04x-%012x', *bytes)
+  def to_uuid
+    [
+      UUID_PREFIX + to_s[0..1],   # 6 digit prefix + first 2 oid digits
+      to_s[2..5],                 # next 4 oid digits
+      UUID_VERSION + to_s[6..8],  # 1 digit version(0x4) + next 3 oid digits
+      UUID_VARIANT + to_s[9..11], # 1 digit variant(0b101) + 1 zero bit + next 3 oid digits
+      to_s[12..23]                # last 12 oid digits
+    ].join('-')
   end
 
   module ClassMethods
     def legal?(string)
-      UUID_REGEX.match(string.to_s) ? true : super
+      UUID_REGEX.match?(string.to_s) ? true : super
     end
 
     def from_string(string)
-      UUID_REGEX.match(string.to_s) ? from_uuid(string) : super
+      UUID_REGEX.match?(string.to_s) ? from_uuid(string) : super
     end
 
-    def from_uuid(string) # rubocop:disable Metrics/AbcSize
-      parts = string.split('-')
-
-      timestamp = parts[0].to_i(16) + (parts[1].to_i(16) << 32) + ((parts[2].to_i(16) & 0x0FFF) << 48)
-      machine_pid = parts[4][2..-1]
-
-      high_counter = parts[4][0..1]
-      mid_counter = parts[3][2..3]
-      low_counter = (timestamp % 10_000_000) & 0xFF
-
-      seconds = (timestamp - GREGORIAN_EPOCH_OFFSET) / 10_000_000
-
-      from_string(format('%06x', seconds) + machine_pid + high_counter + mid_counter + format('%02x', low_counter))
+    def from_uuid(string)
+      from_string(string[6..7] + string[9..12] + string[15..17] + string[20..22] + string[24..35])
     end
   end
 
   def self.prepended(base)
     class << base