Add 'Begin Until' to the loop battle

README.md

@@ -170,22 +170,24 @@ Custom exception: Kernel#raise:   589148.7 i/s
 Custom exception: E2MM#Raise:    29004.8 i/s - 20.31x slower
 ```
 
-##### `loop` vs `while true` [code](code/general/loop-vs-while-true.rb)
+##### `loop` vs `while true` vs `begin..end until` [code](code/general/loop-vs-while-true.rb)
 
 ```
 $ ruby -v code/general/loop-vs-while-true.rb
-ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-linux]
-
-Calculating -------------------------------------
+ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]
+Warming up --------------------------------------
+         Begin Until     1.000  i/100ms
           While Loop     1.000  i/100ms
          Kernel loop     1.000  i/100ms
--------------------------------------------------
-          While Loop      0.536  (± 0.0%) i/s -      3.000  in   5.593042s
-         Kernel loop      0.223  (± 0.0%) i/s -      2.000  in   8.982355s
+Calculating -------------------------------------
+         Begin Until      0.211  (± 0.0%) i/s -      2.000  in   9.469782s
+          While Loop      0.192  (± 0.0%) i/s -      1.000  in   5.212417s
+         Kernel loop      0.072  (± 0.0%) i/s -      1.000  in  13.921672s
 
 Comparison:
-          While Loop:        0.5 i/s
-         Kernel loop:        0.2 i/s - 2.41x slower
+         Begin Until:        0.2 i/s
+          While Loop:        0.2 i/s - 1.10x  slower
+         Kernel loop:        0.1 i/s - 2.94x  slower
 ```
 
 #### Method Invocation

code/general/loop-vs-while-true.rb

@@ -2,6 +2,13 @@
 
 NUMBER = 100_000_000
 
+def fastest
+  index = 0
+  begin
+    index += 1
+  end until index > NUMBER
+end
+
 def fast
   index = 0
   while true
@@ -19,6 +26,7 @@ def slow
 end
 
 Benchmark.ips do |x|
+  x.report("Begin Until") { fastest }
   x.report("While Loop")  { fast }
   x.report("Kernel loop") { slow }
   x.compare!