first commit

nghttp2/third-party/mruby/mrbgems/mruby-enum-chain/mrblib/chain.rb

@@ -0,0 +1,62 @@
+##
+# chain.rb Enumerator::Chain class
+# See Copyright Notice in mruby.h
+
+module Enumerable
+  def chain(*args)
+    Enumerator::Chain.new(self, *args)
+  end
+end
+
+class Enumerator
+  def +(other)
+    Chain.new(self, other)
+  end
+
+  class Chain
+    include Enumerable
+
+    def initialize(*args)
+      @enums = args.freeze
+      @pos = -1
+    end
+
+    def each(&block)
+      return to_enum unless block
+
+      i = 0
+      while i < @enums.size
+        @pos = i
+        @enums[i].each(&block)
+        i += 1
+      end
+
+      self
+    end
+
+    def size
+      @enums.reduce(0) do |a, e|
+        return nil unless e.respond_to?(:size)
+        a + e.size
+      end
+    end
+
+    def rewind
+      while 0 <= @pos && @pos < @enums.size
+        e = @enums[@pos]
+        e.rewind if e.respond_to?(:rewind)
+        @pos -= 1
+      end
+
+      self
+    end
+
+    def +(other)
+      self.class.new(self, other)
+    end
+
+    def inspect
+      "#<#{self.class}: #{@enums.inspect}>"
+    end
+  end
+end