2 files changed, 13 insertions, 9 deletions
diff --git a/mrbgems/mruby-string-ext/mrblib/string.rb b/mrbgems/mruby-string-ext/mrblib/string.rb
index 311803ea2..fdaf2f960 100644
--- a/mrbgems/mruby-string-ext/mrblib/string.rb
+++ b/mrbgems/mruby-string-ext/mrblib/string.rb
@@ -310,11 +310,15 @@ class String
     end
   end
 
+  ##
+  # Call the given block for each character of
+  # +self+.
   def each_char(&block)
     return to_enum :each_char unless block
-
-    split('').each do |i|
-      block.call(i)
+    pos = 0
+    while pos < self.size
+      block.call(self[pos])
+      pos += 1
     end
     self
   end
diff --git a/mrbgems/mruby-string-ext/test/string.rb b/mrbgems/mruby-string-ext/test/string.rb
index 44ca1fde2..02777e594 100644
--- a/mrbgems/mruby-string-ext/test/string.rb
+++ b/mrbgems/mruby-string-ext/test/string.rb
@@ -657,19 +657,19 @@ assert('String#chars(UTF-8)') do
 end if UTF8STRING
 
 assert('String#each_char') do
-  s = ""
+  chars = []
   "hello!".each_char do |x|
-    s += x
+    chars << x
   end
-  assert_equal "hello!", s
+  assert_equal ["h", "e", "l", "l", "o", "!"], chars
 end
 
 assert('String#each_char(UTF-8)') do
-  s = ""
+  chars = []
   "こんにちは世界!".each_char do |x|
-    s += x
+    chars << x
   end
-  assert_equal "こんにちは世界!", s
+  assert_equal ["こ", "ん", "に", "ち", "は", "世", "界", "!"], chars
 end if UTF8STRING
 
 assert('String#codepoints') do