9 files changed, 60 insertions, 22 deletions
diff --git a/mrbgems/mruby-bin-mirb/tools/mirb/mirb.c b/mrbgems/mruby-bin-mirb/tools/mirb/mirb.c
index 81eef7f82..5505e8e5e 100644
--- a/mrbgems/mruby-bin-mirb/tools/mirb/mirb.c
+++ b/mrbgems/mruby-bin-mirb/tools/mirb/mirb.c
@@ -8,21 +8,17 @@
 
 #include <stdlib.h>
 #include <string.h>
-
-#include <mruby.h>
+#include "mruby.h"
 #include "mruby/array.h"
-#include <mruby/proc.h>
-#include <mruby/data.h>
-#include <mruby/compile.h>
+#include "mruby/proc.h"
+#include "mruby/compile.h"
+#include "mruby/string.h"
+
 #ifdef ENABLE_READLINE
 #include <limits.h>
 #include <readline/readline.h>
 #include <readline/history.h>
-#endif
-#include <mruby/string.h>
 
-
-#ifdef ENABLE_READLINE
 static const char *history_file_name = ".mirb_history";
 char history_path[PATH_MAX];
 #endif
diff --git a/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c b/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
index ef0ac4978..54b2f8b65 100644
--- a/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
+++ b/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
@@ -1,13 +1,11 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include "mruby.h"
-#include "mruby/proc.h"
 #include "mruby/array.h"
-#include "mruby/string.h"
 #include "mruby/compile.h"
 #include "mruby/dump.h"
 #include "mruby/variable.h"
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 
 #ifndef ENABLE_STDIO
 static void
diff --git a/mrbgems/mruby-hash-ext/src/hash-ext.c b/mrbgems/mruby-hash-ext/src/hash-ext.c
index 94518924e..c6e72f451 100644
--- a/mrbgems/mruby-hash-ext/src/hash-ext.c
+++ b/mrbgems/mruby-hash-ext/src/hash-ext.c
@@ -6,11 +6,8 @@
 
 #include "mruby.h"
 #include "mruby/array.h"
-#include "mruby/class.h"
 #include "mruby/hash.h"
 #include "mruby/khash.h"
-#include "mruby/string.h"
-#include "mruby/variable.h"
 
 /*
  * call-seq:
diff --git a/mrbgems/mruby-numeric-ext/src/numeric_ext.c b/mrbgems/mruby-numeric-ext/src/numeric_ext.c
index bb6955b45..22c1668fa 100644
--- a/mrbgems/mruby-numeric-ext/src/numeric_ext.c
+++ b/mrbgems/mruby-numeric-ext/src/numeric_ext.c
@@ -1,6 +1,5 @@
 #include <limits.h>
 #include "mruby.h"
-#include "mruby/numeric.h"
 
 static mrb_value
 mrb_int_chr(mrb_state *mrb, mrb_value x)
diff --git a/mrbgems/mruby-random/src/mt19937ar.c b/mrbgems/mruby-random/src/mt19937ar.c
index 3246909e8..41ed2c00d 100644
--- a/mrbgems/mruby-random/src/mt19937ar.c
+++ b/mrbgems/mruby-random/src/mt19937ar.c
@@ -4,7 +4,6 @@
 ** See Copyright Notice in mruby.h
 */
 
-#include <stdio.h>
 #include "mt19937ar.h"
 
 /* Period parameters */  
diff --git a/mrbgems/mruby-string-ext/src/string.c b/mrbgems/mruby-string-ext/src/string.c
index 6718e734a..f194bbc0e 100644
--- a/mrbgems/mruby-string-ext/src/string.c
+++ b/mrbgems/mruby-string-ext/src/string.c
@@ -1,7 +1,7 @@
-#include "mruby.h"
-#include "mruby/string.h"
 #include <ctype.h>
 #include <string.h>
+#include "mruby.h"
+#include "mruby/string.h"
 
 static mrb_value
 mrb_str_getbyte(mrb_state *mrb, mrb_value str)
diff --git a/mrbgems/mruby-string-utf8/src/string.c b/mrbgems/mruby-string-utf8/src/string.c
index 5379dd3aa..c377726a2 100644
--- a/mrbgems/mruby-string-utf8/src/string.c
+++ b/mrbgems/mruby-string-utf8/src/string.c
@@ -247,6 +247,38 @@ mrb_str_aref_m(mrb_state *mrb, mrb_value str)
   return mrb_str_aref(mrb, str, a1);
 }
 
+static mrb_value
+mrb_str_reverse_bang(mrb_state *mrb, mrb_value str)
+{
+  int utf8_len = mrb_utf8_strlen(str);
+  if (utf8_len > 1) {
+    int len = RSTRING_LEN(str);
+    char *buf = (char *)mrb_malloc(mrb, len);
+    unsigned char* p = (unsigned char*)buf;
+    unsigned char* e = (unsigned char*)buf + len;
+    unsigned char* r = (unsigned char*)RSTRING_END(str);
+    
+    memcpy(buf, RSTRING_PTR(str), len);
+    mrb_str_modify(mrb, mrb_str_ptr(str));
+    
+    while (p<e) {
+      int clen = utf8len(p);
+      r -= clen;
+      memcpy(r, p, clen);
+      p += clen;
+    }
+    mrb_free(mrb, buf);
+  }
+  
+  return str;
+}
+
+static mrb_value
+mrb_str_reverse(mrb_state *mrb, mrb_value str)
+{
+  return mrb_str_reverse_bang(mrb, mrb_str_dup(mrb, str));
+}
+
 void
 mrb_mruby_string_utf8_gem_init(mrb_state* mrb)
 {
@@ -255,6 +287,8 @@ mrb_mruby_string_utf8_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, s, "size", mrb_str_size, MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "[]", mrb_str_aref_m, MRB_ARGS_ANY());
   mrb_define_method(mrb, s, "slice", mrb_str_aref_m, MRB_ARGS_ANY());
+  mrb_define_method(mrb, s, "reverse",  mrb_str_reverse,      MRB_ARGS_NONE());
+  mrb_define_method(mrb, s, "reverse!", mrb_str_reverse_bang, MRB_ARGS_NONE());
 }
 
 void
diff --git a/mrbgems/mruby-string-utf8/test/string.rb b/mrbgems/mruby-string-utf8/test/string.rb
index 4ee815a36..fc21c0a93 100644
--- a/mrbgems/mruby-string-utf8/test/string.rb
+++ b/mrbgems/mruby-string-utf8/test/string.rb
@@ -9,3 +9,19 @@ assert('String#[]') do
   assert_equal "んに", "こんにちわ世界"[1,2]
   assert_equal "世", "こんにちわ世界"["世"]
 end
+
+assert('String#reverse', '15.2.10.5.29') do
+  a = 'こんにちわ世界!'
+  a.reverse
+    
+  assert_equal 'こんにちわ世界!', a
+  assert_equal '!界世わちにんこ', 'こんにちわ世界!'.reverse
+end
+
+assert('String#reverse!', '15.2.10.5.30') do
+  a = 'こんにちわ世界!'
+  a.reverse!
+    
+  assert_equal '!界世わちにんこ', a
+  assert_equal '!界世わちにんこ', 'こんにちわ世界!'.reverse!
+end
diff --git a/mrbgems/mruby-struct/src/struct.c b/mrbgems/mruby-struct/src/struct.c
index 309684422..e6d3b0796 100644
--- a/mrbgems/mruby-struct/src/struct.c
+++ b/mrbgems/mruby-struct/src/struct.c
@@ -10,7 +10,6 @@
 #include "mruby/array.h"
 #include "mruby/string.h"
 #include "mruby/class.h"
-#include "mruby/data.h"
 #include "mruby/variable.h"
 
 #define RSTRUCT_ARY(st) mrb_ary_ptr(st)