1 files changed, 37 insertions, 43 deletions

diff --git a/src/string.c b/src/string.c
index ab53c2e69..247ee78c2 100644
--- a/src/string.c
+++ b/src/string.c
@@ -24,7 +24,7 @@
 
 typedef struct mrb_shared_string {
   int refcnt;
-  mrb_int len;
+  mrb_int capa;
   char *ptr;
 } mrb_shared_string;
 
@@ -77,9 +77,9 @@ str_init_shared(mrb_state *mrb, const struct RString *orig, struct RString *s, m
   }
   else {
     shared = (mrb_shared_string *)mrb_malloc(mrb, sizeof(mrb_shared_string));
-    shared->refcnt = 2;
+    shared->refcnt = 1;
     shared->ptr = orig->as.heap.ptr;
-    shared->len = orig->as.heap.len;
+    shared->capa = orig->as.heap.aux.capa;
   }
   s->as.heap.ptr = orig->as.heap.ptr;
   s->as.heap.len = orig->as.heap.len;
@@ -516,7 +516,7 @@ mrb_memsearch(const void *x0, mrb_int m, const void *y0, mrb_int n)
 static void
 str_make_shared(mrb_state *mrb, struct RString *orig, struct RString *s)
 {
-  mrb_int len = RSTR_LEN(orig);
+  size_t len = (size_t)orig->as.heap.len;
 
   mrb_assert(!RSTR_EMBED_P(orig));
   if (RSTR_NOFREE_P(orig)) {
@@ -534,10 +534,10 @@ str_make_shared(mrb_state *mrb, struct RString *orig, struct RString *s)
   else {
     if (orig->as.heap.aux.capa > orig->as.heap.len) {
       orig->as.heap.ptr = (char *)mrb_realloc(mrb, orig->as.heap.ptr, len+1);
+      orig->as.heap.aux.capa = len;
     }
     str_init_shared(mrb, orig, s, NULL);
-    orig->as.heap.aux.shared = s->as.heap.aux.shared;
-    RSTR_SET_TYPE_FLAG(orig, SHARED);
+    str_init_shared(mrb, orig, orig, s->as.heap.aux.shared);
   }
 }
 
@@ -780,7 +780,7 @@ mrb_str_modify_keep_ascii(mrb_state *mrb, struct RString *s)
     mrb_shared_string *shared = s->as.heap.aux.shared;
 
     if (shared->refcnt == 1 && s->as.heap.ptr == shared->ptr) {
-      s->as.heap.aux.capa = shared->len;
+      s->as.heap.aux.capa = shared->capa;
       s->as.heap.ptr[s->as.heap.len] = '\0';
       mrb_free(mrb, shared);
     }
@@ -1759,28 +1759,25 @@ mrb_str_include(mrb_state *mrb, mrb_value self)
 static mrb_value
 mrb_str_index_m(mrb_state *mrb, mrb_value str)
 {
-  mrb_value *argv;
-  mrb_int argc;
   mrb_value sub;
-  mrb_int pos, clen;
+  mrb_int pos;
 
-  mrb_get_args(mrb, "*!", &argv, &argc);
-  if (argc == 2) {
-    mrb_get_args(mrb, "oi", &sub, &pos);
-  }
-  else {
-    pos = 0;
-    if (argc > 0)
-      sub = argv[0];
-    else
+  switch (mrb_get_args(mrb, "|oi", &sub, &pos)) {
+    case 0:
       sub = mrb_nil_value();
-  }
-  if (pos < 0) {
-    clen = RSTRING_CHAR_LEN(str);
-    pos += clen;
-    if (pos < 0) {
-      return mrb_nil_value();
-    }
+      /* fall through */
+    case 1:
+      pos = 0;
+      break;
+    case 2:
+      if (pos < 0) {
+        mrb_int clen = RSTRING_CHAR_LEN(str);
+        pos += clen;
+        if (pos < 0) {
+          return mrb_nil_value();
+        }
+      }
+      break;
   }
 
   switch (mrb_type(sub)) {
@@ -2009,28 +2006,25 @@ mrb_str_reverse(mrb_state *mrb, mrb_value str)
 static mrb_value
 mrb_str_rindex(mrb_state *mrb, mrb_value str)
 {
-  mrb_value *argv;
-  mrb_int argc;
   mrb_value sub;
   mrb_int pos, len = RSTRING_CHAR_LEN(str);
 
-  mrb_get_args(mrb, "*!", &argv, &argc);
-  if (argc == 2) {
-    mrb_get_args(mrb, "oi", &sub, &pos);
-    if (pos < 0) {
-      pos += len;
+  switch (mrb_get_args(mrb, "|oi", &sub, &pos)) {
+    case 0:
+      sub = mrb_nil_value();
+      /* fall through */
+    case 1:
+      pos = len;
+      break;
+    case 2:
       if (pos < 0) {
-        return mrb_nil_value();
+        pos += len;
+        if (pos < 0) {
+          return mrb_nil_value();
+        }
       }
-    }
-    if (pos > len) pos = len;
-  }
-  else {
-    pos = len;
-    if (argc > 0)
-      sub = argv[0];
-    else
-      sub = mrb_nil_value();
+      if (pos > len) pos = len;
+      break;
   }
   pos = chars2bytes(str, 0, pos);