1 files changed, 135 insertions, 1 deletions

diff --git a/mrbgems/mruby-string-ext/src/string.c b/mrbgems/mruby-string-ext/src/string.c
index f04f12c4b..e925a82a7 100644
--- a/mrbgems/mruby-string-ext/src/string.c
+++ b/mrbgems/mruby-string-ext/src/string.c
@@ -1,4 +1,3 @@
-#include <ctype.h>
 #include <string.h>
 #include "mruby.h"
 #include "mruby/array.h"
@@ -239,6 +238,136 @@ mrb_str_lines(mrb_state *mrb, mrb_value self)
   return result;
 }
 
+/*
+ *  call-seq:
+ *     string.succ    ->  string
+ *
+ *  Returns next sequence of the string;
+ *
+ *     a = "abc"
+ *     a.succ    #=> "abd"
+ */
+static mrb_value
+mrb_str_succ_bang(mrb_state *mrb, mrb_value self)
+{
+  mrb_value result;
+  unsigned char *p, *e, *b, *t;
+  const char *prepend;
+  struct RString *s = mrb_str_ptr(self);
+  size_t l;
+
+  if (RSTRING_LEN(self) == 0)
+    return self;
+
+  mrb_str_modify(mrb, s);
+  l = RSTRING_LEN(self);
+  b = p = (unsigned char*) RSTRING_PTR(self);
+  t = e = p + l;
+  *(e--) = 0;
+
+  // find trailing ascii/number
+  while (e >= b) {
+    if (ISALNUM(*e))
+      break;
+    e--;
+  }
+  if (e < b) {
+    e = p + l - 1;
+    result = mrb_str_new_lit(mrb, "");
+  } else {
+    // find leading letter of the ascii/number
+    b = e;
+    while (b > p) {
+      if (!ISALNUM(*b) || (ISALNUM(*b) && *b != '9' && *b != 'z' && *b != 'Z'))
+        break;
+      b--;
+    }
+    if (!ISALNUM(*b))
+      b++;
+    result = mrb_str_new(mrb, (char*) p, b - p);
+  }
+
+  while (e >= b) {
+    if (!ISALNUM(*e)) {
+      if (*e == 0xff) {
+        mrb_str_cat_lit(mrb, result, "\x01");
+        (*e) = 0;
+      } else
+        (*e)++;
+      break;
+    }
+    prepend = NULL;
+    if (*e == '9') {
+      if (e == b) prepend = "1";
+      *e = '0';
+    } else if (*e == 'z') {
+      if (e == b) prepend = "a";
+      *e = 'a';
+    } else if (*e == 'Z') {
+      if (e == b) prepend = "A";
+      *e = 'A';
+    } else {
+      (*e)++;
+      break;
+    }
+    if (prepend) mrb_str_cat_cstr(mrb, result, prepend);
+    e--;
+  }
+  result = mrb_str_cat(mrb, result, (char*) b, t - b);
+  l = RSTRING_LEN(result);
+  mrb_str_resize(mrb, self, l);
+  memcpy(RSTRING_PTR(self), RSTRING_PTR(result), l);
+  return self;
+}
+
+static mrb_value
+mrb_str_succ(mrb_state *mrb, mrb_value self)
+{
+  mrb_value str;
+
+  str = mrb_str_dup(mrb, self);
+  mrb_str_succ_bang(mrb, str);
+  return str;
+}
+
+/*
+ *  call-seq:
+ *     str.prepend(other_str)  -> str
+ *
+ *  Prepend---Prepend the given string to <i>str</i>.
+ *
+ *     a = "world"
+ *     a.prepend("hello ") #=> "hello world"
+ *     a                   #=> "hello world"
+ */
+static mrb_value
+mrb_str_prepend(mrb_state *mrb, mrb_value self)
+{
+  struct RString *s1 = mrb_str_ptr(self), *s2, *temp_s;
+  mrb_int len;
+  mrb_value other, temp_str;
+
+  mrb_get_args(mrb, "S", &other);
+
+  mrb_str_modify(mrb, s1);
+  if (!mrb_string_p(other)) {
+    other = mrb_str_to_str(mrb, other);
+  }
+  s2 = mrb_str_ptr(other);
+  len = RSTR_LEN(s1) + RSTR_LEN(s2);
+  temp_str = mrb_str_new(mrb, NULL, RSTR_LEN(s1));
+  temp_s = mrb_str_ptr(temp_str);
+  memcpy(RSTR_PTR(temp_s), RSTR_PTR(s1), RSTR_LEN(s1));
+  if (RSTRING_CAPA(self) < len) {
+    mrb_str_resize(mrb, self, len);
+  }
+  memcpy(RSTR_PTR(s1), RSTR_PTR(s2), RSTR_LEN(s2));
+  memcpy(RSTR_PTR(s1) + RSTR_LEN(s2), RSTR_PTR(temp_s), RSTR_LEN(temp_s));
+  RSTR_SET_LEN(s1, len);
+  RSTR_PTR(s1)[len] = '\0';
+  return self;
+}
+
 void
 mrb_mruby_string_ext_gem_init(mrb_state* mrb)
 {
@@ -256,6 +385,11 @@ mrb_mruby_string_ext_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, s, "oct",             mrb_str_oct,             MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "chr",             mrb_str_chr,             MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "lines",           mrb_str_lines,           MRB_ARGS_NONE());
+  mrb_define_method(mrb, s, "succ",            mrb_str_succ,            MRB_ARGS_NONE());
+  mrb_define_method(mrb, s, "succ!",           mrb_str_succ_bang,       MRB_ARGS_NONE());
+  mrb_define_method(mrb, s, "prepend",         mrb_str_prepend,         MRB_ARGS_REQ(1));
+  mrb_alias_method(mrb, s, mrb_intern_lit(mrb, "next"), mrb_intern_lit(mrb, "succ"));
+  mrb_alias_method(mrb, s, mrb_intern_lit(mrb, "next!"), mrb_intern_lit(mrb, "succ!"));
 }
 
 void