static mrb_int
str_rindex(mrb_state *mrb, mrb_value str, mrb_value sub, mrb_int pos)
{
char *s, *sbeg, *t;
struct RString *ps = mrb_str_ptr(str);
mrb_int len = RSTRING_LEN(sub);
/* substring longer than string */
if (RSTR_LEN(ps) < len) return -1;
if (RSTR_LEN(ps) - pos < len) {
pos = RSTR_LEN(ps) - len;
}
sbeg = RSTR_PTR(ps);
s = RSTR_PTR(ps) + pos;
t = RSTRING_PTR(sub);
if (len) {
while (sbeg <= s) {
if (memcmp(s, t, len) == 0) {
return s - RSTR_PTR(ps);
}
s--;
}
return -1;
}
else {
return pos;
}
}
/*
* 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;
}
