Improve `utf8len()` performance with
MODIFY
src/string.c
src/string.c
@@ -233,7 +233,9 @@ utf8len(const char* p, const char* e)
mrb_int len;
mrb_int i;
+ if ((unsigned char)*p < 0x80) return 1;
len = utf8len_codepage[(unsigned char)*p];
+ if (len == 1) return 1;
if (len > e - p) return 1;
for (i = 1; i < len; ++i)
if ((p[i] & 0xc0) != 0x80)

Improve `utf8len()` performance with UTF-8