1 files changed, 4 insertions, 2 deletions
diff --git a/string.c b/string.c
index 6988e08ec1..c537bbf4ab 100644
--- a/string.c
+++ b/string.c
@@ -1527,7 +1527,8 @@ enc_strlen(const char *p, const char *e, rb_encoding *enc, int cr)
     const char *q;
 
     if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
-        return (e - p + rb_enc_mbminlen(enc) - 1) / rb_enc_mbminlen(enc);
+	long diff = (long)(e - p);
+	return diff / rb_enc_mbminlen(enc) + !!(diff % rb_enc_mbminlen(enc));
     }
 #ifdef NONASCII_MASK
     else if (cr == ENC_CODERANGE_VALID && enc == rb_utf8_encoding()) {
@@ -1609,7 +1610,8 @@ rb_enc_strlen_cr(const char *p, const char *e, rb_encoding *enc, int *cr)
 
     *cr = 0;
     if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
-	return (e - p + rb_enc_mbminlen(enc) - 1) / rb_enc_mbminlen(enc);
+	long diff = (long)(e - p);
+	return diff / rb_enc_mbminlen(enc) + !!(diff % rb_enc_mbminlen(enc));
     }
     else if (rb_enc_asciicompat(enc)) {
 	c = 0;