}
/*
+=for apidoc A|U8 *|bytes_from_utf8|U8 *s|STRLEN *len|bool *is_utf8
+
+Converts a string C<s> of length C<len> from UTF8 into byte encoding.
+Unlike <utf8_to_bytes> but like C<bytes_to_utf8>, returns a pointer to
+the newly-created string, and updates C<len> to contain the new
+length. Returns the original string if no conversion occurs, C<len>
+is unchanged. Do nothing if C<is_utf8> points to 0. Sets C<is_utf8> to
+0 if C<s> is converted or contains all 7bit characters.
+
+=cut */
+
+U8 *
+Perl_bytes_from_utf8(pTHX_ U8* s, STRLEN *len, bool *is_utf8)
+{
+ U8 *send;
+ U8 *d;
+ U8 *start = s;
+ I32 count = 0;
+
+ if (!*is_utf8)
+ return start;
+
+ /* ensure valid UTF8 and chars < 256 before converting string */
+ for (send = s + *len; s < send;) {
+ U8 c = *s++;
+ if (!UTF8_IS_ASCII(c)) {
+ if (UTF8_IS_CONTINUATION(c) || s >= send ||
+ !UTF8_IS_CONTINUATION(*s) || UTF8_IS_DOWNGRADEABLE_START(c))
+ return start;
+ s++, count++;
+ }
+ }
+
+ *is_utf8 = 0;
+
+ if (!count)
+ return start;
+
+ Newz(801, d, (*len) - count + 1, U8);
+ s = start; start = d;
+ while (s < send) {
+ U8 c = *s++;
+ if (UTF8_IS_ASCII(c))
+ *d++ = c;
+ else
+ *d++ = UTF8_ACCUMULATE(c&3, *s++);
+ }
+ *d = '\0';
+ *len = d - start;
+ return start;
+}
+
+/*
=for apidoc A|U8 *|bytes_to_utf8|U8 *s|STRLEN *len
Converts a string C<s> of length C<len> from ASCII into UTF8 encoding.