bool utf8_is_printable_newline(const char* str, size_t length, bool newline) {
const char *p;
assert(str);
for (p = str; length;) {
int encoded_len, val;
encoded_len = utf8_encoded_valid_unichar(p);
if (encoded_len < 0 ||
(size_t) encoded_len > length)
return false;
val = utf8_encoded_to_unichar(p);
if (val < 0 ||
unichar_is_control(val) ||
(!newline && val == '\n'))
return false;
length -= encoded_len;
p += encoded_len;
}
return true;
}
/* validate one encoded unicode char and return its length */
int utf8_encoded_valid_unichar(const char *str)
{
int len;
int unichar;
int i;
len = utf8_encoded_expected_len(str);
if (len == 0)
return -1;
/* ascii is valid */
if (len == 1)
return 1;
/* check if expected encoded chars are available */
for (i = 0; i < len; i++)
if ((str[i] & 0x80) != 0x80)
return -1;
unichar = utf8_encoded_to_unichar(str);
/* check if encoded length matches encoded value */
if (utf8_unichar_to_encoded_len(unichar) != len)
return -1;
/* check if value has valid range */
if (!utf8_unichar_valid_range(unichar))
return -1;
return len;
}