/* 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;
}
/* decode one unicode char */
int utf8_encoded_to_unichar(const char *str, char32_t *ret_unichar) {
char32_t unichar;
int len, i;
assert(str);
len = utf8_encoded_expected_len(str);
switch (len) {
case 1:
*ret_unichar = (char32_t)str[0];
return 0;
case 2:
unichar = str[0] & 0x1f;
break;
case 3:
unichar = (char32_t)str[0] & 0x0f;
break;
case 4:
unichar = (char32_t)str[0] & 0x07;
break;
case 5:
unichar = (char32_t)str[0] & 0x03;
break;
case 6:
unichar = (char32_t)str[0] & 0x01;
break;
default:
return -EINVAL;
}
for (i = 1; i < len; i++) {
if (((char32_t)str[i] & 0xc0) != 0x80)
return -EINVAL;
unichar <<= 6;
unichar |= (char32_t)str[i] & 0x3f;
}
*ret_unichar = unichar;
return 0;
}
/* decode one unicode char */
static int utf8_encoded_to_unichar(const char *str)
{
int unichar;
int len;
int i;
len = utf8_encoded_expected_len(str);
switch (len) {
case 1:
return (int)str[0];
case 2:
unichar = str[0] & 0x1f;
break;
case 3:
unichar = (int)str[0] & 0x0f;
break;
case 4:
unichar = (int)str[0] & 0x07;
break;
case 5:
unichar = (int)str[0] & 0x03;
break;
case 6:
unichar = (int)str[0] & 0x01;
break;
default:
return -1;
}
for (i = 1; i < len; i++) {
if (((int)str[i] & 0xc0) != 0x80)
return -1;
unichar <<= 6;
unichar |= (int)str[i] & 0x3f;
}
return unichar;
}
