On 20 Feb 2019, at 22:24, i.koptelov <ivan.koptelov@tarantool.org> wrote:

On 20 Feb 2019, at 18:47, i.koptelov <ivan.koptelov@tarantool.org> wrote:

Thanks to Alexander, I fixed my patch to use a function
from icu to count the length of the string.

Changes:

Travis has failed. Please, make sure it is OK before sending the patch.

It doesn’t fail on my local (Mac) machine, so I guess this fail appears

only on Linux system.

Furthermore, description says that it “assumes well-formed UTF-8”,
which in our case is not true. So who knows what may happen if we pass
malformed byte sequence. I am not even saying that behaviour of
this function on invalid inputs may change later.

In it's current implementation U8_FWD_1_UNSAFE satisfy our needs safely. Returned
symbol length would never exceed byte_len.

static int
utf8_char_count(const unsigned char *str, int byte_len)
{
int symbol_count = 0;
for (int i = 0; i < byte_len;) {
U8_FWD_1_UNSAFE(str, i);
symbol_count++;
}
return symbol_count;
}

I agree that it is a bad idea to relay on lib behaviour which may
change lately. So maybe I would just inline these one line macros?
Or use my own implementation, since it’s more efficient (but less beautiful)