Function mbs_chrlen

utf8.c:668–696

* Returns first character length in bytes for multi-byte `text` according to * `encoding`. * * - The `text` pointer is updated to point at the next character. * - When `remainder_p` is not NULL, on entry `*remainder_p` is how much bytes * we can consume from text, and on exit `*remainder_p` is reduced by returned * character length. Otherwise `text` is treated as limited by NUL. */

 *   character length. Otherwise `text` is treated as limited by NUL.
 */
int mbs_chrlen(const char **text, size_t *remainder_p, const char *encoding)
{
	int chrlen;
	const char *p = *text;
	size_t r = (remainder_p ? *remainder_p : SIZE_MAX);

	if (r < 1)
		return 0;

	if (is_encoding_utf8(encoding)) {
		pick_one_utf8_char(&p, &r);

		chrlen = p ? (p - *text)
			   : 1 /* not valid UTF-8 -> raw byte sequence */;
	}
	else {
		/*
		 * TODO use iconv to decode one char and obtain its chrlen
		 * for now, let's treat encodings != UTF-8 as one-byte
		 */
		chrlen = 1;
	}

	*text += chrlen;
	if (remainder_p)
		*remainder_p -= chrlen;

	return chrlen;
}

/*
 * Pick the next char from the stream, ignoring codepoints an HFS+ would.