/* See LICENSE file for copyright and license details. */
#include "lib-common.h"


enum libcharconv_result
libcharconv_transposed(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
{
	uint_least32_t c;
	size_t clen;
	*n = 0;
	while (slen) {
		clen = libcharconv_decode_utf8_(s, slen, &c);
		if (clen > slen) {
			if (*n)
				goto no_conv;
			return LIBCHARCONV_INDETERMINATE;
		}
		if (!clen) {
			*n += 1u;
			slen -= 1u;
			s = &s[1];
			continue;
		}

		if (UINT32_C(0x1F030) <= c && c <= UINT32_C(0x1F061)) {
			c += 0x32u;
			goto conv;
		} else if (UINT32_C(0x1F062) <= c && c <= UINT32_C(0x1F093)) {
			c -= 0x32u;
			goto conv;
		}

		*n += clen;
		s = &s[clen];
		slen -= clen;
	}
no_conv:
	return LIBCHARCONV_NO_CONVERT;

conv:
	if (*n)
		goto no_conv;
	if (*ncp)
		*cp = c;
	*n += clen;
	*ncp = 1u;
	return LIBCHARCONV_CONVERTED;
}