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


static struct {
	uint_least32_t a;
	uint_least32_t b;
} pairs[] = {
	{UINT32_C(0x0020), UINT32_C(0x2588)},
	{UINT32_C(0x1FBA3), UINT32_C(0x1FBBE)},
	{UINT32_C(0x1FBAE), UINT32_C(0x1FBBF)},
	{UINT32_C(0x1FBBD), UINT32_C(0x2573)},
	{UINT32_C(0x1F030), UINT32_C(0x1F031)},
	{UINT32_C(0x1F062), UINT32_C(0x1F063)},
	{UINT32_C(0x2686), UINT32_C(0x2688)},
	{UINT32_C(0x2687), UINT32_C(0x2689)},
	{UINT32_C(0x2616), UINT32_C(0x26C9)},
	{UINT32_C(0x2617), UINT32_C(0x26CA)},
	{UINT32_C(0x26C0), UINT32_C(0x26C2)},
	{UINT32_C(0x26C1), UINT32_C(0x26C3)}
};


enum libcharconv_result
libcharconv_negative(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
{
	uint_least32_t c;
	size_t i, 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(0x1FA60) <= c && c <= UINT32_C(0x1FA66)) {
			c += 7u;
			goto conv;
		} else if (UINT32_C(0x1FA67) <= c && c <= UINT32_C(0x1FA6D)) {
			c -= 7u;
			goto conv;
		} else {
			for (i = 0u; i < sizeof(pairs) / sizeof(*pairs); i++) {
				if (c == pairs[i].a) {
					c = pairs[i].b;
					goto conv;
				}
				if (c == pairs[i].b) {
					c = pairs[i].a;
					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;
}