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


static struct {
	uint_least32_t to;
	uint_least32_t from;
} pairs[] = {
	{UINT32_C(0x1FA04), UINT32_C(0x1FA08)},
	{UINT32_C(0x1FA08), UINT32_C(0x1FA19)},
	{UINT32_C(0x1FA19), UINT32_C(0x1FA1D)},
	{UINT32_C(0x1FA1D), UINT32_C(0x1FA2E)},
	{UINT32_C(0x1FA2E), UINT32_C(0x1FA32)},
	{UINT32_C(0x1FA32), UINT32_C(0x1FA43)},
	{UINT32_C(0x1FA43), UINT32_C(0x1FA47)},
	{UINT32_C(0x1FA47), UINT32_C(0x1FA04)},
	{UINT32_C(0x2658),  UINT32_C(0x1FA06)},
	{UINT32_C(0x1FA06), UINT32_C(0x1FA0D)},
	{UINT32_C(0x1FA0D), UINT32_C(0x1FA1B)},
	{UINT32_C(0x1FA1B), UINT32_C(0x1FA22)},
	{UINT32_C(0x1FA22), UINT32_C(0x1FA30)},
	{UINT32_C(0x1FA30), UINT32_C(0x1FA37)},
	{UINT32_C(0x1FA37), UINT32_C(0x1FA45)},
	{UINT32_C(0x1FA45), UINT32_C(0x2658)},
	{UINT32_C(0x265E),  UINT32_C(0x1FA07)},
	{UINT32_C(0x1FA07), UINT32_C(0x1FA13)},
	{UINT32_C(0x1FA13), UINT32_C(0x1FA1C)},
	{UINT32_C(0x1FA1C), UINT32_C(0x1FA28)},
	{UINT32_C(0x1FA28), UINT32_C(0x1FA31)},
	{UINT32_C(0x1FA31), UINT32_C(0x1FA3D)},
	{UINT32_C(0x1FA3D), UINT32_C(0x1FA46)},
	{UINT32_C(0x1FA46), UINT32_C(0x265E)}
};


enum libcharconv_result
libcharconv_rotated_45deg_ccw(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;
		}

		for (i = 0u; i < sizeof(pairs) / sizeof(*pairs); i++) {
			if (c == pairs[i].from) {
				c = pairs[i].to;
				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;
}