/* 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(0x0032), UINT32_C(0x218A)},
	{UINT32_C(0x0033), UINT32_C(0x218B)},
	{UINT32_C(0x2616), UINT32_C(0x26C9)},
	{UINT32_C(0x2617), UINT32_C(0x26CA)},
	{UINT32_C(0x0021), UINT32_C(0x00A1)},
	{UINT32_C(0x003F), UINT32_C(0x00BF)},
	{UINT32_C(0x2E35), UINT32_C(0x003B)},
	{UINT32_C(0x203D), UINT32_C(0x2E18)},
	{UINT32_C(0xA4EF), (uint_least32_t)'A'},
	{UINT32_C(0xA4ED), (uint_least32_t)'B'},
	{UINT32_C(0xA4DB), (uint_least32_t)'C'},
	{UINT32_C(0xA4F7), (uint_least32_t)'D'},
	{UINT32_C(0xA4F1), (uint_least32_t)'E'},
	{UINT32_C(0xA4DE), (uint_least32_t)'F'}, /* there is a letterlike alternative */
	{UINT32_C(0x2132), (uint_least32_t)'F'}, /* secondary alternative */
	{UINT32_C(0xA4E8), (uint_least32_t)'G'}, /* the one in letterlike is sans-serif */
	{UINT32_C(0xA4E9), (uint_least32_t)'J'},
	{UINT32_C(0xA4D8), (uint_least32_t)'K'},
	{UINT32_C(0xA4F6), (uint_least32_t)'L'}, /* the one in letterlike is sans-serif */
	{UINT32_C(0xA4D2), (uint_least32_t)'P'},
	{UINT32_C(0xA4E4), (uint_least32_t)'R'},
	{UINT32_C(0xA4D5), (uint_least32_t)'Y'}, /* the one in letterlike is sans-serif */
	{UINT32_C(0xA4F5), (uint_least32_t)'U'},
	{UINT32_C(0xA4E5), (uint_least32_t)'V'},
	{UINT32_C(0x1D5A6), UINT32_C(0x2141)},
	{UINT32_C(0x1D5AB), UINT32_C(0x2142)},
	{UINT32_C(0x1D5B8), UINT32_C(0x2144)},
	{UINT32_C(0x1F12F), UINT32_C(0x00A9)},
	{UINT32_C(0x230C), UINT32_C(0x230F)},
	{UINT32_C(0x230E), UINT32_C(0x230D)},
	{UINT32_C(0x268E), UINT32_C(0x268D)},
	{UINT32_C(0x1D301), UINT32_C(0x1D303)},
	{UINT32_C(0x1D302), UINT32_C(0x1D304)},
	{UINT32_C(0x23BE), UINT32_C(0x23CC)},
	{UINT32_C(0x23CB), UINT32_C(0x23BF)},
	{UINT32_C(0x23C9), UINT32_C(0x23CA)},
	{UINT32_C(0x23C1), UINT32_C(0x23C2)},
	{UINT32_C(0x23C7), UINT32_C(0x23C8)},
	{UINT32_C(0x238F), UINT32_C(0x2390)},
	{UINT32_C(0x2391), UINT32_C(0x2392)}
};


enum libcharconv_result
libcharconv_turned(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
{
	uint_least32_t c, x1, x2, x3, x4;
	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;
		}

		PLAIN_RANGE_SWAP(0x1FA00, 0x1FA1D, 0x1FA2A, 0x1FA47);
		PLAIN_RANGE_SWAP(0x1FA1E, 0x1FA29, 0x2654, 0x265F);
		if (UINT32_C(0x1F031) <= c && c <= UINT32_C(0x1F061)) {
			c -= UINT32_C(0x1F031);
			c = c % 7u * 7u + c / 7u;
			c += UINT32_C(0x1F031);
			goto conv;
		} else if (UINT32_C(0x1F063) <= c && c <= UINT32_C(0x1F093)) {
			c -= UINT32_C(0x1F063);
			c = c % 7u * 7u + c / 7u;
			c += UINT32_C(0x1F063);
			goto conv;
		} else if (UINT32_C(0x2630) <= c && c <= UINT32_C(0x2637)) {
			c = ((c & 1u) << 2) | ((c & 4u) >> 2) | (c & ~5u);
			goto conv;
		} else if (UINT32_C(0x1D306) <= c && c <= UINT32_C(0x1D356)) {
			c -= UINT32_C(0x1D306);
			x1 = c /  1u % 3u;
			x2 = c /  3u % 3u;
			x3 = c /  9u % 3u;
			x4 = c / 27u % 3u;
			c = UINT32_C(0x1D306);
			c += x4 *  1u;
			c += x3 *  3u;
			c += x2 *  9u;
			c += x1 * 27u;
			goto conv;
		} else if (UINT32_C(0x4DC0) <= c && c <= UINT32_C(0x4DFF)) {
			for (i = 0u;; i++)
				if ((c & 0xFFu) == libcharconv_yijing_hexagrams_[i])
					break;
			c =  (i & 32u) ?  1u : 0u;
			c |= (i & 16u) ?  2u : 0u;
			c |= (i &  8u) ?  4u : 0u;
			c |= (i &  4u) ?  8u : 0u;
			c |= (i &  2u) ? 16u : 0u;
			c |= (i &  1u) ? 32u : 0u;
			c = UINT32_C(0x4D00) | libcharconv_yijing_hexagrams_[c];
			goto conv;
		} else if (UINT32_C(0x2800) <= c && c <= UINT32_C(0x28FF)) {
			c = ((c & 0x01u) << 7) | ((c & 0x80u) >> 7)
			  | ((c & 0x02u) << 4) | ((c & 0x20u) >> 4)
			  | ((c & 0x04u) << 2) | ((c & 0x10u) >> 2)
			  | ((c & 0x08u) << 3) | ((c & 0x40u) >> 3)
			  | UINT32_C(0x2800);
			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;
}