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


static unsigned char yijing_hexagrams[] = {
	0xC0, 0xEB, 0xCC, 0xE0, 0xC9, 0xC5, 0xD8, 0xCB,
	0xC8, 0xF8, 0xE4, 0xF4, 0xFC, 0xFA, 0xE9, 0xD3,
	0xCD, 0xF1, 0xDD, 0xF7, 0xE5, 0xFF, 0xD4, 0xE2,
	0xD9, 0xD1, 0xD5, 0xF3, 0xE8, 0xC3, 0xDA, 0xD6,
	0xEA, 0xDB, 0xF0, 0xDE, 0xF9, 0xEE, 0xD0, 0xEC,
	0xC4, 0xEF, 0xFE, 0xE6, 0xFB, 0xDC, 0xC2, 0xC7,
	0xE1, 0xDF, 0xF6, 0xFD, 0xF5, 0xE7, 0xF2, 0xCF,
	0xCA, 0xED, 0xE3, 0xCE, 0xD2, 0xC6, 0xD7, 0xC1
};


enum libcharconv_result
libcharconv_yijing_hexagrams(const char *s, size_t slen, size_t *n, uint_least32_t *cp, size_t *ncp)
{
	uint_least32_t c;
	size_t i;
	*n = 0;
	for (; slen--; s++) {
		if ('1' <= s[0] && s[0] <= '2') {
			if (slen == 0u)
				return LIBCHARCONV_INDETERMINATE;
			if ('1' > s[1] || s[1] > '2')
				goto no_match;
			if (slen == 1u)
				return LIBCHARCONV_INDETERMINATE;
			if ('1' > s[2] || s[2] > '2')
				goto no_match;
			if (slen == 2u)
				return LIBCHARCONV_INDETERMINATE;
			if ('1' > s[3] || s[3] > '2')
				goto no_match;
			if (slen == 3u)
				return LIBCHARCONV_INDETERMINATE;
			if ('1' > s[4] || s[4] > '2')
				goto no_match;
			if (slen == 4u)
				return LIBCHARCONV_INDETERMINATE;
			if ('1' > s[5] || s[5] > '2')
				goto no_match;
			i =  s[5] == '2' ?  1u : 0u;
			i |= s[4] == '2' ?  2u : 0u;
			i |= s[3] == '2' ?  4u : 0u;
			i |= s[2] == '2' ?  8u : 0u;
			i |= s[1] == '2' ? 16u : 0u;
			i |= s[0] == '2' ? 32u : 0u;
			c = UINT32_C(0x4D00) | yijing_hexagrams[i];
			goto conv;
		} else {
		no_match:
			*n += 1u;
		}
	}
no_conv:
	return LIBCHARCONV_NO_CONVERT;

conv:
	if (*n)
		goto no_conv;
	if (*ncp)
		*cp = c;
	*n += 6u;
	*ncp = 1u;
	return LIBCHARCONV_CONVERTED;
}