/*
 * This is an implementation of wcwidth() and wcswidth() (defined in
 * IEEE Std 1002.1-2001) for Unicode.
 *
 * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html
 * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html
 *
 * In fixed-width output devices, Latin characters all occupy a single
 * "cell" position of equal width, whereas ideographic CJK characters
 * occupy two such cells. Interoperability between terminal-line
 * applications and (teletype-style) character terminals using the
 * UTF-8 encoding requires agreement on which character should advance
 * the cursor by how many cell positions. No established formal
 * standards exist at present on which Unicode character shall occupy
 * how many cell positions on character terminals. These routines are
 * a first attempt of defining such behavior based on simple rules
 * applied to data provided by the Unicode Consortium.
 *
 * For some graphical characters, the Unicode standard explicitly
 * defines a character-cell width via the definition of the East Asian
 * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes.
 * In all these cases, there is no ambiguity about which width a
 * terminal shall use. For characters in the East Asian Ambiguous (A)
 * class, the width choice depends purely on a preference of backward
 * compatibility with either historic CJK or Western practice.
 * Choosing single-width for these characters is easy to justify as
 * the appropriate long-term solution, as the CJK practice of
 * displaying these characters as double-width comes from historic
 * implementation simplicity (8-bit encoded characters were displayed
 * single-width and 16-bit ones double-width, even for Greek,
 * Cyrillic, etc.) and not any typographic considerations.
 *
 * Much less clear is the choice of width for the Not East Asian
 * (Neutral) class. Existing practice does not dictate a width for any
 * of these characters. It would nevertheless make sense
 * typographically to allocate two character cells to characters such
 * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be
 * represented adequately with a single-width glyph. The following
 * routines at present merely assign a single-cell width to all
 * neutral characters, in the interest of simplicity. This is not
 * entirely satisfactory and should be reconsidered before
 * establishing a formal standard in this area. At the moment, the
 * decision which Not East Asian (Neutral) characters should be
 * represented by double-width glyphs cannot yet be answered by
 * applying a simple rule from the Unicode database content. Setting
 * up a proper standard for the behavior of UTF-8 character terminals
 * will require a careful analysis not only of each Unicode character,
 * but also of each presentation form, something the author of these
 * routines has avoided to do so far.
 *
 * http://www.unicode.org/unicode/reports/tr11/
 *
 * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted. The author
 * disclaims all warranties with regard to this software.
 *
 * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
 */

#include <memory>
#include <string>
#include <wchar.h>

namespace linenoise_ng {

struct interval {
	char32_t first;
	char32_t last;
};

/* auxiliary function for binary search in interval table */
static int bisearch(char32_t ucs, const struct interval *table, int max) {
	int min = 0;
	int mid;

	if (ucs < table[0].first || ucs > table[max].last)
		return 0;
	while (max >= min) {
		mid = (min + max) / 2;
		if (ucs > table[mid].last)
			min = mid + 1;
		else if (ucs < table[mid].first)
			max = mid - 1;
		else
			return 1;
	}

	return 0;
}

/* The following two functions define the column width of an ISO 10646
 * character as follows:
 *
 *    - The null character (U+0000) has a column width of 0.
 *
 *    - Other C0/C1 control characters and DEL will lead to a return
 *      value of -1.
 *
 *    - Non-spacing and enclosing combining characters (general
 *      category code Mn or Me in the Unicode database) have a
 *      column width of 0.
 *
 *    - SOFT HYPHEN (U+00AD) has a column width of 1.
 *
 *    - Other format characters (general category code Cf in the Unicode
 *      database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
 *
 *    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
 *      have a column width of 0.
 *
 *    - Spacing characters in the East Asian Wide (W) or East Asian
 *      Full-width (F) category as defined in Unicode Technical
 *      Report #11 have a column width of 2.
 *
 *    - All remaining characters (including all printable
 *      ISO 8859-1 and WGL4 characters, Unicode control characters,
 *      etc.) have a column width of 1.
 *
 * This implementation assumes that wchar_t characters are encoded
 * in ISO 10646.
 */

int mk_wcwidth(char32_t ucs) {
	/* sorted list of non-overlapping intervals of non-spacing characters */
	/* generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c" */
	static const struct interval combining[] = {{0x0300, 0x036F}, {0x0483, 0x0486}, {0x0488, 0x0489}, {0x0591, 0x05BD},
		{0x05BF, 0x05BF}, {0x05C1, 0x05C2}, {0x05C4, 0x05C5}, {0x05C7, 0x05C7}, {0x0600, 0x0603}, {0x0610, 0x0615},
		{0x064B, 0x065E}, {0x0670, 0x0670}, {0x06D6, 0x06E4}, {0x06E7, 0x06E8}, {0x06EA, 0x06ED}, {0x070F, 0x070F},
		{0x0711, 0x0711}, {0x0730, 0x074A}, {0x07A6, 0x07B0}, {0x07EB, 0x07F3}, {0x0901, 0x0902}, {0x093C, 0x093C},
		{0x0941, 0x0948}, {0x094D, 0x094D}, {0x0951, 0x0954}, {0x0962, 0x0963}, {0x0981, 0x0981}, {0x09BC, 0x09BC},
		{0x09C1, 0x09C4}, {0x09CD, 0x09CD}, {0x09E2, 0x09E3}, {0x0A01, 0x0A02}, {0x0A3C, 0x0A3C}, {0x0A41, 0x0A42},
		{0x0A47, 0x0A48}, {0x0A4B, 0x0A4D}, {0x0A70, 0x0A71}, {0x0A81, 0x0A82}, {0x0ABC, 0x0ABC}, {0x0AC1, 0x0AC5},
		{0x0AC7, 0x0AC8}, {0x0ACD, 0x0ACD}, {0x0AE2, 0x0AE3}, {0x0B01, 0x0B01}, {0x0B3C, 0x0B3C}, {0x0B3F, 0x0B3F},
		{0x0B41, 0x0B43}, {0x0B4D, 0x0B4D}, {0x0B56, 0x0B56}, {0x0B82, 0x0B82}, {0x0BC0, 0x0BC0}, {0x0BCD, 0x0BCD},
		{0x0C3E, 0x0C40}, {0x0C46, 0x0C48}, {0x0C4A, 0x0C4D}, {0x0C55, 0x0C56}, {0x0CBC, 0x0CBC}, {0x0CBF, 0x0CBF},
		{0x0CC6, 0x0CC6}, {0x0CCC, 0x0CCD}, {0x0CE2, 0x0CE3}, {0x0D41, 0x0D43}, {0x0D4D, 0x0D4D}, {0x0DCA, 0x0DCA},
		{0x0DD2, 0x0DD4}, {0x0DD6, 0x0DD6}, {0x0E31, 0x0E31}, {0x0E34, 0x0E3A}, {0x0E47, 0x0E4E}, {0x0EB1, 0x0EB1},
		{0x0EB4, 0x0EB9}, {0x0EBB, 0x0EBC}, {0x0EC8, 0x0ECD}, {0x0F18, 0x0F19}, {0x0F35, 0x0F35}, {0x0F37, 0x0F37},
		{0x0F39, 0x0F39}, {0x0F71, 0x0F7E}, {0x0F80, 0x0F84}, {0x0F86, 0x0F87}, {0x0F90, 0x0F97}, {0x0F99, 0x0FBC},
		{0x0FC6, 0x0FC6}, {0x102D, 0x1030}, {0x1032, 0x1032}, {0x1036, 0x1037}, {0x1039, 0x1039}, {0x1058, 0x1059},
		{0x1160, 0x11FF}, {0x135F, 0x135F}, {0x1712, 0x1714}, {0x1732, 0x1734}, {0x1752, 0x1753}, {0x1772, 0x1773},
		{0x17B4, 0x17B5}, {0x17B7, 0x17BD}, {0x17C6, 0x17C6}, {0x17C9, 0x17D3}, {0x17DD, 0x17DD}, {0x180B, 0x180D},
		{0x18A9, 0x18A9}, {0x1920, 0x1922}, {0x1927, 0x1928}, {0x1932, 0x1932}, {0x1939, 0x193B}, {0x1A17, 0x1A18},
		{0x1B00, 0x1B03}, {0x1B34, 0x1B34}, {0x1B36, 0x1B3A}, {0x1B3C, 0x1B3C}, {0x1B42, 0x1B42}, {0x1B6B, 0x1B73},
		{0x1DC0, 0x1DCA}, {0x1DFE, 0x1DFF}, {0x200B, 0x200F}, {0x202A, 0x202E}, {0x2060, 0x2063}, {0x206A, 0x206F},
		{0x20D0, 0x20EF}, {0x302A, 0x302F}, {0x3099, 0x309A}, {0xA806, 0xA806}, {0xA80B, 0xA80B}, {0xA825, 0xA826},
		{0xFB1E, 0xFB1E}, {0xFE00, 0xFE0F}, {0xFE20, 0xFE23}, {0xFEFF, 0xFEFF}, {0xFFF9, 0xFFFB}, {0x10A01, 0x10A03},
		{0x10A05, 0x10A06}, {0x10A0C, 0x10A0F}, {0x10A38, 0x10A3A}, {0x10A3F, 0x10A3F}, {0x1D167, 0x1D169},
		{0x1D173, 0x1D182}, {0x1D185, 0x1D18B}, {0x1D1AA, 0x1D1AD}, {0x1D242, 0x1D244}, {0xE0001, 0xE0001},
		{0xE0020, 0xE007F}, {0xE0100, 0xE01EF}};

	/* test for 8-bit control characters */
	if (ucs == 0)
		return 0;
	if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))
		return -1;

	/* binary search in table of non-spacing characters */
	if (bisearch(ucs, combining, sizeof(combining) / sizeof(struct interval) - 1))
		return 0;

	/* if we arrive here, ucs is not a combining or C0/C1 control character */

	return 1
		   + (ucs >= 0x1100
			   && (ucs <= 0x115f || /* Hangul Jamo init. consonants */
				   ucs == 0x2329 || ucs == 0x232a || (ucs >= 0x2e80 && ucs <= 0xa4cf && ucs != 0x303f)
				   ||                                  /* CJK ... Yi */
				   (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */
				   (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */
				   (ucs >= 0xfe10 && ucs <= 0xfe19) || /* Vertical forms */
				   (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
				   (ucs >= 0xff00 && ucs <= 0xff60) || /* Fullwidth Forms */
				   (ucs >= 0xffe0 && ucs <= 0xffe6) || (ucs >= 0x20000 && ucs <= 0x2fffd)
				   || (ucs >= 0x30000 && ucs <= 0x3fffd)));
}

int mk_wcswidth(const char32_t *pwcs, size_t n) {
	int w, width = 0;

	for (; *pwcs && n-- > 0; pwcs++)
		if ((w = mk_wcwidth(*pwcs)) < 0)
			return -1;
		else
			width += w;

	return width;
}

/*
 * The following functions are the same as mk_wcwidth() and
 * mk_wcswidth(), except that spacing characters in the East Asian
 * Ambiguous (A) category as defined in Unicode Technical Report #11
 * have a column width of 2. This variant might be useful for users of
 * CJK legacy encodings who want to migrate to UCS without changing
 * the traditional terminal character-width behaviour. It is not
 * otherwise recommended for general use.
 */
int mk_wcwidth_cjk(wchar_t ucs) {
	/* sorted list of non-overlapping intervals of East Asian Ambiguous
	 * characters, generated by "uniset +WIDTH-A -cat=Me -cat=Mn -cat=Cf c" */
	static const struct interval ambiguous[] = {{0x00A1, 0x00A1}, {0x00A4, 0x00A4}, {0x00A7, 0x00A8}, {0x00AA, 0x00AA},
		{0x00AE, 0x00AE}, {0x00B0, 0x00B4}, {0x00B6, 0x00BA}, {0x00BC, 0x00BF}, {0x00C6, 0x00C6}, {0x00D0, 0x00D0},
		{0x00D7, 0x00D8}, {0x00DE, 0x00E1}, {0x00E6, 0x00E6}, {0x00E8, 0x00EA}, {0x00EC, 0x00ED}, {0x00F0, 0x00F0},
		{0x00F2, 0x00F3}, {0x00F7, 0x00FA}, {0x00FC, 0x00FC}, {0x00FE, 0x00FE}, {0x0101, 0x0101}, {0x0111, 0x0111},
		{0x0113, 0x0113}, {0x011B, 0x011B}, {0x0126, 0x0127}, {0x012B, 0x012B}, {0x0131, 0x0133}, {0x0138, 0x0138},
		{0x013F, 0x0142}, {0x0144, 0x0144}, {0x0148, 0x014B}, {0x014D, 0x014D}, {0x0152, 0x0153}, {0x0166, 0x0167},
		{0x016B, 0x016B}, {0x01CE, 0x01CE}, {0x01D0, 0x01D0}, {0x01D2, 0x01D2}, {0x01D4, 0x01D4}, {0x01D6, 0x01D6},
		{0x01D8, 0x01D8}, {0x01DA, 0x01DA}, {0x01DC, 0x01DC}, {0x0251, 0x0251}, {0x0261, 0x0261}, {0x02C4, 0x02C4},
		{0x02C7, 0x02C7}, {0x02C9, 0x02CB}, {0x02CD, 0x02CD}, {0x02D0, 0x02D0}, {0x02D8, 0x02DB}, {0x02DD, 0x02DD},
		{0x02DF, 0x02DF}, {0x0391, 0x03A1}, {0x03A3, 0x03A9}, {0x03B1, 0x03C1}, {0x03C3, 0x03C9}, {0x0401, 0x0401},
		{0x0410, 0x044F}, {0x0451, 0x0451}, {0x2010, 0x2010}, {0x2013, 0x2016}, {0x2018, 0x2019}, {0x201C, 0x201D},
		{0x2020, 0x2022}, {0x2024, 0x2027}, {0x2030, 0x2030}, {0x2032, 0x2033}, {0x2035, 0x2035}, {0x203B, 0x203B},
		{0x203E, 0x203E}, {0x2074, 0x2074}, {0x207F, 0x207F}, {0x2081, 0x2084}, {0x20AC, 0x20AC}, {0x2103, 0x2103},
		{0x2105, 0x2105}, {0x2109, 0x2109}, {0x2113, 0x2113}, {0x2116, 0x2116}, {0x2121, 0x2122}, {0x2126, 0x2126},
		{0x212B, 0x212B}, {0x2153, 0x2154}, {0x215B, 0x215E}, {0x2160, 0x216B}, {0x2170, 0x2179}, {0x2190, 0x2199},
		{0x21B8, 0x21B9}, {0x21D2, 0x21D2}, {0x21D4, 0x21D4}, {0x21E7, 0x21E7}, {0x2200, 0x2200}, {0x2202, 0x2203},
		{0x2207, 0x2208}, {0x220B, 0x220B}, {0x220F, 0x220F}, {0x2211, 0x2211}, {0x2215, 0x2215}, {0x221A, 0x221A},
		{0x221D, 0x2220}, {0x2223, 0x2223}, {0x2225, 0x2225}, {0x2227, 0x222C}, {0x222E, 0x222E}, {0x2234, 0x2237},
		{0x223C, 0x223D}, {0x2248, 0x2248}, {0x224C, 0x224C}, {0x2252, 0x2252}, {0x2260, 0x2261}, {0x2264, 0x2267},
		{0x226A, 0x226B}, {0x226E, 0x226F}, {0x2282, 0x2283}, {0x2286, 0x2287}, {0x2295, 0x2295}, {0x2299, 0x2299},
		{0x22A5, 0x22A5}, {0x22BF, 0x22BF}, {0x2312, 0x2312}, {0x2460, 0x24E9}, {0x24EB, 0x254B}, {0x2550, 0x2573},
		{0x2580, 0x258F}, {0x2592, 0x2595}, {0x25A0, 0x25A1}, {0x25A3, 0x25A9}, {0x25B2, 0x25B3}, {0x25B6, 0x25B7},
		{0x25BC, 0x25BD}, {0x25C0, 0x25C1}, {0x25C6, 0x25C8}, {0x25CB, 0x25CB}, {0x25CE, 0x25D1}, {0x25E2, 0x25E5},
		{0x25EF, 0x25EF}, {0x2605, 0x2606}, {0x2609, 0x2609}, {0x260E, 0x260F}, {0x2614, 0x2615}, {0x261C, 0x261C},
		{0x261E, 0x261E}, {0x2640, 0x2640}, {0x2642, 0x2642}, {0x2660, 0x2661}, {0x2663, 0x2665}, {0x2667, 0x266A},
		{0x266C, 0x266D}, {0x266F, 0x266F}, {0x273D, 0x273D}, {0x2776, 0x277F}, {0xE000, 0xF8FF}, {0xFFFD, 0xFFFD},
		{0xF0000, 0xFFFFD}, {0x100000, 0x10FFFD}};

	/* binary search in table of non-spacing characters */
	if (bisearch(ucs, ambiguous, sizeof(ambiguous) / sizeof(struct interval) - 1))
		return 2;

	return mk_wcwidth(ucs);
}

int mk_wcswidth_cjk(const wchar_t *pwcs, size_t n) {
	int w, width = 0;

	for (; *pwcs && n-- > 0; pwcs++)
		if ((w = mk_wcwidth_cjk(*pwcs)) < 0)
			return -1;
		else
			width += w;

	return width;
}

} // namespace linenoise_ng
