wcwidth.go

/*
 * 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
 *
 * 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
 */

/* Changes made for mutt:
 * - Adapted for Mutt by Edmund Grimley Evans.
 * - Changed 'first'/'last' members of combined[] to wchar_t from
 *   unsigned short to fix compiler warnings, 2007-11-13, Rocco Rutte
 */

/*
 * Translated from https://github.com/fumiyas/wcwidth-cjk/
 * Copyright (c) 2013 SATOH Fumiyasu @ OSS Technology Corp., Japan
 */

package wcwidth

import "unicode/utf8"

type interval struct {
	first rune
	last  rune
}

/* sorted list of non-overlapping intervals of non-spacing characters */
var combining = []interval{
	{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},
}

/* sorted list of non-overlapping intervals of East Asian Ambiguous characters */
var ambiguous = []interval{
	{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},
}

/* For Japanese legacy encodings, the following characters are added. */
var legacyJa = []interval{
	{0x00A2, 0x00A3}, {0x00A5, 0x00A6}, {0x00AC, 0x00AC},
	{0x00AF, 0x00AF}, {0x2212, 0x2212},
}

/* auxiliary function for binary search in interval table */
func bisearch(ucs rune, table []interval) bool {
	min := 0
	max := len(table) - 1
	var mid int

	if ucs < table[0].first || ucs > table[max].last {
		return false
	}

	for 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 true
		}
	}

	return false
}

/* 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.
 */
func WcwidthUcs(ucs rune) int {
	/* 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) {
		return 0
	}

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

	/* fast test for majority of non-wide scripts */
	if ucs < 0x1100 {
		return 1
	}

	if 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)) {
		return 2
	}
	return 1
}

func wcswidthCommon(s string, wcwidth func(rune) int) int {
	w, width := 0, 0
	for _, r := range []rune(s) {
		w = wcwidth(r)
		if w < 0 {
			return -1
		}
		width += w
	}
	return width
}

func WcswidthUcs(s string) int {
	return wcswidthCommon(s, WcwidthUcs)
}

/*
 * The following functions are the same as WcwidthUcs() and
 * WcswidthUcs(), 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.
 */
/*
 * In addition to the explanation mentioned above,
 * several characters in the East Asian Narrow (Na) and Not East Asian
 * (Neutral) category as defined in Unicode Technical Report #11
 * actually have a column width of 2 in CJK legacy encodings.
 */
func Wcwidth(ucs rune) int {
	/* binary search in table of non-spacing characters */
	if bisearch(ucs, ambiguous) || bisearch(ucs, legacyJa) {
		return 2
	}
	return WcwidthUcs(ucs)
}

func Wcswidth(s string) int {
	return wcswidthCommon(s, Wcwidth)
}

func wcswidthCommonWithLimit(s string, wcwidth func(rune) int, max int) (int, int) {
	w, width, offset := 0, 0, 0
	for _, r := range []rune(s) {
		w = wcwidth(r)
		if w < 0 {
			return -1, offset
		}
		if width+w > max {
			break
		}
		width += w
		offset += utf8.RuneLen(r)
	}
	return width, offset
}

func WcswidthWithLimit(s string, max int) (int, int) {
	return wcswidthCommonWithLimit(s, Wcwidth, max)
}