1 #include "wcwidth.h"
2
3 /*
4 * This is an implementation of wcwidth() and wcswidth() (defined in
5 * IEEE Std 1002.1-2001) for Unicode.
6 *
7 * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html
8 * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html
9 *
10 * In fixed-width output devices, Latin characters all occupy a single
11 * "cell" position of equal width, whereas ideographic CJK characters
12 * occupy two such cells. Interoperability between terminal-line
13 * applications and (teletype-style) character terminals using the
14 * UTF-8 encoding requires agreement on which character should advance
15 * the cursor by how many cell positions. No established formal
16 * standards exist at present on which Unicode character shall occupy
17 * how many cell positions on character terminals. These routines are
18 * a first attempt of defining such behavior based on simple rules
19 * applied to data provided by the Unicode Consortium.
20 *
21 * For some graphical characters, the Unicode standard explicitly
22 * defines a character-cell width via the definition of the East Asian
23 * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes.
24 * In all these cases, there is no ambiguity about which width a
25 * terminal shall use. For characters in the East Asian Ambiguous (A)
26 * class, the width choice depends purely on a preference of backward
27 * compatibility with either historic CJK or Western practice.
28 * Choosing single-width for these characters is easy to justify as
29 * the appropriate long-term solution, as the CJK practice of
30 * displaying these characters as double-width comes from historic
31 * implementation simplicity (8-bit encoded characters were displayed
32 * single-width and 16-bit ones double-width, even for Greek,
33 * Cyrillic, etc.) and not any typographic considerations.
34 *
35 * Much less clear is the choice of width for the Not East Asian
36 * (Neutral) class. Existing practice does not dictate a width for any
37 * of these characters. It would nevertheless make sense
38 * typographically to allocate two character cells to characters such
39 * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be
40 * represented adequately with a single-width glyph. The following
41 * routines at present merely assign a single-cell width to all
42 * neutral characters, in the interest of simplicity. This is not
43 * entirely satisfactory and should be reconsidered before
44 * establishing a formal standard in this area. At the moment, the
45 * decision which Not East Asian (Neutral) characters should be
46 * represented by double-width glyphs cannot yet be answered by
47 * applying a simple rule from the Unicode database content. Setting
48 * up a proper standard for the behavior of UTF-8 character terminals
49 * will require a careful analysis not only of each Unicode character,
50 * but also of each presentation form, something the author of these
51 * routines has avoided to do so far.
52 *
53 * http://www.unicode.org/unicode/reports/tr11/
54 *
55 * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
56 *
57 * Permission to use, copy, modify, and distribute this software
58 * for any purpose and without fee is hereby granted. The author
59 * disclaims all warranties with regard to this software.
60 *
61 * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
62 */
63
64 #include <cstdint>
65
66 struct interval {
67 uint32_t first;
68 uint32_t last;
69 };
70
71 /* auxiliary function for binary search in interval table */
bisearch(uint32_t ucs,const struct interval * table,uint32_t max)72 static uint32_t bisearch( uint32_t ucs, const struct interval *table, uint32_t max )
73 {
74 uint32_t min = 0;
75 uint32_t mid = 0;
76
77 if( ucs < table[0].first || ucs > table[max].last ) {
78 return 0;
79 }
80 while( max >= min ) {
81 mid = ( min + max ) / 2;
82 if( ucs > table[mid].last ) {
83 min = mid + 1;
84 } else if( ucs < table[mid].first ) {
85 max = mid - 1;
86 } else {
87 return 1;
88 }
89 }
90
91 return 0;
92 }
93
mk_wcwidth(uint32_t ucs)94 int mk_wcwidth( uint32_t ucs )
95 {
96 /* sorted list of non-overlapping intervals of non-spacing characters */
97 /* generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c" */
98 static const struct interval combining[] = {
99 { 0x0300, 0x036F }, { 0x0483, 0x0486 }, { 0x0488, 0x0489 },
100 { 0x0591, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
101 { 0x05C4, 0x05C5 }, { 0x05C7, 0x05C7 }, { 0x0600, 0x0603 },
102 { 0x0610, 0x0615 }, { 0x064B, 0x065E }, { 0x0670, 0x0670 },
103 { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
104 { 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
105 { 0x07A6, 0x07B0 }, { 0x07EB, 0x07F3 }, { 0x0901, 0x0902 },
106 { 0x093C, 0x093C }, { 0x0941, 0x0948 }, { 0x094D, 0x094D },
107 { 0x0951, 0x0954 }, { 0x0962, 0x0963 }, { 0x0981, 0x0981 },
108 { 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD },
109 { 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 }, { 0x0A3C, 0x0A3C },
110 { 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D },
111 { 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC },
112 { 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD },
113 { 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C },
114 { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 }, { 0x0B4D, 0x0B4D },
115 { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 }, { 0x0BC0, 0x0BC0 },
116 { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 }, { 0x0C46, 0x0C48 },
117 { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 }, { 0x0CBC, 0x0CBC },
118 { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD },
119 { 0x0CE2, 0x0CE3 }, { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D },
120 { 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 },
121 { 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E },
122 { 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC },
123 { 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 },
124 { 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E },
125 { 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 },
126 { 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 },
127 { 0x1032, 0x1032 }, { 0x1036, 0x1037 }, { 0x1039, 0x1039 },
128 { 0x1058, 0x1059 }, { 0x1160, 0x11FF }, { 0x135F, 0x135F },
129 { 0x1712, 0x1714 }, { 0x1732, 0x1734 }, { 0x1752, 0x1753 },
130 { 0x1772, 0x1773 }, { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD },
131 { 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD },
132 { 0x180B, 0x180D }, { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 },
133 { 0x1927, 0x1928 }, { 0x1932, 0x1932 }, { 0x1939, 0x193B },
134 { 0x1A17, 0x1A18 }, { 0x1B00, 0x1B03 }, { 0x1B34, 0x1B34 },
135 { 0x1B36, 0x1B3A }, { 0x1B3C, 0x1B3C }, { 0x1B42, 0x1B42 },
136 { 0x1B6B, 0x1B73 }, { 0x1DC0, 0x1DCA }, { 0x1DFE, 0x1DFF },
137 { 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x2060, 0x2063 },
138 { 0x206A, 0x206F }, { 0x20D0, 0x20EF }, { 0x302A, 0x302F },
139 { 0x3099, 0x309A }, { 0xA806, 0xA806 }, { 0xA80B, 0xA80B },
140 { 0xA825, 0xA826 }, { 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F },
141 { 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB },
142 { 0x10A01, 0x10A03 }, { 0x10A05, 0x10A06 }, { 0x10A0C, 0x10A0F },
143 { 0x10A38, 0x10A3A }, { 0x10A3F, 0x10A3F }, { 0x1D167, 0x1D169 },
144 { 0x1D173, 0x1D182 }, { 0x1D185, 0x1D18B }, { 0x1D1AA, 0x1D1AD },
145 { 0x1D242, 0x1D244 }, { 0xE0001, 0xE0001 }, { 0xE0020, 0xE007F },
146 { 0xE0100, 0xE01EF }
147 };
148
149 /* test for 8-bit control characters */
150 if( ucs == 0 ) {
151 return 0;
152 }
153 if( ( ucs < 32 ) || ( ucs >= 0x7f && ucs < 0xa0 ) ) {
154 return -1;
155 }
156
157 /* binary search in table of non-spacing characters */
158 if( bisearch( ucs, combining,
159 sizeof( combining ) / sizeof( struct interval ) - 1 ) ) {
160 return 0;
161 }
162
163 /* if we arrive here, ucs is not a combining or C0/C1 control character */
164
165 return 1 +
166 ( ucs >= 0x1100 &&
167 ( ucs <= 0x115f || /* Hangul Jamo init. consonants */
168 ucs == 0x2329 || ucs == 0x232a ||
169 ( ucs >= 0x2e80 && ucs <= 0xa4cf &&
170 ucs != 0x303f ) || /* CJK ... Yi */
171 ( ucs >= 0xac00 && ucs <= 0xd7a3 ) || /* Hangul Syllables */
172 ( ucs >= 0xf900 && ucs <= 0xfaff ) || /* CJK Compatibility Ideographs */
173 ( ucs >= 0xfe10 && ucs <= 0xfe19 ) || /* Vertical forms */
174 ( ucs >= 0xfe30 && ucs <= 0xfe6f ) || /* CJK Compatibility Forms */
175 ( ucs >= 0xff00 && ucs <= 0xff60 ) || /* Fullwidth Forms */
176 ( ucs >= 0xffe0 && ucs <= 0xffe6 ) ||
177 ( ucs >= 0x20000 && ucs <= 0x2fffd ) ||
178 ( ucs >= 0x30000 && ucs <= 0x3fffd ) ) );
179 }
180