/src/irssi/src/core/wcwidth.c
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1 | | /* |
2 | | * This is an implementation of wcwidth() and wcswidth() (defined in |
3 | | * IEEE Std 1002.1-2001) for Unicode. |
4 | | * |
5 | | * http://www.opengroup.org/onlinepubs/007904975/functions/wcwidth.html |
6 | | * http://www.opengroup.org/onlinepubs/007904975/functions/wcswidth.html |
7 | | * |
8 | | * In fixed-width output devices, Latin characters all occupy a single |
9 | | * "cell" position of equal width, whereas ideographic CJK characters |
10 | | * occupy two such cells. Interoperability between terminal-line |
11 | | * applications and (teletype-style) character terminals using the |
12 | | * UTF-8 encoding requires agreement on which character should advance |
13 | | * the cursor by how many cell positions. No established formal |
14 | | * standards exist at present on which Unicode character shall occupy |
15 | | * how many cell positions on character terminals. These routines are |
16 | | * a first attempt of defining such behavior based on simple rules |
17 | | * applied to data provided by the Unicode Consortium. |
18 | | * |
19 | | * For some graphical characters, the Unicode standard explicitly |
20 | | * defines a character-cell width via the definition of the East Asian |
21 | | * FullWidth (F), Wide (W), Half-width (H), and Narrow (Na) classes. |
22 | | * In all these cases, there is no ambiguity about which width a |
23 | | * terminal shall use. For characters in the East Asian Ambiguous (A) |
24 | | * class, the width choice depends purely on a preference of backward |
25 | | * compatibility with either historic CJK or Western practice. |
26 | | * Choosing single-width for these characters is easy to justify as |
27 | | * the appropriate long-term solution, as the CJK practice of |
28 | | * displaying these characters as double-width comes from historic |
29 | | * implementation simplicity (8-bit encoded characters were displayed |
30 | | * single-width and 16-bit ones double-width, even for Greek, |
31 | | * Cyrillic, etc.) and not any typographic considerations. |
32 | | * |
33 | | * Much less clear is the choice of width for the Not East Asian |
34 | | * (Neutral) class. Existing practice does not dictate a width for any |
35 | | * of these characters. It would nevertheless make sense |
36 | | * typographically to allocate two character cells to characters such |
37 | | * as for instance EM SPACE or VOLUME INTEGRAL, which cannot be |
38 | | * represented adequately with a single-width glyph. The following |
39 | | * routines at present merely assign a single-cell width to all |
40 | | * neutral characters, in the interest of simplicity. This is not |
41 | | * entirely satisfactory and should be reconsidered before |
42 | | * establishing a formal standard in this area. At the moment, the |
43 | | * decision which Not East Asian (Neutral) characters should be |
44 | | * represented by double-width glyphs cannot yet be answered by |
45 | | * applying a simple rule from the Unicode database content. Setting |
46 | | * up a proper standard for the behavior of UTF-8 character terminals |
47 | | * will require a careful analysis not only of each Unicode character, |
48 | | * but also of each presentation form, something the author of these |
49 | | * routines has avoided to do so far. |
50 | | * |
51 | | * http://www.unicode.org/unicode/reports/tr11/ |
52 | | * |
53 | | * Markus Kuhn -- 2007-05-25 (Unicode 5.0) |
54 | | * |
55 | | * Permission to use, copy, modify, and distribute this software |
56 | | * for any purpose and without fee is hereby granted. The author |
57 | | * disclaims all warranties with regard to this software. |
58 | | * |
59 | | * Latest version: http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c |
60 | | */ |
61 | | |
62 | | #include <irssi/src/core/utf8.h> |
63 | | |
64 | | struct interval { |
65 | | int first; |
66 | | int last; |
67 | | }; |
68 | | |
69 | | /* auxiliary function for binary search in interval table */ |
70 | 0 | static int bisearch(unichar ucs, const struct interval *table, int max) { |
71 | 0 | int min = 0; |
72 | 0 | int mid; |
73 | |
|
74 | 0 | if (ucs < table[0].first || ucs > table[max].last) |
75 | 0 | return 0; |
76 | 0 | while (max >= min) { |
77 | 0 | mid = (min + max) / 2; |
78 | 0 | if (ucs > table[mid].last) |
79 | 0 | min = mid + 1; |
80 | 0 | else if (ucs < table[mid].first) |
81 | 0 | max = mid - 1; |
82 | 0 | else |
83 | 0 | return 1; |
84 | 0 | } |
85 | | |
86 | 0 | return 0; |
87 | 0 | } |
88 | | |
89 | | |
90 | | /* The following two functions define the column width of an ISO 10646 |
91 | | * character as follows: |
92 | | * |
93 | | * - The null character (U+0000) has a column width of 0. |
94 | | * |
95 | | * - Other C0/C1 control characters and DEL will lead to a return |
96 | | * value of -1. |
97 | | * |
98 | | * - Non-spacing and enclosing combining characters (general |
99 | | * category code Mn or Me in the Unicode database) have a |
100 | | * column width of 0. |
101 | | * |
102 | | * - SOFT HYPHEN (U+00AD) has a column width of 1. |
103 | | * |
104 | | * - Other format characters (general category code Cf in the Unicode |
105 | | * database) and ZERO WIDTH SPACE (U+200B) have a column width of 0. |
106 | | * |
107 | | * - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF) |
108 | | * have a column width of 0. |
109 | | * |
110 | | * - Spacing characters in the East Asian Wide (W) or East Asian |
111 | | * Full-width (F) category as defined in Unicode Technical |
112 | | * Report #11 have a column width of 2. |
113 | | * |
114 | | * - All remaining characters (including all printable |
115 | | * ISO 8859-1 and WGL4 characters, Unicode control characters, |
116 | | * etc.) have a column width of 1. |
117 | | * |
118 | | * This implementation assumes that wchar_t characters are encoded |
119 | | * in ISO 10646. |
120 | | */ |
121 | | |
122 | | int mk_wcwidth(unichar ucs) |
123 | 0 | { |
124 | | /* sorted list of non-overlapping intervals of non-spacing characters */ |
125 | | /* generated by "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c" */ |
126 | 0 | static const struct interval combining[] = { |
127 | 0 | { 0x0300, 0x036F }, { 0x0483, 0x0486 }, { 0x0488, 0x0489 }, |
128 | 0 | { 0x0591, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 }, |
129 | 0 | { 0x05C4, 0x05C5 }, { 0x05C7, 0x05C7 }, { 0x0600, 0x0603 }, |
130 | 0 | { 0x0610, 0x0615 }, { 0x064B, 0x065E }, { 0x0670, 0x0670 }, |
131 | 0 | { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED }, |
132 | 0 | { 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A }, |
133 | 0 | { 0x07A6, 0x07B0 }, { 0x07EB, 0x07F3 }, { 0x0901, 0x0902 }, |
134 | 0 | { 0x093C, 0x093C }, { 0x0941, 0x0948 }, { 0x094D, 0x094D }, |
135 | 0 | { 0x0951, 0x0954 }, { 0x0962, 0x0963 }, { 0x0981, 0x0981 }, |
136 | 0 | { 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 }, { 0x09CD, 0x09CD }, |
137 | 0 | { 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 }, { 0x0A3C, 0x0A3C }, |
138 | 0 | { 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 }, { 0x0A4B, 0x0A4D }, |
139 | 0 | { 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC }, |
140 | 0 | { 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD }, |
141 | 0 | { 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C }, |
142 | 0 | { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 }, { 0x0B4D, 0x0B4D }, |
143 | 0 | { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 }, { 0x0BC0, 0x0BC0 }, |
144 | 0 | { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 }, { 0x0C46, 0x0C48 }, |
145 | 0 | { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 }, { 0x0CBC, 0x0CBC }, |
146 | 0 | { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD }, |
147 | 0 | { 0x0CE2, 0x0CE3 }, { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D }, |
148 | 0 | { 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 }, |
149 | 0 | { 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E }, |
150 | 0 | { 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC }, |
151 | 0 | { 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 }, |
152 | 0 | { 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E }, |
153 | 0 | { 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 }, |
154 | 0 | { 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 }, |
155 | 0 | { 0x1032, 0x1032 }, { 0x1036, 0x1037 }, { 0x1039, 0x1039 }, |
156 | 0 | { 0x1058, 0x1059 }, { 0x1160, 0x11FF }, { 0x135F, 0x135F }, |
157 | 0 | { 0x1712, 0x1714 }, { 0x1732, 0x1734 }, { 0x1752, 0x1753 }, |
158 | 0 | { 0x1772, 0x1773 }, { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD }, |
159 | 0 | { 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD }, |
160 | 0 | { 0x180B, 0x180D }, { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 }, |
161 | 0 | { 0x1927, 0x1928 }, { 0x1932, 0x1932 }, { 0x1939, 0x193B }, |
162 | 0 | { 0x1A17, 0x1A18 }, { 0x1B00, 0x1B03 }, { 0x1B34, 0x1B34 }, |
163 | 0 | { 0x1B36, 0x1B3A }, { 0x1B3C, 0x1B3C }, { 0x1B42, 0x1B42 }, |
164 | 0 | { 0x1B6B, 0x1B73 }, { 0x1DC0, 0x1DCA }, { 0x1DFE, 0x1DFF }, |
165 | 0 | { 0x200B, 0x200F }, { 0x202A, 0x202E }, { 0x2060, 0x2063 }, |
166 | 0 | { 0x206A, 0x206F }, { 0x20D0, 0x20EF }, { 0x302A, 0x302F }, |
167 | 0 | { 0x3099, 0x309A }, { 0xA806, 0xA806 }, { 0xA80B, 0xA80B }, |
168 | 0 | { 0xA825, 0xA826 }, { 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F }, |
169 | 0 | { 0xFE20, 0xFE23 }, { 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB }, |
170 | 0 | { 0x10A01, 0x10A03 }, { 0x10A05, 0x10A06 }, { 0x10A0C, 0x10A0F }, |
171 | 0 | { 0x10A38, 0x10A3A }, { 0x10A3F, 0x10A3F }, { 0x1D167, 0x1D169 }, |
172 | 0 | { 0x1D173, 0x1D182 }, { 0x1D185, 0x1D18B }, { 0x1D1AA, 0x1D1AD }, |
173 | 0 | { 0x1D242, 0x1D244 }, { 0xE0001, 0xE0001 }, { 0xE0020, 0xE007F }, |
174 | 0 | { 0xE0100, 0xE01EF } |
175 | 0 | }; |
176 | | |
177 | | /* test for 8-bit control characters */ |
178 | 0 | if (ucs == 0) |
179 | 0 | return 0; |
180 | 0 | if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0)) |
181 | 0 | return -1; |
182 | | |
183 | | /* binary search in table of non-spacing characters */ |
184 | 0 | if (bisearch(ucs, combining, |
185 | 0 | sizeof(combining) / sizeof(struct interval) - 1)) |
186 | 0 | return 0; |
187 | | |
188 | | /* if we arrive here, ucs is not a combining or C0/C1 control character */ |
189 | | |
190 | 0 | return 1 + |
191 | 0 | (ucs >= 0x1100 && |
192 | 0 | (ucs <= 0x115f || /* Hangul Jamo init. consonants */ |
193 | 0 | ucs == 0x2329 || ucs == 0x232a || |
194 | 0 | (ucs >= 0x2e80 && ucs <= 0xa4cf && |
195 | 0 | ucs != 0x303f) || /* CJK ... Yi */ |
196 | 0 | (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */ |
197 | 0 | (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */ |
198 | 0 | (ucs >= 0xfe10 && ucs <= 0xfe19) || /* Vertical forms */ |
199 | 0 | (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */ |
200 | 0 | (ucs >= 0xff00 && ucs <= 0xff60) || /* Fullwidth Forms */ |
201 | 0 | (ucs >= 0xffe0 && ucs <= 0xffe6) || |
202 | 0 | (ucs >= 0x20000 && ucs <= 0x2fffd) || |
203 | 0 | (ucs >= 0x30000 && ucs <= 0x3fffd))); |
204 | 0 | } |
205 | | |
206 | | |
207 | | #if 0 |
208 | | int mk_wcswidth(const unichar *pwcs, size_t n) |
209 | | { |
210 | | int w, width = 0; |
211 | | |
212 | | for (;*pwcs && n-- > 0; pwcs++) |
213 | | if ((w = mk_wcwidth(*pwcs)) < 0) |
214 | | return -1; |
215 | | else |
216 | | width += w; |
217 | | |
218 | | return width; |
219 | | } |
220 | | #endif |