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[git/git.git] / utf8.c
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1#include "git-compat-util.h"
2#include "utf8.h"
3
4/* This code is originally from http://www.cl.cam.ac.uk/~mgk25/ucs/ */
5
6struct interval {
7 int first;
8 int last;
9};
10
11/* auxiliary function for binary search in interval table */
12static int bisearch(wchar_t ucs, const struct interval *table, int max) {
13 int min = 0;
14 int mid;
15
16 if (ucs < table[0].first || ucs > table[max].last)
17 return 0;
18 while (max >= min) {
19 mid = (min + max) / 2;
20 if (ucs > table[mid].last)
21 min = mid + 1;
22 else if (ucs < table[mid].first)
23 max = mid - 1;
24 else
25 return 1;
26 }
27
28 return 0;
29}
30
31/* The following two functions define the column width of an ISO 10646
32 * character as follows:
33 *
34 * - The null character (U+0000) has a column width of 0.
35 *
36 * - Other C0/C1 control characters and DEL will lead to a return
37 * value of -1.
38 *
39 * - Non-spacing and enclosing combining characters (general
40 * category code Mn or Me in the Unicode database) have a
41 * column width of 0.
42 *
43 * - SOFT HYPHEN (U+00AD) has a column width of 1.
44 *
45 * - Other format characters (general category code Cf in the Unicode
46 * database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
47 *
48 * - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
49 * have a column width of 0.
50 *
51 * - Spacing characters in the East Asian Wide (W) or East Asian
52 * Full-width (F) category as defined in Unicode Technical
53 * Report #11 have a column width of 2.
54 *
55 * - All remaining characters (including all printable
56 * ISO 8859-1 and WGL4 characters, Unicode control characters,
57 * etc.) have a column width of 1.
58 *
59 * This implementation assumes that wchar_t characters are encoded
60 * in ISO 10646.
61 */
62
63static int wcwidth(wchar_t ch)
64{
65 /*
66 * Sorted list of non-overlapping intervals of non-spacing characters,
67 * generated by
68 * "uniset +cat=Me +cat=Mn +cat=Cf -00AD +1160-11FF +200B c".
69 */
70 static const struct interval combining[] = {
71 { 0x0300, 0x0357 }, { 0x035D, 0x036F }, { 0x0483, 0x0486 },
72 { 0x0488, 0x0489 }, { 0x0591, 0x05A1 }, { 0x05A3, 0x05B9 },
73 { 0x05BB, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },
74 { 0x05C4, 0x05C4 }, { 0x0600, 0x0603 }, { 0x0610, 0x0615 },
75 { 0x064B, 0x0658 }, { 0x0670, 0x0670 }, { 0x06D6, 0x06E4 },
76 { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED }, { 0x070F, 0x070F },
77 { 0x0711, 0x0711 }, { 0x0730, 0x074A }, { 0x07A6, 0x07B0 },
78 { 0x0901, 0x0902 }, { 0x093C, 0x093C }, { 0x0941, 0x0948 },
79 { 0x094D, 0x094D }, { 0x0951, 0x0954 }, { 0x0962, 0x0963 },
80 { 0x0981, 0x0981 }, { 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 },
81 { 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 },
82 { 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 },
83 { 0x0A4B, 0x0A4D }, { 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 },
84 { 0x0ABC, 0x0ABC }, { 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 },
85 { 0x0ACD, 0x0ACD }, { 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 },
86 { 0x0B3C, 0x0B3C }, { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 },
87 { 0x0B4D, 0x0B4D }, { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 },
88 { 0x0BC0, 0x0BC0 }, { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 },
89 { 0x0C46, 0x0C48 }, { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 },
90 { 0x0CBC, 0x0CBC }, { 0x0CBF, 0x0CBF }, { 0x0CC6, 0x0CC6 },
91 { 0x0CCC, 0x0CCD }, { 0x0D41, 0x0D43 }, { 0x0D4D, 0x0D4D },
92 { 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 },
93 { 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E },
94 { 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC },
95 { 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 },
96 { 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E },
97 { 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F90, 0x0F97 },
98 { 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 },
99 { 0x1032, 0x1032 }, { 0x1036, 0x1037 }, { 0x1039, 0x1039 },
100 { 0x1058, 0x1059 }, { 0x1160, 0x11FF }, { 0x1712, 0x1714 },
101 { 0x1732, 0x1734 }, { 0x1752, 0x1753 }, { 0x1772, 0x1773 },
102 { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD }, { 0x17C6, 0x17C6 },
103 { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD }, { 0x180B, 0x180D },
104 { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 }, { 0x1927, 0x1928 },
105 { 0x1932, 0x1932 }, { 0x1939, 0x193B }, { 0x200B, 0x200F },
106 { 0x202A, 0x202E }, { 0x2060, 0x2063 }, { 0x206A, 0x206F },
107 { 0x20D0, 0x20EA }, { 0x302A, 0x302F }, { 0x3099, 0x309A },
108 { 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F }, { 0xFE20, 0xFE23 },
109 { 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB }, { 0x1D167, 0x1D169 },
110 { 0x1D173, 0x1D182 }, { 0x1D185, 0x1D18B },
111 { 0x1D1AA, 0x1D1AD }, { 0xE0001, 0xE0001 },
112 { 0xE0020, 0xE007F }, { 0xE0100, 0xE01EF }
113 };
114
115 /* test for 8-bit control characters */
116 if (ch == 0)
117 return 0;
118 if (ch < 32 || (ch >= 0x7f && ch < 0xa0))
119 return -1;
120
121 /* binary search in table of non-spacing characters */
122 if (bisearch(ch, combining, sizeof(combining)
123 / sizeof(struct interval) - 1))
124 return 0;
125
126 /*
127 * If we arrive here, ch is neither a combining nor a C0/C1
128 * control character.
129 */
130
131 return 1 +
132 (ch >= 0x1100 &&
133 /* Hangul Jamo init. consonants */
134 (ch <= 0x115f ||
135 ch == 0x2329 || ch == 0x232a ||
136 /* CJK ... Yi */
137 (ch >= 0x2e80 && ch <= 0xa4cf &&
138 ch != 0x303f) ||
139 /* Hangul Syllables */
140 (ch >= 0xac00 && ch <= 0xd7a3) ||
141 /* CJK Compatibility Ideographs */
142 (ch >= 0xf900 && ch <= 0xfaff) ||
143 /* CJK Compatibility Forms */
144 (ch >= 0xfe30 && ch <= 0xfe6f) ||
145 /* Fullwidth Forms */
146 (ch >= 0xff00 && ch <= 0xff60) ||
147 (ch >= 0xffe0 && ch <= 0xffe6) ||
148 (ch >= 0x20000 && ch <= 0x2fffd) ||
149 (ch >= 0x30000 && ch <= 0x3fffd)));
150}
151
152/*
153 * This function returns the number of columns occupied by the character
154 * pointed to by the variable start. The pointer is updated to point at
155 * the next character. If it was not valid UTF-8, the pointer is set to NULL.
156 */
157int utf8_width(const char **start)
158{
159 unsigned char *s = (unsigned char *)*start;
160 wchar_t ch;
161
162 if (*s < 0x80) {
163 /* 0xxxxxxx */
164 ch = *s;
165 *start += 1;
166 } else if ((s[0] & 0xe0) == 0xc0) {
167 /* 110XXXXx 10xxxxxx */
168 if ((s[1] & 0xc0) != 0x80 ||
169 /* overlong? */
170 (s[0] & 0xfe) == 0xc0)
171 goto invalid;
172 ch = ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
173 *start += 2;
174 } else if ((s[0] & 0xf0) == 0xe0) {
175 /* 1110XXXX 10Xxxxxx 10xxxxxx */
176 if ((s[1] & 0xc0) != 0x80 ||
177 (s[2] & 0xc0) != 0x80 ||
178 /* overlong? */
179 (s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
180 /* surrogate? */
181 (s[0] == 0xed && (s[1] & 0xe0) == 0xa0) ||
182 /* U+FFFE or U+FFFF? */
183 (s[0] == 0xef && s[1] == 0xbf &&
184 (s[2] & 0xfe) == 0xbe))
185 goto invalid;
186 ch = ((s[0] & 0x0f) << 12) |
187 ((s[1] & 0x3f) << 6) | (s[2] & 0x3f);
188 *start += 3;
189 } else if ((s[0] & 0xf8) == 0xf0) {
190 /* 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx */
191 if ((s[1] & 0xc0) != 0x80 ||
192 (s[2] & 0xc0) != 0x80 ||
193 (s[3] & 0xc0) != 0x80 ||
194 /* overlong? */
195 (s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
196 /* > U+10FFFF? */
197 (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4)
198 goto invalid;
199 ch = ((s[0] & 0x07) << 18) | ((s[1] & 0x3f) << 12) |
200 ((s[2] & 0x3f) << 6) | (s[3] & 0x3f);
201 *start += 4;
202 } else {
203invalid:
204 *start = NULL;
205 return 0;
206 }
207
208 return wcwidth(ch);
209}
210
211int is_utf8(const char *text)
212{
213 while (*text) {
214 if (*text == '\n' || *text == '\t' || *text == '\r') {
215 text++;
216 continue;
217 }
218 utf8_width(&text);
219 if (!text)
220 return 0;
221 }
222 return 1;
223}
224
225static void print_spaces(int count)
226{
227 static const char s[] = " ";
228 while (count >= sizeof(s)) {
229 fwrite(s, sizeof(s) - 1, 1, stdout);
230 count -= sizeof(s) - 1;
231 }
232 fwrite(s, count, 1, stdout);
233}
234
235/*
236 * Wrap the text, if necessary. The variable indent is the indent for the
237 * first line, indent2 is the indent for all other lines.
238 */
239void print_wrapped_text(const char *text, int indent, int indent2, int width)
240{
241 int w = indent, assume_utf8 = is_utf8(text);
242 const char *bol = text, *space = NULL;
243
244 for (;;) {
245 char c = *text;
246 if (!c || isspace(c)) {
247 if (w < width || !space) {
248 const char *start = bol;
249 if (space)
250 start = space;
251 else
252 print_spaces(indent);
253 fwrite(start, text - start, 1, stdout);
254 if (!c) {
255 putchar('\n');
256 return;
257 } else if (c == '\t')
258 w |= 0x07;
259 space = text;
260 w++;
261 text++;
262 }
263 else {
264 putchar('\n');
265 text = bol = space + 1;
266 space = NULL;
267 w = indent = indent2;
268 }
269 continue;
270 }
271 if (assume_utf8)
272 w += utf8_width(&text);
273 else {
274 w++;
275 text++;
276 }
277 }
278}