1 /* Determine the number of screen columns needed for a string.
2 Copyright (C) 2000-2023 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Bruno Haible <haible@clisp.cons.org>. */
18
19 #include <config.h>
20
21 /* Specification. */
22 #include "mbswidth.h"
23
24 /* Get MB_CUR_MAX. */
25 #include <stdlib.h>
26
27 #include <string.h>
28
29 /* Get isprint(). */
30 #include <ctype.h>
31
32 /* Get mbstate_t, mbsinit(). */
33 #include <wchar.h>
34
35 /* Get char32_t, mbrtoc32(), c32iscntrl(), c32width(). */
36 #include <uchar.h>
37
38 /* Get INT_MAX. */
39 #include <limits.h>
40
41 /* Returns the number of columns needed to represent the multibyte
42 character string pointed to by STRING. If a non-printable character
43 occurs, and MBSW_REJECT_UNPRINTABLE is specified, -1 is returned.
44 With flags = MBSW_REJECT_INVALID | MBSW_REJECT_UNPRINTABLE, this is
45 the multibyte analogue of the wcswidth function. */
46 int
47 mbswidth (const char *string, int flags)
48 {
49 return mbsnwidth (string, strlen (string), flags);
50 }
51
52 /* Returns the number of columns needed to represent the multibyte
53 character string pointed to by STRING of length NBYTES. If a
54 non-printable character occurs, and MBSW_REJECT_UNPRINTABLE is
55 specified, -1 is returned. */
56 int
57 mbsnwidth (const char *string, size_t nbytes, int flags)
58 {
59 const char *p = string;
60 const char *plimit = p + nbytes;
61 int width;
62
63 width = 0;
64 if (MB_CUR_MAX > 1)
65 {
66 while (p < plimit)
67 switch (*p)
68 {
69 case ' ': case '!': case '"': case '#': case '$': case '%':
70 case '&': case '\'': case '(': case ')': case '*':
71 case '+': case ',': case '-': case '.': case '/':
72 case '0': case '1': case '2': case '3': case '4':
73 case '5': case '6': case '7': case '8': case '9':
74 case ':': case ';': case '<': case '=': case '>':
75 case '?': case '@':
76 case 'A': case 'B': case 'C': case 'D': case 'E':
77 case 'F': case 'G': case 'H': case 'I': case 'J':
78 case 'K': case 'L': case 'M': case 'N': case 'O':
79 case 'P': case 'Q': case 'R': case 'S': case 'T':
80 case 'U': case 'V': case 'W': case 'X': case 'Y':
81 case 'Z':
82 case '[': case '\\': case ']': case '^': case '_': case '`':
83 case 'a': case 'b': case 'c': case 'd': case 'e':
84 case 'f': case 'g': case 'h': case 'i': case 'j':
85 case 'k': case 'l': case 'm': case 'n': case 'o':
86 case 'p': case 'q': case 'r': case 's': case 't':
87 case 'u': case 'v': case 'w': case 'x': case 'y':
88 case 'z': case '{': case '|': case '}': case '~':
89 /* These characters are printable ASCII characters. */
90 p++;
91 width++;
92 break;
93 default:
94 /* If we have a multibyte sequence, scan it up to its end. */
95 {
96 mbstate_t mbstate;
97 mbszero (&mbstate);
98 for (;;)
99 {
100 char32_t wc;
101 size_t bytes;
102 int w;
103
104 bytes = mbrtoc32 (&wc, p, plimit - p, &mbstate);
105
106 if (bytes == (size_t) -1)
107 /* An invalid multibyte sequence was encountered. */
108 {
109 if (!(flags & MBSW_REJECT_INVALID))
110 {
111 p++;
112 width++;
113 break;
114 }
115 else
116 return -1;
117 }
118
119 if (bytes == (size_t) -2)
120 /* An incomplete multibyte character at the end. */
121 {
122 if (!(flags & MBSW_REJECT_INVALID))
123 {
124 p = plimit;
125 width++;
126 break;
127 }
128 else
129 return -1;
130 }
131
132 if (bytes == 0)
133 /* A null wide character was encountered. */
134 bytes = 1;
135 #if !GNULIB_MBRTOC32_REGULAR
136 else if (bytes == (size_t) -3)
137 bytes = 0;
138 #endif
139
140 w = c32width (wc);
141 if (w >= 0)
142 /* A printable multibyte character. */
143 {
144 if (w > INT_MAX - width)
145 goto overflow;
146 width += w;
147 }
148 else
149 /* An unprintable multibyte character. */
150 if (!(flags & MBSW_REJECT_UNPRINTABLE))
151 {
152 if (!c32iscntrl (wc))
153 {
154 if (width == INT_MAX)
155 goto overflow;
156 width++;
157 }
158 }
159 else
160 return -1;
161
162 p += bytes;
163 #if !GNULIB_MBRTOC32_REGULAR
164 if (mbsinit (&mbstate))
165 #endif
166 break;
167 }
168 }
169 break;
170 }
171 return width;
172 }
173
174 while (p < plimit)
175 {
176 unsigned char c = (unsigned char) *p++;
177
178 if (isprint (c))
179 {
180 if (width == INT_MAX)
181 goto overflow;
182 width++;
183 }
184 else if (!(flags & MBSW_REJECT_UNPRINTABLE))
185 {
186 if (!iscntrl (c))
187 {
188 if (width == INT_MAX)
189 goto overflow;
190 width++;
191 }
192 }
193 else
194 return -1;
195 }
196 return width;
197
198 overflow:
199 return INT_MAX;
200 }