1 /* Determine the number of screen columns needed for a string.
2 Copyright (C) 2000-2022 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, mbrtowc(), mbsinit(), wcwidth(). */
33 #include <wchar.h>
34
35 /* Get iswcntrl(). */
36 #include <wctype.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 '%':
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 '?':
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 '_':
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 memset (&mbstate, 0, sizeof mbstate);
98 do
99 {
100 wchar_t wc;
101 size_t bytes;
102 int w;
103
104 bytes = mbrtowc (&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
136 w = wcwidth (wc);
137 if (w >= 0)
138 /* A printable multibyte character. */
139 {
140 if (w > INT_MAX - width)
141 goto overflow;
142 width += w;
143 }
144 else
145 /* An unprintable multibyte character. */
146 if (!(flags & MBSW_REJECT_UNPRINTABLE))
147 {
148 if (!iswcntrl (wc))
149 {
150 if (width == INT_MAX)
151 goto overflow;
152 width++;
153 }
154 }
155 else
156 return -1;
157
158 p += bytes;
159 }
160 while (! mbsinit (&mbstate));
161 }
162 break;
163 }
164 return width;
165 }
166
167 while (p < plimit)
168 {
169 unsigned char c = (unsigned char) *p++;
170
171 if (isprint (c))
172 {
173 if (width == INT_MAX)
174 goto overflow;
175 width++;
176 }
177 else if (!(flags & MBSW_REJECT_UNPRINTABLE))
178 {
179 if (!iscntrl (c))
180 {
181 if (width == INT_MAX)
182 goto overflow;
183 width++;
184 }
185 }
186 else
187 return -1;
188 }
189 return width;
190
191 overflow:
192 return INT_MAX;
193 }