1 /*
2 * utils.c - multibyte-string helpers
3 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #ifndef _XOPEN_SOURCE
20 #define _XOPEN_SOURCE
21 #endif
22 #include "aconfig.h"
23 #include <limits.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <wchar.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include "utils.h"
30 #include "mem.h"
31
32 /*
33 * mbs_at_width - compute screen position in a string
34 *
35 * For displaying strings on the screen, we have to know how many character
36 * cells are occupied. This function calculates the position in a multibyte
37 * string that is at a desired position.
38 *
39 * Parameters:
40 * s: the string
41 * width: on input, the desired number of character cells; on output, the actual
42 * position, in character cells, of the return value
43 * dir: -1 or 1; in which direction to round if a multi-column character goes
44 * over the desired width
45 *
46 * Return value:
47 * Pointer to the place in the string that is as near the desired width as
48 * possible. If the string is too short, the return value points to the
49 * terminating zero. If the last character is a multi-column character that
50 * goes over the desired width, the return value may be one character cell
51 * earlier or later than desired, depending on the dir parameter.
52 * In any case, the return value points after any zero-width characters that
53 * follow the last character.
54 */
mbs_at_width(const char * s,int * width,int dir)55 const char *mbs_at_width(const char *s, int *width, int dir)
56 {
57 size_t len;
58 wchar_t wc;
59 int bytes;
60 int width_so_far, w;
61
62 if (*width <= 0)
63 return s;
64 mbtowc(NULL, NULL, 0); /* reset shift state */
65 len = strlen(s);
66 width_so_far = 0;
67 while (len && (bytes = mbtowc(&wc, s, len)) > 0) {
68 w = wcwidth(wc);
69 if (width_so_far + w > *width && dir < 0)
70 break;
71 if (w >= 0)
72 width_so_far += w;
73 s += bytes;
74 len -= bytes;
75 if (width_so_far >= *width) {
76 while (len && (bytes = mbtowc(&wc, s, len)) > 0) {
77 w = wcwidth(wc);
78 if (w != 0)
79 break;
80 s += bytes;
81 len -= bytes;
82 }
83 break;
84 }
85 }
86 *width = width_so_far;
87 return s;
88 }
89
90 /*
91 * get_mbs_width - compute screen width of a string
92 */
get_mbs_width(const char * s)93 unsigned int get_mbs_width(const char *s)
94 {
95 int width;
96
97 width = INT_MAX;
98 mbs_at_width(s, &width, 1);
99 return width;
100 }
101
102 /*
103 * get_max_mbs_width - get width of longest string in an array
104 */
get_max_mbs_width(const char * const * s,unsigned int count)105 unsigned int get_max_mbs_width(const char *const *s, unsigned int count)
106 {
107 unsigned int max_width, i, len;
108
109 max_width = 0;
110 for (i = 0; i < count; ++i) {
111 len = get_mbs_width(s[i]);
112 if (len > max_width)
113 max_width = len;
114 }
115 return max_width;
116 }
117
118 #define MAX_FILE_SIZE 1048576
read_file(const char * file_name,unsigned int * file_size)119 char *read_file(const char *file_name, unsigned int *file_size)
120 {
121 FILE *f;
122 int err;
123 char *buf;
124 unsigned int allocated = 2048;
125 unsigned int bytes_read;
126
127 f = fopen(file_name, "r");
128 if (!f) {
129 err = errno;
130 errno = err;
131 return NULL;
132 }
133 *file_size = 0;
134 buf = NULL;
135 do {
136 allocated *= 2;
137 buf = crealloc(buf, allocated);
138 bytes_read = fread(buf + *file_size, 1, allocated - *file_size, f);
139 *file_size += bytes_read;
140 } while (*file_size == allocated && allocated < MAX_FILE_SIZE);
141 fclose(f);
142 if (*file_size > 0 && buf[*file_size - 1] != '\n' && *file_size < allocated) {
143 buf[*file_size] = '\n';
144 ++*file_size;
145 }
146 return buf;
147 }
148
149