1 /* Line breaking of strings.
2 Copyright (C) 2001-2003, 2006-2023 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2001.
4
5 This file is free software.
6 It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
7 You can redistribute it and/or modify it under either
8 - the terms of the GNU Lesser General Public License as published
9 by the Free Software Foundation, either version 3, or (at your
10 option) any later version, or
11 - the terms of the GNU General Public License as published by the
12 Free Software Foundation; either version 2, or (at your option)
13 any later version, or
14 - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
15
16 This file is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 Lesser General Public License and the GNU General Public License
20 for more details.
21
22 You should have received a copy of the GNU Lesser General Public
23 License and of the GNU General Public License along with this
24 program. If not, see <https://www.gnu.org/licenses/>. */
25
26 #include <config.h>
27
28 /* Specification. */
29 #include "unilbrk.h"
30
31 #include <stdlib.h>
32 #include <string.h>
33
34 #include "c-ctype.h"
35 #include "uniconv.h"
36 #include "unilbrk/internal.h"
37 #include "unilbrk/lbrktables.h"
38 #include "unilbrk/ulc-common.h"
39
40 /* Line breaking of a string in an arbitrary encoding.
41
42 We convert the input string to Unicode.
43
44 The standardized Unicode encodings are UTF-8, UCS-2, UCS-4, UTF-16,
45 UTF-16BE, UTF-16LE, UTF-7. UCS-2 supports only characters up to
46 \U0000FFFF. UTF-16 and variants support only characters up to
47 \U0010FFFF. UTF-7 is way too complex and not supported by glibc-2.1.
48 UCS-4 specification leaves doubts about endianness and byte order mark.
49 glibc currently interprets it as big endian without byte order mark,
50 but this is not backed by an RFC. So we use UTF-8. It supports
51 characters up to \U7FFFFFFF and is unambiguously defined. */
52
53 static int
54 ulc_width_linebreaks_internal (const char *s, size_t n,
55 int width, int start_column, int at_end_columns,
56 const char *o, const char *encoding, int cr,
57 char *p)
58 {
59 if (n > 0)
60 {
61 if (is_utf8_encoding (encoding))
62 return u8_width_linebreaks_internal ((const uint8_t *) s, n, width, start_column, at_end_columns, o, encoding, cr, p);
63 else
64 {
65 /* Convert the string to UTF-8 and build a translation table
66 from offsets into s to offsets into the translated string. */
67 size_t *offsets = (size_t *) malloc (n * sizeof (size_t));
68
69 if (offsets != NULL)
70 {
71 uint8_t *t;
72 size_t m;
73
74 t = u8_conv_from_encoding (encoding, iconveh_question_mark,
75 s, n, offsets, NULL, &m);
76 if (t != NULL)
77 {
78 char *memory =
79 (char *) (m > 0 ? malloc (m + (o != NULL ? m : 0)) : NULL);
80
81 if (m == 0 || memory != NULL)
82 {
83 char *q = (char *) memory;
84 char *o8 = (o != NULL ? (char *) (q + m) : NULL);
85 int res_column;
86 size_t i;
87
88 /* Translate the overrides to the UTF-8 string. */
89 if (o != NULL)
90 {
91 memset (o8, UC_BREAK_UNDEFINED, m);
92 for (i = 0; i < n; i++)
93 if (offsets[i] != (size_t)(-1))
94 o8[offsets[i]] = o[i];
95 }
96
97 /* Determine the line breaks of the UTF-8 string. */
98 res_column =
99 u8_width_linebreaks_internal (t, m, width, start_column, at_end_columns, o8, encoding, cr, q);
100
101 /* Translate the result back to the original string. */
102 memset (p, UC_BREAK_PROHIBITED, n);
103 for (i = 0; i < n; i++)
104 if (offsets[i] != (size_t)(-1))
105 p[i] = q[offsets[i]];
106
107 free (memory);
108 free (t);
109 free (offsets);
110 return res_column;
111 }
112 free (t);
113 }
114 free (offsets);
115 }
116 /* Impossible to convert. */
117 #if C_CTYPE_ASCII
118 if (is_all_ascii (s, n))
119 {
120 /* ASCII is a subset of UTF-8. */
121 return u8_width_linebreaks_internal ((const uint8_t *) s, n, width, start_column, at_end_columns, o, encoding, cr, p);
122 }
123 #endif
124 /* We have a non-ASCII string and cannot convert it.
125 Don't produce line breaks except those already present in the
126 input string. All we assume here is that the encoding is
127 minimally ASCII compatible. */
128 {
129 const char *s_end = s + n;
130 while (s < s_end)
131 {
132 *p = ((o != NULL && *o == UC_BREAK_MANDATORY)
133 || *s == '\n'
134 ? UC_BREAK_MANDATORY
135 : ((o != NULL && *o == UC_BREAK_CR_BEFORE_LF)
136 || (cr >= 0
137 && *s == '\r'
138 && s + 1 < s_end
139 && *(s + 1) == '\n')
140 ? UC_BREAK_CR_BEFORE_LF
141 : UC_BREAK_PROHIBITED));
142 s++;
143 p++;
144 if (o != NULL)
145 o++;
146 }
147 /* We cannot compute widths in this case. */
148 }
149 }
150 }
151 return start_column;
152 }
153
154 #if defined IN_LIBUNISTRING
155 /* For backward compatibility with older versions of libunistring. */
156
157 # undef ulc_width_linebreaks
158
159 int
160 ulc_width_linebreaks (const char *s, size_t n,
161 int width, int start_column, int at_end_columns,
162 const char *o, const char *encoding,
163 char *p)
164 {
165 return ulc_width_linebreaks_internal (s, n,
166 width, start_column, at_end_columns,
167 o, encoding, -1, p);
168 }
169
170 #endif
171
172 int
173 ulc_width_linebreaks_v2 (const char *s, size_t n,
174 int width, int start_column, int at_end_columns,
175 const char *o, const char *encoding,
176 char *p)
177 {
178 return ulc_width_linebreaks_internal (s, n,
179 width, start_column, at_end_columns,
180 o, encoding, LBP_CR, p);
181 }
182
183
184 #ifdef TEST
185
186 #include <stdio.h>
187 #include <locale.h>
188
189 /* Read the contents of an input stream, and return it, terminated with a NUL
190 byte. */
191 char *
192 read_file (FILE *stream)
193 {
194 #define BUFSIZE 4096
195 char *buf = NULL;
196 int alloc = 0;
197 int size = 0;
198 int count;
199
200 while (! feof (stream))
201 {
202 if (size + BUFSIZE > alloc)
203 {
204 alloc = alloc + alloc / 2;
205 if (alloc < size + BUFSIZE)
206 alloc = size + BUFSIZE;
207 buf = realloc (buf, alloc);
208 if (buf == NULL)
209 {
210 fprintf (stderr, "out of memory\n");
211 exit (1);
212 }
213 }
214 count = fread (buf + size, 1, BUFSIZE, stream);
215 if (count == 0)
216 {
217 if (ferror (stream))
218 {
219 perror ("fread");
220 exit (1);
221 }
222 }
223 else
224 size += count;
225 }
226 buf = realloc (buf, size + 1);
227 if (buf == NULL)
228 {
229 fprintf (stderr, "out of memory\n");
230 exit (1);
231 }
232 buf[size] = '\0';
233 return buf;
234 #undef BUFSIZE
235 }
236
237 int
238 main (int argc, char * argv[])
239 {
240 setlocale (LC_CTYPE, "");
241 if (argc == 2)
242 {
243 /* Insert line breaks for a given width. */
244 int width = atoi (argv[1]);
245 char *input = read_file (stdin);
246 int length = strlen (input);
247 char *breaks = malloc (length);
248 int i;
249
250 ulc_width_linebreaks_v2 (input, length, width, 0, 0, NULL, locale_charset (), breaks);
251
252 for (i = 0; i < length; i++)
253 {
254 switch (breaks[i])
255 {
256 case UC_BREAK_POSSIBLE:
257 putc ('\n', stdout);
258 break;
259 case UC_BREAK_MANDATORY:
260 break;
261 case UC_BREAK_CR_BEFORE_LF:
262 break;
263 case UC_BREAK_PROHIBITED:
264 break;
265 default:
266 abort ();
267 }
268 putc (input[i], stdout);
269 }
270
271 free (breaks);
272
273 return 0;
274 }
275 else
276 return 1;
277 }
278
279 #endif /* TEST */