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726f6388 JA |
1 | /* braces.c -- code for doing word expansion in curly braces. */ |
2 | ||
3 | /* Copyright (C) 1987,1991 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GNU Bash, the Bourne Again SHell. | |
6 | ||
7 | Bash is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 1, or (at your option) | |
10 | any later version. | |
11 | ||
12 | Bash is distributed in the hope that it will be useful, but WITHOUT | |
13 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
14 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
15 | License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with Bash; see the file COPYING. If not, write to the Free | |
19 | Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
20 | ||
ccc6cda3 | 21 | /* Stuff in curly braces gets expanded before all other shell expansions. */ |
726f6388 | 22 | |
ccc6cda3 JA |
23 | #include "config.h" |
24 | ||
25 | #if defined (BRACE_EXPANSION) | |
26 | ||
27 | #if defined (HAVE_UNISTD_H) | |
28 | # include <unistd.h> | |
29 | #endif | |
726f6388 JA |
30 | |
31 | #if defined (HAVE_STRING_H) | |
32 | # include <string.h> | |
33 | #else /* !HAVE_STRING_H */ | |
34 | # include <strings.h> | |
35 | #endif /* !HAVE_STRING_H */ | |
36 | ||
37 | #if defined (SHELL) | |
ccc6cda3 | 38 | # include "shell.h" |
726f6388 JA |
39 | #endif /* SHELL */ |
40 | ||
41 | #include "general.h" | |
42 | #define brace_whitespace(c) (!(c) || (c) == ' ' || (c) == '\t' || (c) == '\n') | |
43 | ||
44 | /* Basic idea: | |
45 | ||
46 | Segregate the text into 3 sections: preamble (stuff before an open brace), | |
47 | postamble (stuff after the matching close brace) and amble (stuff after | |
48 | preamble, and before postamble). Expand amble, and then tack on the | |
49 | expansions to preamble. Expand postamble, and tack on the expansions to | |
50 | the result so far. | |
51 | */ | |
52 | ||
53 | /* The character which is used to separate arguments. */ | |
54 | int brace_arg_separator = ','; | |
55 | ||
56 | static int brace_gobbler (); | |
57 | static char **expand_amble (), **array_concat (); | |
58 | ||
59 | /* Return an array of strings; the brace expansion of TEXT. */ | |
60 | char ** | |
61 | brace_expand (text) | |
62 | char *text; | |
63 | { | |
64 | register int start; | |
65 | char *preamble, *postamble, *amble; | |
66 | char **tack, **result; | |
ccc6cda3 | 67 | int i, j, c; |
726f6388 JA |
68 | |
69 | /* Find the text of the preamble. */ | |
70 | i = 0; | |
71 | c = brace_gobbler (text, &i, '{'); | |
72 | ||
73 | preamble = (char *)xmalloc (i + 1); | |
74 | strncpy (preamble, text, i); | |
75 | preamble[i] = '\0'; | |
76 | ||
77 | result = (char **)xmalloc (2 * sizeof (char *)); | |
78 | result[0] = preamble; | |
79 | result[1] = (char *)NULL; | |
ccc6cda3 | 80 | |
726f6388 JA |
81 | /* Special case. If we never found an exciting character, then |
82 | the preamble is all of the text, so just return that. */ | |
83 | if (c != '{') | |
84 | return (result); | |
85 | ||
86 | /* Find the amble. This is the stuff inside this set of braces. */ | |
87 | start = ++i; | |
88 | c = brace_gobbler (text, &i, '}'); | |
89 | ||
90 | /* What if there isn't a matching close brace? */ | |
ccc6cda3 | 91 | if (c == 0) |
726f6388 JA |
92 | { |
93 | #if defined (NOTDEF) | |
726f6388 JA |
94 | /* Well, if we found an unquoted BRACE_ARG_SEPARATOR between START |
95 | and I, then this should be an error. Otherwise, it isn't. */ | |
96 | for (j = start; j < i; j++) | |
97 | { | |
98 | if (text[j] == '\\') | |
99 | { | |
100 | j++; | |
101 | continue; | |
102 | } | |
103 | ||
104 | if (text[j] == brace_arg_separator) | |
105 | { | |
106 | free_array (result); | |
ccc6cda3 | 107 | report_error ("missing `}'"); |
726f6388 JA |
108 | throw_to_top_level (); |
109 | } | |
110 | } | |
111 | #endif | |
112 | free (preamble); /* Same as result[0]; see initialization. */ | |
113 | result[0] = savestring (text); | |
114 | return (result); | |
115 | } | |
116 | ||
117 | amble = (char *)xmalloc (1 + (i - start)); | |
118 | strncpy (amble, &text[start], (i - start)); | |
119 | amble[i - start] = '\0'; | |
120 | ||
121 | #if defined (SHELL) | |
122 | /* If the amble does not contain an unquoted BRACE_ARG_SEPARATOR, then | |
123 | just return without doing any expansion. */ | |
ccc6cda3 JA |
124 | for (j = 0; amble[j]; j++) |
125 | { | |
126 | if (amble[j] == '\\') | |
127 | { | |
128 | j++; | |
129 | continue; | |
130 | } | |
131 | if (amble[j] == brace_arg_separator) | |
132 | break; | |
133 | } | |
134 | ||
135 | if (!amble[j]) | |
136 | { | |
137 | free (amble); | |
138 | free (preamble); | |
139 | result[0] = savestring (text); | |
140 | return (result); | |
141 | } | |
726f6388 JA |
142 | #endif /* SHELL */ |
143 | ||
144 | postamble = &text[i + 1]; | |
145 | ||
146 | tack = expand_amble (amble); | |
147 | result = array_concat (result, tack); | |
148 | free (amble); | |
149 | free_array (tack); | |
150 | ||
151 | tack = brace_expand (postamble); | |
152 | result = array_concat (result, tack); | |
153 | free_array (tack); | |
154 | ||
155 | return (result); | |
156 | } | |
157 | ||
158 | /* Expand the text found inside of braces. We simply try to split the | |
159 | text at BRACE_ARG_SEPARATORs into separate strings. We then brace | |
160 | expand each slot which needs it, until there are no more slots which | |
161 | need it. */ | |
162 | static char ** | |
163 | expand_amble (text) | |
164 | char *text; | |
165 | { | |
166 | char **result, **partial; | |
167 | char *tem; | |
168 | int start, i, c; | |
169 | ||
170 | result = (char **)NULL; | |
171 | ||
172 | for (start = 0, i = 0, c = 1; c; start = ++i) | |
173 | { | |
174 | c = brace_gobbler (text, &i, brace_arg_separator); | |
175 | tem = (char *)xmalloc (1 + (i - start)); | |
176 | strncpy (tem, &text[start], (i - start)); | |
177 | tem[i- start] = '\0'; | |
178 | ||
179 | partial = brace_expand (tem); | |
180 | ||
181 | if (!result) | |
182 | result = partial; | |
183 | else | |
184 | { | |
185 | register int lr = array_len (result); | |
186 | register int lp = array_len (partial); | |
187 | register int j; | |
188 | ||
189 | result = (char **)xrealloc (result, (1 + lp + lr) * sizeof (char *)); | |
190 | ||
191 | for (j = 0; j < lp; j++) | |
192 | result[lr + j] = partial[j]; | |
193 | ||
194 | result[lr + j] = (char *)NULL; | |
195 | free (partial); | |
196 | } | |
197 | free (tem); | |
198 | } | |
199 | return (result); | |
200 | } | |
201 | ||
202 | /* Start at INDEX, and skip characters in TEXT. Set INDEX to the | |
203 | index of the character matching SATISFY. This understands about | |
204 | quoting. Return the character that caused us to stop searching; | |
205 | this is either the same as SATISFY, or 0. */ | |
206 | static int | |
207 | brace_gobbler (text, indx, satisfy) | |
208 | char *text; | |
209 | int *indx; | |
210 | int satisfy; | |
211 | { | |
212 | register int i, c, quoted, level, pass_next; | |
213 | ||
214 | level = quoted = pass_next = 0; | |
215 | ||
216 | for (i = *indx; c = text[i]; i++) | |
217 | { | |
218 | if (pass_next) | |
219 | { | |
220 | pass_next = 0; | |
221 | continue; | |
222 | } | |
223 | ||
224 | /* A backslash escapes the next character. This allows backslash to | |
225 | escape the quote character in a double-quoted string. */ | |
226 | if (c == '\\' && (quoted == 0 || quoted == '"' || quoted == '`')) | |
227 | { | |
228 | pass_next = 1; | |
229 | continue; | |
230 | } | |
231 | ||
232 | if (quoted) | |
233 | { | |
234 | if (c == quoted) | |
235 | quoted = 0; | |
236 | continue; | |
237 | } | |
238 | ||
239 | if (c == '"' || c == '\'' || c == '`') | |
240 | { | |
241 | quoted = c; | |
242 | continue; | |
243 | } | |
ccc6cda3 JA |
244 | |
245 | if (c == satisfy && level == 0 && quoted == 0) | |
726f6388 JA |
246 | { |
247 | /* We ignore an open brace surrounded by whitespace, and also | |
ccc6cda3 JA |
248 | an open brace followed immediately by a close brace preceded |
249 | by whitespace. */ | |
726f6388 JA |
250 | if (c == '{' && |
251 | ((!i || brace_whitespace (text[i - 1])) && | |
252 | (brace_whitespace (text[i + 1]) || text[i + 1] == '}'))) | |
253 | continue; | |
254 | #if defined (SHELL) | |
255 | /* If this is being compiled as part of bash, ignore the `{' | |
256 | in a `${}' construct */ | |
ccc6cda3 JA |
257 | if ((c != '{') || i == 0 || (text[i - 1] != '$')) |
258 | #endif /* SHELL */ | |
726f6388 JA |
259 | break; |
260 | } | |
261 | ||
262 | if (c == '{') | |
263 | level++; | |
264 | else if (c == '}' && level) | |
265 | level--; | |
266 | } | |
267 | ||
268 | *indx = i; | |
269 | return (c); | |
270 | } | |
271 | ||
272 | /* Return a new array of strings which is the result of appending each | |
273 | string in ARR2 to each string in ARR1. The resultant array is | |
274 | len (arr1) * len (arr2) long. For convenience, ARR1 (and its contents) | |
275 | are free ()'ed. ARR1 can be NULL, in that case, a new version of ARR2 | |
276 | is returned. */ | |
277 | static char ** | |
278 | array_concat (arr1, arr2) | |
279 | char **arr1, **arr2; | |
280 | { | |
281 | register int i, j, len, len1, len2; | |
282 | register char **result; | |
283 | ||
ccc6cda3 | 284 | if (arr1 == 0) |
726f6388 JA |
285 | return (copy_array (arr2)); |
286 | ||
ccc6cda3 | 287 | if (arr2 == 0) |
726f6388 JA |
288 | return (copy_array (arr1)); |
289 | ||
290 | len1 = array_len (arr1); | |
291 | len2 = array_len (arr2); | |
292 | ||
293 | result = (char **)xmalloc ((1 + (len1 * len2)) * sizeof (char *)); | |
294 | ||
295 | len = 0; | |
296 | for (i = 0; i < len1; i++) | |
297 | { | |
298 | int strlen_1 = strlen (arr1[i]); | |
299 | ||
300 | for (j = 0; j < len2; j++) | |
301 | { | |
302 | result[len] = | |
303 | (char *)xmalloc (1 + strlen_1 + strlen (arr2[j])); | |
304 | strcpy (result[len], arr1[i]); | |
305 | strcpy (result[len] + strlen_1, arr2[j]); | |
306 | len++; | |
307 | } | |
308 | free (arr1[i]); | |
309 | } | |
310 | free (arr1); | |
311 | ||
312 | result[len] = (char *)NULL; | |
313 | return (result); | |
314 | } | |
315 | ||
316 | #if defined (TEST) | |
317 | #include <stdio.h> | |
318 | ||
319 | fatal_error (format, arg1, arg2) | |
320 | char *format, *arg1, *arg2; | |
321 | { | |
322 | report_error (format, arg1, arg2); | |
323 | exit (1); | |
324 | } | |
325 | ||
326 | report_error (format, arg1, arg2) | |
327 | char *format, *arg1, *arg2; | |
328 | { | |
329 | fprintf (stderr, format, arg1, arg2); | |
330 | fprintf (stderr, "\n"); | |
331 | } | |
332 | ||
333 | main () | |
334 | { | |
335 | char example[256]; | |
336 | ||
337 | for (;;) | |
338 | { | |
339 | char **result; | |
340 | int i; | |
341 | ||
342 | fprintf (stderr, "brace_expand> "); | |
343 | ||
344 | if ((!fgets (example, 256, stdin)) || | |
345 | (strncmp (example, "quit", 4) == 0)) | |
346 | break; | |
347 | ||
348 | if (strlen (example)) | |
349 | example[strlen (example) - 1] = '\0'; | |
350 | ||
351 | result = brace_expand (example); | |
352 | ||
353 | for (i = 0; result[i]; i++) | |
354 | printf ("%s\n", result[i]); | |
355 | ||
356 | free_array (result); | |
357 | } | |
358 | } | |
359 | \f | |
360 | /* | |
361 | * Local variables: | |
362 | * compile-command: "gcc -g -Bstatic -DTEST -o brace_expand braces.c general.o" | |
363 | * end: | |
364 | */ | |
365 | ||
366 | #endif /* TEST */ | |
ccc6cda3 | 367 | #endif /* BRACE_EXPANSION */ |