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path: root/coreutils/cut.c (plain)
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1/* vi: set sw=4 ts=4: */
2/*
3 * cut.c - minimalist version of cut
4 *
5 * Copyright (C) 1999,2000,2001 by Lineo, inc.
6 * Written by Mark Whitley <markw@codepoet.org>
7 * debloated by Bernhard Reutner-Fischer
8 *
9 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 */
11//config:config CUT
12//config: bool "cut"
13//config: default y
14//config: help
15//config: cut is used to print selected parts of lines from
16//config: each file to stdout.
17
18//applet:IF_CUT(APPLET_NOEXEC(cut, cut, BB_DIR_USR_BIN, BB_SUID_DROP, cut))
19
20//kbuild:lib-$(CONFIG_CUT) += cut.o
21
22//usage:#define cut_trivial_usage
23//usage: "[OPTIONS] [FILE]..."
24//usage:#define cut_full_usage "\n\n"
25//usage: "Print selected fields from each input FILE to stdout\n"
26//usage: "\n -b LIST Output only bytes from LIST"
27//usage: "\n -c LIST Output only characters from LIST"
28//usage: "\n -d CHAR Use CHAR instead of tab as the field delimiter"
29//usage: "\n -s Output only the lines containing delimiter"
30//usage: "\n -f N Print only these fields"
31//usage: "\n -n Ignored"
32//usage:
33//usage:#define cut_example_usage
34//usage: "$ echo \"Hello world\" | cut -f 1 -d ' '\n"
35//usage: "Hello\n"
36//usage: "$ echo \"Hello world\" | cut -f 2 -d ' '\n"
37//usage: "world\n"
38
39#include "libbb.h"
40
41/* This is a NOEXEC applet. Be very careful! */
42
43
44/* option vars */
45static const char optstring[] ALIGN1 = "b:c:f:d:sn";
46#define CUT_OPT_BYTE_FLGS (1 << 0)
47#define CUT_OPT_CHAR_FLGS (1 << 1)
48#define CUT_OPT_FIELDS_FLGS (1 << 2)
49#define CUT_OPT_DELIM_FLGS (1 << 3)
50#define CUT_OPT_SUPPRESS_FLGS (1 << 4)
51
52struct cut_list {
53 int startpos;
54 int endpos;
55};
56
57enum {
58 BOL = 0,
59 EOL = INT_MAX,
60 NON_RANGE = -1
61};
62
63static int cmpfunc(const void *a, const void *b)
64{
65 return (((struct cut_list *) a)->startpos -
66 ((struct cut_list *) b)->startpos);
67}
68
69static void cut_file(FILE *file, char delim, const struct cut_list *cut_lists, unsigned nlists)
70{
71 char *line;
72 unsigned linenum = 0; /* keep these zero-based to be consistent */
73
74 /* go through every line in the file */
75 while ((line = xmalloc_fgetline(file)) != NULL) {
76
77 /* set up a list so we can keep track of what's been printed */
78 int linelen = strlen(line);
79 char *printed = xzalloc(linelen + 1);
80 char *orig_line = line;
81 unsigned cl_pos = 0;
82 int spos;
83
84 /* cut based on chars/bytes XXX: only works when sizeof(char) == byte */
85 if (option_mask32 & (CUT_OPT_CHAR_FLGS | CUT_OPT_BYTE_FLGS)) {
86 /* print the chars specified in each cut list */
87 for (; cl_pos < nlists; cl_pos++) {
88 spos = cut_lists[cl_pos].startpos;
89 while (spos < linelen) {
90 if (!printed[spos]) {
91 printed[spos] = 'X';
92 putchar(line[spos]);
93 }
94 spos++;
95 if (spos > cut_lists[cl_pos].endpos
96 /* NON_RANGE is -1, so if below is true,
97 * the above was true too (spos is >= 0) */
98 /* || cut_lists[cl_pos].endpos == NON_RANGE */
99 ) {
100 break;
101 }
102 }
103 }
104 } else if (delim == '\n') { /* cut by lines */
105 spos = cut_lists[cl_pos].startpos;
106
107 /* get out if we have no more lists to process or if the lines
108 * are lower than what we're interested in */
109 if (((int)linenum < spos) || (cl_pos >= nlists))
110 goto next_line;
111
112 /* if the line we're looking for is lower than the one we were
113 * passed, it means we displayed it already, so move on */
114 while (spos < (int)linenum) {
115 spos++;
116 /* go to the next list if we're at the end of this one */
117 if (spos > cut_lists[cl_pos].endpos
118 || cut_lists[cl_pos].endpos == NON_RANGE
119 ) {
120 cl_pos++;
121 /* get out if there's no more lists to process */
122 if (cl_pos >= nlists)
123 goto next_line;
124 spos = cut_lists[cl_pos].startpos;
125 /* get out if the current line is lower than the one
126 * we just became interested in */
127 if ((int)linenum < spos)
128 goto next_line;
129 }
130 }
131
132 /* If we made it here, it means we've found the line we're
133 * looking for, so print it */
134 puts(line);
135 goto next_line;
136 } else { /* cut by fields */
137 int ndelim = -1; /* zero-based / one-based problem */
138 int nfields_printed = 0;
139 char *field = NULL;
140 char delimiter[2];
141
142 delimiter[0] = delim;
143 delimiter[1] = 0;
144
145 /* does this line contain any delimiters? */
146 if (strchr(line, delim) == NULL) {
147 if (!(option_mask32 & CUT_OPT_SUPPRESS_FLGS))
148 puts(line);
149 goto next_line;
150 }
151
152 /* process each list on this line, for as long as we've got
153 * a line to process */
154 for (; cl_pos < nlists && line; cl_pos++) {
155 spos = cut_lists[cl_pos].startpos;
156 do {
157 /* find the field we're looking for */
158 while (line && ndelim < spos) {
159 field = strsep(&line, delimiter);
160 ndelim++;
161 }
162
163 /* we found it, and it hasn't been printed yet */
164 if (field && ndelim == spos && !printed[ndelim]) {
165 /* if this isn't our first time through, we need to
166 * print the delimiter after the last field that was
167 * printed */
168 if (nfields_printed > 0)
169 putchar(delim);
170 fputs(field, stdout);
171 printed[ndelim] = 'X';
172 nfields_printed++; /* shouldn't overflow.. */
173 }
174
175 spos++;
176
177 /* keep going as long as we have a line to work with,
178 * this is a list, and we're not at the end of that
179 * list */
180 } while (spos <= cut_lists[cl_pos].endpos && line
181 && cut_lists[cl_pos].endpos != NON_RANGE);
182 }
183 }
184 /* if we printed anything at all, we need to finish it with a
185 * newline cuz we were handed a chomped line */
186 putchar('\n');
187 next_line:
188 linenum++;
189 free(printed);
190 free(orig_line);
191 }
192}
193
194int cut_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
195int cut_main(int argc UNUSED_PARAM, char **argv)
196{
197 /* growable array holding a series of lists */
198 struct cut_list *cut_lists = NULL;
199 unsigned nlists = 0; /* number of elements in above list */
200 char delim = '\t'; /* delimiter, default is tab */
201 char *sopt, *ltok;
202 unsigned opt;
203
204 opt_complementary = "b--bcf:c--bcf:f--bcf";
205 opt = getopt32(argv, optstring, &sopt, &sopt, &sopt, &ltok);
206// argc -= optind;
207 argv += optind;
208 if (!(opt & (CUT_OPT_BYTE_FLGS | CUT_OPT_CHAR_FLGS | CUT_OPT_FIELDS_FLGS)))
209 bb_error_msg_and_die("expected a list of bytes, characters, or fields");
210
211 if (opt & CUT_OPT_DELIM_FLGS) {
212 if (ltok[0] && ltok[1]) { /* more than 1 char? */
213 bb_error_msg_and_die("the delimiter must be a single character");
214 }
215 delim = ltok[0];
216 }
217
218 /* non-field (char or byte) cutting has some special handling */
219 if (!(opt & CUT_OPT_FIELDS_FLGS)) {
220 static const char _op_on_field[] ALIGN1 = " only when operating on fields";
221
222 if (opt & CUT_OPT_SUPPRESS_FLGS) {
223 bb_error_msg_and_die
224 ("suppressing non-delimited lines makes sense%s",
225 _op_on_field);
226 }
227 if (delim != '\t') {
228 bb_error_msg_and_die
229 ("a delimiter may be specified%s", _op_on_field);
230 }
231 }
232
233 /*
234 * parse list and put values into startpos and endpos.
235 * valid list formats: N, N-, N-M, -M
236 * more than one list can be separated by commas
237 */
238 {
239 char *ntok;
240 int s = 0, e = 0;
241
242 /* take apart the lists, one by one (they are separated with commas) */
243 while ((ltok = strsep(&sopt, ",")) != NULL) {
244
245 /* it's actually legal to pass an empty list */
246 if (!ltok[0])
247 continue;
248
249 /* get the start pos */
250 ntok = strsep(&ltok, "-");
251 if (!ntok[0]) {
252 s = BOL;
253 } else {
254 s = xatoi_positive(ntok);
255 /* account for the fact that arrays are zero based, while
256 * the user expects the first char on the line to be char #1 */
257 if (s != 0)
258 s--;
259 }
260
261 /* get the end pos */
262 if (ltok == NULL) {
263 e = NON_RANGE;
264 } else if (!ltok[0]) {
265 e = EOL;
266 } else {
267 e = xatoi_positive(ltok);
268 /* if the user specified and end position of 0,
269 * that means "til the end of the line" */
270 if (e == 0)
271 e = EOL;
272 e--; /* again, arrays are zero based, lines are 1 based */
273 if (e == s)
274 e = NON_RANGE;
275 }
276
277 /* add the new list */
278 cut_lists = xrealloc_vector(cut_lists, 4, nlists);
279 /* NB: startpos is always >= 0,
280 * while endpos may be = NON_RANGE (-1) */
281 cut_lists[nlists].startpos = s;
282 cut_lists[nlists].endpos = e;
283 nlists++;
284 }
285
286 /* make sure we got some cut positions out of all that */
287 if (nlists == 0)
288 bb_error_msg_and_die("missing list of positions");
289
290 /* now that the lists are parsed, we need to sort them to make life
291 * easier on us when it comes time to print the chars / fields / lines
292 */
293 qsort(cut_lists, nlists, sizeof(cut_lists[0]), cmpfunc);
294 }
295
296 {
297 int retval = EXIT_SUCCESS;
298
299 if (!*argv)
300 *--argv = (char *)"-";
301
302 do {
303 FILE *file = fopen_or_warn_stdin(*argv);
304 if (!file) {
305 retval = EXIT_FAILURE;
306 continue;
307 }
308 cut_file(file, delim, cut_lists, nlists);
309 fclose_if_not_stdin(file);
310 } while (*++argv);
311
312 if (ENABLE_FEATURE_CLEAN_UP)
313 free(cut_lists);
314 fflush_stdout_and_exit(retval);
315 }
316}
317
generated by cgit at 2024-05-16 01:55:13 (GMT)