summaryrefslogtreecommitdiff
path: root/coreutils/cut.c
blob: b9ea3127ce3349d110d29ec21122c1799ec8c375 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
/* vi: set sw=4 ts=4: */
/*
 * cut.c - minimalist version of cut
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc.
 * Written by Mark Whitley <markw@codepoet.org>
 * debloated by Bernhard Fischer
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "busybox.h"

/* This is a NOEXEC applet. Be very careful! */


/* option vars */
static const char optstring[] = "b:c:f:d:sn";
#define CUT_OPT_BYTE_FLGS	(1<<0)
#define CUT_OPT_CHAR_FLGS	(1<<1)
#define CUT_OPT_FIELDS_FLGS	(1<<2)
#define CUT_OPT_DELIM_FLGS	(1<<3)
#define CUT_OPT_SUPPRESS_FLGS (1<<4)

static char delim = '\t';	/* delimiter, default is tab */

struct cut_list {
	int startpos;
	int endpos;
};

enum {
	BOL = 0,
	EOL = INT_MAX,
	NON_RANGE = -1
};

/* growable array holding a series of lists */
static struct cut_list *cut_lists;
static unsigned int nlists;	/* number of elements in above list */


static int cmpfunc(const void *a, const void *b)
{
	return (((struct cut_list *) a)->startpos -
			((struct cut_list *) b)->startpos);

}

static void cut_file(FILE * file)
{
	char *line = NULL;
	unsigned int linenum = 0;	/* keep these zero-based to be consistent */

	/* go through every line in the file */
	while ((line = xmalloc_getline(file)) != NULL) {

		/* set up a list so we can keep track of what's been printed */
		char * printed = xzalloc(strlen(line) * sizeof(char));
		char * orig_line = line;
		unsigned int cl_pos = 0;
		int spos;

		/* cut based on chars/bytes XXX: only works when sizeof(char) == byte */
		if (option_mask32 & (CUT_OPT_CHAR_FLGS | CUT_OPT_BYTE_FLGS)) {
			/* print the chars specified in each cut list */
			for (; cl_pos < nlists; cl_pos++) {
				spos = cut_lists[cl_pos].startpos;
				while (spos < strlen(line)) {
					if (!printed[spos]) {
						printed[spos] = 'X';
						putchar(line[spos]);
					}
					spos++;
					if (spos > cut_lists[cl_pos].endpos
						|| cut_lists[cl_pos].endpos == NON_RANGE)
						break;
				}
			}
		} else if (delim == '\n') {	/* cut by lines */
			spos = cut_lists[cl_pos].startpos;

			/* get out if we have no more lists to process or if the lines
			 * are lower than what we're interested in */
			if (linenum < spos || cl_pos >= nlists)
				goto next_line;

			/* if the line we're looking for is lower than the one we were
			 * passed, it means we displayed it already, so move on */
			while (spos < linenum) {
				spos++;
				/* go to the next list if we're at the end of this one */
				if (spos > cut_lists[cl_pos].endpos
					|| cut_lists[cl_pos].endpos == NON_RANGE) {
					cl_pos++;
					/* get out if there's no more lists to process */
					if (cl_pos >= nlists)
						goto next_line;
					spos = cut_lists[cl_pos].startpos;
					/* get out if the current line is lower than the one
					 * we just became interested in */
					if (linenum < spos)
						goto next_line;
				}
			}

			/* If we made it here, it means we've found the line we're
			 * looking for, so print it */
			puts(line);
			goto next_line;
		} else {		/* cut by fields */
			int ndelim = -1;	/* zero-based / one-based problem */
			int nfields_printed = 0;
			char *field = NULL;
			const char delimiter[2] = { delim, 0 };

			/* does this line contain any delimiters? */
			if (strchr(line, delim) == NULL) {
				if (!(option_mask32 & CUT_OPT_SUPPRESS_FLGS))
					puts(line);
				goto next_line;
			}

			/* process each list on this line, for as long as we've got
			 * a line to process */
			for (; cl_pos < nlists && line; cl_pos++) {
				spos = cut_lists[cl_pos].startpos;
				do {
					/* find the field we're looking for */
					while (line && ndelim < spos) {
						field = strsep(&line, delimiter);
						ndelim++;
					}

					/* we found it, and it hasn't been printed yet */
					if (field && ndelim == spos && !printed[ndelim]) {
						/* if this isn't our first time through, we need to
						 * print the delimiter after the last field that was
						 * printed */
						if (nfields_printed > 0)
							putchar(delim);
						fputs(field, stdout);
						printed[ndelim] = 'X';
						nfields_printed++;	/* shouldn't overflow.. */
					}

					spos++;

					/* keep going as long as we have a line to work with,
					 * this is a list, and we're not at the end of that
					 * list */
				} while (spos <= cut_lists[cl_pos].endpos && line
						 && cut_lists[cl_pos].endpos != NON_RANGE);
			}
		}
		/* if we printed anything at all, we need to finish it with a
		 * newline cuz we were handed a chomped line */
		putchar('\n');
 next_line:
		linenum++;
		free(printed);
		free(orig_line);
	}
}

static const char _op_on_field[] = " only when operating on fields";

int cut_main(int argc, char **argv);
int cut_main(int argc, char **argv)
{
	char *sopt, *ltok;

	opt_complementary = "b--bcf:c--bcf:f--bcf";
	getopt32(argc, argv, optstring, &sopt, &sopt, &sopt, &ltok);
//	argc -= optind;
	argv += optind;
	if (!(option_mask32 & (CUT_OPT_BYTE_FLGS | CUT_OPT_CHAR_FLGS | CUT_OPT_FIELDS_FLGS)))
		bb_error_msg_and_die("expected a list of bytes, characters, or fields");
	if (option_mask32 & BB_GETOPT_ERROR)
		bb_error_msg_and_die("only one type of list may be specified");

	if (option_mask32 & CUT_OPT_DELIM_FLGS) {
		if (strlen(ltok) > 1) {
			bb_error_msg_and_die("the delimiter must be a single character");
		}
		delim = ltok[0];
	}

	/*  non-field (char or byte) cutting has some special handling */
	if (!(option_mask32 & CUT_OPT_FIELDS_FLGS)) {
		if (option_mask32 & CUT_OPT_SUPPRESS_FLGS) {
			bb_error_msg_and_die
				("suppressing non-delimited lines makes sense%s",
				 _op_on_field);
		}
		if (delim != '\t') {
			bb_error_msg_and_die
				("a delimiter may be specified%s", _op_on_field);
		}
	}

	/*
	 * parse list and put values into startpos and endpos.
	 * valid list formats: N, N-, N-M, -M
	 * more than one list can be separated by commas
	 */
	{
		char *ntok;
		int s = 0, e = 0;

		/* take apart the lists, one by one (they are separated with commas */
		while ((ltok = strsep(&sopt, ",")) != NULL) {

			/* it's actually legal to pass an empty list */
			if (strlen(ltok) == 0)
				continue;

			/* get the start pos */
			ntok = strsep(&ltok, "-");
			if (ntok == NULL) {
				bb_error_msg
					("internal error: ntok is null for start pos!?\n");
			} else if (strlen(ntok) == 0) {
				s = BOL;
			} else {
				s = xatoi_u(ntok);
				/* account for the fact that arrays are zero based, while
				 * the user expects the first char on the line to be char #1 */
				if (s != 0)
					s--;
			}

			/* get the end pos */
			ntok = strsep(&ltok, "-");
			if (ntok == NULL) {
				e = NON_RANGE;
			} else if (strlen(ntok) == 0) {
				e = EOL;
			} else {
				e = xatoi_u(ntok);
				/* if the user specified and end position of 0, that means "til the
				 * end of the line */
				if (e == 0)
					e = EOL;
				e--;	/* again, arrays are zero based, lines are 1 based */
				if (e == s)
					e = NON_RANGE;
			}

			/* if there's something left to tokenize, the user passed
			 * an invalid list */
			if (ltok)
				bb_error_msg_and_die("invalid byte or field list");

			/* add the new list */
			cut_lists = xrealloc(cut_lists, sizeof(struct cut_list) * (++nlists));
			cut_lists[nlists-1].startpos = s;
			cut_lists[nlists-1].endpos = e;
		}

		/* make sure we got some cut positions out of all that */
		if (nlists == 0)
			bb_error_msg_and_die("missing list of positions");

		/* now that the lists are parsed, we need to sort them to make life
		 * easier on us when it comes time to print the chars / fields / lines
		 */
		qsort(cut_lists, nlists, sizeof(struct cut_list), cmpfunc);
	}

	/* argv[0..argc-1] should be names of file to process. If no
	 * files were specified or '-' was specified, take input from stdin.
	 * Otherwise, we process all the files specified. */
	if (argv[0] == NULL || LONE_DASH(argv[0])) {
		cut_file(stdin);
	} else {
		FILE *file;

		do {
			file = fopen_or_warn(argv[0], "r");
			if (file) {
				cut_file(file);
				fclose(file);
			}
		} while (*++argv);
	}
	if (ENABLE_FEATURE_CLEAN_UP)
		free(cut_lists);
	return EXIT_SUCCESS;
}