1/*	$OpenBSD: seq.c,v 1.8 2023/06/13 21:10:41 millert Exp $	*/
2
3/*-
4 * Copyright (c) 2005 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Brian Ginsbach.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <ctype.h>
33#include <err.h>
34#include <errno.h>
35#include <getopt.h>
36#include <math.h>
37#include <locale.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <unistd.h>
42
43#define VERSION	"1.0"
44#define ZERO	'0'
45#define SPACE	' '
46
47#define MAXIMUM(a, b)	(((a) < (b))? (b) : (a))
48#define ISSIGN(c)	((int)(c) == '-' || (int)(c) == '+')
49#define ISEXP(c)	((int)(c) == 'e' || (int)(c) == 'E')
50#define ISODIGIT(c)	((int)(c) >= '0' && (int)(c) <= '7')
51
52/* Globals */
53
54static const char *decimal_point = ".";	/* default */
55static char default_format[] = { "%g" };	/* default */
56
57static const struct option long_opts[] = {
58	{"format",	required_argument,	NULL, 'f'},
59	{"help",	no_argument,		NULL, 'h'},
60	{"separator",	required_argument,	NULL, 's'},
61	{"version",	no_argument,		NULL, 'v'},
62	{"equal-width",	no_argument,		NULL, 'w'},
63	{NULL,		no_argument,		NULL, 0}
64};
65
66/* Prototypes */
67
68static double e_atof(const char *);
69
70static int decimal_places(const char *);
71static int numeric(const char *);
72static int valid_format(const char *);
73
74static char *generate_format(double, double, double, int, char);
75
76static __dead void usage(int error);
77
78/*
79 * The seq command will print out a numeric sequence from 1, the default,
80 * to a user specified upper limit by 1.  The lower bound and increment
81 * maybe indicated by the user on the command line.  The sequence can
82 * be either whole, the default, or decimal numbers.
83 */
84int
85main(int argc, char *argv[])
86{
87	int c = 0;
88	int equalize = 0;
89	double first = 1.0;
90	double last = 0.0;
91	double incr = 0.0;
92	double prev = 0.0;
93	double cur, step;
94	struct lconv *locale;
95	char *fmt = NULL;
96	const char *sep = "\n";
97	const char *term = "\n";
98	char *cur_print, *last_print, *prev_print;
99	char pad = ZERO;
100
101	if (pledge("stdio", NULL) == -1)
102		err(1, "pledge");
103
104	/* Determine the locale's decimal point. */
105	locale = localeconv();
106	if (locale && locale->decimal_point && locale->decimal_point[0] != '\0')
107		decimal_point = locale->decimal_point;
108
109	/*
110	 * Process options, but handle negative numbers separately
111	 * least they trip up getopt(3).
112	 */
113	while ((optind < argc) && !numeric(argv[optind]) &&
114	    (c = getopt_long(argc, argv, "+f:s:w", long_opts, NULL)) != -1) {
115
116		switch (c) {
117		case 'f':	/* format (plan9/GNU) */
118			fmt = optarg;
119			equalize = 0;
120			break;
121		case 's':	/* separator (GNU) */
122			sep = optarg;
123			break;
124		case 'v':	/* version (GNU) */
125			printf("seq version %s\n", VERSION);
126			return 0;
127		case 'w':	/* equal width (plan9/GNU) */
128			if (fmt == NULL) {
129				if (equalize++)
130					pad = SPACE;
131			}
132			break;
133		case 'h':	/* help (GNU) */
134			usage(0);
135			break;
136		default:
137			usage(1);
138			break;
139		}
140	}
141
142	argc -= optind;
143	argv += optind;
144	if (argc < 1 || argc > 3)
145		usage(1);
146
147	last = e_atof(argv[argc - 1]);
148
149	if (argc > 1)
150		first = e_atof(argv[0]);
151
152	if (argc > 2) {
153		incr = e_atof(argv[1]);
154		/* Plan 9/GNU don't do zero */
155		if (incr == 0.0)
156			errx(1, "zero %screment", (first < last) ? "in" : "de");
157	}
158
159	/* default is one for Plan 9/GNU work alike */
160	if (incr == 0.0)
161		incr = (first < last) ? 1.0 : -1.0;
162
163	if (incr <= 0.0 && first < last)
164		errx(1, "needs positive increment");
165
166	if (incr >= 0.0 && first > last)
167		errx(1, "needs negative decrement");
168
169	if (fmt != NULL) {
170		if (!valid_format(fmt))
171			errx(1, "invalid format string: `%s'", fmt);
172		/*
173		 * XXX to be bug for bug compatible with Plan 9 add a
174		 * newline if none found at the end of the format string.
175		 */
176	} else
177		fmt = generate_format(first, incr, last, equalize, pad);
178
179	for (step = 1, cur = first; incr > 0 ? cur <= last : cur >= last;
180	    cur = first + incr * step++) {
181		if (cur != first)
182			fputs(sep, stdout);
183		printf(fmt, cur);
184		prev = cur;
185	}
186
187	/*
188	 * Did we miss the last value of the range in the loop above?
189	 *
190	 * We might have, so check if the printable version of the last
191	 * computed value ('cur') and desired 'last' value are equal.  If
192	 * they are equal after formatting truncation, but 'cur' and 'prev'
193	 * are different, it means the exit condition of the loop held true
194	 * due to a rounding error and we still need to print 'last'.
195	 */
196	if (asprintf(&cur_print, fmt, cur) == -1 ||
197	    asprintf(&last_print, fmt, last) == -1 ||
198	    asprintf(&prev_print, fmt, prev) == -1)
199		err(1, "asprintf");
200	if (strcmp(cur_print, last_print) == 0 &&
201	    strcmp(cur_print, prev_print) != 0) {
202		if (cur != first)
203			fputs(sep, stdout);
204		fputs(last_print, stdout);
205	}
206	free(cur_print);
207	free(last_print);
208	free(prev_print);
209
210	fputs(term, stdout);
211
212	return 0;
213}
214
215/*
216 * numeric - verify that string is numeric
217 */
218static int
219numeric(const char *s)
220{
221	int seen_decimal_pt, decimal_pt_len;
222
223	/* skip any sign */
224	if (ISSIGN((unsigned char)*s))
225		s++;
226
227	seen_decimal_pt = 0;
228	decimal_pt_len = strlen(decimal_point);
229	while (*s) {
230		if (!isdigit((unsigned char)*s)) {
231			if (!seen_decimal_pt &&
232			    strncmp(s, decimal_point, decimal_pt_len) == 0) {
233				s += decimal_pt_len;
234				seen_decimal_pt = 1;
235				continue;
236			}
237			if (ISEXP((unsigned char)*s)) {
238				s++;
239				if (ISSIGN((unsigned char)*s) ||
240				    isdigit((unsigned char)*s)) {
241					s++;
242					continue;
243				}
244			}
245			break;
246		}
247		s++;
248	}
249	return *s == '\0';
250}
251
252/*
253 * valid_format - validate user specified format string
254 */
255static int
256valid_format(const char *fmt)
257{
258	unsigned conversions = 0;
259
260	while (*fmt != '\0') {
261		/* scan for conversions */
262		if (*fmt != '%') {
263			fmt++;
264			continue;
265		}
266		fmt++;
267
268		/* allow %% but not things like %10% */
269		if (*fmt == '%') {
270			fmt++;
271			continue;
272		}
273
274		/* flags */
275		while (*fmt != '\0' && strchr("#0- +'", *fmt)) {
276			fmt++;
277		}
278
279		/* field width */
280		while (*fmt != '\0' && strchr("0123456789", *fmt)) {
281			fmt++;
282		}
283
284		/* precision */
285		if (*fmt == '.') {
286			fmt++;
287			while (*fmt != '\0' && strchr("0123456789", *fmt)) {
288				fmt++;
289			}
290		}
291
292		/* conversion */
293		switch (*fmt) {
294		case 'A':
295		case 'a':
296		case 'E':
297		case 'e':
298		case 'F':
299		case 'f':
300		case 'G':
301		case 'g':
302			/* floating point formats are accepted */
303			conversions++;
304			break;
305		default:
306			/* anything else is not */
307			return 0;
308		}
309	}
310
311	/* PR 236347 -- user format strings must have a conversion */
312	return conversions == 1;
313}
314
315/*
316 * e_atof - convert an ASCII string to a double
317 *	exit if string is not a valid double, or if converted value would
318 *	cause overflow or underflow
319 */
320static double
321e_atof(const char *num)
322{
323	char *endp;
324	double dbl;
325
326	errno = 0;
327	dbl = strtod(num, &endp);
328
329	if (errno == ERANGE)
330		/* under or overflow */
331		err(2, "%s", num);
332	else if (*endp != '\0')
333		/* "junk" left in number */
334		errx(2, "invalid floating point argument: %s", num);
335
336	/* zero shall have no sign */
337	if (dbl == -0.0)
338		dbl = 0;
339	return dbl;
340}
341
342/*
343 * decimal_places - count decimal places in a number (string)
344 */
345static int
346decimal_places(const char *number)
347{
348	int places = 0;
349	char *dp;
350
351	/* look for a decimal point */
352	if ((dp = strstr(number, decimal_point))) {
353		dp += strlen(decimal_point);
354
355		while (isdigit((unsigned char)*dp++))
356			places++;
357	}
358	return places;
359}
360
361/*
362 * generate_format - create a format string
363 *
364 * XXX to be bug for bug compatible with Plan9 and GNU return "%g"
365 * when "%g" prints as "%e" (this way no width adjustments are made)
366 */
367static char *
368generate_format(double first, double incr, double last, int equalize, char pad)
369{
370	static char buf[256];
371	char cc = '\0';
372	int precision, width1, width2, places;
373
374	if (equalize == 0)
375		return default_format;
376
377	/* figure out "last" value printed */
378	if (first > last)
379		last = first - incr * floor((first - last) / incr);
380	else
381		last = first + incr * floor((last - first) / incr);
382
383	snprintf(buf, sizeof(buf), "%g", incr);
384	if (strchr(buf, 'e'))
385		cc = 'e';
386	precision = decimal_places(buf);
387
388	width1 = snprintf(buf, sizeof(buf), "%g", first);
389	if (strchr(buf, 'e'))
390		cc = 'e';
391	if ((places = decimal_places(buf)))
392		width1 -= (places + strlen(decimal_point));
393
394	precision = MAXIMUM(places, precision);
395
396	width2 = snprintf(buf, sizeof(buf), "%g", last);
397	if (strchr(buf, 'e'))
398		cc = 'e';
399	if ((places = decimal_places(buf)))
400		width2 -= (places + strlen(decimal_point));
401
402	/* XXX if incr is floating point fix the precision */
403	if (precision) {
404		snprintf(buf, sizeof(buf), "%%%c%d.%d%c", pad,
405		    MAXIMUM(width1, width2) + (int)strlen(decimal_point) +
406		    precision, precision, (cc) ? cc : 'f');
407	} else {
408		snprintf(buf, sizeof(buf), "%%%c%d%c", pad,
409		    MAXIMUM(width1, width2), (cc) ? cc : 'g');
410	}
411
412	return buf;
413}
414
415static __dead void
416usage(int error)
417{
418	fprintf(stderr,
419	    "usage: %s [-w] [-f format] [-s string] [first [incr]] last\n",
420	    getprogname());
421	exit(error);
422}
423