1 /*	$OpenBSD: fmt_scaled.c,v 1.16 2017/03/16 02:40:46 dtucker Exp $	*/
2 
3 /*
4  * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
30 
31 /*
32  * fmt_scaled: Format numbers scaled for human comprehension
33  * scan_scaled: Scan numbers in this format.
34  *
35  * "Human-readable" output uses 4 digits max, and puts a unit suffix at
36  * the end.  Makes output compact and easy-to-read esp. on huge disks.
37  * Formatting code was originally in OpenBSD "df", converted to library routine.
38  * Scanning code written for OpenBSD libutil.
39  */
40 
41 #include "includes.h"
42 
43 #ifndef HAVE_FMT_SCALED
44 
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <errno.h>
48 #include <string.h>
49 #include <ctype.h>
50 #include <limits.h>
51 
52 typedef enum {
53 	NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
54 } unit_type;
55 
56 /* These three arrays MUST be in sync!  XXX make a struct */
57 static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
58 static char scale_chars[] = "BKMGTPE";
59 static long long scale_factors[] = {
60 	1LL,
61 	1024LL,
62 	1024LL*1024,
63 	1024LL*1024*1024,
64 	1024LL*1024*1024*1024,
65 	1024LL*1024*1024*1024*1024,
66 	1024LL*1024*1024*1024*1024*1024,
67 };
68 #define	SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
69 
70 #define MAX_DIGITS (SCALE_LENGTH * 3)	/* XXX strlen(sprintf("%lld", -1)? */
71 
72 /* Convert the given input string "scaled" into numeric in "result".
73  * Return 0 on success, -1 and errno set on error.
74  */
75 int
76 scan_scaled(char *scaled, long long *result)
77 {
78 	char *p = scaled;
79 	int sign = 0;
80 	unsigned int i, ndigits = 0, fract_digits = 0;
81 	long long scale_fact = 1, whole = 0, fpart = 0;
82 
83 	/* Skip leading whitespace */
84 	while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
85 		++p;
86 
87 	/* Then at most one leading + or - */
88 	while (*p == '-' || *p == '+') {
89 		if (*p == '-') {
90 			if (sign) {
91 				errno = EINVAL;
92 				return -1;
93 			}
94 			sign = -1;
95 			++p;
96 		} else if (*p == '+') {
97 			if (sign) {
98 				errno = EINVAL;
99 				return -1;
100 			}
101 			sign = +1;
102 			++p;
103 		}
104 	}
105 
106 	/* Main loop: Scan digits, find decimal point, if present.
107 	 * We don't allow exponentials, so no scientific notation
108 	 * (but note that E for Exa might look like e to some!).
109 	 * Advance 'p' to end, to get scale factor.
110 	 */
111 	for (; isascii((unsigned char)*p) &&
112 	    (isdigit((unsigned char)*p) || *p=='.'); ++p) {
113 		if (*p == '.') {
114 			if (fract_digits > 0) {	/* oops, more than one '.' */
115 				errno = EINVAL;
116 				return -1;
117 			}
118 			fract_digits = 1;
119 			continue;
120 		}
121 
122 		i = (*p) - '0';			/* whew! finally a digit we can use */
123 		if (fract_digits > 0) {
124 			if (fract_digits >= MAX_DIGITS-1)
125 				/* ignore extra fractional digits */
126 				continue;
127 			fract_digits++;		/* for later scaling */
128 			if (fpart > LLONG_MAX / 10) {
129 				errno = ERANGE;
130 				return -1;
131 			}
132 			fpart *= 10;
133 			if (i > LLONG_MAX - fpart) {
134 				errno = ERANGE;
135 				return -1;
136 			}
137 			fpart += i;
138 		} else {				/* normal digit */
139 			if (++ndigits >= MAX_DIGITS) {
140 				errno = ERANGE;
141 				return -1;
142 			}
143 			if (whole > LLONG_MAX / 10) {
144 				errno = ERANGE;
145 				return -1;
146 			}
147 			whole *= 10;
148 			if (i > LLONG_MAX - whole) {
149 				errno = ERANGE;
150 				return -1;
151 			}
152 			whole += i;
153 		}
154 	}
155 
156 	if (sign) {
157 		whole *= sign;
158 		fpart *= sign;
159 	}
160 
161 	/* If no scale factor given, we're done. fraction is discarded. */
162 	if (!*p) {
163 		*result = whole;
164 		return 0;
165 	}
166 
167 	/* Validate scale factor, and scale whole and fraction by it. */
168 	for (i = 0; i < SCALE_LENGTH; i++) {
169 
170 		/* Are we there yet? */
171 		if (*p == scale_chars[i] ||
172 			*p == tolower((unsigned char)scale_chars[i])) {
173 
174 			/* If it ends with alphanumerics after the scale char, bad. */
175 			if (isalnum((unsigned char)*(p+1))) {
176 				errno = EINVAL;
177 				return -1;
178 			}
179 			scale_fact = scale_factors[i];
180 
181 			/* check for overflow and underflow after scaling */
182 			if (whole > LLONG_MAX / scale_fact ||
183 			    whole < LLONG_MIN / scale_fact) {
184 				errno = ERANGE;
185 				return -1;
186 			}
187 
188 			/* scale whole part */
189 			whole *= scale_fact;
190 
191 			/* truncate fpart so it doesn't overflow.
192 			 * then scale fractional part.
193 			 */
194 			while (fpart >= LLONG_MAX / scale_fact) {
195 				fpart /= 10;
196 				fract_digits--;
197 			}
198 			fpart *= scale_fact;
199 			if (fract_digits > 0) {
200 				for (i = 0; i < fract_digits -1; i++)
201 					fpart /= 10;
202 			}
203 			whole += fpart;
204 			*result = whole;
205 			return 0;
206 		}
207 	}
208 
209 	/* Invalid unit or character */
210 	errno = EINVAL;
211 	return -1;
212 }
213 
214 /* Format the given "number" into human-readable form in "result".
215  * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
216  * Return 0 on success, -1 and errno set if error.
217  */
218 int
219 fmt_scaled(long long number, char *result)
220 {
221 	long long abval, fract = 0;
222 	unsigned int i;
223 	unit_type unit = NONE;
224 
225 	abval = llabs(number);
226 
227 	/* Not every negative long long has a positive representation.
228 	 * Also check for numbers that are just too darned big to format
229 	 */
230 	if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
231 		errno = ERANGE;
232 		return -1;
233 	}
234 
235 	/* scale whole part; get unscaled fraction */
236 	for (i = 0; i < SCALE_LENGTH; i++) {
237 		if (abval/1024 < scale_factors[i]) {
238 			unit = units[i];
239 			fract = (i == 0) ? 0 : abval % scale_factors[i];
240 			number /= scale_factors[i];
241 			if (i > 0)
242 				fract /= scale_factors[i - 1];
243 			break;
244 		}
245 	}
246 
247 	fract = (10 * fract + 512) / 1024;
248 	/* if the result would be >= 10, round main number */
249 	if (fract == 10) {
250 		if (number >= 0)
251 			number++;
252 		else
253 			number--;
254 		fract = 0;
255 	}
256 
257 	if (number == 0)
258 		strlcpy(result, "0B", FMT_SCALED_STRSIZE);
259 	else if (unit == NONE || number >= 100 || number <= -100) {
260 		if (fract >= 5) {
261 			if (number >= 0)
262 				number++;
263 			else
264 				number--;
265 		}
266 		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
267 			number, scale_chars[unit]);
268 	} else
269 		(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
270 			number, fract, scale_chars[unit]);
271 
272 	return 0;
273 }
274 
275 #ifdef	MAIN
276 /*
277  * This is the original version of the program in the man page.
278  * Copy-and-paste whatever you need from it.
279  */
280 int
281 main(int argc, char **argv)
282 {
283 	char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
284 	long long ninput = 10483892, result;
285 
286 	if (scan_scaled(cinput, &result) == 0)
287 		printf("\"%s\" -> %lld\n", cinput, result);
288 	else
289 		perror(cinput);
290 
291 	if (fmt_scaled(ninput, buf) == 0)
292 		printf("%lld -> \"%s\"\n", ninput, buf);
293 	else
294 		fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
295 
296 	return 0;
297 }
298 #endif
299 
300 #endif /* HAVE_FMT_SCALED */
301