1 /* $OpenBSD: fmt_scaled.c,v 1.21 2022/03/11 07:29:53 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 const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
58 static const char scale_chars[] = "BKMGTPE";
59 static const 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
scan_scaled(char * scaled,long long * result)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
159 /* If no scale factor given, we're done. fraction is discarded. */
160 if (!*p) {
161 *result = whole;
162 return 0;
163 }
164
165 /* Validate scale factor, and scale whole and fraction by it. */
166 for (i = 0; i < SCALE_LENGTH; i++) {
167
168 /* Are we there yet? */
169 if (*p == scale_chars[i] ||
170 *p == tolower((unsigned char)scale_chars[i])) {
171
172 /* If it ends with alphanumerics after the scale char, bad. */
173 if (isalnum((unsigned char)*(p+1))) {
174 errno = EINVAL;
175 return -1;
176 }
177 scale_fact = scale_factors[i];
178
179 /* check for overflow and underflow after scaling */
180 if (whole > LLONG_MAX / scale_fact ||
181 whole < LLONG_MIN / scale_fact) {
182 errno = ERANGE;
183 return -1;
184 }
185
186 /* scale whole part */
187 whole *= scale_fact;
188
189 /* truncate fpart so it doesn't overflow.
190 * then scale fractional part.
191 */
192 while (fpart >= LLONG_MAX / scale_fact ||
193 fpart <= LLONG_MIN / scale_fact) {
194 fpart /= 10;
195 fract_digits--;
196 }
197 fpart *= scale_fact;
198 if (fract_digits > 0) {
199 for (i = 0; i < fract_digits -1; i++)
200 fpart /= 10;
201 }
202 if (sign == -1)
203 whole -= fpart;
204 else
205 whole += fpart;
206 *result = whole;
207 return 0;
208 }
209 }
210
211 /* Invalid unit or character */
212 errno = EINVAL;
213 return -1;
214 }
215
216 /* Format the given "number" into human-readable form in "result".
217 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
218 * Return 0 on success, -1 and errno set if error.
219 */
220 int
fmt_scaled(long long number,char * result)221 fmt_scaled(long long number, char *result)
222 {
223 long long abval, fract = 0;
224 unsigned int i;
225 unit_type unit = NONE;
226
227 /* Not every negative long long has a positive representation. */
228 if (number == LLONG_MIN) {
229 errno = ERANGE;
230 return -1;
231 }
232
233 abval = llabs(number);
234
235 /* Also check for numbers that are just too darned big to format. */
236 if (abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
237 errno = ERANGE;
238 return -1;
239 }
240
241 /* scale whole part; get unscaled fraction */
242 for (i = 0; i < SCALE_LENGTH; i++) {
243 if (abval/1024 < scale_factors[i]) {
244 unit = units[i];
245 fract = (i == 0) ? 0 : abval % scale_factors[i];
246 number /= scale_factors[i];
247 if (i > 0)
248 fract /= scale_factors[i - 1];
249 break;
250 }
251 }
252
253 fract = (10 * fract + 512) / 1024;
254 /* if the result would be >= 10, round main number */
255 if (fract >= 10) {
256 if (number >= 0)
257 number++;
258 else
259 number--;
260 fract = 0;
261 } else if (fract < 0) {
262 /* shouldn't happen */
263 fract = 0;
264 }
265
266 if (number == 0)
267 strlcpy(result, "0B", FMT_SCALED_STRSIZE);
268 else if (unit == NONE || number >= 100 || number <= -100) {
269 if (fract >= 5) {
270 if (number >= 0)
271 number++;
272 else
273 number--;
274 }
275 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
276 number, scale_chars[unit]);
277 } else
278 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
279 number, fract, scale_chars[unit]);
280
281 return 0;
282 }
283
284 #ifdef MAIN
285 /*
286 * This is the original version of the program in the man page.
287 * Copy-and-paste whatever you need from it.
288 */
289 int
main(int argc,char ** argv)290 main(int argc, char **argv)
291 {
292 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
293 long long ninput = 10483892, result;
294
295 if (scan_scaled(cinput, &result) == 0)
296 printf("\"%s\" -> %lld\n", cinput, result);
297 else
298 perror(cinput);
299
300 if (fmt_scaled(ninput, buf) == 0)
301 printf("%lld -> \"%s\"\n", ninput, buf);
302 else
303 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
304
305 return 0;
306 }
307 #endif
308
309 #endif /* HAVE_FMT_SCALED */
310