1 /* $OpenBSD: fmt_scaled.c,v 1.17 2018/05/14 04:39:04 djm 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
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 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
fmt_scaled(long long number,char * result)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 } else if (fract < 0) {
256 /* shouldn't happen */
257 fract = 0;
258 }
259
260 if (number == 0)
261 strlcpy(result, "0B", FMT_SCALED_STRSIZE);
262 else if (unit == NONE || number >= 100 || number <= -100) {
263 if (fract >= 5) {
264 if (number >= 0)
265 number++;
266 else
267 number--;
268 }
269 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
270 number, scale_chars[unit]);
271 } else
272 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
273 number, fract, scale_chars[unit]);
274
275 return 0;
276 }
277
278 #ifdef MAIN
279 /*
280 * This is the original version of the program in the man page.
281 * Copy-and-paste whatever you need from it.
282 */
283 int
main(int argc,char ** argv)284 main(int argc, char **argv)
285 {
286 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
287 long long ninput = 10483892, result;
288
289 if (scan_scaled(cinput, &result) == 0)
290 printf("\"%s\" -> %lld\n", cinput, result);
291 else
292 perror(cinput);
293
294 if (fmt_scaled(ninput, buf) == 0)
295 printf("%lld -> \"%s\"\n", ninput, buf);
296 else
297 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
298
299 return 0;
300 }
301 #endif
302
303 #endif /* HAVE_FMT_SCALED */
304