1 /* $NetBSD: fmt_scaled.c,v 1.8 2019/01/27 02:08:33 pgoyette Exp $ */
2 /* $OpenBSD: fmt_scaled.c,v 1.9 2007/03/20 03:42:52 tedu Exp $ */
3
4 /*
5 * Copyright (c) 2001, 2002, 2003 Ian F. Darwin. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
31
32 /*
33 * fmt_scaled: Format numbers scaled for human comprehension
34 * scan_scaled: Scan numbers in this format.
35 *
36 * "Human-readable" output uses 4 digits max, and puts a unit suffix at
37 * the end. Makes output compact and easy-to-read esp. on huge disks.
38 * Formatting code was originally in OpenBSD "df", converted to library routine.
39 * Scanning code written for OpenBSD libutil.
40 */
41
42 #include "includes.h"
43 __RCSID("$NetBSD: fmt_scaled.c,v 1.8 2019/01/27 02:08:33 pgoyette Exp $");
44
45 #ifndef HAVE_FMT_SCALED
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <errno.h>
49 #include <string.h>
50 #include <ctype.h>
51 #include <limits.h>
52
53 #include "fmt_scaled.h"
54
55 typedef enum {
56 NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
57 } unit_type;
58
59 /* These three arrays MUST be in sync! XXX make a struct */
60 static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
61 static char scale_chars[] = "BKMGTPE";
62 static long long scale_factors[] = {
63 1LL,
64 1024LL,
65 1024LL*1024,
66 1024LL*1024*1024,
67 1024LL*1024*1024*1024,
68 1024LL*1024*1024*1024*1024,
69 1024LL*1024*1024*1024*1024*1024,
70 };
71 #define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
72
73 #define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */
74
75 /** Convert the given input string "scaled" into numeric in "result".
76 * Return 0 on success, -1 and errno set on error.
77 */
78 int
scan_scaled(const char * scaled,long long * result)79 scan_scaled(const char *scaled, long long *result)
80 {
81 const char *p = scaled;
82 int sign = 0;
83 unsigned int i, ndigits = 0, fract_digits = 0;
84 long long scale_fact = 1, whole = 0, fpart = 0;
85
86 /* Skip leading whitespace */
87 while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
88 ++p;
89
90 /* Then at most one leading + or - */
91 while (*p == '-' || *p == '+') {
92 if (*p == '-') {
93 if (sign) {
94 errno = EINVAL;
95 return -1;
96 }
97 sign = -1;
98 ++p;
99 } else if (*p == '+') {
100 if (sign) {
101 errno = EINVAL;
102 return -1;
103 }
104 sign = +1;
105 ++p;
106 }
107 }
108
109 /* Main loop: Scan digits, find decimal point, if present.
110 * We don't allow exponentials, so no scientific notation
111 * (but note that E for Exa might look like e to some!).
112 * Advance 'p' to end, to get scale factor.
113 */
114 for (; isascii((unsigned char)*p) && (isdigit((unsigned char)*p) || *p=='.'); ++p) {
115 if (*p == '.') {
116 if (fract_digits > 0) { /* oops, more than one '.' */
117 errno = EINVAL;
118 return -1;
119 }
120 fract_digits = 1;
121 continue;
122 }
123
124 i = (*p) - '0'; /* whew! finally a digit we can use */
125 if (fract_digits > 0) {
126 if (fract_digits >= MAX_DIGITS-1)
127 /* ignore extra fractional digits */
128 continue;
129 fract_digits++; /* for later scaling */
130 fpart *= 10;
131 fpart += i;
132 } else { /* normal digit */
133 if (++ndigits >= MAX_DIGITS) {
134 errno = ERANGE;
135 return -1;
136 }
137 whole *= 10;
138 whole += i;
139 }
140 }
141
142 if (sign) {
143 whole *= sign;
144 fpart *= sign;
145 }
146
147 /* If no scale factor given, we're done. fraction is discarded. */
148 if (!*p) {
149 *result = whole;
150 return 0;
151 }
152
153 /* Validate scale factor, and scale whole and fraction by it. */
154 for (i = 0; i < SCALE_LENGTH; i++) {
155
156 /** Are we there yet? */
157 if (*p == scale_chars[i] ||
158 *p == tolower((unsigned char)scale_chars[i])) {
159
160 /* If it ends with alphanumerics after the scale char, bad. */
161 if (isalnum((unsigned char)*(p+1))) {
162 errno = EINVAL;
163 return -1;
164 }
165 scale_fact = scale_factors[i];
166
167 /* scale whole part */
168 whole *= scale_fact;
169
170 /* truncate fpart so it does't overflow.
171 * then scale fractional part.
172 */
173 while (fpart >= LLONG_MAX / scale_fact) {
174 fpart /= 10;
175 fract_digits--;
176 }
177 fpart *= scale_fact;
178 if (fract_digits > 0) {
179 for (i = 0; i < fract_digits -1; i++)
180 fpart /= 10;
181 }
182 whole += fpart;
183 *result = whole;
184 return 0;
185 }
186 }
187 errno = ERANGE;
188 return -1;
189 }
190
191 /* Format the given "number" into human-readable form in "result".
192 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
193 * Return 0 on success, -1 and errno set if error.
194 */
195 int
fmt_scaled(long long number,char * result)196 fmt_scaled(long long number, char *result)
197 {
198 long long abval, fract = 0;
199 unsigned int i;
200 unit_type unit = NONE;
201
202 abval = (number < 0LL) ? -number : number; /* no long long_abs yet */
203
204 /* Not every negative long long has a positive representation.
205 * Also check for numbers that are just too darned big to format
206 */
207 if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
208 errno = ERANGE;
209 return -1;
210 }
211
212 /* scale whole part; get unscaled fraction */
213 for (i = 0; i < SCALE_LENGTH; i++) {
214 if (abval/1024 < scale_factors[i]) {
215 unit = units[i];
216 fract = (i == 0) ? 0 : abval % scale_factors[i];
217 number /= scale_factors[i];
218 if (i > 0)
219 fract /= scale_factors[i - 1];
220 break;
221 }
222 }
223
224 fract = (10 * fract + 512) / 1024;
225 /* if the result would be >= 10, round main number */
226 if (fract == 10) {
227 if (number >= 0)
228 number++;
229 else
230 number--;
231 fract = 0;
232 }
233
234 if (number == 0)
235 strlcpy(result, "0B", FMT_SCALED_STRSIZE);
236 else if (unit == NONE || number >= 100 || number <= -100) {
237 if (fract >= 5) {
238 if (number >= 0)
239 number++;
240 else
241 number--;
242 }
243 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
244 number, scale_chars[unit]);
245 } else
246 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
247 number, fract, scale_chars[unit]);
248
249 return 0;
250 }
251
252 #ifdef MAIN
253 /*
254 * This is the original version of the program in the man page.
255 * Copy-and-paste whatever you need from it.
256 */
257 int
main(int argc,char ** argv)258 main(int argc, char **argv)
259 {
260 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
261 long long ninput = 10483892, result;
262
263 if (scan_scaled(cinput, &result) == 0)
264 printf("\"%s\" -> %lld\n", cinput, result);
265 else
266 perror(cinput);
267
268 if (fmt_scaled(ninput, buf) == 0)
269 printf("%lld -> \"%s\"\n", ninput, buf);
270 else
271 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
272
273 return 0;
274 }
275 #endif
276
277 #endif /* HAVE_FMT_SCALED */
278