1 /* $NetBSD: fmt_scaled.c,v 1.2 2013/11/08 19:18:25 christos 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 44 #ifndef HAVE_FMT_SCALED 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 #include "fmt_scaled.h" 53 54 typedef enum { 55 NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6 56 } unit_type; 57 58 /* These three arrays MUST be in sync! XXX make a struct */ 59 static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA }; 60 static char scale_chars[] = "BKMGTPE"; 61 static long long scale_factors[] = { 62 1LL, 63 1024LL, 64 1024LL*1024, 65 1024LL*1024*1024, 66 1024LL*1024*1024*1024, 67 1024LL*1024*1024*1024*1024, 68 1024LL*1024*1024*1024*1024*1024, 69 }; 70 #define SCALE_LENGTH (sizeof(units)/sizeof(units[0])) 71 72 #define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */ 73 74 /** Convert the given input string "scaled" into numeric in "result". 75 * Return 0 on success, -1 and errno set on error. 76 */ 77 int 78 scan_scaled(const char *scaled, long long *result) 79 { 80 const char *p = scaled; 81 int sign = 0; 82 unsigned int i, ndigits = 0, fract_digits = 0; 83 long long scale_fact = 1, whole = 0, fpart = 0; 84 85 /* Skip leading whitespace */ 86 while (isascii((unsigned char)*p) && isspace((unsigned char)*p)) 87 ++p; 88 89 /* Then at most one leading + or - */ 90 while (*p == '-' || *p == '+') { 91 if (*p == '-') { 92 if (sign) { 93 errno = EINVAL; 94 return -1; 95 } 96 sign = -1; 97 ++p; 98 } else if (*p == '+') { 99 if (sign) { 100 errno = EINVAL; 101 return -1; 102 } 103 sign = +1; 104 ++p; 105 } 106 } 107 108 /* Main loop: Scan digits, find decimal point, if present. 109 * We don't allow exponentials, so no scientific notation 110 * (but note that E for Exa might look like e to some!). 111 * Advance 'p' to end, to get scale factor. 112 */ 113 for (; isascii((unsigned char)*p) && (isdigit((unsigned char)*p) || *p=='.'); ++p) { 114 if (*p == '.') { 115 if (fract_digits > 0) { /* oops, more than one '.' */ 116 errno = EINVAL; 117 return -1; 118 } 119 fract_digits = 1; 120 continue; 121 } 122 123 i = (*p) - '0'; /* whew! finally a digit we can use */ 124 if (fract_digits > 0) { 125 if (fract_digits >= MAX_DIGITS-1) 126 /* ignore extra fractional digits */ 127 continue; 128 fract_digits++; /* for later scaling */ 129 fpart *= 10; 130 fpart += i; 131 } else { /* normal digit */ 132 if (++ndigits >= MAX_DIGITS) { 133 errno = ERANGE; 134 return -1; 135 } 136 whole *= 10; 137 whole += i; 138 } 139 } 140 141 if (sign) { 142 whole *= sign; 143 fpart *= sign; 144 } 145 146 /* If no scale factor given, we're done. fraction is discarded. */ 147 if (!*p) { 148 *result = whole; 149 return 0; 150 } 151 152 /* Validate scale factor, and scale whole and fraction by it. */ 153 for (i = 0; i < SCALE_LENGTH; i++) { 154 155 /** Are we there yet? */ 156 if (*p == scale_chars[i] || 157 *p == tolower((unsigned char)scale_chars[i])) { 158 159 /* If it ends with alphanumerics after the scale char, bad. */ 160 if (isalnum((unsigned char)*(p+1))) { 161 errno = EINVAL; 162 return -1; 163 } 164 scale_fact = scale_factors[i]; 165 166 /* scale whole part */ 167 whole *= scale_fact; 168 169 /* truncate fpart so it does't overflow. 170 * then scale fractional part. 171 */ 172 while (fpart >= LLONG_MAX / scale_fact) { 173 fpart /= 10; 174 fract_digits--; 175 } 176 fpart *= scale_fact; 177 if (fract_digits > 0) { 178 for (i = 0; i < fract_digits -1; i++) 179 fpart /= 10; 180 } 181 whole += fpart; 182 *result = whole; 183 return 0; 184 } 185 } 186 errno = ERANGE; 187 return -1; 188 } 189 190 /* Format the given "number" into human-readable form in "result". 191 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE. 192 * Return 0 on success, -1 and errno set if error. 193 */ 194 int 195 fmt_scaled(long long number, char *result) 196 { 197 long long abval, fract = 0; 198 unsigned int i; 199 unit_type unit = NONE; 200 201 abval = (number < 0LL) ? -number : number; /* no long long_abs yet */ 202 203 /* Not every negative long long has a positive representation. 204 * Also check for numbers that are just too darned big to format 205 */ 206 if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) { 207 errno = ERANGE; 208 return -1; 209 } 210 211 /* scale whole part; get unscaled fraction */ 212 for (i = 0; i < SCALE_LENGTH; i++) { 213 if (abval/1024 < scale_factors[i]) { 214 unit = units[i]; 215 fract = (i == 0) ? 0 : abval % scale_factors[i]; 216 number /= scale_factors[i]; 217 if (i > 0) 218 fract /= scale_factors[i - 1]; 219 break; 220 } 221 } 222 223 fract = (10 * fract + 512) / 1024; 224 /* if the result would be >= 10, round main number */ 225 if (fract == 10) { 226 if (number >= 0) 227 number++; 228 else 229 number--; 230 fract = 0; 231 } 232 233 if (number == 0) 234 strlcpy(result, "0B", FMT_SCALED_STRSIZE); 235 else if (unit == NONE || number >= 100 || number <= -100) { 236 if (fract >= 5) { 237 if (number >= 0) 238 number++; 239 else 240 number--; 241 } 242 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c", 243 number, scale_chars[unit]); 244 } else 245 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c", 246 number, fract, scale_chars[unit]); 247 248 return 0; 249 } 250 251 #ifdef MAIN 252 /* 253 * This is the original version of the program in the man page. 254 * Copy-and-paste whatever you need from it. 255 */ 256 int 257 main(int argc, char **argv) 258 { 259 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE]; 260 long long ninput = 10483892, result; 261 262 if (scan_scaled(cinput, &result) == 0) 263 printf("\"%s\" -> %lld\n", cinput, result); 264 else 265 perror(cinput); 266 267 if (fmt_scaled(ninput, buf) == 0) 268 printf("%lld -> \"%s\"\n", ninput, buf); 269 else 270 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno)); 271 272 return 0; 273 } 274 #endif 275 276 #endif /* HAVE_FMT_SCALED */ 277