1 /* $OpenBSD: fmt_scaled.c,v 1.9 2007/03/20 03:42:52 tedu 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(*p) && isspace(*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(*p) && (isdigit(*p) || *p=='.'); ++p) { 112 if (*p == '.') { 113 if (fract_digits > 0) { /* oops, more than one '.' */ 114 errno = EINVAL; 115 return -1; 116 } 117 fract_digits = 1; 118 continue; 119 } 120 121 i = (*p) - '0'; /* whew! finally a digit we can use */ 122 if (fract_digits > 0) { 123 if (fract_digits >= MAX_DIGITS-1) 124 /* ignore extra fractional digits */ 125 continue; 126 fract_digits++; /* for later scaling */ 127 fpart *= 10; 128 fpart += i; 129 } else { /* normal digit */ 130 if (++ndigits >= MAX_DIGITS) { 131 errno = ERANGE; 132 return -1; 133 } 134 whole *= 10; 135 whole += i; 136 } 137 } 138 139 if (sign) { 140 whole *= sign; 141 fpart *= sign; 142 } 143 144 /* If no scale factor given, we're done. fraction is discarded. */ 145 if (!*p) { 146 *result = whole; 147 return 0; 148 } 149 150 /* Validate scale factor, and scale whole and fraction by it. */ 151 for (i = 0; i < SCALE_LENGTH; i++) { 152 153 /** Are we there yet? */ 154 if (*p == scale_chars[i] || 155 *p == tolower(scale_chars[i])) { 156 157 /* If it ends with alphanumerics after the scale char, bad. */ 158 if (isalnum(*(p+1))) { 159 errno = EINVAL; 160 return -1; 161 } 162 scale_fact = scale_factors[i]; 163 164 /* scale whole part */ 165 whole *= scale_fact; 166 167 /* truncate fpart so it does't overflow. 168 * then scale fractional part. 169 */ 170 while (fpart >= LLONG_MAX / scale_fact) { 171 fpart /= 10; 172 fract_digits--; 173 } 174 fpart *= scale_fact; 175 if (fract_digits > 0) { 176 for (i = 0; i < fract_digits -1; i++) 177 fpart /= 10; 178 } 179 whole += fpart; 180 *result = whole; 181 return 0; 182 } 183 } 184 errno = ERANGE; 185 return -1; 186 } 187 188 /* Format the given "number" into human-readable form in "result". 189 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE. 190 * Return 0 on success, -1 and errno set if error. 191 */ 192 int 193 fmt_scaled(long long number, char *result) 194 { 195 long long abval, fract = 0; 196 unsigned int i; 197 unit_type unit = NONE; 198 199 abval = (number < 0LL) ? -number : number; /* no long long_abs yet */ 200 201 /* Not every negative long long has a positive representation. 202 * Also check for numbers that are just too darned big to format 203 */ 204 if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) { 205 errno = ERANGE; 206 return -1; 207 } 208 209 /* scale whole part; get unscaled fraction */ 210 for (i = 0; i < SCALE_LENGTH; i++) { 211 if (abval/1024 < scale_factors[i]) { 212 unit = units[i]; 213 fract = (i == 0) ? 0 : abval % scale_factors[i]; 214 number /= scale_factors[i]; 215 if (i > 0) 216 fract /= scale_factors[i - 1]; 217 break; 218 } 219 } 220 221 fract = (10 * fract + 512) / 1024; 222 /* if the result would be >= 10, round main number */ 223 if (fract == 10) { 224 if (number >= 0) 225 number++; 226 else 227 number--; 228 fract = 0; 229 } 230 231 if (number == 0) 232 strlcpy(result, "0B", FMT_SCALED_STRSIZE); 233 else if (unit == NONE || number >= 100 || number <= -100) { 234 if (fract >= 5) { 235 if (number >= 0) 236 number++; 237 else 238 number--; 239 } 240 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c", 241 number, scale_chars[unit]); 242 } else 243 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c", 244 number, fract, scale_chars[unit]); 245 246 return 0; 247 } 248 249 #ifdef MAIN 250 /* 251 * This is the original version of the program in the man page. 252 * Copy-and-paste whatever you need from it. 253 */ 254 int 255 main(int argc, char **argv) 256 { 257 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE]; 258 long long ninput = 10483892, result; 259 260 if (scan_scaled(cinput, &result) == 0) 261 printf("\"%s\" -> %lld\n", cinput, result); 262 else 263 perror(cinput); 264 265 if (fmt_scaled(ninput, buf) == 0) 266 printf("%lld -> \"%s\"\n", ninput, buf); 267 else 268 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno)); 269 270 return 0; 271 } 272 #endif 273 274 #endif /* HAVE_FMT_SCALED */ 275