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 /* 30 * fmt_scaled: Format numbers scaled for human comprehension 31 * scan_scaled: Scan numbers in this format. 32 * 33 * "Human-readable" output uses 4 digits max, and puts a unit suffix at 34 * the end. Makes output compact and easy-to-read esp. on huge disks. 35 * Formatting code was originally in OpenBSD "df", converted to library routine. 36 * Scanning code written for OpenBSD libutil. 37 */ 38 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <errno.h> 42 #include <string.h> 43 #include <ctype.h> 44 #include <limits.h> 45 46 #include "util.h" 47 48 typedef enum { 49 NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6 50 } unit_type; 51 52 /* These three arrays MUST be in sync! XXX make a struct */ 53 static unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA }; 54 static char scale_chars[] = "BKMGTPE"; 55 static long long scale_factors[] = { 56 1LL, 57 1024LL, 58 1024LL*1024, 59 1024LL*1024*1024, 60 1024LL*1024*1024*1024, 61 1024LL*1024*1024*1024*1024, 62 1024LL*1024*1024*1024*1024*1024, 63 }; 64 #define SCALE_LENGTH (sizeof(units)/sizeof(units[0])) 65 66 #define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */ 67 68 /** Convert the given input string "scaled" into numeric in "result". 69 * Return 0 on success, -1 and errno set on error. 70 */ 71 int 72 scan_scaled(char *scaled, long long *result) 73 { 74 char *p = scaled; 75 int sign = 0; 76 unsigned int i, ndigits = 0, fract_digits = 0; 77 long long scale_fact = 1, whole = 0, fpart = 0; 78 79 /* Skip leading whitespace */ 80 while (isascii(*p) && isspace(*p)) 81 ++p; 82 83 /* Then at most one leading + or - */ 84 while (*p == '-' || *p == '+') { 85 if (*p == '-') { 86 if (sign) { 87 errno = EINVAL; 88 return -1; 89 } 90 sign = -1; 91 ++p; 92 } else if (*p == '+') { 93 if (sign) { 94 errno = EINVAL; 95 return -1; 96 } 97 sign = +1; 98 ++p; 99 } 100 } 101 102 /* Main loop: Scan digits, find decimal point, if present. 103 * We don't allow exponentials, so no scientific notation 104 * (but note that E for Exa might look like e to some!). 105 * Advance 'p' to end, to get scale factor. 106 */ 107 for (; isascii(*p) && (isdigit(*p) || *p=='.'); ++p) { 108 if (*p == '.') { 109 if (fract_digits > 0) { /* oops, more than one '.' */ 110 errno = EINVAL; 111 return -1; 112 } 113 fract_digits = 1; 114 continue; 115 } 116 117 i = (*p) - '0'; /* whew! finally a digit we can use */ 118 if (fract_digits > 0) { 119 if (fract_digits >= MAX_DIGITS-1) 120 /* ignore extra fractional digits */ 121 continue; 122 fract_digits++; /* for later scaling */ 123 fpart *= 10; 124 fpart += i; 125 } else { /* normal digit */ 126 if (++ndigits >= MAX_DIGITS) { 127 errno = ERANGE; 128 return -1; 129 } 130 whole *= 10; 131 whole += i; 132 } 133 } 134 135 if (sign) { 136 whole *= sign; 137 fpart *= sign; 138 } 139 140 /* If no scale factor given, we're done. fraction is discarded. */ 141 if (!*p) { 142 *result = whole; 143 return 0; 144 } 145 146 /* Validate scale factor, and scale whole and fraction by it. */ 147 for (i = 0; i < SCALE_LENGTH; i++) { 148 149 /** Are we there yet? */ 150 if (*p == scale_chars[i] || 151 *p == tolower(scale_chars[i])) { 152 153 /* If it ends with alphanumerics after the scale char, bad. */ 154 if (isalnum(*(p+1))) { 155 errno = EINVAL; 156 return -1; 157 } 158 scale_fact = scale_factors[i]; 159 160 /* scale whole part */ 161 whole *= scale_fact; 162 163 /* truncate fpart so it does't overflow. 164 * then scale fractional part. 165 */ 166 while (fpart >= LLONG_MAX / scale_fact) { 167 fpart /= 10; 168 fract_digits--; 169 } 170 fpart *= scale_fact; 171 if (fract_digits > 0) { 172 for (i = 0; i < fract_digits -1; i++) 173 fpart /= 10; 174 } 175 whole += fpart; 176 *result = whole; 177 return 0; 178 } 179 } 180 errno = ERANGE; 181 return -1; 182 } 183 184 /* Format the given "number" into human-readable form in "result". 185 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE. 186 * Return 0 on success, -1 and errno set if error. 187 */ 188 int 189 fmt_scaled(long long number, char *result) 190 { 191 long long abval, fract = 0; 192 unsigned int i; 193 unit_type unit = NONE; 194 195 abval = (number < 0LL) ? -number : number; /* no long long_abs yet */ 196 197 /* Not every negative long long has a positive representation. 198 * Also check for numbers that are just too darned big to format 199 */ 200 if (abval < 0 || abval / 1024 >= scale_factors[SCALE_LENGTH-1]) { 201 errno = ERANGE; 202 return -1; 203 } 204 205 /* scale whole part; get unscaled fraction */ 206 for (i = 0; i < SCALE_LENGTH; i++) { 207 if (abval/1024 < scale_factors[i]) { 208 unit = units[i]; 209 fract = (i == 0) ? 0 : abval % scale_factors[i]; 210 number /= scale_factors[i]; 211 if (i > 0) 212 fract /= scale_factors[i - 1]; 213 break; 214 } 215 } 216 217 fract = (10 * fract + 512) / 1024; 218 /* if the result would be >= 10, round main number */ 219 if (fract == 10) { 220 if (number >= 0) 221 number++; 222 else 223 number--; 224 fract = 0; 225 } 226 227 if (number == 0) 228 strlcpy(result, "0B", FMT_SCALED_STRSIZE); 229 else if (unit == NONE || number >= 100 || number <= -100) { 230 if (fract >= 5) { 231 if (number >= 0) 232 number++; 233 else 234 number--; 235 } 236 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c", 237 number, scale_chars[unit]); 238 } else 239 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c", 240 number, fract, scale_chars[unit]); 241 242 return 0; 243 } 244 245 #ifdef MAIN 246 /* 247 * This is the original version of the program in the man page. 248 * Copy-and-paste whatever you need from it. 249 */ 250 int 251 main(int argc, char **argv) 252 { 253 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE]; 254 long long ninput = 10483892, result; 255 256 if (scan_scaled(cinput, &result) == 0) 257 printf("\"%s\" -> %lld\n", cinput, result); 258 else 259 perror(cinput); 260 261 if (fmt_scaled(ninput, buf) == 0) 262 printf("%lld -> \"%s\"\n", ninput, buf); 263 else 264 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno)); 265 266 return 0; 267 } 268 #endif 269