lib/libutil/humanize_number.c

   1 /*      $NetBSD: humanize_number.c,v 1.13 2007/12/14 17:26:19 christos Exp $    */
   2
   3 /*
   4  * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
   9  * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the NetBSD
  22  *      Foundation, Inc. and its contributors.
  23  * 4. Neither the name of The NetBSD Foundation nor the names of its
  24  *    contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  37  * POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD$");
  42
  43 #include <sys/types.h>
  44 #include <assert.h>
  45 #include <inttypes.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <locale.h>
  50 #include <libutil.h>
  51
  52 int
  53 humanize_number(char *buf, size_t len, int64_t bytes,
  54     const char *suffix, int scale, int flags)
  55 {
  56         const char *prefixes, *sep;
  57         int     b, i, r, maxscale, s1, s2, sign;
  58         int64_t divisor, max;
  59         size_t  baselen;
  60
  61         assert(buf != NULL);
  62         assert(suffix != NULL);
  63         assert(scale >= 0);
  64
  65         if (flags & HN_DIVISOR_1000) {
  66                 /* SI for decimal multiplies */
  67                 divisor = 1000;
  68                 if (flags & HN_B)
  69                         prefixes = "B\0k\0M\0G\0T\0P\0E";
  70                 else
  71                         prefixes = "\0\0k\0M\0G\0T\0P\0E";
  72         } else {
  73                 /*
  74                  * binary multiplies
  75                  * XXX IEC 60027-2 recommends Ki, Mi, Gi...
  76                  */
  77                 divisor = 1024;
  78                 if (flags & HN_B)
  79                         prefixes = "B\0K\0M\0G\0T\0P\0E";
  80                 else
  81                         prefixes = "\0\0K\0M\0G\0T\0P\0E";
  82         }
  83
  84 #define SCALE2PREFIX(scale)     (&prefixes[(scale) << 1])
  85         maxscale = 7;
  86
  87         if (scale >= maxscale &&
  88             (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
  89                 return (-1);
  90
  91         if (buf == NULL || suffix == NULL)
  92                 return (-1);
  93
  94         if (len > 0)
  95                 buf[0] = '\0';
  96         if (bytes < 0) {
  97                 sign = -1;
  98                 bytes *= -100;
  99                 baselen = 3;            /* sign, digit, prefix */
 100         } else {
 101                 sign = 1;
 102                 bytes *= 100;
 103                 baselen = 2;            /* digit, prefix */
 104         }
 105         if (flags & HN_NOSPACE)
 106                 sep = "";
 107         else {
 108                 sep = " ";
 109                 baselen++;
 110         }
 111         baselen += strlen(suffix);
 112
 113         /* Check if enough room for `x y' + suffix + `\0' */
 114         if (len < baselen + 1)
 115                 return (-1);
 116
 117         if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
 118                 /* See if there is additional columns can be used. */
 119                 for (max = 100, i = len - baselen; i-- > 0;)
 120                         max *= 10;
 121
 122                 /*
 123                  * Divide the number until it fits the given column.
 124                  * If there will be an overflow by the rounding below,
 125                  * divide once more.
 126                  */
 127                 for (i = 0; bytes >= max - 50 && i < maxscale; i++)
 128                         bytes /= divisor;
 129
 130                 if (scale & HN_GETSCALE)
 131                         return (i);
 132         } else
 133                 for (i = 0; i < scale && i < maxscale; i++)
 134                         bytes /= divisor;
 135
 136         /* If a value <= 9.9 after rounding and ... */
 137         if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
 138                 /* baselen + \0 + .N */
 139                 if (len < baselen + 1 + 2)
 140                         return (-1);
 141                 b = ((int)bytes + 5) / 10;
 142                 s1 = b / 10;
 143                 s2 = b % 10;
 144                 r = snprintf(buf, len, "%d%s%d%s%s%s",
 145                     sign * s1, localeconv()->decimal_point, s2,
 146                     sep, SCALE2PREFIX(i), suffix);
 147         } else
 148                 r = snprintf(buf, len, "%" PRId64 "%s%s%s",
 149                     sign * ((bytes + 50) / 100),
 150                     sep, SCALE2PREFIX(i), suffix);
 151
 152         return (r);
 153 }