humanize_number.c

   1 /*      $NetBSD: humanize_number.c,v 1.8 2004/07/27 01:56:24 enami 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
  42 #include <sys/types.h>
  43 #include <assert.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <locale.h>
  48 #include <libutil.h>
  49 #include <stdint.h>
  50 #include <limits.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         // We multiply bytes by 100 to deal with rounding, so we need something
  60         // big enough to hold LLONG_MAX * 100. On 64-bit we can use 128-bit wide
  61         // integers with __int128_t, but on 32-bit we have to use long double.
  62 #ifdef __LP64__
  63         __int128_t scalable = (__int128_t)bytes;
  64 #else
  65         long double scalable = (long double)bytes;
  66 #endif
  67         size_t  baselen;
  68
  69         assert(buf != NULL);
  70         assert(suffix != NULL);
  71         assert(scale >= 0);
  72
  73         if (flags & HN_DIVISOR_1000) {
  74                 /* SI for decimal multiplies */
  75                 divisor = 1000;
  76                 if (flags & HN_B)
  77                         prefixes = "B\0k\0M\0G\0T\0P\0E";
  78                 else
  79                         prefixes = "\0\0k\0M\0G\0T\0P\0E";
  80         } else {
  81                 /*
  82                  * binary multiplies
  83                  * XXX IEC 60027-2 recommends Ki, Mi, Gi...
  84                  */
  85                 divisor = 1024;
  86                 if (flags & HN_B)
  87                         prefixes = "B\0K\0M\0G\0T\0P\0E";
  88                 else
  89                         prefixes = "\0\0K\0M\0G\0T\0P\0E";
  90         }
  91
  92 #define SCALE2PREFIX(scale)     (&prefixes[(scale) << 1])
  93         maxscale = 7;
  94
  95         if (scale >= maxscale &&
  96             (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
  97                 return (-1);
  98
  99         if (buf == NULL || suffix == NULL)
 100                 return (-1);
 101
 102         if (len > 0)
 103                 buf[0] = '\0';
 104         if (bytes < 0) {
 105                 sign = -1;
 106                 scalable *= -100;
 107                 baselen = 3;            /* sign, digit, prefix */
 108         } else {
 109                 sign = 1;
 110                 scalable *= 100;
 111                 baselen = 2;            /* digit, prefix */
 112         }
 113         if (flags & HN_NOSPACE)
 114                 sep = "";
 115         else {
 116                 sep = " ";
 117                 baselen++;
 118         }
 119         baselen += strlen(suffix);
 120
 121         /* Check if enough room for `x y' + suffix + `\0' */
 122         if (len < baselen + 1)
 123                 return (-1);
 124
 125         if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
 126                 /* See if there is additional columns can be used. */
 127                 for (max = 100, i = len - baselen; i-- > 0;)
 128                         max *= 10;
 129
 130                 for (i = 0; scalable >= max && i < maxscale; i++)
 131                         scalable /= divisor;
 132
 133                 if (scale & HN_GETSCALE)
 134                         return (i);
 135         } else
 136                 for (i = 0; i < scale && i < maxscale; i++)
 137                         scalable /= divisor;
 138
 139         /* If a value <= 9.9 after rounding and ... */
 140         if (scalable < 995 && i > 0 && flags & HN_DECIMAL) {
 141                 /* baselen + \0 + .N */
 142                 if (len < baselen + 1 + 2)
 143                         return (-1);
 144                 b = ((int)scalable + 5) / 10;
 145                 s1 = b / 10;
 146                 s2 = b % 10;
 147                 r = snprintf(buf, len, "%s%d%s%d%s%s%s",
 148                         ((sign == -1) ? "-" : ""),
 149                     s1, localeconv()->decimal_point, s2,
 150                     sep, SCALE2PREFIX(i), suffix);
 151         } else
 152                 r = snprintf(buf, len, "%s%lld%s%s%s",
 153                     /* LONGLONG */
 154                         ((sign == -1) ? "-" : ""),
 155                     (long long)((scalable + 50) / 100),
 156                     sep, SCALE2PREFIX(i), suffix);
 157
 158         return (r);
 159 }