lib/libc/gen/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  *
  20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #include <sys/cdefs.h>
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 __RCSID("$NetBSD: humanize_number.c,v 1.13 2007/12/14 17:26:19 christos Exp $");
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include "namespace.h"
  39 #include <assert.h>
  40 #include <inttypes.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <locale.h>
  45
  46 int
  47 humanize_number(char *buf, size_t len, int64_t bytes,
  48     const char *suffix, int scale, int flags)
  49 {
  50         const char *prefixes, *sep;
  51         int     b, i, r, maxscale, s1, s2, sign;
  52         int64_t divisor, max;
  53         size_t  baselen;
  54
  55         _DIAGASSERT(buf != NULL);
  56         _DIAGASSERT(suffix != NULL);
  57         _DIAGASSERT(scale >= 0);
  58
  59         if (flags & HN_DIVISOR_1000) {
  60                 /* SI for decimal multiplies */
  61                 divisor = 1000;
  62                 if (flags & HN_B)
  63                         prefixes = "B\0k\0M\0G\0T\0P\0E";
  64                 else
  65                         prefixes = "\0\0k\0M\0G\0T\0P\0E";
  66         } else {
  67                 /*
  68                  * binary multiplies
  69                  * XXX IEC 60027-2 recommends Ki, Mi, Gi...
  70                  */
  71                 divisor = 1024;
  72                 if (flags & HN_B)
  73                         prefixes = "B\0K\0M\0G\0T\0P\0E";
  74                 else
  75                         prefixes = "\0\0K\0M\0G\0T\0P\0E";
  76         }
  77
  78 #define SCALE2PREFIX(scale)     (&prefixes[(scale) << 1])
  79         maxscale = 7;
  80
  81         if (scale >= maxscale &&
  82             (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
  83                 return (-1);
  84
  85         if (buf == NULL || suffix == NULL)
  86                 return (-1);
  87
  88         if (len > 0)
  89                 buf[0] = '\0';
  90         if (bytes < 0) {
  91                 sign = -1;
  92                 bytes *= -100;
  93                 baselen = 3;            /* sign, digit, prefix */
  94         } else {
  95                 sign = 1;
  96                 bytes *= 100;
  97                 baselen = 2;            /* digit, prefix */
  98         }
  99         if (flags & HN_NOSPACE)
 100                 sep = "";
 101         else {
 102                 sep = " ";
 103                 baselen++;
 104         }
 105         baselen += strlen(suffix);
 106
 107         /* Check if enough room for `x y' + suffix + `\0' */
 108         if (len < baselen + 1)
 109                 return (-1);
 110
 111         if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
 112                 /* See if there is additional columns can be used. */
 113                 for (max = 100, i = len - baselen; i-- > 0;)
 114                         max *= 10;
 115
 116                 /*
 117                  * Divide the number until it fits the given column.
 118                  * If there will be an overflow by the rounding below,
 119                  * divide once more.
 120                  */
 121                 for (i = 0; bytes >= max - 50 && i < maxscale; i++)
 122                         bytes /= divisor;
 123
 124                 if (scale & HN_GETSCALE)
 125                         return (i);
 126         } else
 127                 for (i = 0; i < scale && i < maxscale; i++)
 128                         bytes /= divisor;
 129
 130         /* If a value <= 9.9 after rounding and ... */
 131         if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
 132                 /* baselen + \0 + .N */
 133                 if (len < baselen + 1 + 2)
 134                         return (-1);
 135                 b = ((int)bytes + 5) / 10;
 136                 s1 = b / 10;
 137                 s2 = b % 10;
 138                 r = snprintf(buf, len, "%d%s%d%s%s%s",
 139                     sign * s1, localeconv()->decimal_point, s2,
 140                     sep, SCALE2PREFIX(i), suffix);
 141         } else
 142                 r = snprintf(buf, len, "%" PRId64 "%s%s%s",
 143                     sign * ((bytes + 50) / 100),
 144                     sep, SCALE2PREFIX(i), suffix);
 145
 146         return (r);
 147 }