lib/libutil/humanize_unsigned.c

   1 /*      $NetBSD: subr_humanize.c,v 1.1 2009/10/02 15:48:41 pooka Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Luke Mewburn.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <libutil.h>
  35
  36 /*
  37  * snprintf() `bytes' into `buf', reformatting it so that the number,
  38  * plus a possible `x' + suffix extension) fits into len bytes (including
  39  * the terminating NUL).
  40  * Returns the number of bytes stored in buf, or -1 if there was a problem.
  41  * E.g, given a len of 9 and a suffix of `B':
  42  *      bytes           result
  43  *      -----           ------
  44  *      99999           `99999 B'
  45  *      100000          `97 kB'
  46  *      66715648        `65152 kB'
  47  *      252215296       `240 MB'
  48  */
  49 int
  50 humanize_unsigned(char *buf, size_t len, uint64_t bytes, const char *suffix,
  51     int divisor)
  52 {
  53         /* prefixes are: (none), kilo, Mega, Giga, Tera, Peta, Exa */
  54         const char *prefixes;
  55         int             r;
  56         uint64_t        umax;
  57         size_t          i, suffixlen;
  58
  59         if (buf == NULL || suffix == NULL)
  60                 return (-1);
  61         if (len > 0)
  62                 buf[0] = '\0';
  63         suffixlen = strlen(suffix);
  64         /* check if enough room for `x y' + suffix + `\0' */
  65         if (len < 4 + suffixlen)
  66                 return (-1);
  67
  68         if (divisor == 1024) {
  69                 /*
  70                  * binary multiplies
  71                  * XXX IEC 60027-2 recommends Ki, Mi, Gi...
  72                  */
  73                 prefixes = " KMGTPE";
  74         } else
  75                 prefixes = " kMGTPE"; /* SI for decimal multiplies */
  76
  77         umax = 1;
  78         for (i = 0; i < len - suffixlen - 3; i++) {
  79                 umax *= 10;
  80                 if (umax > bytes)
  81                         break;
  82         }
  83         for (i = 0; bytes >= umax && prefixes[i + 1]; i++)
  84                 bytes /= divisor;
  85
  86         r = snprintf(buf, len, "%qu%s%c%s", (unsigned long long)bytes,
  87             i == 0 ? "" : " ", prefixes[i], suffix);
  88
  89         return (r);
  90 }
  91
  92 int
  93 format_bytes(char *buf, size_t len, uint64_t bytes)
  94 {
  95         int     rv;
  96         size_t  nlen;
  97
  98         rv = humanize_unsigned(buf, len, bytes, "B", 1024);
  99         if (rv != -1) {
 100                         /* nuke the trailing ` B' if it exists */
 101                 nlen = strlen(buf) - 2;
 102                 if (strcmp(&buf[nlen], " B") == 0)
 103                         buf[nlen] = '\0';
 104         }
 105         return (rv);
 106 }