usr.bin/systat/convtbl.c

   1 /*
   2  * Copyright (c) 2003, Trent Nelson, <trent@arpa.com>.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/usr.bin/systat/convtbl.c,v 1.1 2003/01/04 22:07:24 phk Exp $
  29  * $DragonFly: src/usr.bin/systat/convtbl.c,v 1.2 2008/11/10 04:59:45 swildner Exp $
  30  */
  31
  32 #include <sys/types.h>
  33 #include <unistd.h>
  34 #include "convtbl.h"
  35
  36 struct  convtbl convtbl[] = {
  37         /* mul, scale, str */
  38         { BYTE, BYTES, "bytes" },       /* SC_BYTE      (0) */
  39         { BYTE, KILO, "KB" },           /* SC_KILOBYTE  (1) */
  40         { BYTE, MEGA, "MB" },           /* SC_MEGABYTE  (2) */
  41         { BYTE, GIGA, "GB" },           /* SC_GIGABYTE  (3) */
  42
  43         { BIT, BITS, "b" },             /* SC_BITS      (4) */
  44         { BIT, KILO, "Kb" },            /* SC_KILOBITS  (5) */
  45         { BIT, MEGA, "Mb" },            /* SC_MEGABITS  (6) */
  46         { BIT, GIGA, "Gb" },            /* SC_GIGABITS  (7) */
  47
  48         { 0, 0, "" }                    /* SC_AUTO      (8) */
  49
  50 };
  51
  52
  53 static __inline__
  54 struct convtbl *
  55 get_tbl_ptr(const u_long size, const u_int scale)
  56 {
  57         struct  convtbl *tbl_ptr = NULL;
  58         u_long  tmp = 0;
  59         u_int   index = scale;
  60
  61         /* If our index is out of range, default to auto-scaling. */
  62         if (index > SC_AUTO)
  63                 index = SC_AUTO;
  64
  65         if (index == SC_AUTO)
  66                 /*
  67                  * Simple but elegant algorithm.  Count how many times
  68                  * we can shift our size value right by a factor of ten,
  69                  * incrementing an index each time.  We then use the
  70                  * index as the array index into the conversion table.
  71                  */
  72                 for (tmp = size, index = SC_KILOBYTE;
  73                      tmp >= MEGA && index <= SC_GIGABYTE;
  74                      tmp >>= 10, index++);
  75
  76         tbl_ptr = &convtbl[index];
  77         return tbl_ptr;
  78 }
  79
  80 double
  81 convert(const u_long size, const u_int scale)
  82 {
  83         struct  convtbl *tp = NULL;
  84
  85         tp = get_tbl_ptr(size, scale);
  86
  87         return ((double)size * tp->mul / tp->scale);
  88
  89 }
  90
  91 const char *
  92 get_string(const u_long size, const u_int scale)
  93 {
  94         struct  convtbl *tp = NULL;
  95
  96         tp = get_tbl_ptr(size, scale);
  97
  98         return tp->str;
  99 }