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      1 /*	$NetBSD: convtbl.c,v 1.2 2016/08/02 17:53:46 scole Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2003, Trent Nelson, <trent (at) arpa.com>.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. The name of the author may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  *
     30  * $FreeBSD: releng/10.1/usr.bin/systat/convtbl.c 175387 2008-01-16 19:27:43Z delphij $
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 #ifndef lint
     35 __RCSID("$NetBSD: convtbl.c,v 1.2 2016/08/02 17:53:46 scole Exp $");
     36 #endif /* not lint */
     37 
     38 #include <sys/types.h>
     39 
     40 #include <stdlib.h>
     41 #include <string.h>
     42 
     43 #include "convtbl.h"
     44 
     45 #define BIT		(8)
     46 #define BITS		(1)
     47 #define KILOBIT		(1000LL)
     48 #define MEGABIT		(KILOBIT * 1000)
     49 #define GIGABIT		(MEGABIT * 1000)
     50 #define TERABIT		(GIGABIT * 1000)
     51 
     52 #define BYTE		(1)
     53 #define BYTES		(1)
     54 #define KILOBYTE	(1024LL)
     55 #define MEGABYTE	(KILOBYTE * 1024)
     56 #define GIGABYTE	(MEGABYTE * 1024)
     57 #define TERABYTE	(GIGABYTE * 1024)
     58 
     59 struct convtbl {
     60 	uintmax_t	 mul;
     61 	uintmax_t	 scale;
     62 	const char	*str;
     63 	const char	*name;
     64 };
     65 
     66 static struct convtbl convtbl[] = {
     67 	/* mul, scale, str, name */
     68 	[SC_BYTE] =	{ BYTE, BYTES, "B", "byte" },
     69 	[SC_KILOBYTE] =	{ BYTE, KILOBYTE, "KB", "kbyte" },
     70 	[SC_MEGABYTE] =	{ BYTE, MEGABYTE, "MB", "mbyte" },
     71 	[SC_GIGABYTE] =	{ BYTE, GIGABYTE, "GB", "gbyte" },
     72 	[SC_TERABYTE] =	{ BYTE, TERABYTE, "TB", "tbyte" },
     73 
     74 	[SC_BIT] =	{ BIT, BITS, "b", "bit" },
     75 	[SC_KILOBIT] =	{ BIT, KILOBIT, "Kb", "kbit" },
     76 	[SC_MEGABIT] =	{ BIT, MEGABIT, "Mb", "mbit" },
     77 	[SC_GIGABIT] =	{ BIT, GIGABIT, "Gb", "gbit" },
     78 	[SC_TERABIT] =	{ BIT, TERABIT, "Tb", "tbit" },
     79 
     80 	[SC_AUTO] =	{ 0, 0, "", "auto" }
     81 };
     82 
     83 static
     84 struct convtbl *
     85 get_tbl_ptr(const uintmax_t size, const int scale)
     86 {
     87 	uintmax_t	 tmp;
     88 	int		 idx;
     89 
     90 	/* If our index is out of range, default to auto-scaling. */
     91 	idx = scale < SC_AUTO ? scale : SC_AUTO;
     92 
     93 	if (idx == SC_AUTO)
     94 		/*
     95 		 * Simple but elegant algorithm.  Count how many times
     96 		 * we can shift our size value right by a factor of ten,
     97 		 * incrementing an index each time.  We then use the
     98 		 * index as the array index into the conversion table.
     99 		 */
    100 		for (tmp = size, idx = SC_KILOBYTE;
    101 		     tmp >= MEGABYTE && idx < SC_BIT - 1;
    102 		     tmp >>= 10, idx++);
    103 
    104 	return (&convtbl[idx]);
    105 }
    106 
    107 double
    108 convert(const uintmax_t size, const int scale)
    109 {
    110 	struct convtbl	*tp;
    111 
    112 	tp = get_tbl_ptr(size, scale);
    113 	return ((double)size * tp->mul / tp->scale);
    114 
    115 }
    116 
    117 const char *
    118 get_string(const uintmax_t size, const int scale)
    119 {
    120 	struct convtbl	*tp;
    121 
    122 	tp = get_tbl_ptr(size, scale);
    123 	return (tp->str);
    124 }
    125 
    126 int
    127 get_scale(const char *name)
    128 {
    129 	int i;
    130 
    131 	for (i = 0; i <= SC_AUTO; i++)
    132 		if (strcmp(convtbl[i].name, name) == 0)
    133 			return (i);
    134 	return (-1);
    135 }
    136 
    137 const char *
    138 get_helplist(void)
    139 {
    140 	int i;
    141 	size_t len;
    142 	static char *buf;
    143 
    144 	if (buf == NULL) {
    145 		len = 0;
    146 		for (i = 0; i <= SC_AUTO; i++)
    147 			len += strlen(convtbl[i].name) + 2;
    148 		if ((buf = malloc(len)) != NULL) {
    149 			buf[0] = '\0';
    150 			for (i = 0; i <= SC_AUTO; i++) {
    151 				strcat(buf, convtbl[i].name);
    152 				if (i < SC_AUTO)
    153 					strcat(buf, ", ");
    154 			}
    155 		} else
    156 			return ("");
    157 	}
    158 	return (buf);
    159 }
    160