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/*
* Copyright (c) 2003, Trent Nelson, <trent@arpa.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include "convtbl.h"
#define BIT (8)
#define BITS (1)
#define KILOBIT (1000LL)
#define MEGABIT (KILOBIT * 1000)
#define GIGABIT (MEGABIT * 1000)
#define TERABIT (GIGABIT * 1000)
#define BYTE (1)
#define BYTES (1)
#define KILOBYTE (1024LL)
#define MEGABYTE (KILOBYTE * 1024)
#define GIGABYTE (MEGABYTE * 1024)
#define TERABYTE (GIGABYTE * 1024)
struct convtbl {
uintmax_t mul;
uintmax_t scale;
const char *str;
const char *name;
};
static struct convtbl convtbl[] = {
/* mul, scale, str, name */
[SC_BYTE] = { BYTE, BYTES, "B", "byte" },
[SC_KILOBYTE] = { BYTE, KILOBYTE, "KB", "kbyte" },
[SC_MEGABYTE] = { BYTE, MEGABYTE, "MB", "mbyte" },
[SC_GIGABYTE] = { BYTE, GIGABYTE, "GB", "gbyte" },
[SC_TERABYTE] = { BYTE, TERABYTE, "TB", "tbyte" },
[SC_BIT] = { BIT, BITS, "b", "bit" },
[SC_KILOBIT] = { BIT, KILOBIT, "Kb", "kbit" },
[SC_MEGABIT] = { BIT, MEGABIT, "Mb", "mbit" },
[SC_GIGABIT] = { BIT, GIGABIT, "Gb", "gbit" },
[SC_TERABIT] = { BIT, TERABIT, "Tb", "tbit" },
[SC_AUTO] = { 0, 0, "", "auto" }
};
static
struct convtbl *
get_tbl_ptr(const uintmax_t size, const int scale)
{
uintmax_t tmp;
int idx;
/* If our index is out of range, default to auto-scaling. */
idx = scale < SC_AUTO ? scale : SC_AUTO;
if (idx == SC_AUTO)
/*
* Simple but elegant algorithm. Count how many times
* we can shift our size value right by a factor of ten,
* incrementing an index each time. We then use the
* index as the array index into the conversion table.
*/
for (tmp = size, idx = SC_KILOBYTE;
tmp >= MEGABYTE && idx < SC_BIT - 1;
tmp >>= 10, idx++);
return (&convtbl[idx]);
}
double
convert(const uintmax_t size, const int scale)
{
struct convtbl *tp;
tp = get_tbl_ptr(size, scale);
return ((double)size * tp->mul / tp->scale);
}
const char *
get_string(const uintmax_t size, const int scale)
{
struct convtbl *tp;
tp = get_tbl_ptr(size, scale);
return (tp->str);
}
int
get_scale(const char *name)
{
int i;
for (i = 0; i <= SC_AUTO; i++)
if (strcmp(convtbl[i].name, name) == 0)
return (i);
return (-1);
}
const char *
get_helplist(void)
{
int i;
size_t len;
static char *buf;
if (buf == NULL) {
len = 0;
for (i = 0; i <= SC_AUTO; i++)
len += strlen(convtbl[i].name) + 2;
if ((buf = malloc(len)) != NULL) {
buf[0] = '\0';
for (i = 0; i <= SC_AUTO; i++) {
strcat(buf, convtbl[i].name);
if (i < SC_AUTO)
strcat(buf, ", ");
}
} else
return ("");
}
return (buf);
}
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