1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2003, Trent Nelson, <trent@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
31 #include <sys/types.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include "convtbl.h"
35
36 #define BIT (8)
37 #define BITS (1)
38 #define KILOBIT (1000LL)
39 #define MEGABIT (KILOBIT * 1000)
40 #define GIGABIT (MEGABIT * 1000)
41 #define TERABIT (GIGABIT * 1000)
42
43 #define BYTE (1)
44 #define BYTES (1)
45 #define KILOBYTE (1024LL)
46 #define MEGABYTE (KILOBYTE * 1024)
47 #define GIGABYTE (MEGABYTE * 1024)
48 #define TERABYTE (GIGABYTE * 1024)
49
50 struct convtbl {
51 uintmax_t mul;
52 uintmax_t scale;
53 const char *str;
54 const char *name;
55 };
56
57 static struct convtbl convtbl[] = {
58 /* mul, scale, str, name */
59 [SC_BYTE] = { BYTE, BYTES, "B", "byte" },
60 [SC_KILOBYTE] = { BYTE, KILOBYTE, "KB", "kbyte" },
61 [SC_MEGABYTE] = { BYTE, MEGABYTE, "MB", "mbyte" },
62 [SC_GIGABYTE] = { BYTE, GIGABYTE, "GB", "gbyte" },
63 [SC_TERABYTE] = { BYTE, TERABYTE, "TB", "tbyte" },
64
65 [SC_BIT] = { BIT, BITS, "b", "bit" },
66 [SC_KILOBIT] = { BIT, KILOBIT, "Kb", "kbit" },
67 [SC_MEGABIT] = { BIT, MEGABIT, "Mb", "mbit" },
68 [SC_GIGABIT] = { BIT, GIGABIT, "Gb", "gbit" },
69 [SC_TERABIT] = { BIT, TERABIT, "Tb", "tbit" },
70
71 [SC_AUTO] = { 0, 0, "", "auto" }
72 };
73
74 static
75 struct convtbl *
get_tbl_ptr(const uintmax_t size,const int scale)76 get_tbl_ptr(const uintmax_t size, const int scale)
77 {
78 uintmax_t tmp;
79 int idx;
80
81 /* If our index is out of range, default to auto-scaling. */
82 idx = scale < SC_AUTO ? scale : SC_AUTO;
83
84 if (idx == SC_AUTO)
85 /*
86 * Simple but elegant algorithm. Count how many times
87 * we can shift our size value right by a factor of ten,
88 * incrementing an index each time. We then use the
89 * index as the array index into the conversion table.
90 */
91 for (tmp = size, idx = SC_KILOBYTE;
92 tmp >= MEGABYTE && idx < SC_BIT - 1;
93 tmp >>= 10, idx++);
94
95 return (&convtbl[idx]);
96 }
97
98 double
convert(const uintmax_t size,const int scale)99 convert(const uintmax_t size, const int scale)
100 {
101 struct convtbl *tp;
102
103 tp = get_tbl_ptr(size, scale);
104 return ((double)size * tp->mul / tp->scale);
105
106 }
107
108 const char *
get_string(const uintmax_t size,const int scale)109 get_string(const uintmax_t size, const int scale)
110 {
111 struct convtbl *tp;
112
113 tp = get_tbl_ptr(size, scale);
114 return (tp->str);
115 }
116
117 int
get_scale(const char * name)118 get_scale(const char *name)
119 {
120 int i;
121
122 for (i = 0; i <= SC_AUTO; i++)
123 if (strcmp(convtbl[i].name, name) == 0)
124 return (i);
125 return (-1);
126 }
127
128 const char *
get_helplist(void)129 get_helplist(void)
130 {
131 int i;
132 size_t len;
133 static char *buf;
134
135 if (buf == NULL) {
136 len = 0;
137 for (i = 0; i <= SC_AUTO; i++)
138 len += strlen(convtbl[i].name) + 2;
139 if ((buf = malloc(len)) != NULL) {
140 buf[0] = '\0';
141 for (i = 0; i <= SC_AUTO; i++) {
142 strcat(buf, convtbl[i].name);
143 if (i < SC_AUTO)
144 strcat(buf, ", ");
145 }
146 } else
147 return ("");
148 }
149 return (buf);
150 }
151