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 * 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 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 * 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 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 * 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