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