convtbl.c revision 164672
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: head/usr.bin/systat/convtbl.c 164672 2006-11-27 16:14:32Z yar $ 29 */ 30 31#include <sys/types.h> 32#include <stdlib.h> 33#include <string.h> 34#include "convtbl.h" 35 36struct convtbl convtbl[] = { 37 /* mul, scale, str, name */ 38 [SC_BYTE] = { BYTE, BYTES, "B", "byte" }, 39 [SC_KILOBYTE] = { BYTE, KILO, "KB", "kbyte" }, 40 [SC_MEGABYTE] = { BYTE, MEGA, "MB", "mbyte" }, 41 [SC_GIGABYTE] = { BYTE, GIGA, "GB", "gbyte" }, 42 43 [SC_BIT] = { BIT, BITS, "b", "bit" }, 44 [SC_KILOBIT] = { BIT, KILO, "Kb", "kbit" }, 45 [SC_MEGABIT] = { BIT, MEGA, "Mb", "mbit" }, 46 [SC_GIGABIT] = { BIT, GIGA, "Gb", "gbit" }, 47 48 [SC_AUTO] = { 0, 0, "", "auto" } 49}; 50 51static 52struct convtbl * 53get_tbl_ptr(const uintmax_t size, const int scale) 54{ 55 uintmax_t tmp; 56 int idx; 57 58 /* If our index is out of range, default to auto-scaling. */ 59 idx = scale < SC_AUTO ? scale : SC_AUTO; 60 61 if (idx == SC_AUTO) 62 /* 63 * Simple but elegant algorithm. Count how many times 64 * we can shift our size value right by a factor of ten, 65 * incrementing an index each time. We then use the 66 * index as the array index into the conversion table. 67 */ 68 for (tmp = size, idx = SC_KILOBYTE; 69 tmp >= MEGA && idx < SC_GIGABYTE; 70 tmp >>= 10, idx++); 71 72 return (&convtbl[idx]); 73} 74 75double 76convert(const uintmax_t size, const int scale) 77{ 78 struct convtbl *tp; 79 80 tp = get_tbl_ptr(size, scale); 81 return ((double)size * tp->mul / tp->scale); 82 83} 84 85const char * 86get_string(const uintmax_t size, const int scale) 87{ 88 struct convtbl *tp; 89 90 tp = get_tbl_ptr(size, scale); 91 return (tp->str); 92} 93 94int 95get_scale(const char *name) 96{ 97 int i; 98 99 for (i = 0; i <= SC_AUTO; i++) 100 if (strcmp(convtbl[i].name, name) == 0) 101 return (i); 102 return (-1); 103} 104 105const char * 106get_helplist() 107{ 108 int i; 109 size_t len; 110 static char *buf; 111 112 if (buf == NULL) { 113 len = 0; 114 for (i = 0; i <= SC_AUTO; i++) 115 len += strlen(convtbl[i].name) + 2; 116 if ((buf = malloc(len)) != NULL) { 117 buf[0] = '\0'; 118 for (i = 0; i <= SC_AUTO; i++) { 119 strcat(buf, convtbl[i].name); 120 if (i < SC_AUTO) 121 strcat(buf, ", "); 122 } 123 } else 124 return (""); 125 } 126 return (buf); 127} 128