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 <unistd.h> 33 #include "convtbl.h" 34 35 struct convtbl convtbl[] = { 36 /* mul, scale, str */ 37 { BYTE, BYTES, "bytes" }, /* SC_BYTE (0) */ 38 { BYTE, KILO, "KB" }, /* SC_KILOBYTE (1) */ 39 { BYTE, MEGA, "MB" }, /* SC_MEGABYTE (2) */ 40 { BYTE, GIGA, "GB" }, /* SC_GIGABYTE (3) */ 41 42 { BIT, BITS, "b" }, /* SC_BITS (4) */ 43 { BIT, KILO, "Kb" }, /* SC_KILOBITS (5) */ 44 { BIT, MEGA, "Mb" }, /* SC_MEGABITS (6) */ 45 { BIT, GIGA, "Gb" }, /* SC_GIGABITS (7) */ 46 47 { 0, 0, "" } /* SC_AUTO (8) */ 48 49 }; 50 51 52 static __inline 53 struct convtbl * 54 get_tbl_ptr(const u_long size, const u_int scale) 55 { 56 struct convtbl *tbl_ptr = NULL; 57 u_long tmp = 0; 58 u_int idx = scale; 59 60 /* If our index is out of range, default to auto-scaling. */ 61 if (idx > SC_AUTO) 62 idx = SC_AUTO; 63 64 if (idx == SC_AUTO) 65 /* 66 * Simple but elegant algorithm. Count how many times 67 * we can shift our size value right by a factor of ten, 68 * incrementing an index each time. We then use the 69 * index as the array index into the conversion table. 70 */ 71 for (tmp = size, idx = SC_KILOBYTE; 72 tmp >= MEGA && idx <= SC_GIGABYTE; 73 tmp >>= 10, idx++); 74 75 tbl_ptr = &convtbl[idx]; 76 return tbl_ptr; 77 } 78 79 double 80 convert(const u_long size, const u_int scale) 81 { 82 struct convtbl *tp = NULL; 83 84 tp = get_tbl_ptr(size, scale); 85 86 return ((double)size * tp->mul / tp->scale); 87 88 } 89 90 const char * 91 get_string(const u_long size, const u_int scale) 92 { 93 struct convtbl *tp = NULL; 94 95 tp = get_tbl_ptr(size, scale); 96 97 return tp->str; 98 } 99