1// 2// bitfield.h - extract and set bit fields 3// 4// Written by Eryk Vershen 5// 6// Bitfields are not particularly transportable between big and little 7// endian machines. Big endian machines lay out bitfields starting 8// from the most significant bit of the (one, two or four byte) number, 9// whereas little endian machines lay out bitfields starting from the 10// least signifcant bit. 11// 12// These routines were written to support some bitfields in a disk 13// data structure (partition map) whose original definition was on 14// a big-endian machine. 15// 16// They only work on 32-bit values because I didn't need 16-bit support. 17// The bits in the long word are numbered from 0 (least significant) to 18// 31 (most significant). 19// 20 21/* 22 * Copyright 1996,1998 by Apple Computer, Inc. 23 * All Rights Reserved 24 * 25 * Permission to use, copy, modify, and distribute this software and 26 * its documentation for any purpose and without fee is hereby granted, 27 * provided that the above copyright notice appears in all copies and 28 * that both the copyright notice and this permission notice appear in 29 * supporting documentation. 30 * 31 * APPLE COMPUTER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 32 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 33 * FOR A PARTICULAR PURPOSE. 34 * 35 * IN NO EVENT SHALL APPLE COMPUTER BE LIABLE FOR ANY SPECIAL, INDIRECT, OR 36 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 37 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, 38 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 39 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 40 */ 41 42#ifndef __bitfield__ 43#define __bitfield__ 44 45 46// 47// Defines 48// 49 50 51// 52// Types 53// 54 55 56// 57// Global Constants 58// 59 60 61// 62// Global Variables 63// 64 65 66// 67// Forward declarations 68// 69unsigned int bitfield_set(unsigned int *bf, int base, int length, unsigned int value); 70unsigned int bitfield_get(unsigned int bf, int base, int length); 71 72#endif /* __bitfield__ */ 73