// // bitfield.h - extract and set bit fields // // Written by Eryk Vershen // // Bitfields are not particularly transportable between big and little // endian machines. Big endian machines lay out bitfields starting // from the most significant bit of the (one, two or four byte) number, // whereas little endian machines lay out bitfields starting from the // least signifcant bit. // // These routines were written to support some bitfields in a disk // data structure (partition map) whose original definition was on // a big-endian machine. // // They only work on 32-bit values because I didn't need 16-bit support. // The bits in the long word are numbered from 0 (least significant) to // 31 (most significant). // /* * Copyright 1996,1998 by Apple Computer, Inc. * All Rights Reserved * * Permission to use, copy, modify, and distribute this software and * its documentation for any purpose and without fee is hereby granted, * provided that the above copyright notice appears in all copies and * that both the copyright notice and this permission notice appear in * supporting documentation. * * APPLE COMPUTER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE. * * IN NO EVENT SHALL APPLE COMPUTER BE LIABLE FOR ANY SPECIAL, INDIRECT, OR * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifndef __bitfield__ #define __bitfield__ // // Defines // // // Types // // // Global Constants // // // Global Variables // // // Forward declarations // uint32_t bitfield_set(uint32_t *bf, int base, int length, uint32_t value); uint32_t bitfield_get(uint32_t bf, int base, int length); #endif /* __bitfield__ */ |