1 /* 2 * support.h - Useful definitions and macros. Originated from the Linux-NTFS project. 3 * 4 * Copyright (c) 2000-2004 Anton Altaparmakov 5 * 6 * This program/include file is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as published 8 * by the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program/include file is distributed in the hope that it will be 12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty 13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program (in the main directory of the NTFS-3G 18 * distribution in the file COPYING); if not, write to the Free Software 19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #ifndef _NTFS_SUPPORT_H 23 #define _NTFS_SUPPORT_H 24 25 #ifdef HAVE_CONFIG_H 26 #include "config.h" 27 #endif 28 29 #ifdef HAVE_STDDEF_H 30 #include <stddef.h> 31 #endif 32 33 /* 34 * Our mailing list. Use this define to prevent typos in email address. 35 */ 36 #define NTFS_DEV_LIST "ntfs-3g-devel@lists.sf.net" 37 38 /* 39 * Generic macro to convert pointers to values for comparison purposes. 40 */ 41 #ifndef p2n 42 #define p2n(p) ((ptrdiff_t)((ptrdiff_t*)(p))) 43 #endif 44 45 /* 46 * The classic min and max macros. 47 */ 48 #ifndef min 49 #define min(a,b) ((a) <= (b) ? (a) : (b)) 50 #endif 51 52 #ifndef max 53 #define max(a,b) ((a) >= (b) ? (a) : (b)) 54 #endif 55 56 /* 57 * Useful macro for determining the offset of a struct member. 58 */ 59 #ifndef offsetof 60 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) 61 #endif 62 63 /* 64 * Simple bit operation macros. NOTE: These are NOT atomic. 65 */ 66 #define test_bit(bit, var) ((var) & (1 << (bit))) 67 #define set_bit(bit, var) (var) |= 1 << (bit) 68 #define clear_bit(bit, var) (var) &= ~(1 << (bit)) 69 70 #define test_and_set_bit(bit, var) \ 71 ({ \ 72 const BOOL old_state = test_bit(bit, var); \ 73 set_bit(bit, var); \ 74 old_state; \ 75 }) 76 77 #define test_and_clear_bit(bit, var) \ 78 ({ \ 79 const BOOL old_state = test_bit(bit, var); \ 80 clear_bit(bit, var); \ 81 old_state; \ 82 }) 83 84 #endif /* defined _NTFS_SUPPORT_H */ 85 86