1 /* Copyright (C) 2011 The Android Open Source Project 2 ** 3 ** This software is licensed under the terms of the GNU General Public 4 ** License version 2, as published by the Free Software Foundation, and 5 ** may be copied, distributed, and modified under those terms. 6 ** 7 ** This program is distributed in the hope that it will be useful, 8 ** but WITHOUT ANY WARRANTY; without even the implied warranty of 9 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 ** GNU General Public License for more details. 11 */ 12 #ifndef ANDROID_UTILS_DUFF_H 13 #define ANDROID_UTILS_DUFF_H 14 15 /********************************************************************* 16 ********************************************************************* 17 ***** 18 ***** DUFF'S DEVICES 19 ***** 20 *****/ 21 22 #define DUFF1(_count,_stmnt) \ 23 do { \ 24 int __n = (_count); \ 25 do { \ 26 _stmnt; \ 27 } while (--__n > 0); \ 28 } while (0); 29 30 #define DUFF2(_count,_stmnt) \ 31 ({ \ 32 int __count = (_count); \ 33 int __n = (__count +1)/2; \ 34 switch (__count & 1) { \ 35 case 0: do { _stmnt; \ 36 case 1: _stmnt; \ 37 } while (--__n > 0); \ 38 } \ 39 }) 40 41 #define DUFF4(_count,_stmnt) \ 42 ({ \ 43 int __count = (_count); \ 44 int __n = (__count +3)/4; \ 45 switch (__count & 3) { \ 46 case 0: do { _stmnt; \ 47 case 3: _stmnt; \ 48 case 2: _stmnt; \ 49 case 1: _stmnt; \ 50 } while (--__n > 0); \ 51 } \ 52 }) 53 54 #define DUFF8(_count,_stmnt) \ 55 ({ \ 56 int __count = (_count); \ 57 int __n = (__count+7)/8; \ 58 switch (__count & 7) { \ 59 case 0: do { _stmnt; \ 60 case 7: _stmnt; \ 61 case 6: _stmnt; \ 62 case 5: _stmnt; \ 63 case 4: _stmnt; \ 64 case 3: _stmnt; \ 65 case 2: _stmnt; \ 66 case 1: _stmnt; \ 67 } while (--__n > 0); \ 68 } \ 69 }) 70 71 #endif /* ANDROID_UTILS_DUFF_H */ 72
