macros.h (2408B)
1 /* 2 * This file is part of FFmpeg. 3 * 4 * FFmpeg is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation; either 7 * version 2.1 of the License, or (at your option) any later version. 8 * 9 * FFmpeg is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Lesser General Public License for more details. 13 * 14 * You should have received a copy of the GNU Lesser General Public 15 * License along with FFmpeg; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 19 /** 20 * @file 21 * @ingroup lavu 22 * Utility Preprocessor macros 23 */ 24 25 #ifndef AVUTIL_MACROS_H 26 #define AVUTIL_MACROS_H 27 28 #include "libavutil/avconfig.h" 29 30 #if AV_HAVE_BIGENDIAN 31 # define AV_NE(be, le) (be) 32 #else 33 # define AV_NE(be, le) (le) 34 #endif 35 36 /** 37 * Comparator. 38 * For two numerical expressions x and y, gives 1 if x > y, -1 if x < y, and 0 39 * if x == y. This is useful for instance in a qsort comparator callback. 40 * Furthermore, compilers are able to optimize this to branchless code, and 41 * there is no risk of overflow with signed types. 42 * As with many macros, this evaluates its argument multiple times, it thus 43 * must not have a side-effect. 44 */ 45 #define FFDIFFSIGN(x, y) (((x) > (y)) - ((x) < (y))) 46 47 #define FFMAX(a, b) ((a) > (b) ? (a) : (b)) 48 #define FFMAX3(a, b, c) FFMAX(FFMAX(a, b), c) 49 #define FFMIN(a, b) ((a) > (b) ? (b) : (a)) 50 #define FFMIN3(a, b, c) FFMIN(FFMIN(a, b), c) 51 52 #define FFSWAP(type, a, b) \ 53 do { \ 54 type SWAP_tmp = b; \ 55 b = a; \ 56 a = SWAP_tmp; \ 57 } while (0) 58 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0])) 59 60 #define MKTAG(a, b, c, d) \ 61 ((a) | ((b) << 8) | ((c) << 16) | ((unsigned)(d) << 24)) 62 #define MKBETAG(a, b, c, d) \ 63 ((d) | ((c) << 8) | ((b) << 16) | ((unsigned)(a) << 24)) 64 65 /** 66 * @addtogroup preproc_misc Preprocessor String Macros 67 * 68 * String manipulation macros 69 * 70 * @{ 71 */ 72 73 #define AV_STRINGIFY(s) AV_TOSTRING(s) 74 #define AV_TOSTRING(s) #s 75 76 #define AV_GLUE(a, b) a##b 77 #define AV_JOIN(a, b) AV_GLUE(a, b) 78 79 /** 80 * @} 81 */ 82 83 #define AV_PRAGMA(s) _Pragma(#s) 84 85 #define FFALIGN(x, a) (((x) + (a)-1) & ~((a)-1)) 86 87 #endif /* AVUTIL_MACROS_H */