1 /* 2 * Copyright (c) 2020, The OpenThread Authors. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Neither the name of the copyright holder nor the 13 * names of its contributors may be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /** 30 * @file 31 * This file includes macros for parsing variadic arguments. 32 */ 33 34 #ifndef OT_INCLUDE_COMMON_ARG_MACROS_HPP_ 35 #define OT_INCLUDE_COMMON_ARG_MACROS_HPP_ 36 37 /** 38 * Returns the first argument in a list of input arguments. 39 * 40 * @param[in] ... A list of arguments (MUST contain at least one). 41 * 42 * @returns The first argument in the given list of input arguments. 43 */ 44 #define OT_FIRST_ARG(...) _OT_GET_FIRST_ARG(__VA_ARGS__, JUNK) 45 46 /** 47 * Returns the second argument in a list of input arguments if any. 48 * 49 * @note: This macro works when the list contains either one or two arguments. 50 * 51 * @param[in] ... A list of arguments (MUST contain either one or two arguments). 52 * 53 * @returns The second argument if any. 54 */ 55 #define OT_SECOND_ARG(...) _OT_GET_SECOND_ARG(_OT_HAS_ONE_ARG_OR_TWO_ARGS(__VA_ARGS__), __VA_ARGS__) 56 57 /** 58 * Expands to comma separated list of arguments excluding the first one. 59 * 60 * If there is only one argument, it expands to empty. If there is more than one argument, it expands to an initial 61 * comma followed by all the rest of arguments excluding the first one. 62 * 63 * @note: This macro supports up to 20 arguments. 64 * 65 * @param[in] ... A list of arguments (MUST contain at least one). 66 * 67 * @returns A comma separated list of arguments excluding the first one. 68 */ 69 #define OT_REST_ARGS(...) _OT_GET_REST_ARGS(_OT_HAS_ONE_ARG_VS_TWO_OR_MORE(__VA_ARGS__), __VA_ARGS__) 70 71 //--------------------------------------------------------------------------------------------------------------------- 72 // Private/local macros - for use in this header only. 73 74 #define _OT_GET_FIRST_ARG(aFirst, ...) aFirst 75 76 #define _OT_HAS_ONE_ARG_OR_TWO_ARGS(...) _OT_SELECT_3(__VA_ARGS__, TWO_ARGS, ONE_ARG, JUNK) 77 #define _OT_SELECT_3(a1, a2, a3, ...) a3 78 79 #define _OT_GET_SECOND_ARG(aNum, ...) _OT_GET_SECOND_APPEND_NUM_ARGS(aNum, __VA_ARGS__) 80 #define _OT_GET_SECOND_APPEND_NUM_ARGS(aNum, ...) _OT_GET_SECOND_WITH_##aNum(__VA_ARGS__) 81 82 #define _OT_GET_SECOND_WITH_ONE_ARG(aFirst) 83 #define _OT_GET_SECOND_WITH_TWO_ARGS(aFirst, aSecond) aSecond 84 85 #define _OT_GET_REST_ARGS(aNum, ...) _OT_GET_REST_APPEND_NUM_ARGS(aNum, __VA_ARGS__) 86 #define _OT_GET_REST_APPEND_NUM_ARGS(aNum, ...) _OT_GET_REST_WITH_##aNum(__VA_ARGS__) 87 88 #define _OT_GET_REST_WITH_ONE_ARG(aFirst) 89 #define _OT_GET_REST_WITH_TWO_OR_MORE_ARGS(aFirst, ...) , __VA_ARGS__ 90 91 #define _OT_HAS_ONE_ARG_VS_TWO_OR_MORE(...) \ 92 _OT_SELECT_20(__VA_ARGS__, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, \ 93 TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, \ 94 TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, \ 95 TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, TWO_OR_MORE_ARGS, ONE_ARG, JUNK) 96 97 #define _OT_SELECT_20(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20, ...) \ 98 a20 99 100 #endif // OT_INCLUDE_COMMON_ARG_MACROS_HPP_ 101
