| // Copyright Cromwell D. Enage 2013. |
| // Distributed under the Boost Software License, Version 1.0. |
| // (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_PARAMETER_AUX_PREPROCESSOR_INC_BINARY_SEQ_HPP |
| #define BOOST_PARAMETER_AUX_PREPROCESSOR_INC_BINARY_SEQ_HPP |
| |
| #include <boost/preprocessor/seq/push_back.hpp> |
| |
| // This macro keeps the rest of the sequence if carry == 0. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_0(seq, element) \ |
| (BOOST_PP_SEQ_PUSH_BACK(seq, element), 0) |
| /**/ |
| |
| #include <boost/preprocessor/control/iif.hpp> |
| |
| // This macro updates the rest of the sequence if carry == 1. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_1(seq, element) \ |
| (BOOST_PP_SEQ_PUSH_BACK(seq, BOOST_PP_IIF(element, 0, 1)), element) |
| /**/ |
| |
| #include <boost/preprocessor/tuple/elem.hpp> |
| #include <boost/preprocessor/cat.hpp> |
| |
| // This macro maintains a tuple (seq, carry), where seq is the intermediate |
| // result and carry is a flag that will unset upon finding an element == 0. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_OP(s, result_tuple, element) \ |
| BOOST_PP_CAT( \ |
| BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_ \ |
| , BOOST_PP_TUPLE_ELEM(2, 1, result_tuple) \ |
| )(BOOST_PP_TUPLE_ELEM(2, 0, result_tuple), element) |
| /**/ |
| |
| // This macro keeps the sequence at its original length if carry == 0. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_IMPL_0(seq) seq |
| /**/ |
| |
| // This macro appends a zero to seq if carry == 1. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_IMPL_1(seq) \ |
| BOOST_PP_SEQ_PUSH_BACK(seq, 0) |
| /**/ |
| |
| // This macro takes in the tuple (seq, carry), with carry indicating whether |
| // or not seq originally contained all 1s. If so, then seq now contains all |
| // 0s, and this macro pushes an extra 0 before expanding to the new sequence. |
| // Otherwise, this macro expands to seq as is. |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_IMPL(seq_and_carry) \ |
| BOOST_PP_CAT( \ |
| BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_IMPL_ \ |
| , BOOST_PP_TUPLE_ELEM(2, 1, seq_and_carry) \ |
| )(BOOST_PP_TUPLE_ELEM(2, 0, seq_and_carry)) |
| /**/ |
| |
| #include <boost/preprocessor/seq/seq.hpp> |
| #include <boost/preprocessor/seq/fold_left.hpp> |
| |
| // This macro treats the specified sequence of 1s and 0s like a binary number |
| // in reverse and expands to a sequence representing the next value up. |
| // However, if the input sequence contains all 1s, then the output sequence |
| // will contain one more element but all 0s. |
| // |
| // Examples: |
| // seq = (1)(0)(1)(0) --> return (0)(1)(1)(0) |
| // seq = (1)(1)(1)(0) --> return (0)(0)(0)(1) |
| // seq = (1)(1)(1)(1) --> return (0)(0)(0)(0)(0) |
| #define BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ(seq) \ |
| BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_IMPL( \ |
| BOOST_PP_SEQ_FOLD_LEFT( \ |
| BOOST_PARAMETER_AUX_PP_INC_BINARY_SEQ_OP \ |
| , (BOOST_PP_SEQ_NIL, 1) \ |
| , seq \ |
| ) \ |
| ) |
| /**/ |
| |
| #endif // include guard |
| |