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- // 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
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