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