2019-08-10 11:59:47 +02:00
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/*
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* Copyright 2019 Max Kellermann <max.kellermann@gmail.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TRANSFORM_N_HXX
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#define TRANSFORM_N_HXX
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2020-03-13 00:46:28 +01:00
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#include <cstddef>
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2019-08-10 11:59:47 +02:00
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/**
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* The std::transform_n() function that is missing in the C++ standard
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* library.
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*/
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template<class InputIt, class OutputIt, class UnaryOperation>
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OutputIt
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transform_n(InputIt input, size_t n, OutputIt output,
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UnaryOperation unary_op)
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{
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while (n-- > 0)
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*output++ = unary_op(*input++);
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return output;
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}
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/**
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* Optimized overload for the above transform_n() implementation for
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* the special case that both input and output are regular pointers.
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* Turns out that most compilers generate better code this way.
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*/
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template<class InputType, class OutputType, class UnaryOperation>
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OutputType *
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transform_n(const InputType *input, size_t n, OutputType *output,
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UnaryOperation unary_op)
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{
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for (size_t i = 0; i < n; ++i)
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output[i] = unary_op(input[i]);
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return output + n;
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}
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#endif
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