2db8bcc353
The former is deprecated with C++14. The standard says both are the same: The contents and meaning of the header<cstddef>are the same as the C standard library header<stddef.h>,except that it does not declare the type wchar_t, that it also declares the type byte and its associated operations (21.2.5), and as noted in 21.2.3 and 21.2.4. Signed-off-by: Rosen Penev <rosenp@gmail.com>
65 lines
2.2 KiB
C++
65 lines
2.2 KiB
C++
/*
|
|
* Copyright 2019 Max Kellermann <max.kellermann@gmail.com>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* - Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* - Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
|
* OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef TRANSFORM_N_HXX
|
|
#define TRANSFORM_N_HXX
|
|
|
|
#include <cstddef>
|
|
|
|
/**
|
|
* The std::transform_n() function that is missing in the C++ standard
|
|
* library.
|
|
*/
|
|
template<class InputIt, class OutputIt, class UnaryOperation>
|
|
OutputIt
|
|
transform_n(InputIt input, size_t n, OutputIt output,
|
|
UnaryOperation unary_op)
|
|
{
|
|
while (n-- > 0)
|
|
*output++ = unary_op(*input++);
|
|
return output;
|
|
}
|
|
|
|
/**
|
|
* Optimized overload for the above transform_n() implementation for
|
|
* the special case that both input and output are regular pointers.
|
|
* Turns out that most compilers generate better code this way.
|
|
*/
|
|
template<class InputType, class OutputType, class UnaryOperation>
|
|
OutputType *
|
|
transform_n(const InputType *input, size_t n, OutputType *output,
|
|
UnaryOperation unary_op)
|
|
{
|
|
for (size_t i = 0; i < n; ++i)
|
|
output[i] = unary_op(input[i]);
|
|
return output + n;
|
|
}
|
|
|
|
#endif
|