kopia lustrzana https://gitlab.com/sane-project/backends
89 wiersze
3.0 KiB
C++
89 wiersze
3.0 KiB
C++
/* sane - Scanner Access Now Easy.
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Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>
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This file is part of the SANE package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA.
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As a special exception, the authors of SANE give permission for
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additional uses of the libraries contained in this release of SANE.
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The exception is that, if you link a SANE library with other files
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to produce an executable, this does not by itself cause the
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resulting executable to be covered by the GNU General Public
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License. Your use of that executable is in no way restricted on
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account of linking the SANE library code into it.
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This exception does not, however, invalidate any other reasons why
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the executable file might be covered by the GNU General Public
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License.
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If you submit changes to SANE to the maintainers to be included in
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a subsequent release, you agree by submitting the changes that
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those changes may be distributed with this exception intact.
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If you write modifications of your own for SANE, it is your choice
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whether to permit this exception to apply to your modifications.
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If you do not wish that, delete this exception notice.
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*/
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#ifndef BACKEND_GENESYS_UTILITIES_H
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#define BACKEND_GENESYS_UTILITIES_H
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#include "error.h"
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#include <algorithm>
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#include <vector>
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namespace genesys {
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template<class T>
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void compute_array_percentile_approx(T* result, const T* data,
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std::size_t line_count, std::size_t elements_per_line,
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float percentile)
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{
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if (line_count == 0) {
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throw SaneException("invalid line count");
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}
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if (line_count == 1) {
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std::copy(data, data + elements_per_line, result);
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return;
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}
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std::vector<T> column_elems;
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column_elems.resize(line_count, 0);
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std::size_t select_elem = std::min(static_cast<std::size_t>(line_count * percentile),
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line_count - 1);
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auto select_it = column_elems.begin() + select_elem;
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for (std::size_t ix = 0; ix < elements_per_line; ++ix) {
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for (std::size_t iy = 0; iy < line_count; ++iy) {
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column_elems[iy] = data[iy * elements_per_line + ix];
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}
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std::nth_element(column_elems.begin(), select_it, column_elems.end());
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*result++ = *select_it;
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}
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}
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} // namespace genesys
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#endif // BACKEND_GENESYS_UTILITIES_H
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