Xisco Fauli
cfd3309a5d
Check existing ones that can be removed Change-Id: I6ee6fc1772c620ac5d12fea915681b094b7c3bfd Reviewed-on: https://gerrit.libreoffice.org/c/core/+/204583 Tested-by: Jenkins Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>
57 lines
2.3 KiB
C++
57 lines
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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#include <sal/config.h>
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#include <cmath>
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#include <limits>
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#include <type_traits>
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#include <o3tl/concepts.hxx>
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namespace o3tl
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{
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// Return true iff `value` of floating-point type `F` converts to a value of integral type `I` no
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// smaller than `min`:
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template <floating_point F, integral I> constexpr bool convertsToAtLeast(F value, I min)
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{
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// If `F(min)`, `F(min) - F(1)` are too large in magnitude for `F`'s precision, then they either
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// fall into the same bucket, in which case we should return false if `value` represents that
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// bucket, or they are on the boundary of two adjacent buckets, in which case we should return
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// true if `value`represents the higher bucket containing `F(min)`:
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return value > F(min) - F(1);
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}
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// Return true iff `value` of floating-point type `F` converts to a value of integral type `I` no
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// larger than `max`:
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template <floating_point F, integral I> constexpr bool convertsToAtMost(F value, I max)
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{
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// If `F(max)`, `F(max) + F(1)` are too large in magnitude for `F`'s precision, then they either
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// fall into the same bucket, in which case we should return false if `value` represents that
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// bucket, or they are on the boundary of two adjacent buckets, in which case we should return
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// true if `value`represents the lower bucket containing `F(max)`:
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return value < F(max) + F(1);
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}
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// Casts a floating-point to an integer, avoiding overflow. Used like:
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// sal_Int64 n = o3tl::saturating_cast<sal_Int64>(f);
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template <integral I, floating_point F> constexpr I saturating_cast(F f)
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{
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if constexpr (std::is_signed_v<I>)
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if (!convertsToAtLeast(f, std::numeric_limits<I>::min()))
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return std::numeric_limits<I>::min();
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if (!convertsToAtMost(f, std::numeric_limits<I>::max()))
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return std::numeric_limits<I>::max();
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return f;
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}
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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