rotl.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_BIT_ROTL_HPP
#define TETL_BIT_ROTL_HPP
 
#include <etl/_concepts/builtin_unsigned_integer.hpp>
#include <etl/_limits/numeric_limits.hpp>
 
namespace etl {
 
/// \brief Computes the result of bitwise left-rotating the value of x by s
/// positions. This operation is also known as a left circular shift.
///
/// \ingroup bit
template <etl::builtin_unsigned_integer UInt>
constexpr auto rotl(UInt t, int s) noexcept -> UInt
{
    auto const c = static_cast<unsigned>(s);
    auto const d = static_cast<unsigned>(etl::numeric_limits<UInt>::digits);
    if ((c % d) == 0U) {
        return t;
    }
    return static_cast<UInt>((t << (c % d)) | (t >> (d - (c % d))));
}
 
} // namespace etl
 
#endif // TETL_BIT_ROTL_HPP