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 // This file is part of the ACTS project.
 //
 // Copyright (C) 2016 CERN for the benefit of the ACTS project
 //
 // This Source Code Form is subject to the terms of the Mozilla Public
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
 #pragma once
 
 #include "Acts/Utilities/PointerTraits.hpp"
 
 #include <algorithm>
 #include <array>
 #include <cmath>
 #include <iostream>
 #include <limits>
 #include <memory>
 #include <ranges>
 #include <type_traits>
 #include <vector>
 
 #define ACTS_CHECK_BIT(value, mask) ((value & mask) == mask)
 
 namespace Acts {
 
 /// Helper function to unpack a vector of smart pointers (e.g. @c shared_ptr ) into a vector of raw
 /// const pointers
 /// @tparam T the stored type
 /// @param items The vector of smart pointers
 /// @return The unpacked vector
 
 template <SmartPointerConcept T>
 std::vector<std::add_pointer_t<std::add_const_t<typename T::element_type>>>
 unpackConstSmartPointers(const std::vector<T>& items) {
   std::vector<std::add_pointer_t<std::add_const_t<typename T::element_type>>>
       rawPtrs{};
   rawPtrs.reserve(items.size());
   for (const auto& ptr : items) {
     rawPtrs.push_back(ptr.operator->());
   }
   return rawPtrs;
 }
 
 /// Helper function to unpack a vector of @c shared_ptr into a vector of raw
 /// pointers
 /// @tparam T the stored type
 /// @param items The vector of @c shared_ptr
 /// @return The unpacked vector
 template <SmartPointerConcept T>
 std::vector<std::add_pointer_t<typename T::element_type>> unpackSmartPointers(
     const std::vector<T>& items) {
   std::vector<std::add_pointer_t<typename T::element_type>> rawPtrs{};
   rawPtrs.reserve(items.size());
   for (const auto& ptr : items) {
     rawPtrs.push_back(&*ptr);
   }
   return rawPtrs;
 }
 
 /// Helper function to unpack a vector of @c shared_ptr into a vector of raw
 /// pointers (const version)
 /// @tparam T the stored type
 /// @param items The vector of @c shared_ptr
 /// @return The unpacked vector
 template <typename T>
 std::vector<const T*> unpackSmartPointers(
     const std::vector<std::shared_ptr<const T>>& items) {
   std::vector<const T*> rawPtrs;
   rawPtrs.reserve(items.size());
   for (const std::shared_ptr<const T>& item : items) {
     rawPtrs.push_back(item.get());
   }
   return rawPtrs;
 }
 
 /// @brief Converts a vector to a fixed-size array with truncating or padding.
 ///
 /// This function copies elements from the input vector into a fixed-size array.
 /// If the vector contains more than `kDIM` elements, the array is truncated to
 /// fit. If the vector contains fewer elements than `kDIM`, the remaining array
 /// elements are value-initialized (default-initialized, i.e., filled with zero
 /// or default values).
 ///
 /// @tparam kDIM The size of the resulting array.
 /// @tparam value_t The type of elements in the vector and the array.
 /// @param vecvals The input vector to be converted to an array.
 ///
 /// @return An array containing the first `kDIM` elements of the vector.
 template <std::size_t kDIM, typename value_t>
 std::array<value_t, kDIM> toArray(const std::vector<value_t>& vecvals) {
   std::array<value_t, kDIM> arr = {};
   std::copy_n(vecvals.begin(), std::min(vecvals.size(), kDIM), arr.begin());
   return arr;
 }
 
 /// @brief Dispatch a call based on a runtime value on a function taking the
 /// value at compile time.
 ///
 /// This function allows to write a templated functor, which accepts a @c std::size_t
 /// like parameter at compile time. It is then possible to make a call to the
 /// corresponding instance of the functor based on a runtime value. To achieve
 /// this, the function essentially created a if cascade between @c N and @c
 /// NMAX, attempting to find the right instance. Because the cascade is visible
 /// to the compiler entirely, it should be able to optimize.
 ///
 /// @tparam Callable Type which takes a std::size_t as a compile time param
 /// @tparam N Value from which to start the dispatch chain, i.e. 0 in most cases
 /// @tparam NMAX Maximum value up to which to attempt a dispatch
 /// @param v The runtime value to dispatch on
 /// @param args Additional arguments passed to @c Callable::invoke().
 /// @return The result of calling the dispatched template instance
 /// @note @c Callable is expected to have a static member function @c invoke
 /// that is callable with @c Args
 template <template <std::size_t> class Callable, std::size_t N,
           std::size_t NMAX, typename... Args>
 auto template_switch(std::size_t v, Args&&... args) {
   if (v == N) {
     return Callable<N>::invoke(std::forward<Args>(args)...);
   }
   if (v == 0) {
     std::cerr << "template_switch<Fn, " << N << ", " << NMAX << ">(v=" << v
               << ") is not valid (v == 0 and N != 0)" << std::endl;
     std::abort();
   }
   if constexpr (N < NMAX) {
     return template_switch<Callable, N + 1, NMAX>(v,
                                                   std::forward<Args>(args)...);
   }
   std::cerr << "template_switch<Fn, " << N << ", " << NMAX << ">(v=" << v
             << ") is not valid (v > NMAX)" << std::endl;
   std::abort();
 }
 
 /// Alternative version of @c template_switch which accepts a generic
 /// lambda and communicates the dimension via an integral constant type
 /// @tparam N Value from which to start the dispatch chain, i.e. 0 in most cases
 /// @tparam NMAX Maximum value up to which to attempt a dispatch
 /// @param v The runtime value to dispatch on
 /// @param func The lambda to invoke
 /// @param args Additional arguments passed to @p func
 /// @return The result of calling the dispatched lambda function
 template <std::size_t N, std::size_t NMAX, typename Lambda, typename... Args>
 auto template_switch_lambda(std::size_t v, Lambda&& func, Args&&... args) {
   if (v == N) {
     return func(std::integral_constant<std::size_t, N>{},
                 std::forward<Args>(args)...);
   }
   if (v == 0) {
     std::cerr << "template_switch<Fn, " << N << ", " << NMAX << ">(v=" << v
               << ") is not valid (v == 0 and N != 0)" << std::endl;
     std::abort();
   }
   if constexpr (N < NMAX) {
     return template_switch_lambda<N + 1, NMAX>(v, func,
                                                std::forward<Args>(args)...);
   }
   std::cerr << "template_switch<Fn, " << N << ", " << NMAX << ">(v=" << v
             << ") is not valid (v > NMAX)" << std::endl;
   std::abort();
 }
 
 /// Clamp a numeric value to another type, respecting range of the target type
 /// @tparam T the target type
 /// @tparam U the source type
 /// @param value the value to clamp
 /// @return the clamped value
 template <typename T, typename U>
 T clampValue(U value) {
   if (std::numeric_limits<U>::has_infinity && std::isinf(value)) {
     if (!std::numeric_limits<T>::has_infinity) {
       throw std::logic_error(
           "Cannot convert infinite value to type without infinity support");
     }
     return (value > 0) ? std::numeric_limits<T>::infinity()
                        : -std::numeric_limits<T>::infinity();
   }
   if (std::numeric_limits<U>::has_quiet_NaN && std::isnan(value)) {
     if (!std::numeric_limits<T>::has_quiet_NaN) {
       throw std::logic_error(
           "Cannot convert NaN value to type without NaN support");
     }
     return std::numeric_limits<T>::quiet_NaN();
   }
   return static_cast<T>(
       std::clamp(value, static_cast<U>(std::numeric_limits<T>::lowest()),
                  static_cast<U>(std::numeric_limits<T>::max())));
 }
 
 /// Return range and medium of an unsorted numeric series
 ///
 /// @tparam T a numeric series
 ///
 /// @param tseries is the number series
 ///
 /// @return [ range, medium ] in an tuple
 template <typename T>
 std::tuple<typename T::value_type, double> range_medium(const T& tseries) {
   auto [minIt, maxIt] = std::ranges::minmax_element(tseries);
   typename T::value_type range = (*maxIt - *minIt);
   double medium = static_cast<double>((*maxIt + *minIt) * 0.5);
   return {range, medium};
 }
 
 /// Convert enum to its underlying type value
 /// @param value Enum value to convert
 /// @return Underlying type value
 template <typename enum_t>
 constexpr std::underlying_type_t<enum_t> toUnderlying(enum_t value) {
   return static_cast<std::underlying_type_t<enum_t>>(value);
 }
 
 /// This can be replaced with C++23 to use the std::ranges::contains method
 ///
 /// This function searches through the given range for a specified value
 /// and returns `true` if the value is found, or `false` otherwise.
 ///
 /// @tparam R The type of the range (e.g., vector, list, array).
 /// @tparam T The type of the value to search for within the range.
 ///
 /// @param range The range to search within. This can be any range-compatible container.
 /// @param value The value to search for in the range.
 ///
 /// @return `true` if the value is found within the range, `false` otherwise.
 template <typename R, typename T>
 bool rangeContainsValue(const R& range, const T& value) {
   return std::ranges::find(range, value) != std::ranges::end(range);
 }
 
 /// This function checks if at least one string from a given range is
 /// contained within a specified string (value).
 ///
 /// @tparam R The type of the range (e.g., vector<string>, list<string>, array<string>).
 /// @param range The range to search within.
 /// @param value The string in which we search for substrings from the range
 ///
 /// @return `true` if a such a string in range is found, `false` otherwise.
 template <typename R>
 bool rangeContainsSubstring(const R& range, std::string_view value) {
   return std::ranges::any_of(range, [&](std::string_view s) {
     return value.find(s) != std::string_view::npos;
   });
 }
 
 /// Helper struct that can turn a set of lambdas into a single entity with
 /// overloaded call operator. This can be useful for example in a std::visit
 /// call.
 /// ```cpp
 /// std::visit(overloaded{
 ///  [](const int& i) { std::cout << "int: " << i << std::endl; },
 ///  [](const std::string& s) { std::cout << "string: " << s << std::endl; },
 /// }, variant);
 /// ```
 template <class... Ts>
 struct overloaded : Ts... {
   using Ts::operator()...;
 };
 
 /// Deduction guide for overloaded visitor pattern
 template <class... Ts>
 overloaded(Ts...) -> overloaded<Ts...>;
 
 namespace detail {
 
 /// Computes the minimum, maximum, and bin count for a given vector of values.
 ///
 /// This function processes a vector of doubles to compute:
 /// - The minimum value (@c xMin)
 /// - The maximum value (@c xMax), adjusted to include an additional bin
 /// - The bin count (@c xBinCount) based on the number of unique values
 ///
 /// The computation is performed as follows:
 /// 1. Sorts the input vector using @c std::ranges::sort to prepare for uniqueness.
 /// 2. Determines the number of unique values using @c std::ranges::unique and
 ///    calculates the bin count from the size of the unique prefix (not the tail
 ///    subrange).
 /// 3. Calculates the minimum and maximum using @c std::ranges::minmax.
 /// 4. Adjusts the maximum to include an additional bin by adding the bin step
 /// size.
 ///
 /// @param xPos A reference to a vector of doubles.
 /// @return A tuple containing:
 ///         - The minimum value (double)
 ///         - The adjusted maximum value (double)
 ///         - The bin count (std::size_t)
 ///
 /// @note The vector xPos will be modified during the call.
 inline auto getMinMaxAndBinCount(std::vector<double>& xPos) {
   // sort the values for unique()
   std::ranges::sort(xPos);
 
   // get the number of bins over unique values
   // ranges::unique returns [ret, end): duplicate tail; unique elements are
   // [begin, ret)
   const auto uniqueTail = std::ranges::unique(xPos);
   const std::size_t xBinCount = static_cast<std::size_t>(
       std::ranges::distance(xPos.begin(), uniqueTail.begin()));
 
   // get the minimum and maximum
   auto [xMin, xMax] = std::ranges::minmax(xPos);
 
   // calculate maxima (add one last bin, because bin value always corresponds to
   // left boundary)
   const double stepX = (xMax - xMin) / static_cast<double>(xBinCount - 1);
   xMax += stepX;
 
   // Return all values as a tuple
   return std::make_tuple(xMin, xMax, xBinCount);
 }
 
 }  // namespace detail
 
 }  // namespace Acts

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