diff options
Diffstat (limited to 'extern/ceres/include/ceres/internal/integer_sequence_algorithm.h')
| -rw-r--r-- | extern/ceres/include/ceres/internal/integer_sequence_algorithm.h | 123 |
1 files changed, 122 insertions, 1 deletions
diff --git a/extern/ceres/include/ceres/internal/integer_sequence_algorithm.h b/extern/ceres/include/ceres/internal/integer_sequence_algorithm.h index 8c0f3bc8ac4..777c119a77f 100644 --- a/extern/ceres/include/ceres/internal/integer_sequence_algorithm.h +++ b/extern/ceres/include/ceres/internal/integer_sequence_algorithm.h @@ -1,5 +1,5 @@ // Ceres Solver - A fast non-linear least squares minimizer -// Copyright 2018 Google Inc. All rights reserved. +// Copyright 2022 Google Inc. All rights reserved. // http://ceres-solver.org/ // // Redistribution and use in source and binary forms, with or without @@ -27,6 +27,7 @@ // POSSIBILITY OF SUCH DAMAGE. // // Author: jodebo_beck@gmx.de (Johannes Beck) +// sergiu.deitsch@gmail.com (Sergiu Deitsch) // // Algorithms to be used together with integer_sequence, like computing the sum // or the exclusive scan (sometimes called exclusive prefix sum) at compile @@ -37,6 +38,8 @@ #include <utility> +#include "ceres/jet_fwd.h" + namespace ceres { namespace internal { @@ -164,6 +167,124 @@ class ExclusiveScanT { template <typename Seq> using ExclusiveScan = typename ExclusiveScanT<Seq>::Type; +// Removes all elements from a integer sequence corresponding to specified +// ValueToRemove. +// +// This type should not be used directly but instead RemoveValue. +template <typename T, T ValueToRemove, typename... Sequence> +struct RemoveValueImpl; + +// Final filtered sequence +template <typename T, T ValueToRemove, T... Values> +struct RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T, Values...>, + std::integer_sequence<T>> { + using type = std::integer_sequence<T, Values...>; +}; + +// Found a matching value +template <typename T, T ValueToRemove, T... Head, T... Tail> +struct RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T, Head...>, + std::integer_sequence<T, ValueToRemove, Tail...>> + : RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T, Head...>, + std::integer_sequence<T, Tail...>> {}; + +// Move one element from the tail to the head +template <typename T, T ValueToRemove, T... Head, T MiddleValue, T... Tail> +struct RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T, Head...>, + std::integer_sequence<T, MiddleValue, Tail...>> + : RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T, Head..., MiddleValue>, + std::integer_sequence<T, Tail...>> {}; + +// Start recursion by splitting the integer sequence into two separate ones +template <typename T, T ValueToRemove, T... Tail> +struct RemoveValueImpl<T, ValueToRemove, std::integer_sequence<T, Tail...>> + : RemoveValueImpl<T, + ValueToRemove, + std::integer_sequence<T>, + std::integer_sequence<T, Tail...>> {}; + +// RemoveValue takes an integer Sequence of arbitrary type and removes all +// elements matching ValueToRemove. +// +// In contrast to RemoveValueImpl, this implementation deduces the value type +// eliminating the need to specify it explicitly. +// +// As an example, RemoveValue<std::integer_sequence<int, 1, 2, 3>, 4>::type will +// not transform the type of the original sequence. However, +// RemoveValue<std::integer_sequence<int, 0, 0, 2>, 2>::type will generate a new +// sequence of type std::integer_sequence<int, 0, 0> by removing the value 2. +template <typename Sequence, typename Sequence::value_type ValueToRemove> +struct RemoveValue + : RemoveValueImpl<typename Sequence::value_type, ValueToRemove, Sequence> { +}; + +// Convenience template alias for RemoveValue. +template <typename Sequence, typename Sequence::value_type ValueToRemove> +using RemoveValue_t = typename RemoveValue<Sequence, ValueToRemove>::type; + +// Determines whether the values of an integer sequence are all the same. +// +// The integer sequence must contain at least one value. The predicate is +// undefined for empty sequences. The evaluation result of the predicate for a +// sequence containing only one value is defined to be true. +template <typename... Sequence> +struct AreAllEqual; + +// The predicate result for a sequence containing one element is defined to be +// true. +template <typename T, T Value> +struct AreAllEqual<std::integer_sequence<T, Value>> : std::true_type {}; + +// Recursion end. +template <typename T, T Value1, T Value2> +struct AreAllEqual<std::integer_sequence<T, Value1, Value2>> + : std::integral_constant<bool, Value1 == Value2> {}; + +// Recursion for sequences containing at least two elements. +template <typename T, T Value1, T Value2, T... Values> +// clang-format off +struct AreAllEqual<std::integer_sequence<T, Value1, Value2, Values...> > + : std::integral_constant +< + bool, + AreAllEqual<std::integer_sequence<T, Value1, Value2> >::value && + AreAllEqual<std::integer_sequence<T, Value2, Values...> >::value +> +// clang-format on +{}; + +// Convenience variable template for AreAllEqual. +template <class Sequence> +constexpr bool AreAllEqual_v = AreAllEqual<Sequence>::value; + +// Predicate determining whether an integer sequence is either empty or all +// values are equal. +template <typename Sequence> +struct IsEmptyOrAreAllEqual; + +// Empty case. +template <typename T> +struct IsEmptyOrAreAllEqual<std::integer_sequence<T>> : std::true_type {}; + +// General case for sequences containing at least one value. +template <typename T, T HeadValue, T... Values> +struct IsEmptyOrAreAllEqual<std::integer_sequence<T, HeadValue, Values...>> + : AreAllEqual<std::integer_sequence<T, HeadValue, Values...>> {}; + +// Convenience variable template for IsEmptyOrAreAllEqual. +template <class Sequence> +constexpr bool IsEmptyOrAreAllEqual_v = IsEmptyOrAreAllEqual<Sequence>::value; + } // namespace internal } // namespace ceres |