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Diffstat (limited to 'llvm/include/llvm/ADT/STLExtras.h')
-rw-r--r-- | llvm/include/llvm/ADT/STLExtras.h | 146 |
1 files changed, 0 insertions, 146 deletions
diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h index 6b18e3bee03..4435b46f462 100644 --- a/llvm/include/llvm/ADT/STLExtras.h +++ b/llvm/include/llvm/ADT/STLExtras.h @@ -31,7 +31,6 @@ #include "llvm/ADT/iterator.h" #include "llvm/ADT/iterator_range.h" #include "llvm/Support/Compiler.h" -#include "llvm/Support/ErrorHandling.h" namespace llvm { @@ -436,151 +435,6 @@ detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u, std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...); } -/// Iterator wrapper that concatenates sequences together. -/// -/// This can concatenate different iterators, even with different types, into -/// a single iterator provided the value types of all the concatenated -/// iterators expose `reference` and `pointer` types that can be converted to -/// `ValueT &` and `ValueT *` respectively. It doesn't support more -/// interesting/customized pointer or reference types. -/// -/// Currently this only supports forward or higher iterator categories as -/// inputs and always exposes a forward iterator interface. -template <typename ValueT, typename... IterTs> -class concat_iterator - : public iterator_facade_base<concat_iterator<ValueT, IterTs...>, - std::forward_iterator_tag, ValueT> { - typedef typename concat_iterator::iterator_facade_base BaseT; - - /// We store both the current and end iterators for each concatenated - /// sequence in a tuple of pairs. - /// - /// Note that something like iterator_range seems nice at first here, but the - /// range properties are of little benefit and end up getting in the way - /// because we need to do mutation on the current iterators. - std::tuple<std::pair<IterTs, IterTs>...> IterPairs; - - /// Attempts to increment a specific iterator. - /// - /// Returns true if it was able to increment the iterator. Returns false if - /// the iterator is already at the end iterator. - template <size_t Index> bool incrementHelper() { - auto &IterPair = std::get<Index>(IterPairs); - if (IterPair.first == IterPair.second) - return false; - - ++IterPair.first; - return true; - } - - /// Increments the first non-end iterator. - /// - /// It is an error to call this with all iterators at the end. - template <size_t... Ns> void increment(index_sequence<Ns...>) { - // Build a sequence of functions to increment each iterator if possible. - decltype(&concat_iterator::incrementHelper<0>) IncrementHelperFns[] = { - &concat_iterator::incrementHelper<Ns>...}; - - // Loop over them, and stop as soon as we succeed at incrementing one. - for (auto &IncrementHelperFn : IncrementHelperFns) - if ((this->*IncrementHelperFn)()) - return; - - llvm_unreachable("Attempted to increment an end concat iterator!"); - } - - /// Returns null if the specified iterator is at the end. Otherwise, - /// dereferences the iterator and returns the address of the resulting - /// reference. - template <size_t Index> ValueT *getHelper() const { - auto &IterPair = std::get<Index>(IterPairs); - if (IterPair.first == IterPair.second) - return nullptr; - - return &*IterPair.first; - } - - /// Finds the first non-end iterator, dereferences, and returns the resulting - /// reference. - /// - /// It is an error to call this with all iterators at the end. - template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const { - // Build a sequence of functions to get from iterator if possible. - decltype(&concat_iterator::getHelper<0>) GetHelperFns[] = { - &concat_iterator::getHelper<Ns>...}; - - // Loop over them, and return the first result we find. - for (auto &GetHelperFn : GetHelperFns) - if (ValueT *P = (this->*GetHelperFn)()) - return *P; - - llvm_unreachable("Attempted to get a pointer from an end concat iterator!"); - } - -public: - /// Constructs an iterator from a squence of ranges. - /// - /// We need the full range to know how to switch between each of the - /// iterators. - template <typename... RangeTs> - explicit concat_iterator(RangeTs &&... Ranges) - : IterPairs({std::begin(Ranges), std::end(Ranges)}...) {} - - using BaseT::operator++; - concat_iterator &operator++() { - increment(index_sequence_for<IterTs...>()); - return *this; - } - - ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); } - - bool operator==(const concat_iterator &RHS) const { - return IterPairs == RHS.IterPairs; - } -}; - -namespace detail { -/// Helper to store a sequence of ranges being concatenated and access them. -/// -/// This is designed to facilitate providing actual storage when temporaries -/// are passed into the constructor such that we can use it as part of range -/// based for loops. -template <typename ValueT, typename... RangeTs> class concat_range { -public: - typedef concat_iterator<ValueT, - decltype(std::begin(std::declval<RangeTs &>()))...> - iterator; - -private: - std::tuple<RangeTs...> Ranges; - - template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) { - return iterator(std::get<Ns>(Ranges)...); - } - template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) { - return iterator(make_range(std::end(std::get<Ns>(Ranges)), - std::end(std::get<Ns>(Ranges)))...); - } - -public: - iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); } - iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); } - concat_range(RangeTs &&... Ranges) - : Ranges(std::forward<RangeTs>(Ranges)...) {} -}; -} - -/// Concatenated range across two or more ranges. -/// -/// The desired value type must be explicitly specified. -template <typename ValueT, typename... RangeTs> -detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) { - static_assert(sizeof...(RangeTs) > 1, - "Need more than one range to concatenate!"); - return detail::concat_range<ValueT, RangeTs...>( - std::forward<RangeTs>(Ranges)...); -} - //===----------------------------------------------------------------------===// // Extra additions to <utility> //===----------------------------------------------------------------------===// |