libartbase/base/stl_util.h - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef ART_LIBARTBASE_BASE_STL_UTIL_H_
 #define ART_LIBARTBASE_BASE_STL_UTIL_H_

 #include <algorithm>
 #include <iterator>
 #include <set>
 #include <sstream>

 #include <android-base/logging.h>

 #include "base/iteration_range.h"

 namespace art {

 // STLDeleteContainerPointers()
 //  For a range within a container of pointers, calls delete
 //  (non-array version) on these pointers.
 // NOTE: for these three functions, we could just implement a DeleteObject
 // functor and then call for_each() on the range and functor, but this
 // requires us to pull in all of algorithm.h, which seems expensive.
 // For hash_[multi]set, it is important that this deletes behind the iterator
 // because the hash_set may call the hash function on the iterator when it is
 // advanced, which could result in the hash function trying to deference a
 // stale pointer.
 template <class ForwardIterator>
 void STLDeleteContainerPointers(ForwardIterator begin,
                                 ForwardIterator end) {
   while (begin != end) {
     ForwardIterator temp = begin;
     ++begin;
     delete *temp;
   }
 }

 // STLDeleteElements() deletes all the elements in an STL container and clears
 // the container.  This function is suitable for use with a vector, set,
 // hash_set, or any other STL container which defines sensible begin(), end(),
 // and clear() methods.
 //
 // If container is null, this function is a no-op.
 //
 // As an alternative to calling STLDeleteElements() directly, consider
 // using a container of std::unique_ptr, which ensures that your container's
 // elements are deleted when the container goes out of scope.
 template <class T>
 void STLDeleteElements(T *container) {
   if (container != nullptr) {
     STLDeleteContainerPointers(container->begin(), container->end());
     container->clear();
   }
 }

 // Given an STL container consisting of (key, value) pairs, STLDeleteValues
 // deletes all the "value" components and clears the container.  Does nothing
 // in the case it's given a null pointer.
 template <class T>
 void STLDeleteValues(T *v) {
   if (v != nullptr) {
     for (typename T::iterator i = v->begin(); i != v->end(); ++i) {
       delete i->second;
     }
     v->clear();
   }
 }

 // Deleter using free() for use with std::unique_ptr<>. See also UniqueCPtr<> below.
 struct FreeDelete {
   // NOTE: Deleting a const object is valid but free() takes a non-const pointer.
   void operator()(const void* ptr) const {
     free(const_cast<void*>(ptr));
   }
 };

 // Alias for std::unique_ptr<> that uses the C function free() to delete objects.
 template <typename T>
 using UniqueCPtr = std::unique_ptr<T, FreeDelete>;

 // Find index of the first element with the specified value known to be in the container.
 template <typename Container, typename T>
 size_t IndexOfElement(const Container& container, const T& value) {
   auto it = std::find(container.begin(), container.end(), value);
   DCHECK(it != container.end());  // Must exist.
   return std::distance(container.begin(), it);
 }

 // Remove the first element with the specified value known to be in the container.
 template <typename Container, typename T>
 void RemoveElement(Container& container, const T& value) {
   auto it = std::find(container.begin(), container.end(), value);
   DCHECK(it != container.end());  // Must exist.
   container.erase(it);
 }

 // Replace the first element with the specified old_value known to be in the container.
 template <typename Container, typename T>
 void ReplaceElement(Container& container, const T& old_value, const T& new_value) {
   auto it = std::find(container.begin(), container.end(), old_value);
   DCHECK(it != container.end());  // Must exist.
   *it = new_value;
 }

 // Search for an element with the specified value and return true if it was found, false otherwise.
 template <typename Container, typename T>
 bool ContainsElement(const Container& container, const T& value, size_t start_pos = 0u) {
   DCHECK_LE(start_pos, container.size());
   auto start = container.begin();
   std::advance(start, start_pos);
   auto it = std::find(start, container.end(), value);
   return it != container.end();
 }

 template <typename T>
 bool ContainsElement(const std::set<T>& container, const T& value) {
   return container.count(value) != 0u;
 }

 // 32-bit FNV-1a hash function suitable for std::unordered_map.
 // It can be used with any container which works with range-based for loop.
 // See http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
 template <typename Vector>
 struct FNVHash {
   size_t operator()(const Vector& vector) const {
     uint32_t hash = 2166136261u;
     for (const auto& value : vector) {
       hash = (hash ^ value) * 16777619u;
     }
     return hash;
   }
 };

 // Returns a copy of the passed vector that doesn't memory-own its entries.
 template <typename T>
 static inline std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
   std::vector<T*> result;
   result.reserve(src.size());
   for (const std::unique_ptr<T>& t : src) {
     result.push_back(t.get());
   }
   return result;
 }

 template <typename IterLeft, typename IterRight>
 class ZipLeftIter : public std::iterator<
                         std::forward_iterator_tag,
                         std::pair<typename IterLeft::value_type, typename IterRight::value_type>> {
  public:
   ZipLeftIter(IterLeft left, IterRight right) : left_iter_(left), right_iter_(right) {}
   ZipLeftIter<IterLeft, IterRight>& operator++() {
     ++left_iter_;
     ++right_iter_;
     return *this;
   }
   ZipLeftIter<IterLeft, IterRight> operator++(int) {
     ZipLeftIter<IterLeft, IterRight> ret(left_iter_, right_iter_);
     ++(*this);
     return ret;
   }
   bool operator==(const ZipLeftIter<IterLeft, IterRight>& other) const {
     return left_iter_ == other.left_iter_;
   }
   bool operator!=(const ZipLeftIter<IterLeft, IterRight>& other) const {
     return !(*this == other);
   }
   std::pair<typename IterLeft::value_type, typename IterRight::value_type> operator*() const {
     return std::make_pair(*left_iter_, *right_iter_);
   }

  private:
   IterLeft left_iter_;
   IterRight right_iter_;
 };

 class CountIter : public std::iterator<std::forward_iterator_tag, size_t, size_t, size_t, size_t> {
  public:
   CountIter() : count_(0) {}
   explicit CountIter(size_t count) : count_(count) {}
   CountIter& operator++() {
     ++count_;
     return *this;
   }
   CountIter operator++(int) {
     size_t ret = count_;
     ++count_;
     return CountIter(ret);
   }
   bool operator==(const CountIter& other) const {
     return count_ == other.count_;
   }
   bool operator!=(const CountIter& other) const {
     return !(*this == other);
   }
   size_t operator*() const {
     return count_;
   }

  private:
   size_t count_;
 };

 // Make an iteration range that returns a pair of the element and the index of the element.
 template <typename Iter>
 static inline IterationRange<ZipLeftIter<Iter, CountIter>> ZipCount(IterationRange<Iter> iter) {
   return IterationRange(ZipLeftIter(iter.begin(), CountIter(0)),
                         ZipLeftIter(iter.end(), CountIter(-1)));
 }

 // Make an iteration range that returns a pair of the outputs of two iterators. Stops when the first
 // (left) one is exhausted. The left iterator must be at least as long as the right one.
 template <typename IterLeft, typename IterRight>
 static inline IterationRange<ZipLeftIter<IterLeft, IterRight>> ZipLeft(
     IterationRange<IterLeft> iter_left, IterationRange<IterRight> iter_right) {
   return IterationRange(ZipLeftIter(iter_left.begin(), iter_right.begin()),
                         ZipLeftIter(iter_left.end(), iter_right.end()));
 }

 static inline IterationRange<CountIter> Range(size_t start, size_t end) {
   return IterationRange(CountIter(start), CountIter(end));
 }

 static inline IterationRange<CountIter> Range(size_t end) {
   return Range(0, end);
 }

 template <typename RealIter, typename Filter>
 struct FilterIterator
     : public std::iterator<std::forward_iterator_tag, typename RealIter::value_type> {
  public:
   FilterIterator(RealIter rl,
                  Filter cond,
                  std::optional<RealIter> end = std::nullopt)
       : real_iter_(rl), cond_(cond), end_(end) {
     DCHECK(std::make_optional(rl) == end_ || cond_(*real_iter_));
   }

   FilterIterator<RealIter, Filter>& operator++() {
     DCHECK(std::make_optional(real_iter_) != end_);
     do {
       if (std::make_optional(++real_iter_) == end_) {
         break;
       }
     } while (!cond_(*real_iter_));
     return *this;
   }
   FilterIterator<RealIter, Filter> operator++(int) {
     FilterIterator<RealIter, Filter> ret(real_iter_, cond_, end_);
     ++(*this);
     return ret;
   }
   bool operator==(const FilterIterator<RealIter, Filter>& other) const {
     return real_iter_ == other.real_iter_;
   }
   bool operator!=(const FilterIterator<RealIter, Filter>& other) const {
     return !(*this == other);
   }
   typename RealIter::value_type operator*() const {
     return *real_iter_;
   }

  private:
   RealIter real_iter_;
   Filter cond_;
   std::optional<RealIter> end_;
 };

 template <typename Iter, typename Filter>
 static inline IterationRange<FilterIterator<Iter, Filter>> Filter(
     IterationRange<Iter> it, Filter cond) {
   auto end = it.end();
   auto start = std::find_if(it.begin(), end, cond);
   return MakeIterationRange(FilterIterator(start, cond, std::make_optional(end)),
                             FilterIterator(end, cond, std::make_optional(end)));
 }

 template <typename Val>
 struct NonNullFilter {
  public:
   static_assert(std::is_pointer_v<Val>, "Must be pointer type!");
   constexpr bool operator()(Val v) const {
     return v != nullptr;
   }
 };

 template <typename InnerIter>
 using FilterNull = FilterIterator<InnerIter, NonNullFilter<typename InnerIter::value_type>>;

 template <typename InnerIter>
 static inline IterationRange<FilterNull<InnerIter>> FilterOutNull(IterationRange<InnerIter> inner) {
   return Filter(inner, NonNullFilter<typename InnerIter::value_type>());
 }

 template <typename Val>
 struct SafePrinter  {
   const Val* val_;
 };

 template<typename Val>
 std::ostream& operator<<(std::ostream& os, const SafePrinter<Val>& v) {
   if (v.val_ == nullptr) {
     return os << "NULL";
   } else {
     return os << *v.val_;
   }
 }

 template<typename Val>
 SafePrinter<Val> SafePrint(const Val* v) {
   return SafePrinter<Val>{v};
 }

 // Helper struct for iterating a split-string without allocation.
 struct SplitStringIter : public std::iterator<std::forward_iterator_tag, std::string_view> {
  public:
   // Direct iterator constructor. The iteration state is only the current index.
   // We use that with the split char and the full string to get the current and
   // next segment.
   SplitStringIter(size_t index, char split, std::string_view sv)
       : cur_index_(index), split_on_(split), sv_(sv) {}
   SplitStringIter(const SplitStringIter&) = default;
   SplitStringIter(SplitStringIter&&) = default;
   SplitStringIter& operator=(SplitStringIter&&) = default;
   SplitStringIter& operator=(const SplitStringIter&) = default;

   SplitStringIter& operator++() {
     size_t nxt = sv_.find(split_on_, cur_index_);
     if (nxt == std::string_view::npos) {
       cur_index_ = std::string_view::npos;
     } else {
       cur_index_ = nxt + 1;
     }
     return *this;
   }

   SplitStringIter operator++(int) {
     SplitStringIter ret(cur_index_, split_on_, sv_);
     ++(*this);
     return ret;
   }

   bool operator==(const SplitStringIter& other) const {
     return sv_ == other.sv_ && split_on_ == other.split_on_ && cur_index_== other.cur_index_;
   }

   bool operator!=(const SplitStringIter& other) const {
     return !(*this == other);
   }

   typename std::string_view operator*() const {
     return sv_.substr(cur_index_, sv_.substr(cur_index_).find(split_on_));
   }

  private:
   size_t cur_index_;
   char split_on_;
   std::string_view sv_;
 };

 // Create an iteration range over the string 'sv' split at each 'target' occurrence.
 // Eg: SplitString(":foo::bar") -> ["", "foo", "", "bar"]
 inline IterationRange<SplitStringIter> SplitString(std::string_view sv, char target) {
   return MakeIterationRange(SplitStringIter(0, target, sv),
                             SplitStringIter(std::string_view::npos, target, sv));
 }

 }  // namespace art

 #endif  // ART_LIBARTBASE_BASE_STL_UTIL_H_
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef ART_LIBARTBASE_BASE_STL_UTIL_H_
	#define ART_LIBARTBASE_BASE_STL_UTIL_H_

	#include <algorithm>
	#include <iterator>
	#include <set>
	#include <sstream>

	#include <android-base/logging.h>

	#include "base/iteration_range.h"

	namespace art {

	// STLDeleteContainerPointers()
	// For a range within a container of pointers, calls delete
	// (non-array version) on these pointers.
	// NOTE: for these three functions, we could just implement a DeleteObject
	// functor and then call for_each() on the range and functor, but this
	// requires us to pull in all of algorithm.h, which seems expensive.
	// For hash_[multi]set, it is important that this deletes behind the iterator
	// because the hash_set may call the hash function on the iterator when it is
	// advanced, which could result in the hash function trying to deference a
	// stale pointer.
	template <class ForwardIterator>
	void STLDeleteContainerPointers(ForwardIterator begin,
	ForwardIterator end) {
	while (begin != end) {
	ForwardIterator temp = begin;
	++begin;
	delete *temp;
	}
	}

	// STLDeleteElements() deletes all the elements in an STL container and clears
	// the container. This function is suitable for use with a vector, set,
	// hash_set, or any other STL container which defines sensible begin(), end(),
	// and clear() methods.
	//
	// If container is null, this function is a no-op.
	//
	// As an alternative to calling STLDeleteElements() directly, consider
	// using a container of std::unique_ptr, which ensures that your container's
	// elements are deleted when the container goes out of scope.
	template <class T>
	void STLDeleteElements(T *container) {
	if (container != nullptr) {
	STLDeleteContainerPointers(container->begin(), container->end());
	container->clear();
	}
	}

	// Given an STL container consisting of (key, value) pairs, STLDeleteValues
	// deletes all the "value" components and clears the container. Does nothing
	// in the case it's given a null pointer.
	template <class T>
	void STLDeleteValues(T *v) {
	if (v != nullptr) {
	for (typename T::iterator i = v->begin(); i != v->end(); ++i) {
	delete i->second;
	}
	v->clear();
	}
	}

	// Deleter using free() for use with std::unique_ptr<>. See also UniqueCPtr<> below.
	struct FreeDelete {
	// NOTE: Deleting a const object is valid but free() takes a non-const pointer.
	void operator()(const void* ptr) const {
	free(const_cast<void*>(ptr));
	}
	};

	// Alias for std::unique_ptr<> that uses the C function free() to delete objects.
	template <typename T>
	using UniqueCPtr = std::unique_ptr<T, FreeDelete>;

	// Find index of the first element with the specified value known to be in the container.
	template <typename Container, typename T>
	size_t IndexOfElement(const Container& container, const T& value) {
	auto it = std::find(container.begin(), container.end(), value);
	DCHECK(it != container.end()); // Must exist.
	return std::distance(container.begin(), it);
	}

	// Remove the first element with the specified value known to be in the container.
	template <typename Container, typename T>
	void RemoveElement(Container& container, const T& value) {
	auto it = std::find(container.begin(), container.end(), value);
	DCHECK(it != container.end()); // Must exist.
	container.erase(it);
	}

	// Replace the first element with the specified old_value known to be in the container.
	template <typename Container, typename T>
	void ReplaceElement(Container& container, const T& old_value, const T& new_value) {
	auto it = std::find(container.begin(), container.end(), old_value);
	DCHECK(it != container.end()); // Must exist.
	*it = new_value;
	}

	// Search for an element with the specified value and return true if it was found, false otherwise.
	template <typename Container, typename T>
	bool ContainsElement(const Container& container, const T& value, size_t start_pos = 0u) {
	DCHECK_LE(start_pos, container.size());
	auto start = container.begin();
	std::advance(start, start_pos);
	auto it = std::find(start, container.end(), value);
	return it != container.end();
	}

	template <typename T>
	bool ContainsElement(const std::set<T>& container, const T& value) {
	return container.count(value) != 0u;
	}

	// 32-bit FNV-1a hash function suitable for std::unordered_map.
	// It can be used with any container which works with range-based for loop.
	// See http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
	template <typename Vector>
	struct FNVHash {
	size_t operator()(const Vector& vector) const {
	uint32_t hash = 2166136261u;
	for (const auto& value : vector) {
	hash = (hash ^ value) * 16777619u;
	}
	return hash;
	}
	};

	// Returns a copy of the passed vector that doesn't memory-own its entries.
	template <typename T>
	static inline std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
	std::vector<T*> result;
	result.reserve(src.size());
	for (const std::unique_ptr<T>& t : src) {
	result.push_back(t.get());
	}
	return result;
	}

	template <typename IterLeft, typename IterRight>
	class ZipLeftIter : public std::iterator<
	std::forward_iterator_tag,
	std::pair<typename IterLeft::value_type, typename IterRight::value_type>> {
	public:
	ZipLeftIter(IterLeft left, IterRight right) : left_iter_(left), right_iter_(right) {}
	ZipLeftIter<IterLeft, IterRight>& operator++() {
	++left_iter_;
	++right_iter_;
	return *this;
	}
	ZipLeftIter<IterLeft, IterRight> operator++(int) {
	ZipLeftIter<IterLeft, IterRight> ret(left_iter_, right_iter_);
	++(*this);
	return ret;
	}
	bool operator==(const ZipLeftIter<IterLeft, IterRight>& other) const {
	return left_iter_ == other.left_iter_;
	}
	bool operator!=(const ZipLeftIter<IterLeft, IterRight>& other) const {
	return !(*this == other);
	}
	std::pair<typename IterLeft::value_type, typename IterRight::value_type> operator*() const {
	return std::make_pair(left_iter_, right_iter_);
	}

	private:
	IterLeft left_iter_;
	IterRight right_iter_;
	};

	class CountIter : public std::iterator<std::forward_iterator_tag, size_t, size_t, size_t, size_t> {
	public:
	CountIter() : count_(0) {}
	explicit CountIter(size_t count) : count_(count) {}
	CountIter& operator++() {
	++count_;
	return *this;
	}
	CountIter operator++(int) {
	size_t ret = count_;
	++count_;
	return CountIter(ret);
	}
	bool operator==(const CountIter& other) const {
	return count_ == other.count_;
	}
	bool operator!=(const CountIter& other) const {
	return !(*this == other);
	}
	size_t operator*() const {
	return count_;
	}

	private:
	size_t count_;
	};

	// Make an iteration range that returns a pair of the element and the index of the element.
	template <typename Iter>
	static inline IterationRange<ZipLeftIter<Iter, CountIter>> ZipCount(IterationRange<Iter> iter) {
	return IterationRange(ZipLeftIter(iter.begin(), CountIter(0)),
	ZipLeftIter(iter.end(), CountIter(-1)));
	}

	// Make an iteration range that returns a pair of the outputs of two iterators. Stops when the first
	// (left) one is exhausted. The left iterator must be at least as long as the right one.
	template <typename IterLeft, typename IterRight>
	static inline IterationRange<ZipLeftIter<IterLeft, IterRight>> ZipLeft(
	IterationRange<IterLeft> iter_left, IterationRange<IterRight> iter_right) {
	return IterationRange(ZipLeftIter(iter_left.begin(), iter_right.begin()),
	ZipLeftIter(iter_left.end(), iter_right.end()));
	}

	static inline IterationRange<CountIter> Range(size_t start, size_t end) {
	return IterationRange(CountIter(start), CountIter(end));
	}

	static inline IterationRange<CountIter> Range(size_t end) {
	return Range(0, end);
	}

	template <typename RealIter, typename Filter>
	struct FilterIterator
	: public std::iterator<std::forward_iterator_tag, typename RealIter::value_type> {
	public:
	FilterIterator(RealIter rl,
	Filter cond,
	std::optional<RealIter> end = std::nullopt)
	: real_iter_(rl), cond_(cond), end_(end) {
	DCHECK(std::make_optional(rl) == end_ \|\| cond_(*real_iter_));
	}

	FilterIterator<RealIter, Filter>& operator++() {
	DCHECK(std::make_optional(real_iter_) != end_);
	do {
	if (std::make_optional(++real_iter_) == end_) {
	break;
	}
	} while (!cond_(*real_iter_));
	return *this;
	}
	FilterIterator<RealIter, Filter> operator++(int) {
	FilterIterator<RealIter, Filter> ret(real_iter_, cond_, end_);
	++(*this);
	return ret;
	}
	bool operator==(const FilterIterator<RealIter, Filter>& other) const {
	return real_iter_ == other.real_iter_;
	}
	bool operator!=(const FilterIterator<RealIter, Filter>& other) const {
	return !(*this == other);
	}
	typename RealIter::value_type operator*() const {
	return *real_iter_;
	}

	private:
	RealIter real_iter_;
	Filter cond_;
	std::optional<RealIter> end_;
	};

	template <typename Iter, typename Filter>
	static inline IterationRange<FilterIterator<Iter, Filter>> Filter(
	IterationRange<Iter> it, Filter cond) {
	auto end = it.end();
	auto start = std::find_if(it.begin(), end, cond);
	return MakeIterationRange(FilterIterator(start, cond, std::make_optional(end)),
	FilterIterator(end, cond, std::make_optional(end)));
	}

	template <typename Val>
	struct NonNullFilter {
	public:
	static_assert(std::is_pointer_v<Val>, "Must be pointer type!");
	constexpr bool operator()(Val v) const {
	return v != nullptr;
	}
	};

	template <typename InnerIter>
	using FilterNull = FilterIterator<InnerIter, NonNullFilter<typename InnerIter::value_type>>;

	template <typename InnerIter>
	static inline IterationRange<FilterNull<InnerIter>> FilterOutNull(IterationRange<InnerIter> inner) {
	return Filter(inner, NonNullFilter<typename InnerIter::value_type>());
	}

	template <typename Val>
	struct SafePrinter {
	const Val* val_;
	};

	template<typename Val>
	std::ostream& operator<<(std::ostream& os, const SafePrinter<Val>& v) {
	if (v.val_ == nullptr) {
	return os << "NULL";
	} else {
	return os << *v.val_;
	}
	}

	template<typename Val>
	SafePrinter<Val> SafePrint(const Val* v) {
	return SafePrinter<Val>{v};
	}

	// Helper struct for iterating a split-string without allocation.
	struct SplitStringIter : public std::iterator<std::forward_iterator_tag, std::string_view> {
	public:
	// Direct iterator constructor. The iteration state is only the current index.
	// We use that with the split char and the full string to get the current and
	// next segment.
	SplitStringIter(size_t index, char split, std::string_view sv)
	: cur_index_(index), split_on_(split), sv_(sv) {}
	SplitStringIter(const SplitStringIter&) = default;
	SplitStringIter(SplitStringIter&&) = default;
	SplitStringIter& operator=(SplitStringIter&&) = default;
	SplitStringIter& operator=(const SplitStringIter&) = default;

	SplitStringIter& operator++() {
	size_t nxt = sv_.find(split_on_, cur_index_);
	if (nxt == std::string_view::npos) {
	cur_index_ = std::string_view::npos;
	} else {
	cur_index_ = nxt + 1;
	}
	return *this;
	}

	SplitStringIter operator++(int) {
	SplitStringIter ret(cur_index_, split_on_, sv_);
	++(*this);
	return ret;
	}

	bool operator==(const SplitStringIter& other) const {
	return sv_ == other.sv_ && split_on_ == other.split_on_ && cur_index_== other.cur_index_;
	}

	bool operator!=(const SplitStringIter& other) const {
	return !(*this == other);
	}

	typename std::string_view operator*() const {
	return sv_.substr(cur_index_, sv_.substr(cur_index_).find(split_on_));
	}

	private:
	size_t cur_index_;
	char split_on_;
	std::string_view sv_;
	};

	// Create an iteration range over the string 'sv' split at each 'target' occurrence.
	// Eg: SplitString(":foo::bar") -> ["", "foo", "", "bar"]
	inline IterationRange<SplitStringIter> SplitString(std::string_view sv, char target) {
	return MakeIterationRange(SplitStringIter(0, target, sv),
	SplitStringIter(std::string_view::npos, target, sv));
	}

	} // namespace art

	#endif // ART_LIBARTBASE_BASE_STL_UTIL_H_