Move ArrayRef to runtime/base
Will be used in upcoming CLs regarding VDEX and VerifierDeps.
Test: m test-art-host
Change-Id: I68e611a4a52246c2bdf45eab7c61f3212908afd4
diff --git a/runtime/base/array_ref.h b/runtime/base/array_ref.h
new file mode 100644
index 0000000..00b9bad
--- /dev/null
+++ b/runtime/base/array_ref.h
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2014 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_RUNTIME_BASE_ARRAY_REF_H_
+#define ART_RUNTIME_BASE_ARRAY_REF_H_
+
+#include <type_traits>
+#include <vector>
+
+#include "base/logging.h"
+
+namespace art {
+
+/**
+ * @brief A container that references an array.
+ *
+ * @details The template class ArrayRef provides a container that references
+ * an external array. This external array must remain alive while the ArrayRef
+ * object is in use. The external array may be a std::vector<>-backed storage
+ * or any other contiguous chunk of memory but that memory must remain valid,
+ * i.e. the std::vector<> must not be resized for example.
+ *
+ * Except for copy/assign and insert/erase/capacity functions, the interface
+ * is essentially the same as std::vector<>. Since we don't want to throw
+ * exceptions, at() is also excluded.
+ */
+template <typename T>
+class ArrayRef {
+ public:
+ typedef T value_type;
+ typedef T& reference;
+ typedef const T& const_reference;
+ typedef T* pointer;
+ typedef const T* const_pointer;
+ typedef T* iterator;
+ typedef const T* const_iterator;
+ typedef std::reverse_iterator<iterator> reverse_iterator;
+ typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+ typedef ptrdiff_t difference_type;
+ typedef size_t size_type;
+
+ // Constructors.
+
+ constexpr ArrayRef()
+ : array_(nullptr), size_(0u) {
+ }
+
+ template <size_t size>
+ explicit constexpr ArrayRef(T (&array)[size])
+ : array_(array), size_(size) {
+ }
+
+ template <typename U,
+ size_t size,
+ typename = typename std::enable_if<std::is_same<T, const U>::value>::type>
+ explicit constexpr ArrayRef(U (&array)[size])
+ : array_(array), size_(size) {
+ }
+
+ constexpr ArrayRef(T* array_in, size_t size_in)
+ : array_(array_in), size_(size_in) {
+ }
+
+ template <typename Vector,
+ typename = typename std::enable_if<
+ std::is_same<typename Vector::value_type, value_type>::value>::type>
+ explicit ArrayRef(Vector& v)
+ : array_(v.data()), size_(v.size()) {
+ }
+
+ template <typename Vector,
+ typename = typename std::enable_if<
+ std::is_same<
+ typename std::add_const<typename Vector::value_type>::type,
+ value_type>::value>::type>
+ explicit ArrayRef(const Vector& v)
+ : array_(v.data()), size_(v.size()) {
+ }
+
+ ArrayRef(const ArrayRef&) = default;
+
+ // Assignment operators.
+
+ ArrayRef& operator=(const ArrayRef& other) {
+ array_ = other.array_;
+ size_ = other.size_;
+ return *this;
+ }
+
+ template <typename U>
+ typename std::enable_if<std::is_same<T, const U>::value, ArrayRef>::type&
+ operator=(const ArrayRef<U>& other) {
+ return *this = ArrayRef(other);
+ }
+
+ // Destructor.
+ ~ArrayRef() = default;
+
+ // Iterators.
+ iterator begin() { return array_; }
+ const_iterator begin() const { return array_; }
+ const_iterator cbegin() const { return array_; }
+ iterator end() { return array_ + size_; }
+ const_iterator end() const { return array_ + size_; }
+ const_iterator cend() const { return array_ + size_; }
+ reverse_iterator rbegin() { return reverse_iterator(end()); }
+ const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
+ const_reverse_iterator crbegin() const { return const_reverse_iterator(cend()); }
+ reverse_iterator rend() { return reverse_iterator(begin()); }
+ const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
+ const_reverse_iterator crend() const { return const_reverse_iterator(cbegin()); }
+
+ // Size.
+ size_type size() const { return size_; }
+ bool empty() const { return size() == 0u; }
+
+ // Element access. NOTE: Not providing at().
+
+ reference operator[](size_type n) {
+ DCHECK_LT(n, size_);
+ return array_[n];
+ }
+
+ const_reference operator[](size_type n) const {
+ DCHECK_LT(n, size_);
+ return array_[n];
+ }
+
+ reference front() {
+ DCHECK_NE(size_, 0u);
+ return array_[0];
+ }
+
+ const_reference front() const {
+ DCHECK_NE(size_, 0u);
+ return array_[0];
+ }
+
+ reference back() {
+ DCHECK_NE(size_, 0u);
+ return array_[size_ - 1u];
+ }
+
+ const_reference back() const {
+ DCHECK_NE(size_, 0u);
+ return array_[size_ - 1u];
+ }
+
+ value_type* data() { return array_; }
+ const value_type* data() const { return array_; }
+
+ ArrayRef SubArray(size_type pos) {
+ return SubArray(pos, size() - pos);
+ }
+ ArrayRef<const T> SubArray(size_type pos) const {
+ return SubArray(pos, size() - pos);
+ }
+ ArrayRef SubArray(size_type pos, size_type length) {
+ DCHECK_LE(pos, size());
+ DCHECK_LE(length, size() - pos);
+ return ArrayRef(data() + pos, length);
+ }
+ ArrayRef<const T> SubArray(size_type pos, size_type length) const {
+ DCHECK_LE(pos, size());
+ DCHECK_LE(length, size() - pos);
+ return ArrayRef<const T>(data() + pos, length);
+ }
+
+ private:
+ T* array_;
+ size_t size_;
+};
+
+template <typename T>
+bool operator==(const ArrayRef<T>& lhs, const ArrayRef<T>& rhs) {
+ return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
+}
+
+template <typename T>
+bool operator!=(const ArrayRef<T>& lhs, const ArrayRef<T>& rhs) {
+ return !(lhs == rhs);
+}
+
+} // namespace art
+
+
+#endif // ART_RUNTIME_BASE_ARRAY_REF_H_
diff --git a/runtime/base/transform_array_ref.h b/runtime/base/transform_array_ref.h
new file mode 100644
index 0000000..a4e0bc2
--- /dev/null
+++ b/runtime/base/transform_array_ref.h
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2016 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_RUNTIME_BASE_TRANSFORM_ARRAY_REF_H_
+#define ART_RUNTIME_BASE_TRANSFORM_ARRAY_REF_H_
+
+#include <type_traits>
+
+#include "base/array_ref.h"
+#include "base/transform_iterator.h"
+
+namespace art {
+
+/**
+ * @brief An ArrayRef<> wrapper that uses a transformation function for element access.
+ */
+template <typename BaseType, typename Function>
+class TransformArrayRef {
+ private:
+ using Iter = TransformIterator<typename ArrayRef<BaseType>::iterator, Function>;
+
+ // The Function may take a non-const reference, so const_iterator may not exist.
+ using FallbackConstIter = std::iterator<std::random_access_iterator_tag, void, void, void, void>;
+ using PreferredConstIter =
+ TransformIterator<typename ArrayRef<BaseType>::const_iterator, Function>;
+ template <typename F, typename = typename std::result_of<F(const BaseType&)>::type>
+ static PreferredConstIter ConstIterHelper(int&);
+ template <typename F>
+ static FallbackConstIter ConstIterHelper(const int&);
+
+ using ConstIter = decltype(ConstIterHelper<Function>(*reinterpret_cast<int*>(0)));
+
+ public:
+ using value_type = typename Iter::value_type;
+ using reference = typename Iter::reference;
+ using const_reference = typename ConstIter::reference;
+ using pointer = typename Iter::pointer;
+ using const_pointer = typename ConstIter::pointer;
+ using iterator = Iter;
+ using const_iterator = typename std::conditional<
+ std::is_same<ConstIter, FallbackConstIter>::value,
+ void,
+ ConstIter>::type;
+ using reverse_iterator = std::reverse_iterator<Iter>;
+ using const_reverse_iterator = typename std::conditional<
+ std::is_same<ConstIter, FallbackConstIter>::value,
+ void,
+ std::reverse_iterator<ConstIter>>::type;
+ using difference_type = typename ArrayRef<BaseType>::difference_type;
+ using size_type = typename ArrayRef<BaseType>::size_type;
+
+ // Constructors.
+
+ TransformArrayRef(const TransformArrayRef& other) = default;
+
+ template <typename OtherBT>
+ TransformArrayRef(const ArrayRef<OtherBT>& base, Function fn)
+ : data_(base, fn) { }
+
+ template <typename OtherBT,
+ typename = typename std::enable_if<std::is_same<BaseType, const OtherBT>::value>::type>
+ TransformArrayRef(const TransformArrayRef<OtherBT, Function>& other)
+ : TransformArrayRef(other.base(), other.GetFunction()) { }
+
+ // Assignment operators.
+
+ TransformArrayRef& operator=(const TransformArrayRef& other) = default;
+
+ template <typename OtherBT,
+ typename = typename std::enable_if<std::is_same<BaseType, const OtherBT>::value>::type>
+ TransformArrayRef& operator=(const TransformArrayRef<OtherBT, Function>& other) {
+ return *this = TransformArrayRef(other.base(), other.GetFunction());
+ }
+
+ // Destructor.
+ ~TransformArrayRef() = default;
+
+ // Iterators.
+ iterator begin() { return MakeIterator(base().begin()); }
+ const_iterator begin() const { return MakeIterator(base().cbegin()); }
+ const_iterator cbegin() const { return MakeIterator(base().cbegin()); }
+ iterator end() { return MakeIterator(base().end()); }
+ const_iterator end() const { MakeIterator(base().cend()); }
+ const_iterator cend() const { return MakeIterator(base().cend()); }
+ reverse_iterator rbegin() { return reverse_iterator(end()); }
+ const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
+ const_reverse_iterator crbegin() const { return const_reverse_iterator(cend()); }
+ reverse_iterator rend() { return reverse_iterator(begin()); }
+ const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
+ const_reverse_iterator crend() const { return const_reverse_iterator(cbegin()); }
+
+ // Size.
+ size_type size() const { return base().size(); }
+ bool empty() const { return base().empty(); }
+
+ // Element access. NOTE: Not providing data().
+
+ reference operator[](size_type n) { return GetFunction()(base()[n]); }
+ const_reference operator[](size_type n) const { return GetFunction()(base()[n]); }
+
+ reference front() { return GetFunction()(base().front()); }
+ const_reference front() const { return GetFunction()(base().front()); }
+
+ reference back() { return GetFunction()(base().back()); }
+ const_reference back() const { return GetFunction()(base().back()); }
+
+ TransformArrayRef SubArray(size_type pos) {
+ return TransformArrayRef(base().subarray(pos), GetFunction());
+ }
+ TransformArrayRef SubArray(size_type pos) const {
+ return TransformArrayRef(base().subarray(pos), GetFunction());
+ }
+ TransformArrayRef SubArray(size_type pos, size_type length) const {
+ return TransformArrayRef(base().subarray(pos, length), GetFunction());
+ }
+
+ // Retrieve the base ArrayRef<>.
+ ArrayRef<BaseType> base() {
+ return data_.base_;
+ }
+ ArrayRef<const BaseType> base() const {
+ return ArrayRef<const BaseType>(data_.base_);
+ }
+
+ private:
+ // Allow EBO for state-less Function.
+ struct Data : Function {
+ public:
+ Data(ArrayRef<BaseType> base, Function fn) : Function(fn), base_(base) { }
+
+ ArrayRef<BaseType> base_;
+ };
+
+ const Function& GetFunction() const {
+ return static_cast<const Function&>(data_);
+ }
+
+ template <typename BaseIterator>
+ auto MakeIterator(BaseIterator base) const {
+ return MakeTransformIterator(base, GetFunction());
+ }
+
+ Data data_;
+
+ template <typename OtherBT, typename OtherFunction>
+ friend class TransformArrayRef;
+};
+
+template <typename BaseType, typename Function>
+bool operator==(const TransformArrayRef<BaseType, Function>& lhs,
+ const TransformArrayRef<BaseType, Function>& rhs) {
+ return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
+}
+
+template <typename BaseType, typename Function>
+bool operator!=(const TransformArrayRef<BaseType, Function>& lhs,
+ const TransformArrayRef<BaseType, Function>& rhs) {
+ return !(lhs == rhs);
+}
+
+template <typename ValueType, typename Function>
+TransformArrayRef<ValueType, Function> MakeTransformArrayRef(
+ ArrayRef<ValueType> container, Function f) {
+ return TransformArrayRef<ValueType, Function>(container, f);
+}
+
+template <typename Container, typename Function>
+TransformArrayRef<typename Container::value_type, Function> MakeTransformArrayRef(
+ Container& container, Function f) {
+ return TransformArrayRef<typename Container::value_type, Function>(
+ ArrayRef<typename Container::value_type>(container.data(), container.size()), f);
+}
+
+template <typename Container, typename Function>
+TransformArrayRef<const typename Container::value_type, Function> MakeTransformArrayRef(
+ const Container& container, Function f) {
+ return TransformArrayRef<const typename Container::value_type, Function>(
+ ArrayRef<const typename Container::value_type>(container.data(), container.size()), f);
+}
+
+} // namespace art
+
+#endif // ART_RUNTIME_BASE_TRANSFORM_ARRAY_REF_H_
diff --git a/runtime/base/transform_array_ref_test.cc b/runtime/base/transform_array_ref_test.cc
new file mode 100644
index 0000000..494dbb2
--- /dev/null
+++ b/runtime/base/transform_array_ref_test.cc
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include <algorithm>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+#include "base/transform_array_ref.h"
+
+namespace art {
+
+namespace { // anonymous namespace
+
+struct ValueHolder {
+ // Deliberately not explicit.
+ ValueHolder(int v) : value(v) { } // NOLINT
+ int value;
+};
+
+ATTRIBUTE_UNUSED bool operator==(const ValueHolder& lhs, const ValueHolder& rhs) {
+ return lhs.value == rhs.value;
+}
+
+} // anonymous namespace
+
+TEST(TransformArrayRef, ConstRefAdd1) {
+ auto add1 = [](const ValueHolder& h) { return h.value + 1; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> input({ 7, 6, 4, 0 });
+ std::vector<int> output;
+
+ auto taref = MakeTransformArrayRef(input, add1);
+ using TarefIter = decltype(taref)::iterator;
+ using ConstTarefIter = decltype(taref)::const_iterator;
+ static_assert(std::is_same<int, decltype(taref)::value_type>::value, "value_type");
+ static_assert(std::is_same<TarefIter, decltype(taref)::pointer>::value, "pointer");
+ static_assert(std::is_same<int, decltype(taref)::reference>::value, "reference");
+ static_assert(std::is_same<ConstTarefIter, decltype(taref)::const_pointer>::value,
+ "const_pointer");
+ static_assert(std::is_same<int, decltype(taref)::const_reference>::value, "const_reference");
+
+ std::copy(taref.begin(), taref.end(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 7, 5, 1 }), output);
+ output.clear();
+
+ std::copy(taref.cbegin(), taref.cend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 7, 5, 1 }), output);
+ output.clear();
+
+ std::copy(taref.rbegin(), taref.rend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 5, 7, 8 }), output);
+ output.clear();
+
+ std::copy(taref.crbegin(), taref.crend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 5, 7, 8 }), output);
+ output.clear();
+
+ ASSERT_EQ(input.size(), taref.size());
+ ASSERT_EQ(input.empty(), taref.empty());
+ ASSERT_EQ(input.front().value + 1, taref.front());
+ ASSERT_EQ(input.back().value + 1, taref.back());
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value + 1, taref[i]);
+ }
+}
+
+TEST(TransformArrayRef, NonConstRefSub1) {
+ auto sub1 = [](ValueHolder& h) { return h.value - 1; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> input({ 4, 4, 5, 7, 10 });
+ std::vector<int> output;
+
+ auto taref = MakeTransformArrayRef(input, sub1);
+ using TarefIter = decltype(taref)::iterator;
+ static_assert(std::is_same<void, decltype(taref)::const_iterator>::value, "const_iterator");
+ static_assert(std::is_same<int, decltype(taref)::value_type>::value, "value_type");
+ static_assert(std::is_same<TarefIter, decltype(taref)::pointer>::value, "pointer");
+ static_assert(std::is_same<int, decltype(taref)::reference>::value, "reference");
+ static_assert(std::is_same<void, decltype(taref)::const_pointer>::value, "const_pointer");
+ static_assert(std::is_same<void, decltype(taref)::const_reference>::value, "const_reference");
+
+ std::copy(taref.begin(), taref.end(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 3, 3, 4, 6, 9 }), output);
+ output.clear();
+
+ std::copy(taref.rbegin(), taref.rend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 9, 6, 4, 3, 3 }), output);
+ output.clear();
+
+ ASSERT_EQ(input.size(), taref.size());
+ ASSERT_EQ(input.empty(), taref.empty());
+ ASSERT_EQ(input.front().value - 1, taref.front());
+ ASSERT_EQ(input.back().value - 1, taref.back());
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value - 1, taref[i]);
+ }
+}
+
+TEST(TransformArrayRef, ConstAndNonConstRef) {
+ struct Ref {
+ int& operator()(ValueHolder& h) const { return h.value; }
+ const int& operator()(const ValueHolder& h) const { return h.value; }
+ };
+ Ref ref;
+ std::vector<ValueHolder> input({ 1, 0, 1, 0, 3, 1 });
+ std::vector<int> output;
+
+ auto taref = MakeTransformArrayRef(input, ref);
+ static_assert(std::is_same<int, decltype(taref)::value_type>::value, "value_type");
+ static_assert(std::is_same<int*, decltype(taref)::pointer>::value, "pointer");
+ static_assert(std::is_same<int&, decltype(taref)::reference>::value, "reference");
+ static_assert(std::is_same<const int*, decltype(taref)::const_pointer>::value, "const_pointer");
+ static_assert(std::is_same<const int&, decltype(taref)::const_reference>::value,
+ "const_reference");
+
+ std::copy(taref.begin(), taref.end(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 0, 1, 0, 3, 1 }), output);
+ output.clear();
+
+ std::copy(taref.cbegin(), taref.cend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 0, 1, 0, 3, 1 }), output);
+ output.clear();
+
+ std::copy(taref.rbegin(), taref.rend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 3, 0, 1, 0, 1 }), output);
+ output.clear();
+
+ std::copy(taref.crbegin(), taref.crend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 3, 0, 1, 0, 1 }), output);
+ output.clear();
+
+ ASSERT_EQ(input.size(), taref.size());
+ ASSERT_EQ(input.empty(), taref.empty());
+ ASSERT_EQ(input.front().value, taref.front());
+ ASSERT_EQ(input.back().value, taref.back());
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value, taref[i]);
+ }
+
+ // Test writing through the transform iterator.
+ std::vector<int> transform_input({ 24, 37, 11, 71 });
+ std::vector<ValueHolder> transformed(transform_input.size(), 0);
+ taref = MakeTransformArrayRef(transformed, ref);
+ for (size_t i = 0; i != transform_input.size(); ++i) {
+ taref[i] = transform_input[i];
+ }
+ ASSERT_EQ(std::vector<ValueHolder>({ 24, 37, 11, 71 }), transformed);
+
+ const std::vector<ValueHolder>& cinput = input;
+
+ auto ctaref = MakeTransformArrayRef(cinput, ref);
+ static_assert(std::is_same<int, decltype(ctaref)::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, decltype(ctaref)::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, decltype(ctaref)::reference>::value, "reference");
+ static_assert(std::is_same<const int*, decltype(ctaref)::const_pointer>::value, "const_pointer");
+ static_assert(std::is_same<const int&, decltype(ctaref)::const_reference>::value,
+ "const_reference");
+
+ std::copy(ctaref.begin(), ctaref.end(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 0, 1, 0, 3, 1 }), output);
+ output.clear();
+
+ std::copy(ctaref.cbegin(), ctaref.cend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 0, 1, 0, 3, 1 }), output);
+ output.clear();
+
+ std::copy(ctaref.rbegin(), ctaref.rend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 3, 0, 1, 0, 1 }), output);
+ output.clear();
+
+ std::copy(ctaref.crbegin(), ctaref.crend(), std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 3, 0, 1, 0, 1 }), output);
+ output.clear();
+
+ ASSERT_EQ(cinput.size(), ctaref.size());
+ ASSERT_EQ(cinput.empty(), ctaref.empty());
+ ASSERT_EQ(cinput.front().value, ctaref.front());
+ ASSERT_EQ(cinput.back().value, ctaref.back());
+
+ for (size_t i = 0; i != cinput.size(); ++i) {
+ ASSERT_EQ(cinput[i].value, ctaref[i]);
+ }
+
+ // Test conversion adding const.
+ decltype(ctaref) ctaref2 = taref;
+ ASSERT_EQ(taref.size(), ctaref2.size());
+ for (size_t i = 0; i != taref.size(); ++i) {
+ ASSERT_EQ(taref[i], ctaref2[i]);
+ }
+}
+
+} // namespace art
diff --git a/runtime/base/transform_iterator.h b/runtime/base/transform_iterator.h
new file mode 100644
index 0000000..9c8f822
--- /dev/null
+++ b/runtime/base/transform_iterator.h
@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2016 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_RUNTIME_BASE_TRANSFORM_ITERATOR_H_
+#define ART_RUNTIME_BASE_TRANSFORM_ITERATOR_H_
+
+#include <iterator>
+#include <type_traits>
+
+#include "base/iteration_range.h"
+
+namespace art {
+
+// The transform iterator transforms values from the base iterator with a given
+// transformation function. It can serve as a replacement for std::transform(), i.e.
+// std::copy(MakeTransformIterator(begin, f), MakeTransformIterator(end, f), out)
+// is equivalent to
+// std::transform(begin, end, f)
+// If the function returns an l-value reference or a wrapper that supports assignment,
+// the TransformIterator can be used also as an output iterator, i.e.
+// std::copy(begin, end, MakeTransformIterator(out, f))
+// is equivalent to
+// for (auto it = begin; it != end; ++it) {
+// f(*out++) = *it;
+// }
+template <typename BaseIterator, typename Function>
+class TransformIterator {
+ private:
+ static_assert(std::is_base_of<
+ std::input_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "Transform iterator base must be an input iterator.");
+
+ using InputType = typename std::iterator_traits<BaseIterator>::reference;
+ using ResultType = typename std::result_of<Function(InputType)>::type;
+
+ public:
+ using iterator_category = typename std::iterator_traits<BaseIterator>::iterator_category;
+ using value_type =
+ typename std::remove_const<typename std::remove_reference<ResultType>::type>::type;
+ using difference_type = typename std::iterator_traits<BaseIterator>::difference_type;
+ using pointer = typename std::conditional<
+ std::is_reference<ResultType>::value,
+ typename std::add_pointer<typename std::remove_reference<ResultType>::type>::type,
+ TransformIterator>::type;
+ using reference = ResultType;
+
+ TransformIterator(BaseIterator base, Function fn)
+ : data_(base, fn) { }
+
+ template <typename OtherBI>
+ TransformIterator(const TransformIterator<OtherBI, Function>& other)
+ : data_(other.base(), other.GetFunction()) {
+ }
+
+ TransformIterator& operator++() {
+ ++data_.base_;
+ return *this;
+ }
+
+ TransformIterator& operator++(int) {
+ TransformIterator tmp(*this);
+ ++*this;
+ return tmp;
+ }
+
+ TransformIterator& operator--() {
+ static_assert(
+ std::is_base_of<std::bidirectional_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "BaseIterator must be bidirectional iterator to use operator--()");
+ --data_.base_;
+ return *this;
+ }
+
+ TransformIterator& operator--(int) {
+ TransformIterator tmp(*this);
+ --*this;
+ return tmp;
+ }
+
+ reference operator*() const {
+ return GetFunction()(*base());
+ }
+
+ reference operator[](difference_type n) const {
+ static_assert(
+ std::is_base_of<std::random_access_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "BaseIterator must be random access iterator to use operator[]");
+ return GetFunction()(base()[n]);
+ }
+
+ TransformIterator operator+(difference_type n) const {
+ static_assert(
+ std::is_base_of<std::random_access_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "BaseIterator must be random access iterator to use operator+");
+ return TransformIterator(base() + n, GetFunction());
+ }
+
+ TransformIterator operator-(difference_type n) const {
+ static_assert(
+ std::is_base_of<std::random_access_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "BaseIterator must be random access iterator to use operator-");
+ return TransformIterator(base() - n, GetFunction());
+ }
+
+ difference_type operator-(const TransformIterator& other) const {
+ static_assert(
+ std::is_base_of<std::random_access_iterator_tag,
+ typename std::iterator_traits<BaseIterator>::iterator_category>::value,
+ "BaseIterator must be random access iterator to use operator-");
+ return base() - other.base();
+ }
+
+ // Retrieve the base iterator.
+ BaseIterator base() const {
+ return data_.base_;
+ }
+
+ // Retrieve the transformation function.
+ const Function& GetFunction() const {
+ return static_cast<const Function&>(data_);
+ }
+
+ private:
+ // Allow EBO for state-less Function.
+ struct Data : Function {
+ public:
+ Data(BaseIterator base, Function fn) : Function(fn), base_(base) { }
+
+ BaseIterator base_;
+ };
+
+ Data data_;
+};
+
+template <typename BaseIterator1, typename BaseIterator2, typename Function>
+bool operator==(const TransformIterator<BaseIterator1, Function>& lhs,
+ const TransformIterator<BaseIterator2, Function>& rhs) {
+ return lhs.base() == rhs.base();
+}
+
+template <typename BaseIterator1, typename BaseIterator2, typename Function>
+bool operator!=(const TransformIterator<BaseIterator1, Function>& lhs,
+ const TransformIterator<BaseIterator2, Function>& rhs) {
+ return !(lhs == rhs);
+}
+
+template <typename BaseIterator, typename Function>
+TransformIterator<BaseIterator, Function> MakeTransformIterator(BaseIterator base, Function f) {
+ return TransformIterator<BaseIterator, Function>(base, f);
+}
+
+template <typename BaseRange, typename Function>
+auto MakeTransformRange(BaseRange& range, Function f) {
+ return MakeIterationRange(MakeTransformIterator(range.begin(), f),
+ MakeTransformIterator(range.end(), f));
+}
+
+} // namespace art
+
+#endif // ART_RUNTIME_BASE_TRANSFORM_ITERATOR_H_
diff --git a/runtime/base/transform_iterator_test.cc b/runtime/base/transform_iterator_test.cc
new file mode 100644
index 0000000..a85dda8
--- /dev/null
+++ b/runtime/base/transform_iterator_test.cc
@@ -0,0 +1,531 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#include <algorithm>
+#include <forward_list>
+#include <list>
+#include <type_traits>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+#include "base/transform_iterator.h"
+
+namespace art {
+
+namespace { // anonymous namespace
+
+struct ValueHolder {
+ // Deliberately not explicit.
+ ValueHolder(int v) : value(v) { } // NOLINT
+ int value;
+};
+
+bool operator==(const ValueHolder& lhs, const ValueHolder& rhs) {
+ return lhs.value == rhs.value;
+}
+
+} // anonymous namespace
+
+TEST(TransformIterator, VectorAdd1) {
+ auto add1 = [](const ValueHolder& h) { return h.value + 1; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> input({ 1, 7, 3, 8 });
+ std::vector<int> output;
+
+ using vector_titer = decltype(MakeTransformIterator(input.begin(), add1));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<vector_titer, vector_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<int, vector_titer::reference>::value, "reference");
+
+ using vector_ctiter = decltype(MakeTransformIterator(input.cbegin(), add1));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_ctiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_ctiter::value_type>::value, "value_type");
+ static_assert(std::is_same<vector_ctiter, vector_ctiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, vector_ctiter::reference>::value, "reference");
+
+ using vector_rtiter = decltype(MakeTransformIterator(input.rbegin(), add1));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_rtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_rtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<vector_rtiter, vector_rtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, vector_rtiter::reference>::value, "reference");
+
+ using vector_crtiter = decltype(MakeTransformIterator(input.crbegin(), add1));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_crtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_crtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<vector_crtiter, vector_crtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, vector_crtiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), add1),
+ MakeTransformIterator(input.end(), add1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 2, 8, 4, 9 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.cbegin(), add1),
+ MakeTransformIterator(input.cend(), add1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 2, 8, 4, 9 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.rbegin(), add1),
+ MakeTransformIterator(input.rend(), add1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 9, 4, 8, 2 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.crbegin(), add1),
+ MakeTransformIterator(input.crend(), add1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 9, 4, 8, 2 }), output);
+ output.clear();
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.begin(), add1)[i]);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.cbegin(), add1)[i]);
+ ptrdiff_t index_from_rbegin = static_cast<ptrdiff_t>(input.size() - i - 1u);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.rbegin(), add1)[index_from_rbegin]);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.crbegin(), add1)[index_from_rbegin]);
+ ptrdiff_t index_from_end = -static_cast<ptrdiff_t>(input.size() - i);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.end(), add1)[index_from_end]);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.cend(), add1)[index_from_end]);
+ ptrdiff_t index_from_rend = -1 - static_cast<ptrdiff_t>(i);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.rend(), add1)[index_from_rend]);
+ ASSERT_EQ(input[i].value + 1, MakeTransformIterator(input.crend(), add1)[index_from_rend]);
+
+ ASSERT_EQ(MakeTransformIterator(input.begin(), add1) + i,
+ MakeTransformIterator(input.begin() + i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.cbegin(), add1) + i,
+ MakeTransformIterator(input.cbegin() + i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.rbegin(), add1) + i,
+ MakeTransformIterator(input.rbegin() + i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.crbegin(), add1) + i,
+ MakeTransformIterator(input.crbegin() + i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.end(), add1) - i,
+ MakeTransformIterator(input.end() - i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.cend(), add1) - i,
+ MakeTransformIterator(input.cend() - i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.rend(), add1) - i,
+ MakeTransformIterator(input.rend() - i, add1));
+ ASSERT_EQ(MakeTransformIterator(input.crend(), add1) - i,
+ MakeTransformIterator(input.crend() - i, add1));
+ }
+ ASSERT_EQ(input.end(),
+ (MakeTransformIterator(input.begin(), add1) + input.size()).base());
+ ASSERT_EQ(MakeTransformIterator(input.end(), add1) - MakeTransformIterator(input.begin(), add1),
+ static_cast<ptrdiff_t>(input.size()));
+
+ // Test iterator->const_iterator conversion and comparison.
+ auto it = MakeTransformIterator(input.begin(), add1);
+ decltype(MakeTransformIterator(input.cbegin(), add1)) cit = it;
+ static_assert(!std::is_same<decltype(it), decltype(cit)>::value, "Types must be different");
+ ASSERT_EQ(it, cit);
+ auto rit = MakeTransformIterator(input.rbegin(), add1);
+ decltype(MakeTransformIterator(input.crbegin(), add1)) crit(rit);
+ static_assert(!std::is_same<decltype(rit), decltype(crit)>::value, "Types must be different");
+ ASSERT_EQ(rit, crit);
+}
+
+TEST(TransformIterator, ListSub1) {
+ auto sub1 = [](const ValueHolder& h) { return h.value - 1; }; // NOLINT [readability/braces]
+ std::list<ValueHolder> input({ 2, 3, 5, 7, 11 });
+ std::vector<int> output;
+
+ using list_titer = decltype(MakeTransformIterator(input.begin(), sub1));
+ static_assert(std::is_same<std::bidirectional_iterator_tag,
+ list_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, list_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<list_titer, list_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<int, list_titer::reference>::value, "reference");
+
+ using list_ctiter = decltype(MakeTransformIterator(input.cbegin(), sub1));
+ static_assert(std::is_same<std::bidirectional_iterator_tag,
+ list_ctiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, list_ctiter::value_type>::value, "value_type");
+ static_assert(std::is_same<list_ctiter, list_ctiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, list_ctiter::reference>::value, "reference");
+
+ using list_rtiter = decltype(MakeTransformIterator(input.rbegin(), sub1));
+ static_assert(std::is_same<std::bidirectional_iterator_tag,
+ list_rtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, list_rtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<list_rtiter, list_rtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, list_rtiter::reference>::value, "reference");
+
+ using list_crtiter = decltype(MakeTransformIterator(input.crbegin(), sub1));
+ static_assert(std::is_same<std::bidirectional_iterator_tag,
+ list_crtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, list_crtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<list_crtiter, list_crtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, list_crtiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), sub1),
+ MakeTransformIterator(input.end(), sub1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 2, 4, 6, 10 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.cbegin(), sub1),
+ MakeTransformIterator(input.cend(), sub1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 1, 2, 4, 6, 10 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.rbegin(), sub1),
+ MakeTransformIterator(input.rend(), sub1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 10, 6, 4, 2, 1 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.crbegin(), sub1),
+ MakeTransformIterator(input.crend(), sub1),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 10, 6, 4, 2, 1 }), output);
+ output.clear();
+
+ // Test iterator->const_iterator conversion and comparison.
+ auto it = MakeTransformIterator(input.begin(), sub1);
+ decltype(MakeTransformIterator(input.cbegin(), sub1)) cit = it;
+ static_assert(!std::is_same<decltype(it), decltype(cit)>::value, "Types must be different");
+ ASSERT_EQ(it, cit);
+}
+
+TEST(TransformIterator, ForwardListSub1) {
+ auto mul3 = [](const ValueHolder& h) { return h.value * 3; }; // NOLINT [readability/braces]
+ std::forward_list<ValueHolder> input({ 1, 1, 2, 3, 5, 8 });
+ std::vector<int> output;
+
+ using flist_titer = decltype(MakeTransformIterator(input.begin(), mul3));
+ static_assert(std::is_same<std::forward_iterator_tag,
+ flist_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, flist_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<flist_titer, flist_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<int, flist_titer::reference>::value, "reference");
+
+ using flist_ctiter = decltype(MakeTransformIterator(input.cbegin(), mul3));
+ static_assert(std::is_same<std::forward_iterator_tag,
+ flist_ctiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, flist_ctiter::value_type>::value, "value_type");
+ static_assert(std::is_same<flist_ctiter, flist_ctiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int, flist_ctiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), mul3),
+ MakeTransformIterator(input.end(), mul3),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 3, 3, 6, 9, 15, 24 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.cbegin(), mul3),
+ MakeTransformIterator(input.cend(), mul3),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 3, 3, 6, 9, 15, 24 }), output);
+ output.clear();
+
+ // Test iterator->const_iterator conversion and comparison.
+ auto it = MakeTransformIterator(input.begin(), mul3);
+ decltype(MakeTransformIterator(input.cbegin(), mul3)) cit = it;
+ static_assert(!std::is_same<decltype(it), decltype(cit)>::value, "Types must be different");
+ ASSERT_EQ(it, cit);
+}
+
+TEST(TransformIterator, VectorConstReference) {
+ auto ref = [](const ValueHolder& h) -> const int& { return h.value; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> input({ 7, 3, 1, 2, 4, 8 });
+ std::vector<int> output;
+
+ using vector_titer = decltype(MakeTransformIterator(input.begin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_titer::reference>::value, "reference");
+
+ using vector_ctiter = decltype(MakeTransformIterator(input.cbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_ctiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_ctiter::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_ctiter::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_ctiter::reference>::value, "reference");
+
+ using vector_rtiter = decltype(MakeTransformIterator(input.rbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_rtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_rtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_rtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_rtiter::reference>::value, "reference");
+
+ using vector_crtiter = decltype(MakeTransformIterator(input.crbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_crtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_crtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_crtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_crtiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), ref),
+ MakeTransformIterator(input.end(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 7, 3, 1, 2, 4, 8 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.cbegin(), ref),
+ MakeTransformIterator(input.cend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 7, 3, 1, 2, 4, 8 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.rbegin(), ref),
+ MakeTransformIterator(input.rend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 4, 2, 1, 3, 7 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.crbegin(), ref),
+ MakeTransformIterator(input.crend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 4, 2, 1, 3, 7 }), output);
+ output.clear();
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.begin(), ref)[i]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.cbegin(), ref)[i]);
+ ptrdiff_t index_from_rbegin = static_cast<ptrdiff_t>(input.size() - i - 1u);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rbegin(), ref)[index_from_rbegin]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.crbegin(), ref)[index_from_rbegin]);
+ ptrdiff_t index_from_end = -static_cast<ptrdiff_t>(input.size() - i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.end(), ref)[index_from_end]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.cend(), ref)[index_from_end]);
+ ptrdiff_t index_from_rend = -1 - static_cast<ptrdiff_t>(i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rend(), ref)[index_from_rend]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.crend(), ref)[index_from_rend]);
+
+ ASSERT_EQ(MakeTransformIterator(input.begin(), ref) + i,
+ MakeTransformIterator(input.begin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.cbegin(), ref) + i,
+ MakeTransformIterator(input.cbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rbegin(), ref) + i,
+ MakeTransformIterator(input.rbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.crbegin(), ref) + i,
+ MakeTransformIterator(input.crbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - i,
+ MakeTransformIterator(input.end() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.cend(), ref) - i,
+ MakeTransformIterator(input.cend() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rend(), ref) - i,
+ MakeTransformIterator(input.rend() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.crend(), ref) - i,
+ MakeTransformIterator(input.crend() - i, ref));
+ }
+ ASSERT_EQ(input.end(),
+ (MakeTransformIterator(input.begin(), ref) + input.size()).base());
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - MakeTransformIterator(input.begin(), ref),
+ static_cast<ptrdiff_t>(input.size()));
+}
+
+TEST(TransformIterator, VectorNonConstReference) {
+ auto ref = [](ValueHolder& h) -> int& { return h.value; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> input({ 7, 3, 1, 2, 4, 8 });
+ std::vector<int> output;
+
+ using vector_titer = decltype(MakeTransformIterator(input.begin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<int*, vector_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<int&, vector_titer::reference>::value, "reference");
+
+ using vector_rtiter = decltype(MakeTransformIterator(input.rbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_rtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_rtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<int*, vector_rtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int&, vector_rtiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), ref),
+ MakeTransformIterator(input.end(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 7, 3, 1, 2, 4, 8 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.rbegin(), ref),
+ MakeTransformIterator(input.rend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 4, 2, 1, 3, 7 }), output);
+ output.clear();
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.begin(), ref)[i]);
+ ptrdiff_t index_from_rbegin = static_cast<ptrdiff_t>(input.size() - i - 1u);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rbegin(), ref)[index_from_rbegin]);
+ ptrdiff_t index_from_end = -static_cast<ptrdiff_t>(input.size() - i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.end(), ref)[index_from_end]);
+ ptrdiff_t index_from_rend = -1 - static_cast<ptrdiff_t>(i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rend(), ref)[index_from_rend]);
+
+ ASSERT_EQ(MakeTransformIterator(input.begin(), ref) + i,
+ MakeTransformIterator(input.begin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rbegin(), ref) + i,
+ MakeTransformIterator(input.rbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - i,
+ MakeTransformIterator(input.end() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rend(), ref) - i,
+ MakeTransformIterator(input.rend() - i, ref));
+ }
+ ASSERT_EQ(input.end(),
+ (MakeTransformIterator(input.begin(), ref) + input.size()).base());
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - MakeTransformIterator(input.begin(), ref),
+ static_cast<ptrdiff_t>(input.size()));
+
+ // Test writing through the transform iterator.
+ std::list<int> transform_input({ 1, -1, 2, -2, 3, -3 });
+ std::vector<ValueHolder> transformed(transform_input.size(), 0);
+ std::transform(transform_input.begin(),
+ transform_input.end(),
+ MakeTransformIterator(transformed.begin(), ref),
+ [](int v) { return -2 * v; });
+ ASSERT_EQ(std::vector<ValueHolder>({ -2, 2, -4, 4, -6, 6 }), transformed);
+}
+
+TEST(TransformIterator, VectorConstAndNonConstReference) {
+ struct Ref {
+ int& operator()(ValueHolder& h) const { return h.value; }
+ const int& operator()(const ValueHolder& h) const { return h.value; }
+ };
+ Ref ref;
+ std::vector<ValueHolder> input({ 7, 3, 1, 2, 4, 8 });
+ std::vector<int> output;
+
+ using vector_titer = decltype(MakeTransformIterator(input.begin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_titer::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_titer::value_type>::value, "value_type");
+ static_assert(std::is_same<int*, vector_titer::pointer>::value, "pointer");
+ static_assert(std::is_same<int&, vector_titer::reference>::value, "reference");
+
+ using vector_ctiter = decltype(MakeTransformIterator(input.cbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_ctiter::iterator_category>::value, "category");
+ // static_assert(std::is_same<int, vector_ctiter::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_ctiter::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_ctiter::reference>::value, "reference");
+
+ using vector_rtiter = decltype(MakeTransformIterator(input.rbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_rtiter::iterator_category>::value, "category");
+ static_assert(std::is_same<int, vector_rtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<int*, vector_rtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<int&, vector_rtiter::reference>::value, "reference");
+
+ using vector_crtiter = decltype(MakeTransformIterator(input.crbegin(), ref));
+ static_assert(std::is_same<std::random_access_iterator_tag,
+ vector_crtiter::iterator_category>::value, "category");
+ // static_assert(std::is_same<int, vector_crtiter::value_type>::value, "value_type");
+ static_assert(std::is_same<const int*, vector_crtiter::pointer>::value, "pointer");
+ static_assert(std::is_same<const int&, vector_crtiter::reference>::value, "reference");
+
+ std::copy(MakeTransformIterator(input.begin(), ref),
+ MakeTransformIterator(input.end(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 7, 3, 1, 2, 4, 8 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.cbegin(), ref),
+ MakeTransformIterator(input.cend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 7, 3, 1, 2, 4, 8 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.rbegin(), ref),
+ MakeTransformIterator(input.rend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 4, 2, 1, 3, 7 }), output);
+ output.clear();
+
+ std::copy(MakeTransformIterator(input.crbegin(), ref),
+ MakeTransformIterator(input.crend(), ref),
+ std::back_inserter(output));
+ ASSERT_EQ(std::vector<int>({ 8, 4, 2, 1, 3, 7 }), output);
+ output.clear();
+
+ for (size_t i = 0; i != input.size(); ++i) {
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.begin(), ref)[i]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.cbegin(), ref)[i]);
+ ptrdiff_t index_from_rbegin = static_cast<ptrdiff_t>(input.size() - i - 1u);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rbegin(), ref)[index_from_rbegin]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.crbegin(), ref)[index_from_rbegin]);
+ ptrdiff_t index_from_end = -static_cast<ptrdiff_t>(input.size() - i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.end(), ref)[index_from_end]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.cend(), ref)[index_from_end]);
+ ptrdiff_t index_from_rend = -1 - static_cast<ptrdiff_t>(i);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.rend(), ref)[index_from_rend]);
+ ASSERT_EQ(input[i].value, MakeTransformIterator(input.crend(), ref)[index_from_rend]);
+
+ ASSERT_EQ(MakeTransformIterator(input.begin(), ref) + i,
+ MakeTransformIterator(input.begin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.cbegin(), ref) + i,
+ MakeTransformIterator(input.cbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rbegin(), ref) + i,
+ MakeTransformIterator(input.rbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.crbegin(), ref) + i,
+ MakeTransformIterator(input.crbegin() + i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - i,
+ MakeTransformIterator(input.end() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.cend(), ref) - i,
+ MakeTransformIterator(input.cend() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.rend(), ref) - i,
+ MakeTransformIterator(input.rend() - i, ref));
+ ASSERT_EQ(MakeTransformIterator(input.crend(), ref) - i,
+ MakeTransformIterator(input.crend() - i, ref));
+ }
+ ASSERT_EQ(input.end(),
+ (MakeTransformIterator(input.begin(), ref) + input.size()).base());
+ ASSERT_EQ(MakeTransformIterator(input.end(), ref) - MakeTransformIterator(input.begin(), ref),
+ static_cast<ptrdiff_t>(input.size()));
+
+ // Test iterator->const_iterator conversion and comparison.
+ auto it = MakeTransformIterator(input.begin(), ref);
+ decltype(MakeTransformIterator(input.cbegin(), ref)) cit = it;
+ static_assert(!std::is_same<decltype(it), decltype(cit)>::value, "Types must be different");
+ ASSERT_EQ(it, cit);
+ auto rit = MakeTransformIterator(input.rbegin(), ref);
+ decltype(MakeTransformIterator(input.crbegin(), ref)) crit(rit);
+ static_assert(!std::is_same<decltype(rit), decltype(crit)>::value, "Types must be different");
+ ASSERT_EQ(rit, crit);
+
+ // Test writing through the transform iterator.
+ std::list<int> transform_input({ 42, 73, 11, 17 });
+ std::vector<ValueHolder> transformed(transform_input.size(), 0);
+ std::transform(transform_input.begin(),
+ transform_input.end(),
+ MakeTransformIterator(transformed.begin(), ref),
+ [](int v) { return -v; });
+ ASSERT_EQ(std::vector<ValueHolder>({ -42, -73, -11, -17 }), transformed);
+}
+
+TEST(TransformIterator, TransformRange) {
+ auto ref = [](ValueHolder& h) -> int& { return h.value; }; // NOLINT [readability/braces]
+ std::vector<ValueHolder> data({ 1, 0, 1, 3, 1, 0 });
+
+ for (int& v : MakeTransformRange(data, ref)) {
+ v += 11;
+ }
+ ASSERT_EQ(std::vector<ValueHolder>({ 12, 11, 12, 14, 12, 11 }), data);
+}
+
+} // namespace art