v1.4.4

source/core/StarSmallVector.hpp

@@ -0,0 +1,447 @@
+#ifndef STAR_SMALL_VECTOR_HPP
+#define STAR_SMALL_VECTOR_HPP
+
+#include "StarAlgorithm.hpp"
+
+namespace Star {
+
+// A vector that is stack allocated up to a maximum size, becoming heap
+// allocated when it grows beyond that size.  Always takes up stack space of
+// MaxStackSize * sizeof(Element).
+template <typename Element, size_t MaxStackSize>
+class SmallVector {
+public:
+  typedef Element* iterator;
+  typedef Element const* const_iterator;
+
+  typedef std::reverse_iterator<iterator> reverse_iterator;
+  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+  typedef Element value_type;
+
+  typedef Element& reference;
+  typedef Element const& const_reference;
+
+  SmallVector();
+  SmallVector(SmallVector const& other);
+  SmallVector(SmallVector&& other);
+  template <typename OtherElement, size_t OtherMaxStackSize>
+  SmallVector(SmallVector<OtherElement, OtherMaxStackSize> const& other);
+  template <class Iterator>
+  SmallVector(Iterator first, Iterator last);
+  SmallVector(size_t size, Element const& value = Element());
+  SmallVector(initializer_list<Element> list);
+  ~SmallVector();
+
+  SmallVector& operator=(SmallVector const& other);
+  SmallVector& operator=(SmallVector&& other);
+  SmallVector& operator=(std::initializer_list<Element> list);
+
+  size_t size() const;
+  bool empty() const;
+  void resize(size_t size, Element const& e = Element());
+  void reserve(size_t capacity);
+
+  reference at(size_t i);
+  const_reference at(size_t i) const;
+
+  reference operator[](size_t i);
+  const_reference operator[](size_t i) const;
+
+  const_iterator begin() const;
+  const_iterator end() const;
+
+  iterator begin();
+  iterator end();
+
+  const_reverse_iterator rbegin() const;
+  const_reverse_iterator rend() const;
+
+  reverse_iterator rbegin();
+  reverse_iterator rend();
+
+  // Pointer to internal data, always valid even if empty.
+  Element const* ptr() const;
+  Element* ptr();
+
+  void push_back(Element e);
+  void pop_back();
+
+  iterator insert(iterator pos, Element e);
+  template <typename Iterator>
+  iterator insert(iterator pos, Iterator begin, Iterator end);
+  iterator insert(iterator pos, initializer_list<Element> list);
+
+  template <typename... Args>
+  void emplace(iterator pos, Args&&... args);
+
+  template <typename... Args>
+  void emplace_back(Args&&... args);
+
+  void clear();
+
+  iterator erase(iterator pos);
+  iterator erase(iterator begin, iterator end);
+
+  bool operator==(SmallVector const& other) const;
+  bool operator!=(SmallVector const& other) const;
+  bool operator<(SmallVector const& other) const;
+
+private:
+  typename std::aligned_storage<MaxStackSize * sizeof(Element), alignof(Element)>::type m_stackElements;
+
+  bool isHeapAllocated() const;
+
+  Element* m_begin;
+  Element* m_end;
+  Element* m_capacity;
+};
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector() {
+  m_begin = (Element*)&m_stackElements;
+  m_end = m_begin;
+  m_capacity = m_begin + MaxStackSize;
+}
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::~SmallVector() {
+  clear();
+  if (isHeapAllocated()) {
+    free(m_begin, (m_capacity - m_begin) * sizeof(Element));
+  }
+}
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector(SmallVector const& other)
+  : SmallVector() {
+  insert(begin(), other.begin(), other.end());
+}
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector(SmallVector&& other)
+  : SmallVector() {
+    for (auto& e : other)
+      emplace_back(move(e));
+}
+
+template <typename Element, size_t MaxStackSize>
+template <typename OtherElement, size_t OtherMaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector(SmallVector<OtherElement, OtherMaxStackSize> const& other)
+  : SmallVector() {
+    for (auto const& e : other)
+      emplace_back(e);
+}
+
+template <typename Element, size_t MaxStackSize>
+template <class Iterator>
+SmallVector<Element, MaxStackSize>::SmallVector(Iterator first, Iterator last)
+  : SmallVector() {
+    insert(begin(), first, last);
+}
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector(size_t size, Element const& value)
+  : SmallVector() {
+    resize(size, value);
+}
+
+template <typename Element, size_t MaxStackSize>
+SmallVector<Element, MaxStackSize>::SmallVector(initializer_list<Element> list)
+  : SmallVector() {
+    for (auto const& e : list)
+      emplace_back(e);
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::operator=(SmallVector const& other) -> SmallVector& {
+  if (this == &other)
+    return *this;
+
+  resize(other.size());
+  for (size_t i = 0; i < size(); ++i)
+    operator[](i) = other[i];
+
+  return *this;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::operator=(SmallVector&& other) -> SmallVector& {
+  resize(other.size());
+  for (size_t i = 0; i < size(); ++i)
+    operator[](i) = move(other[i]);
+
+  return *this;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::operator=(std::initializer_list<Element> list) -> SmallVector& {
+  resize(list.size());
+  for (size_t i = 0; i < size(); ++i)
+    operator[](i) = move(list[i]);
+  return *this;
+}
+
+template <typename Element, size_t MaxStackSize>
+size_t SmallVector<Element, MaxStackSize>::size() const {
+  return m_end - m_begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+bool SmallVector<Element, MaxStackSize>::empty() const {
+  return m_begin == m_end;
+}
+
+template <typename Element, size_t MaxStackSize>
+void SmallVector<Element, MaxStackSize>::resize(size_t size, Element const& e) {
+  reserve(size);
+
+  for (size_t i = this->size(); i > size; --i)
+    pop_back();
+  for (size_t i = this->size(); i < size; ++i)
+    emplace_back(e);
+}
+
+template <typename Element, size_t MaxStackSize>
+void SmallVector<Element, MaxStackSize>::reserve(size_t newCapacity) {
+  size_t oldCapacity = m_capacity - m_begin;
+  if (newCapacity > oldCapacity) {
+    newCapacity = max(oldCapacity * 2, newCapacity);
+    auto newMem = (Element*)Star::malloc(newCapacity * sizeof(Element));
+    if (!newMem)
+      throw MemoryException::format("Could not set new SmallVector capacity %s\n", newCapacity);
+
+    size_t size = m_end - m_begin;
+    auto oldMem = m_begin;
+    auto oldHeapAllocated = isHeapAllocated();
+
+    // We assume that move constructors can never throw.
+    for (size_t i = 0; i < size; ++i) {
+      new (&newMem[i]) Element(move(oldMem[i]));
+    }
+
+    m_begin = newMem;
+    m_end = m_begin + size;
+    m_capacity = m_begin + newCapacity;
+
+    auto freeOldMem = finally([=]() {
+      if (oldHeapAllocated)
+          Star::free(oldMem, oldCapacity * sizeof(Element));
+    });
+
+    for (size_t i = 0; i < size; ++i) {
+      oldMem[i].~Element();
+    }
+  }
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::at(size_t i) -> reference {
+  if (i >= size())
+    throw OutOfRangeException::format("out of range in SmallVector::at(%s)", i);
+  return m_begin[i];
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::at(size_t i) const -> const_reference {
+  if (i >= size())
+    throw OutOfRangeException::format("out of range in SmallVector::at(%s)", i);
+  return m_begin[i];
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::operator[](size_t i) -> reference {
+  starAssert(i < size());
+  return m_begin[i];
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::operator[](size_t i) const -> const_reference {
+  starAssert(i < size());
+  return m_begin[i];
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::begin() const -> const_iterator {
+  return m_begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::end() const -> const_iterator {
+  return m_end;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::begin() -> iterator {
+  return m_begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::end() -> iterator {
+  return m_end;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::rbegin() const -> const_reverse_iterator {
+    return const_reverse_iterator(end());
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::rend() const -> const_reverse_iterator {
+    return const_reverse_iterator(begin());
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::rbegin() -> reverse_iterator {
+    return reverse_iterator(end());
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::rend() -> reverse_iterator {
+    return reverse_iterator(begin());
+}
+
+template <typename Element, size_t MaxStackSize>
+Element const* SmallVector<Element, MaxStackSize>::ptr() const {
+  return m_begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+Element* SmallVector<Element, MaxStackSize>::ptr() {
+  return m_begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+void SmallVector<Element, MaxStackSize>::push_back(Element e) {
+  emplace_back(move(e));
+}
+
+template <typename Element, size_t MaxStackSize>
+void SmallVector<Element, MaxStackSize>::pop_back() {
+  if (m_begin == m_end)
+    throw OutOfRangeException("SmallVector::pop_back called on empty SmallVector");
+  --m_end;
+  m_end->~Element();
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::insert(iterator pos, Element e) -> iterator {
+  emplace(pos, move(e));
+  return pos;
+}
+
+template <typename Element, size_t MaxStackSize>
+template <typename Iterator>
+auto SmallVector<Element, MaxStackSize>::insert(iterator pos, Iterator begin, Iterator end) -> iterator {
+  size_t toAdd = std::distance(begin, end);
+  size_t startIndex = pos - m_begin;
+  size_t endIndex = startIndex + toAdd;
+  size_t toShift = size() - startIndex;
+
+  resize(size() + toAdd);
+
+  for (size_t i = toShift; i != 0; --i)
+    operator[](endIndex + i - 1) = move(operator[](startIndex + i - 1));
+
+  for (size_t i = 0; i != toAdd; ++i)
+    operator[](startIndex + i) = *begin++;
+
+  return pos;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::insert(iterator pos, initializer_list<Element> list) -> iterator {
+  return insert(pos, list.begin(), list.end());
+}
+
+template <typename Element, size_t MaxStackSize>
+template <typename... Args>
+void SmallVector<Element, MaxStackSize>::emplace(iterator pos, Args&&... args) {
+  size_t index = pos - m_begin;
+  emplace_back(Element());
+  for (size_t i = size() - 1; i != index; --i)
+    operator[](i) = move(operator[](i - 1));
+  operator[](index) = Element(forward<Args>(args)...);
+}
+
+template <typename Element, size_t MaxStackSize>
+template <typename... Args>
+void SmallVector<Element, MaxStackSize>::emplace_back(Args&&... args) {
+  if (m_end == m_capacity)
+    reserve(size() + 1);
+  new (m_end) Element(forward<Args>(args)...);
+  ++m_end;
+}
+
+template <typename Element, size_t MaxStackSize>
+void SmallVector<Element, MaxStackSize>::clear() {
+  while (m_begin != m_end)
+    pop_back();
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::erase(iterator pos) -> iterator {
+  size_t index = pos - ptr();
+  for (size_t i = index; i < size() - 1; ++i)
+    operator[](i) = move(operator[](i + 1));
+  pop_back();
+  return pos;
+}
+
+template <typename Element, size_t MaxStackSize>
+auto SmallVector<Element, MaxStackSize>::erase(iterator begin, iterator end) -> iterator {
+  size_t startIndex = begin - ptr();
+  size_t endIndex = end - ptr();
+  size_t toRemove = endIndex - startIndex;
+  for (size_t i = endIndex; i < size(); ++i)
+    operator[](startIndex + (i - endIndex)) = move(operator[](i));
+  resize(size() - toRemove);
+  return begin;
+}
+
+template <typename Element, size_t MaxStackSize>
+bool SmallVector<Element, MaxStackSize>::operator==(SmallVector const& other) const {
+  if (this == &other)
+    return true;
+
+  if (size() != other.size())
+    return false;
+
+  for (size_t i = 0; i < size(); ++i) {
+    if (operator[](i) != other[i])
+      return false;
+  }
+  return true;
+}
+
+template <typename Element, size_t MaxStackSize>
+bool SmallVector<Element, MaxStackSize>::operator!=(SmallVector const& other) const {
+  return !operator==(other);
+}
+
+template <typename Element, size_t MaxStackSize>
+bool SmallVector<Element, MaxStackSize>::operator<(SmallVector const& other) const {
+  for (size_t i = 0; i < size(); ++i) {
+    if (i >= other.size())
+      return false;
+
+    Element const& a = operator[](i);
+    Element const& b = other[i];
+
+    if (a < b)
+      return true;
+    else if (b < a)
+      return false;
+  }
+
+  return size() < other.size();
+}
+
+template <typename Element, size_t MaxStackSize>
+bool SmallVector<Element, MaxStackSize>::isHeapAllocated() const {
+  return m_begin != (Element*)&m_stackElements;
+}
+
+}
+
+#endif