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ds: Actually fix iterators and add clear
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@rHermes
rHermes committed Jun 23, 2024
1 parent 212de76 commit e1b1025
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Showing 2 changed files with 91 additions and 33 deletions.
88 changes: 56 additions & 32 deletions include/hage/ds/avl_tree.hpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@ class AVLTree

AVLTree()
{
// This nodes parent is always the last node.
// This nodes parent is always the last node. It's value is always 0
m_end = get_node();
}

Expand All @@ -43,11 +43,11 @@ class AVLTree
m_nodes[m_end].m_parent = m_root;

m_size++;
return { make_iterator<false>(m_root), true };
return { make_iterator(m_root), true };
}

const auto [id, inserted] = internal_try_emplace(m_root, std::forward<K>(key), std::forward<Args>(args)...);
return { make_iterator<false>(id), inserted };
return { make_iterator(id), inserted };
}

[[nodiscard]] constexpr iterator find(const Key& key)
Expand All @@ -56,51 +56,73 @@ class AVLTree
if (id == -1) {
return end();
} else {
return make_iterator<false>(id);
return make_iterator(id);
}
}

[[nodiscard]] constexpr iterator end() noexcept { return make_iterator<false>(m_end); }
[[nodiscard]] constexpr iterator begin() noexcept { return make_iterator<false>(m_begin); }
[[nodiscard]] constexpr const_iterator find(const Key& key) const
{
auto id = internal_find(m_root, key);
if (id == -1) {
return end();
} else {
return make_const_iterator(id);
}
}

[[nodiscard]] constexpr bool contains(const Key& key) const { return internal_find(m_root, key) != -1; }

[[nodiscard]] constexpr size_type size() const { return m_size; }
[[nodiscard]] constexpr bool empty() const { return size() == 0; }

[[nodiscard]] constexpr const_iterator end() const noexcept { return make_iterator<true>(m_end); }
[[nodiscard]] constexpr const_iterator begin() const noexcept { return make_iterator<true>(m_begin); }
constexpr void clear()
{
// Important to note here, that the end iterator, must be valid.
// we have the understanding that m_last is always 0.
// we are freeing from the back, so that the smallest nodes will be used first.
for (std::size_t i = m_nodes.size() - 1; 0 < i; i--) {
free_node(i);
}
m_size = 0;
m_root = -1;
}

[[nodiscard]] constexpr const_iterator cend() const noexcept { return make_iterator<true>(m_end); }
[[nodiscard]] constexpr const_iterator cbegin() const noexcept { return make_iterator<true>(m_begin); }
[[nodiscard]] constexpr iterator end() noexcept { return make_iterator(m_end); }
[[nodiscard]] constexpr iterator begin() noexcept { return make_iterator(m_begin); }

[[nodiscard]] constexpr const_iterator end() const noexcept { return make_const_iterator(m_end); }
[[nodiscard]] constexpr const_iterator begin() const noexcept { return make_const_iterator(m_begin); }

[[nodiscard]] constexpr const_iterator cend() const noexcept { return make_const_iterator(m_end); }
[[nodiscard]] constexpr const_iterator cbegin() const noexcept { return make_const_iterator(m_begin); }

[[nodiscard]] constexpr reverse_iterator rbegin() noexcept
{
return std::make_reverse_iterator(make_iterator<false>(m_end));
return std::make_reverse_iterator(make_iterator(m_end));
}
[[nodiscard]] constexpr reverse_iterator rend() noexcept
{
return std::make_reverse_iterator(make_iterator<false>(m_begin));
return std::make_reverse_iterator(make_iterator(m_begin));
}

[[nodiscard]] constexpr reverse_iterator rbegin() const noexcept
[[nodiscard]] constexpr const_reverse_iterator rbegin() const noexcept
{
return std::make_reverse_iterator(make_iterator<true>(m_end));
return std::make_reverse_iterator(make_const_iterator(m_end));
}
[[nodiscard]] constexpr reverse_iterator rend() const noexcept
[[nodiscard]] constexpr const_reverse_iterator rend() const noexcept
{
return std::make_reverse_iterator(make_iterator<true>(m_begin));
return std::make_reverse_iterator(make_const_iterator(m_begin));
}

[[nodiscard]] constexpr reverse_iterator crbegin() const noexcept
[[nodiscard]] constexpr const_reverse_iterator crbegin() const noexcept
{
return std::make_reverse_iterator(make_iterator<true>(m_end));
return std::make_reverse_iterator(make_const_iterator(m_end));
}
[[nodiscard]] constexpr reverse_iterator crend() const noexcept
[[nodiscard]] constexpr const_reverse_iterator crend() const noexcept
{
return std::make_reverse_iterator(make_iterator<true>(m_begin));
return std::make_reverse_iterator(make_const_iterator(m_begin));
}

[[nodiscard]] constexpr bool contains(const Key& key) const { return internal_find(m_root, key) != -1; }

[[nodiscard]] constexpr size_type size() const { return m_size; }
[[nodiscard]] constexpr bool empty() const { return size() == 0; }

private:
class Node
{
Expand Down Expand Up @@ -141,17 +163,18 @@ class AVLTree
class Iterator
{
private:
using tree_type = std::conditional_t<IsConst, const AVLTree, AVLTree>;
using node_type = std::conditional_t<IsConst, const Node, Node>;

public:
using iterator_category = std::bidirectional_iterator_tag;
using value_type = node_type;
using difference_type = std::int32_t;
using pointer = node_type*;
using reference = node_type&;
using pointer = value_type*;
using reference = value_type&;

Iterator() = default;
Iterator(AVLTree* tree, node_id_type id) : m_tree{ tree }, m_id{ id } {}
Iterator(tree_type* tree, node_id_type id) : m_tree{ tree }, m_id{ id } {}

constexpr reference operator*() const { return m_tree->m_nodes[m_id]; }
constexpr pointer operator->() const { return &m_tree->m_nodes[m_id]; }
Expand Down Expand Up @@ -243,17 +266,18 @@ class AVLTree
private:
friend class AVLTree;

AVLTree* m_tree{ nullptr };
tree_type* m_tree{ nullptr };
node_id_type m_id{ -1 };

// TODO(rHermes): create an "end" iterator, that doesn't take up a node. This could be done if we track the
// iterators a bit differently.
};

template<bool IsConst>
[[nodiscard]] constexpr Iterator<IsConst> make_iterator(node_id_type id)
[[nodiscard]] constexpr iterator make_iterator(node_id_type id) { return iterator{ this, id }; }

[[nodiscard]] constexpr const_iterator make_const_iterator(node_id_type id) const
{
return Iterator<IsConst>{ this, id };
return const_iterator{ this, id };
}

template<typename K, typename V>
Expand Down
36 changes: 35 additions & 1 deletion tests/avl_tree_tests.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ TEST_CASE("Simple avl tests")
REQUIRE_EQ(it, tree.end());
}

SUBCASE("We should be able to use -- to iteratte")
SUBCASE("We should be able to use -- to iterate")
{
auto it = tree.find(10);
REQUIRE_EQ(it->key(), 10);
Expand All @@ -54,6 +54,16 @@ TEST_CASE("Simple avl tests")
REQUIRE_EQ(it->key(), 100);
REQUIRE_EQ(it->value(), 10);
}

SUBCASE("Clearing should return all nodes to zero")
{
tree.clear();
REQUIRE_EQ(tree.size(), 0);

// inserting should work again
auto res = tree.try_emplace(10, 0xf001);
REQUIRE_UNARY(res.second);
}
}

TEST_CASE("AVL Tree iterator tests")
Expand Down Expand Up @@ -93,6 +103,18 @@ TEST_CASE("AVL Tree iterator tests")
}
}

SUBCASE("Const Forward iteration should work")
{
auto it = tree.cbegin();
int i = 0;
while (it != tree.cend()) {
REQUIRE_EQ(it->key(), i);
REQUIRE_EQ(it->value(), N - i);
it++;
i++;
}
}

SUBCASE("Reverse iteration should work")
{
auto it = tree.rbegin();
Expand All @@ -104,6 +126,18 @@ TEST_CASE("AVL Tree iterator tests")
i--;
}
}

SUBCASE("Const Reverse iteration should work")
{
auto it = tree.crbegin();
int i = N - 1;
while (it != tree.crend()) {
REQUIRE_EQ(it->key(), i);
REQUIRE_EQ(it->value(), N - i);
it++;
i--;
}
}
}

TEST_SUITE_END();

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