Introduce ctl::set and ctl::map

We now have a C++ red-black tree implementation that implements standard
template library compatible APIs while compiling 10x faster than libcxx.
It's not as beautiful as the red-black tree implementation in Plinko but
this will get the job done and the test proves it upholds all invariants

This change also restores CheckForMemoryLeaks() support and fixes a real
actual bug I discovered with Doug Lea's dlmalloc_inspect_all() function.

ctl/equal.h

@@ -0,0 +1,64 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef CTL_EQUAL_H_
+#define CTL_EQUAL_H_
+
+namespace ctl {
+
+template<class InputIt1, class InputIt2>
+bool
+equal(InputIt1 first1, InputIt1 last1, InputIt2 first2)
+{
+    for (; first1 != last1; ++first1, ++first2) {
+        if (!(*first1 == *first2)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// Overload that takes a predicate
+template<class InputIt1, class InputIt2, class BinaryPredicate>
+bool
+equal(InputIt1 first1, InputIt1 last1, InputIt2 first2, BinaryPredicate pred)
+{
+    for (; first1 != last1; ++first1, ++first2) {
+        if (!pred(*first1, *first2)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+// Overloads that take two ranges (C++14 and later)
+template<class InputIt1, class InputIt2>
+bool
+equal(InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2)
+{
+    for (; first1 != last1 && first2 != last2; ++first1, ++first2) {
+        if (!(*first1 == *first2)) {
+            return false;
+        }
+    }
+    return first1 == last1 && first2 == last2;
+}
+
+template<class InputIt1, class InputIt2, class BinaryPredicate>
+bool
+equal(InputIt1 first1,
+      InputIt1 last1,
+      InputIt2 first2,
+      InputIt2 last2,
+      BinaryPredicate pred)
+{
+    for (; first1 != last1 && first2 != last2; ++first1, ++first2) {
+        if (!pred(*first1, *first2)) {
+            return false;
+        }
+    }
+    return first1 == last1 && first2 == last2;
+}
+
+} // namespace ctl
+
+#endif /* CTL_EQUAL_H_ */

ctl/initializer_list.h

@@ -0,0 +1,64 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef _LIBCPP_INITIALIZER_LIST
+#define _LIBCPP_INITIALIZER_LIST
+
+namespace std {
+
+template<class T>
+class initializer_list
+{
+    constexpr initializer_list(const T* b, size_t s) noexcept
+      : begin_(b), size_(s)
+    {
+    }
+
+  public:
+    typedef T value_type;
+    typedef const T& reference;
+    typedef const T& const_reference;
+    typedef size_t size_type;
+    typedef const T* iterator;
+    typedef const T* const_iterator;
+
+    constexpr initializer_list() noexcept : begin_(nullptr), size_(0)
+    {
+    }
+
+    constexpr size_t size() const noexcept
+    {
+        return size_;
+    }
+
+    constexpr const T* begin() const noexcept
+    {
+        return begin_;
+    }
+
+    constexpr const T* end() const noexcept
+    {
+        return begin_ + size_;
+    }
+
+  private:
+    const T* begin_;
+    size_t size_;
+};
+
+template<class T>
+inline constexpr const T*
+begin(initializer_list<T> i) noexcept
+{
+    return i.begin();
+}
+
+template<class T>
+inline constexpr const T*
+end(initializer_list<T> i) noexcept
+{
+    return i.end();
+}
+
+} // namespace std
+
+#endif // _LIBCPP_INITIALIZER_LIST

ctl/less.h

@@ -0,0 +1,38 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef CTL_LESS_H_
+#define CTL_LESS_H_
+#include "utility.h"
+
+namespace ctl {
+
+template<class T = void>
+struct less
+{
+    constexpr bool operator()(const T& lhs, const T& rhs) const
+    {
+        return lhs < rhs;
+    }
+
+    typedef T first_argument_type;
+    typedef T second_argument_type;
+    typedef bool result_type;
+};
+
+template<>
+struct less<void>
+{
+    template<class T, class U>
+    constexpr auto operator()(T&& lhs,
+                              U&& rhs) const -> decltype(ctl::forward<T>(lhs) <
+                                                         ctl::forward<U>(rhs))
+    {
+        return ctl::forward<T>(lhs) < ctl::forward<U>(rhs);
+    }
+
+    typedef void is_transparent;
+};
+
+} // namespace ctl
+
+#endif /* CTL_LESS_H_ */

ctl/map.h

@@ -0,0 +1,352 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef CTL_MAP_H_
+#define CTL_MAP_H_
+#include "set.h"
+
+namespace ctl {
+
+template<typename Key, typename Value, typename Compare = ctl::less<Key>>
+class map
+{
+    class EntryCompare
+    {
+      public:
+        explicit EntryCompare(Compare comp = Compare()) : comp_(comp)
+        {
+        }
+
+        bool operator()(const ctl::pair<const Key, Value>& lhs,
+                        const ctl::pair<const Key, Value>& rhs) const
+        {
+            return comp_(lhs.first, rhs.first);
+        }
+
+      private:
+        Compare comp_;
+    };
+
+    ctl::set<ctl::pair<const Key, Value>, EntryCompare> data_;
+
+  public:
+    using key_type = Key;
+    using mapped_type = Value;
+    using value_type = ctl::pair<const Key, Value>;
+    using size_type = typename ctl::set<value_type, EntryCompare>::size_type;
+    using difference_type =
+      typename ctl::set<value_type, EntryCompare>::difference_type;
+    using key_compare = Compare;
+    using value_compare = EntryCompare;
+    using iterator = typename ctl::set<value_type, EntryCompare>::iterator;
+    using const_iterator =
+      typename ctl::set<value_type, EntryCompare>::const_iterator;
+    using reverse_iterator =
+      typename ctl::set<value_type, EntryCompare>::reverse_iterator;
+    using const_reverse_iterator =
+      typename ctl::set<value_type, EntryCompare>::const_reverse_iterator;
+
+    map() : data_(EntryCompare())
+    {
+    }
+
+    explicit map(const Compare& comp) : data_(EntryCompare(comp))
+    {
+    }
+
+    map(const map& other) = default;
+    map(map&& other) noexcept = default;
+    map(std::initializer_list<value_type> init, const Compare& comp = Compare())
+      : data_(init, EntryCompare(comp))
+    {
+    }
+
+    template<typename InputIt>
+    map(InputIt first, InputIt last, const Compare& comp = Compare())
+      : data_(first, last, EntryCompare(comp))
+    {
+    }
+
+    map& operator=(const map& other) = default;
+    map& operator=(map&& other) noexcept = default;
+    map& operator=(std::initializer_list<value_type> ilist)
+    {
+        data_ = ilist;
+        return *this;
+    }
+
+    iterator begin() noexcept
+    {
+        return data_.begin();
+    }
+
+    const_iterator begin() const noexcept
+    {
+        return data_.begin();
+    }
+
+    const_iterator cbegin() const noexcept
+    {
+        return data_.cbegin();
+    }
+
+    iterator end() noexcept
+    {
+        return data_.end();
+    }
+
+    const_iterator end() const noexcept
+    {
+        return data_.end();
+    }
+
+    const_iterator cend() const noexcept
+    {
+        return data_.cend();
+    }
+
+    reverse_iterator rbegin() noexcept
+    {
+        return data_.rbegin();
+    }
+
+    const_reverse_iterator rbegin() const noexcept
+    {
+        return data_.rbegin();
+    }
+
+    const_reverse_iterator crbegin() const noexcept
+    {
+        return data_.crbegin();
+    }
+
+    reverse_iterator rend() noexcept
+    {
+        return data_.rend();
+    }
+
+    const_reverse_iterator rend() const noexcept
+    {
+        return data_.rend();
+    }
+
+    const_reverse_iterator crend() const noexcept
+    {
+        return data_.crend();
+    }
+
+    bool empty() const noexcept
+    {
+        return data_.empty();
+    }
+
+    size_type size() const noexcept
+    {
+        return data_.size();
+    }
+
+    size_type max_size() const noexcept
+    {
+        return data_.max_size();
+    }
+
+    Value& operator[](const Key& key)
+    {
+        return ((data_.insert(make_pair(key, Value()))).first)->second;
+    }
+
+    Value& operator[](Key&& key)
+    {
+        return ((data_.insert(make_pair(ctl::move(key), Value()))).first)
+          ->second;
+    }
+
+    Value& at(const Key& key)
+    {
+        auto it = find(key);
+        if (it == end())
+            __builtin_trap();
+        return it->second;
+    }
+
+    const Value& at(const Key& key) const
+    {
+        auto it = find(key);
+        if (it == end())
+            __builtin_trap();
+        return it->second;
+    }
+
+    ctl::pair<iterator, bool> insert(const value_type& value)
+    {
+        return data_.insert(value);
+    }
+
+    ctl::pair<iterator, bool> insert(value_type&& value)
+    {
+        return data_.insert(ctl::move(value));
+    }
+
+    template<typename P>
+    ctl::pair<iterator, bool> insert(P&& value)
+    {
+        return data_.insert(value_type(ctl::forward<P>(value)));
+    }
+
+    iterator insert(const_iterator hint, const value_type& value)
+    {
+        return data_.insert(hint, value);
+    }
+
+    iterator insert(const_iterator hint, value_type&& value)
+    {
+        return data_.insert(hint, ctl::move(value));
+    }
+
+    template<typename P>
+    iterator insert(const_iterator hint, P&& value)
+    {
+        return data_.insert(hint, value_type(ctl::forward<P>(value)));
+    }
+
+    template<typename InputIt>
+    void insert(InputIt first, InputIt last)
+    {
+        data_.insert(first, last);
+    }
+
+    void insert(std::initializer_list<value_type> ilist)
+    {
+        data_.insert(ilist);
+    }
+
+    template<typename... Args>
+    ctl::pair<iterator, bool> emplace(Args&&... args)
+    {
+        return data_.emplace(ctl::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    iterator emplace_hint(const_iterator hint, Args&&... args)
+    {
+        return data_.emplace_hint(hint, ctl::forward<Args>(args)...);
+    }
+
+    iterator erase(const_iterator pos)
+    {
+        return data_.erase(pos);
+    }
+
+    iterator erase(const_iterator first, const_iterator last)
+    {
+        return data_.erase(first, last);
+    }
+
+    size_type erase(const Key& key)
+    {
+        return data_.erase(make_pair(key, Value()));
+    }
+
+    void swap(map& other) noexcept
+    {
+        data_.swap(other.data_);
+    }
+
+    void clear() noexcept
+    {
+        data_.clear();
+    }
+
+    iterator find(const Key& key)
+    {
+        return data_.find(make_pair(key, Value()));
+    }
+
+    const_iterator find(const Key& key) const
+    {
+        return data_.find(make_pair(key, Value()));
+    }
+
+    size_type count(const Key& key) const
+    {
+        return data_.count(make_pair(key, Value()));
+    }
+
+    iterator lower_bound(const Key& key)
+    {
+        return data_.lower_bound(make_pair(key, Value()));
+    }
+
+    const_iterator lower_bound(const Key& key) const
+    {
+        return data_.lower_bound(make_pair(key, Value()));
+    }
+
+    iterator upper_bound(const Key& key)
+    {
+        return data_.upper_bound(make_pair(key, Value()));
+    }
+
+    const_iterator upper_bound(const Key& key) const
+    {
+        return data_.upper_bound(make_pair(key, Value()));
+    }
+
+    ctl::pair<iterator, iterator> equal_range(const Key& key)
+    {
+        return data_.equal_range(make_pair(key, Value()));
+    }
+
+    ctl::pair<const_iterator, const_iterator> equal_range(const Key& key) const
+    {
+        return data_.equal_range(make_pair(key, Value()));
+    }
+
+    key_compare key_comp() const
+    {
+        return data_.value_comp().comp;
+    }
+
+    value_compare value_comp() const
+    {
+        return data_.value_comp();
+    }
+
+    friend bool operator==(const map& lhs, const map& rhs)
+    {
+        return lhs.data_ == rhs.data_;
+    }
+
+    friend bool operator!=(const map& lhs, const map& rhs)
+    {
+        return !(lhs == rhs);
+    }
+
+    friend bool operator<(const map& lhs, const map& rhs)
+    {
+        return lhs.data_ < rhs.data_;
+    }
+
+    friend bool operator<=(const map& lhs, const map& rhs)
+    {
+        return !(rhs < lhs);
+    }
+
+    friend bool operator>(const map& lhs, const map& rhs)
+    {
+        return rhs < lhs;
+    }
+
+    friend bool operator>=(const map& lhs, const map& rhs)
+    {
+        return !(lhs < rhs);
+    }
+
+    friend void swap(map& lhs, map& rhs) noexcept
+    {
+        lhs.swap(rhs);
+    }
+};
+
+} // namespace ctl
+
+#endif // CTL_MAP_H_

ctl/new.cc

@@ -34,7 +34,10 @@ _ctl_alloc(size_t n, size_t a)
 static void*
 _ctl_alloc1(size_t n)
 {
-    return _ctl_alloc(n, 1);
+    void* p;
+    if (!(p = malloc(n)))
+        __builtin_trap();
+    return p;
 }
 
 static void*
@@ -68,10 +71,21 @@ COSMOPOLITAN_C_END_
    now. If you have any brain cells left after reading this comment then go
    look at the eight operator delete weak references to free in the below. */
 
-__weak_reference(void* operator new(size_t, ctl::align_val_t), _ctl_alloc);
-__weak_reference(void* operator new[](size_t, ctl::align_val_t), _ctl_alloc);
-__weak_reference(void* operator new(size_t), _ctl_alloc1);
-__weak_reference(void* operator new[](size_t), _ctl_alloc1);
+__weak_reference(void*
+                 operator new(size_t, ctl::align_val_t),
+                 _ctl_alloc);
+
+__weak_reference(void*
+                 operator new[](size_t, ctl::align_val_t),
+                 _ctl_alloc);
+
+__weak_reference(void*
+                 operator new(size_t),
+                 _ctl_alloc1);
+
+__weak_reference(void*
+                 operator new[](size_t),
+                 _ctl_alloc1);
 
 // XXX clang-format currently mutilates these for some reason.
 // clang-format off

ctl/new.h

@@ -3,6 +3,10 @@
 #ifndef COSMOPOLITAN_CTL_NEW_H_
 #define COSMOPOLITAN_CTL_NEW_H_
 
+#ifndef TINY
+__static_yoink("__demangle");
+#endif
+
 namespace ctl {
 
 enum class align_val_t : size_t

ctl/pair.h

@@ -0,0 +1,150 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef CTL_PAIR_H_
+#define CTL_PAIR_H_
+#include "utility.h"
+
+namespace ctl {
+
+template<typename T1, typename T2>
+struct pair
+{
+    using first_type = T1;
+    using second_type = T2;
+
+    T1 first;
+    T2 second;
+
+    constexpr pair() : first(), second()
+    {
+    }
+
+    constexpr pair(const T1& x, const T2& y) : first(x), second(y)
+    {
+    }
+
+    constexpr pair(const pair<T1, T2>& p) : first(p.first), second(p.second)
+    {
+    }
+
+    template<class U1, class U2>
+    constexpr pair(U1&& x, U2&& y)
+      : first(ctl::forward<U1>(x)), second(ctl::forward<U2>(y))
+    {
+    }
+
+    template<class U1, class U2>
+    constexpr pair(const pair<U1, U2>& p) : first(p.first), second(p.second)
+    {
+    }
+
+    constexpr pair(pair<T1, T2>&& p)
+      : first(ctl::move(p.first)), second(ctl::move(p.second))
+    {
+    }
+
+    template<class U1, class U2>
+    constexpr pair(pair<U1, U2>&& p)
+      : first(ctl::move(p.first)), second(ctl::move(p.second))
+    {
+    }
+
+    pair& operator=(const pair& other)
+    {
+        first = other.first;
+        second = other.second;
+        return *this;
+    }
+
+    pair& operator=(pair&& other) noexcept
+    {
+        first = ctl::move(other.first);
+        second = ctl::move(other.second);
+        return *this;
+    }
+
+    template<class U1, class U2>
+    pair& operator=(const pair<U1, U2>& other)
+    {
+        first = other.first;
+        second = other.second;
+        return *this;
+    }
+
+    template<class U1, class U2>
+    pair& operator=(pair<U1, U2>&& other)
+    {
+        first = ctl::move(other.first);
+        second = ctl::move(other.second);
+        return *this;
+    }
+
+    void swap(pair& other) noexcept
+    {
+        using ctl::swap;
+        swap(first, other.first);
+        swap(second, other.second);
+    }
+};
+
+template<class T1, class T2>
+constexpr pair<T1, T2>
+make_pair(T1&& t, T2&& u)
+{
+    return pair<T1, T2>(ctl::forward<T1>(t), ctl::forward<T2>(u));
+}
+
+// Comparison operators
+template<class T1, class T2>
+constexpr bool
+operator==(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return lhs.first == rhs.first && lhs.second == rhs.second;
+}
+
+template<class T1, class T2>
+constexpr bool
+operator!=(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return !(lhs == rhs);
+}
+
+template<class T1, class T2>
+constexpr bool
+operator<(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return lhs.first < rhs.first ||
+           (!(rhs.first < lhs.first) && lhs.second < rhs.second);
+}
+
+template<class T1, class T2>
+constexpr bool
+operator<=(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return !(rhs < lhs);
+}
+
+template<class T1, class T2>
+constexpr bool
+operator>(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return rhs < lhs;
+}
+
+template<class T1, class T2>
+constexpr bool
+operator>=(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs)
+{
+    return !(lhs < rhs);
+}
+
+template<class T1, class T2>
+void
+swap(pair<T1, T2>& lhs, pair<T1, T2>& rhs) noexcept(noexcept(lhs.swap(rhs)))
+{
+    lhs.swap(rhs);
+}
+
+} // namespace ctl
+
+#endif // CTL_PAIR_H_

ctl/set.h

@@ -0,0 +1,945 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef CTL_SET_H_
+#define CTL_SET_H_
+#include "initializer_list.h"
+#include "less.h"
+#include "pair.h"
+
+namespace ctl {
+
+template<typename Key, typename Compare = less<Key>>
+class set
+{
+    struct rbtree
+    {
+        rbtree* left;
+        rbtree* right;
+        rbtree* parent;
+        bool is_red;
+        Key value;
+
+        rbtree(const Key& val)
+          : left(nullptr)
+          , right(nullptr)
+          , parent(nullptr)
+          , is_red(true)
+          , value(val)
+        {
+        }
+    };
+
+  public:
+    using key_type = Key;
+    using value_type = Key;
+    using size_type = size_t;
+    using node_type = rbtree;
+    using key_compare = Compare;
+    using value_compare = Compare;
+    using difference_type = ptrdiff_t;
+    using reference = value_type&;
+    using pointer = value_type*;
+    using const_pointer = const value_type*;
+    using const_reference = const value_type&;
+
+    class iterator
+    {
+      public:
+        using value_type = Key;
+        using difference_type = ptrdiff_t;
+        using pointer = Key*;
+        using reference = Key&;
+
+        iterator() : node_(nullptr)
+        {
+        }
+
+        reference operator*() const
+        {
+            return node_->value;
+        }
+
+        pointer operator->() const
+        {
+            return &(node_->value);
+        }
+
+        iterator& operator++()
+        {
+            if (node_ == nullptr)
+                return *this;
+            if (node_->right) {
+                node_ = leftmost(node_->right);
+            } else {
+                node_type* parent = node_->parent;
+                while (parent && node_ == parent->right) {
+                    node_ = parent;
+                    parent = parent->parent;
+                }
+                node_ = parent;
+            }
+            return *this;
+        }
+
+        iterator& operator--()
+        {
+            if (node_ == nullptr)
+                __builtin_trap();
+            if (node_->left) {
+                node_ = rightmost(node_->left);
+            } else {
+                node_type* parent = node_->parent;
+                for (;;) {
+                    if (parent == nullptr)
+                        break;
+                    if (node_ == parent->left) {
+                        node_ = parent;
+                        parent = parent->parent;
+                    } else {
+                        break;
+                    }
+                }
+                node_ = parent;
+            }
+            return *this;
+        }
+
+        iterator operator++(int)
+        {
+            iterator tmp = *this;
+            ++(*this);
+            return tmp;
+        }
+
+        iterator operator--(int)
+        {
+            iterator tmp = *this;
+            --(*this);
+            return tmp;
+        }
+
+        bool operator==(const iterator& other) const
+        {
+            return node_ == other.node_;
+        }
+
+        bool operator!=(const iterator& other) const
+        {
+            return !(*this == other);
+        }
+
+      private:
+        friend class set;
+        node_type* node_;
+
+        explicit iterator(node_type* node) : node_(node)
+        {
+        }
+    };
+
+    class reverse_iterator
+    {
+      public:
+        using value_type = Key;
+        using difference_type = ptrdiff_t;
+        using pointer = Key*;
+        using reference = Key&;
+
+        reverse_iterator() : node_(nullptr)
+        {
+        }
+
+        reference operator*() const
+        {
+            return node_->value;
+        }
+
+        pointer operator->() const
+        {
+            return &(node_->value);
+        }
+
+        reverse_iterator& operator++()
+        {
+            if (node_->left) {
+                node_ = rightmost(node_->left);
+            } else {
+                node_type* parent = node_->parent;
+                while (parent && node_ == parent->left) {
+                    node_ = parent;
+                    parent = parent->parent;
+                }
+                node_ = parent;
+            }
+            return *this;
+        }
+
+        reverse_iterator operator++(int)
+        {
+            reverse_iterator tmp = *this;
+            ++(*this);
+            return tmp;
+        }
+
+        reverse_iterator& operator--()
+        {
+            if (node_->right) {
+                node_ = leftmost(node_->right);
+            } else {
+                node_type* parent = node_->parent;
+                while (parent && node_ == parent->right) {
+                    node_ = parent;
+                    parent = parent->parent;
+                }
+                node_ = parent;
+            }
+            return *this;
+        }
+
+        reverse_iterator operator--(int)
+        {
+            reverse_iterator tmp = *this;
+            --(*this);
+            return tmp;
+        }
+
+        bool operator==(const reverse_iterator& other) const
+        {
+            return node_ == other.node_;
+        }
+
+        bool operator!=(const reverse_iterator& other) const
+        {
+            return !(*this == other);
+        }
+
+        iterator base() const
+        {
+            if (node_ == nullptr)
+                return iterator(leftmost(root_));
+            reverse_iterator tmp = *this;
+            ++tmp;
+            return iterator(tmp.node_);
+        }
+
+      private:
+        friend class set;
+        node_type* node_;
+
+        explicit reverse_iterator(node_type* node) : node_(node)
+        {
+        }
+    };
+
+    using const_iterator = iterator;
+    using const_reverse_iterator = reverse_iterator;
+
+    set() : root_(nullptr), size_(0), comp_(Compare())
+    {
+    }
+
+    explicit set(const Compare& comp) : root_(nullptr), size_(0), comp_(comp)
+    {
+    }
+
+    template<class InputIt>
+    set(InputIt first, InputIt last, const Compare& comp = Compare())
+      : root_(nullptr), size_(0), comp_(comp)
+    {
+        for (; first != last; ++first)
+            insert(*first);
+    }
+
+    set(const set& other) : root_(nullptr), size_(0)
+    {
+        if (other.root_) {
+            root_ = copier(other.root_);
+            size_ = other.size_;
+        }
+    }
+
+    set(set&& other) noexcept : root_(other.root_), size_(other.size_)
+    {
+        other.root_ = nullptr;
+        other.size_ = 0;
+    }
+
+    set(std::initializer_list<value_type> init, const Compare& comp = Compare())
+      : root_(nullptr), size_(0), comp_(comp)
+    {
+        for (const auto& value : init)
+            insert(value);
+    }
+
+    ~set()
+    {
+        clear();
+    }
+
+    set& operator=(const set& other)
+    {
+        if (this != &other) {
+            clear();
+            if (other.root_) {
+                root_ = copier(other.root_);
+                size_ = other.size_;
+            }
+        }
+        return *this;
+    }
+
+    set& operator=(set&& other) noexcept
+    {
+        if (this != &other) {
+            clear();
+            root_ = other.root_;
+            size_ = other.size_;
+            other.root_ = nullptr;
+            other.size_ = 0;
+        }
+        return *this;
+    }
+
+    bool empty() const noexcept
+    {
+        return size_ == 0;
+    }
+
+    size_type size() const noexcept
+    {
+        return size_;
+    }
+
+    iterator begin() noexcept
+    {
+        if (root_)
+            return iterator(leftmost(root_));
+        return iterator(nullptr);
+    }
+
+    const_iterator begin() const noexcept
+    {
+        if (root_)
+            return const_iterator(leftmost(root_));
+        return const_iterator(nullptr);
+    }
+
+    const_iterator cbegin() const noexcept
+    {
+        return begin();
+    }
+
+    reverse_iterator rbegin()
+    {
+        return reverse_iterator(rightmost(root_));
+    }
+
+    const_reverse_iterator rbegin() const
+    {
+        return const_reverse_iterator(rightmost(root_));
+    }
+
+    const_reverse_iterator crbegin() const
+    {
+        return const_reverse_iterator(rightmost(root_));
+    }
+
+    iterator end() noexcept
+    {
+        return iterator(nullptr);
+    }
+
+    const_iterator end() const noexcept
+    {
+        return const_iterator(nullptr);
+    }
+
+    const_iterator cend() const noexcept
+    {
+        return end();
+    }
+
+    reverse_iterator rend()
+    {
+        return reverse_iterator(nullptr);
+    }
+
+    const_reverse_iterator rend() const
+    {
+        return const_reverse_iterator(nullptr);
+    }
+
+    const_reverse_iterator crend() const
+    {
+        return const_reverse_iterator(nullptr);
+    }
+
+    void clear() noexcept
+    {
+        clearer(root_);
+        root_ = nullptr;
+        size_ = 0;
+    }
+
+    pair<iterator, bool> insert(value_type&& value)
+    {
+        return insert_node(new node_type(ctl::move(value)));
+    }
+
+    pair<iterator, bool> insert(const value_type& value)
+    {
+        return insert_node(new node_type(value));
+    }
+
+    iterator insert(const_iterator hint, const value_type& value)
+    {
+        return insert(value).first;
+    }
+
+    iterator insert(const_iterator hint, value_type&& value)
+    {
+        return insert(ctl::move(value)).first;
+    }
+
+    template<class InputIt>
+    void insert(InputIt first, InputIt last)
+    {
+        for (; first != last; ++first)
+            insert(*first);
+    }
+
+    void insert(std::initializer_list<value_type> ilist)
+    {
+        for (const auto& value : ilist)
+            insert(value);
+    }
+
+    template<class... Args>
+    pair<iterator, bool> emplace(Args&&... args)
+    {
+        value_type value(ctl::forward<Args>(args)...);
+        return insert(ctl::move(value));
+    }
+
+    iterator erase(iterator pos)
+    {
+        node_type* node = pos.node_;
+        iterator res = ++pos;
+        erase_node(node);
+        return res;
+    }
+
+    size_type erase(const key_type& key)
+    {
+        node_type* node = get_element(key);
+        if (node == nullptr)
+            return 0;
+        erase_node(node);
+        return 1;
+    }
+
+    iterator erase(const_iterator first, const_iterator last)
+    {
+        while (first != last)
+            first = erase(first);
+        return iterator(const_cast<node_type*>(last.node_));
+    }
+
+    void swap(set& other) noexcept
+    {
+        ctl::swap(root_, other.root_);
+        ctl::swap(size_, other.size_);
+    }
+
+    pair<iterator, iterator> equal_range(const key_type& key)
+    {
+        return { iterator(get_floor(key)), iterator(get_ceiling(key)) };
+    }
+
+    pair<const_iterator, const_iterator> equal_range(const key_type& key) const
+    {
+        return { const_iterator(get_floor(key)),
+                 const_iterator(get_ceiling(key)) };
+    }
+
+    iterator lower_bound(const key_type& key)
+    {
+        return iterator(get_floor(key));
+    }
+
+    const_iterator lower_bound(const key_type& key) const
+    {
+        return const_iterator(get_floor(key));
+    }
+
+    iterator upper_bound(const key_type& key)
+    {
+        return iterator(get_ceiling(key));
+    }
+
+    const_iterator upper_bound(const key_type& key) const
+    {
+        return const_iterator(get_ceiling(key));
+    }
+
+    size_type count(const key_type& key) const
+    {
+        return !!get_element(key);
+    }
+
+    iterator find(const key_type& key)
+    {
+        return iterator(get_element(key));
+    }
+
+    const_iterator find(const key_type& key) const
+    {
+        return const_iterator(get_element(key));
+    }
+
+    template<class... Args>
+    iterator emplace_hint(const_iterator hint, Args&&... args)
+    {
+        return emplace(ctl::forward<Args>(args)...).first;
+    }
+
+    void check() const
+    {
+        size_type count = 0;
+        if (root_ != nullptr) {
+            if (root_->is_red)
+                // ILLEGAL TREE: root node must be black
+                __builtin_trap();
+            int black_height = -1;
+            checker(root_, nullptr, 0, black_height);
+            count = tally(root_);
+        }
+        if (count != size_)
+            // ILLEGAL TREE: unexpected number of nodes
+            __builtin_trap();
+    }
+
+  private:
+    static node_type* leftmost(node_type* node) noexcept
+    {
+        while (node && node->left)
+            node = node->left;
+        return node;
+    }
+
+    static node_type* rightmost(node_type* node) noexcept
+    {
+        while (node && node->right)
+            node = node->right;
+        return node;
+    }
+
+    static void clearer(node_type* node) noexcept
+    {
+        node_type* right;
+        for (; node; node = right) {
+            right = node->right;
+            clearer(node->left);
+            delete node;
+        }
+    }
+
+    static node_type* copier(const node_type* node)
+    {
+        if (node == nullptr)
+            return nullptr;
+        node_type* new_node = new node_type(node->value);
+        new_node->left = copier(node->left);
+        new_node->right = copier(node->right);
+        if (new_node->left)
+            new_node->left->parent = new_node;
+        if (new_node->right)
+            new_node->right->parent = new_node;
+        return new_node;
+    }
+
+    static size_type tally(const node_type* node)
+    {
+        if (node == nullptr)
+            return 0;
+        return 1 + tally(node->left) + tally(node->right);
+    }
+
+    template<typename K>
+    node_type* get_element(const K& key) const
+    {
+        node_type* current = root_;
+        while (current != nullptr) {
+            if (comp_(key, current->value)) {
+                current = current->left;
+            } else if (comp_(current->value, key)) {
+                current = current->right;
+            } else {
+                return current;
+            }
+        }
+        return nullptr;
+    }
+
+    template<typename K>
+    node_type* get_floor(const K& key) const
+    {
+        node_type* result = nullptr;
+        node_type* current = root_;
+        while (current != nullptr) {
+            if (!comp_(current->value, key)) {
+                result = current;
+                current = current->left;
+            } else {
+                current = current->right;
+            }
+        }
+        return result;
+    }
+
+    template<typename K>
+    node_type* get_ceiling(const K& key) const
+    {
+        node_type* result = nullptr;
+        node_type* current = root_;
+        while (current != nullptr) {
+            if (comp_(key, current->value)) {
+                result = current;
+                current = current->left;
+            } else {
+                current = current->right;
+            }
+        }
+        return result;
+    }
+
+    pair<iterator, bool> insert_node(node_type* node)
+    {
+        if (root_ == nullptr) {
+            root_ = node;
+            root_->is_red = false;
+            size_++;
+            return { iterator(root_), true };
+        }
+        node_type* current = root_;
+        node_type* parent = nullptr;
+        while (current != nullptr) {
+            parent = current;
+            if (comp_(node->value, current->value)) {
+                current = current->left;
+            } else if (comp_(current->value, node->value)) {
+                current = current->right;
+            } else {
+                delete node; // already exists
+                return { iterator(current), false };
+            }
+        }
+        if (comp_(node->value, parent->value)) {
+            parent->left = node;
+        } else {
+            parent->right = node;
+        }
+        node->parent = parent;
+        size_++;
+        rebalance_after_insert(node);
+        return { iterator(node), true };
+    }
+
+    void erase_node(node_type* node)
+    {
+        node_type* y = node;
+        node_type* x = nullptr;
+        node_type* x_parent = nullptr;
+        bool y_original_color = y->is_red;
+        if (node->left == nullptr) {
+            x = node->right;
+            transplant(node, node->right);
+            x_parent = node->parent;
+        } else if (node->right == nullptr) {
+            x = node->left;
+            transplant(node, node->left);
+            x_parent = node->parent;
+        } else {
+            y = leftmost(node->right);
+            y_original_color = y->is_red;
+            x = y->right;
+            if (y->parent == node) {
+                if (x)
+                    x->parent = y;
+                x_parent = y;
+            } else {
+                transplant(y, y->right);
+                y->right = node->right;
+                y->right->parent = y;
+                x_parent = y->parent;
+            }
+            transplant(node, y);
+            y->left = node->left;
+            y->left->parent = y;
+            y->is_red = node->is_red;
+        }
+        if (!y_original_color)
+            rebalance_after_erase(x, x_parent);
+        delete node;
+        --size_;
+    }
+
+    void left_rotate(node_type* x)
+    {
+        node_type* y = x->right;
+        x->right = y->left;
+        if (y->left != nullptr)
+            y->left->parent = x;
+        y->parent = x->parent;
+        if (x->parent == nullptr) {
+            root_ = y;
+        } else if (x == x->parent->left) {
+            x->parent->left = y;
+        } else {
+            x->parent->right = y;
+        }
+        y->left = x;
+        x->parent = y;
+    }
+
+    void right_rotate(node_type* y)
+    {
+        node_type* x = y->left;
+        y->left = x->right;
+        if (x->right != nullptr)
+            x->right->parent = y;
+        x->parent = y->parent;
+        if (y->parent == nullptr) {
+            root_ = x;
+        } else if (y == y->parent->right) {
+            y->parent->right = x;
+        } else {
+            y->parent->left = x;
+        }
+        x->right = y;
+        y->parent = x;
+    }
+
+    void transplant(node_type* u, node_type* v)
+    {
+        if (u->parent == nullptr) {
+            root_ = v;
+        } else if (u == u->parent->left) {
+            u->parent->left = v;
+        } else {
+            u->parent->right = v;
+        }
+        if (v != nullptr)
+            v->parent = u->parent;
+    }
+
+    void checker(const node_type* node,
+                 const node_type* parent,
+                 int black_count,
+                 int& black_height) const
+    {
+        if (node == nullptr) {
+            // Leaf nodes are considered black
+            if (black_height == -1) {
+                black_height = black_count;
+            } else if (black_count != black_height) {
+                // ILLEGAL TREE: Black height mismatch
+                __builtin_trap();
+            }
+            return;
+        }
+        if (node->parent != parent)
+            // ILLEGAL TREE: Parent link is incorrect
+            __builtin_trap();
+        if (parent) {
+            if (parent->left == node && !comp_(node->value, parent->value))
+                // ILLEGAL TREE: Binary search property violated on left child
+                __builtin_trap();
+            if (parent->right == node && !comp_(parent->value, node->value))
+                // ILLEGAL TREE: Binary search property violated on right child
+                __builtin_trap();
+        }
+        if (!node->is_red) {
+            black_count++;
+        } else if (parent != nullptr && parent->is_red) {
+            // ILLEGAL TREE: Red node has red child
+            __builtin_trap();
+        }
+        checker(node->left, node, black_count, black_height);
+        checker(node->right, node, black_count, black_height);
+    }
+
+    void rebalance_after_insert(node_type* node)
+    {
+        node->is_red = true;
+        while (node != root_ && node->parent->is_red) {
+            if (node->parent == node->parent->parent->left) {
+                node_type* uncle = node->parent->parent->right;
+                if (uncle && uncle->is_red) {
+                    node->parent->is_red = false;
+                    uncle->is_red = false;
+                    node->parent->parent->is_red = true;
+                    node = node->parent->parent;
+                } else {
+                    if (node == node->parent->right) {
+                        node = node->parent;
+                        left_rotate(node);
+                    }
+                    node->parent->is_red = false;
+                    node->parent->parent->is_red = true;
+                    right_rotate(node->parent->parent);
+                }
+            } else {
+                node_type* uncle = node->parent->parent->left;
+                if (uncle && uncle->is_red) {
+                    node->parent->is_red = false;
+                    uncle->is_red = false;
+                    node->parent->parent->is_red = true;
+                    node = node->parent->parent;
+                } else {
+                    if (node == node->parent->left) {
+                        node = node->parent;
+                        right_rotate(node);
+                    }
+                    node->parent->is_red = false;
+                    node->parent->parent->is_red = true;
+                    left_rotate(node->parent->parent);
+                }
+            }
+        }
+        root_->is_red = false;
+    }
+
+    void rebalance_after_erase(node_type* node, node_type* parent)
+    {
+        while (node != root_ && (node == nullptr || !node->is_red)) {
+            if (node == parent->left) {
+                node_type* sibling = parent->right;
+                if (sibling->is_red) {
+                    sibling->is_red = false;
+                    parent->is_red = true;
+                    left_rotate(parent);
+                    sibling = parent->right;
+                }
+                if ((sibling->left == nullptr || !sibling->left->is_red) &&
+                    (sibling->right == nullptr || !sibling->right->is_red)) {
+                    sibling->is_red = true;
+                    node = parent;
+                    parent = node->parent;
+                } else {
+                    if (sibling->right == nullptr || !sibling->right->is_red) {
+                        sibling->left->is_red = false;
+                        sibling->is_red = true;
+                        right_rotate(sibling);
+                        sibling = parent->right;
+                    }
+                    sibling->is_red = parent->is_red;
+                    parent->is_red = false;
+                    sibling->right->is_red = false;
+                    left_rotate(parent);
+                    node = root_;
+                    break;
+                }
+            } else {
+                node_type* sibling = parent->left;
+                if (sibling->is_red) {
+                    sibling->is_red = false;
+                    parent->is_red = true;
+                    right_rotate(parent);
+                    sibling = parent->left;
+                }
+                if ((sibling->right == nullptr || !sibling->right->is_red) &&
+                    (sibling->left == nullptr || !sibling->left->is_red)) {
+                    sibling->is_red = true;
+                    node = parent;
+                    parent = node->parent;
+                } else {
+                    if (sibling->left == nullptr || !sibling->left->is_red) {
+                        sibling->right->is_red = false;
+                        sibling->is_red = true;
+                        left_rotate(sibling);
+                        sibling = parent->left;
+                    }
+                    sibling->is_red = parent->is_red;
+                    parent->is_red = false;
+                    sibling->left->is_red = false;
+                    right_rotate(parent);
+                    node = root_;
+                    break;
+                }
+            }
+        }
+        if (node != nullptr)
+            node->is_red = false;
+    }
+
+    node_type* root_;
+    size_type size_;
+    Compare comp_;
+};
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator==(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    if (lhs.size() != rhs.size())
+        return false;
+    auto i = lhs.cbegin();
+    auto j = rhs.cbegin();
+    for (; i != lhs.end(); ++i, ++j) {
+        if (!(*i == *j))
+            return false;
+    }
+    return true;
+}
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator<(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    auto i = lhs.cbegin();
+    auto j = rhs.cbegin();
+    for (; i != lhs.end() && j != rhs.end(); ++i, ++j) {
+        if (Compare()(*i, *j))
+            return true;
+        if (Compare()(*j, *i))
+            return false;
+    }
+    return i == lhs.end() && j != rhs.end();
+}
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator!=(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    return !(lhs == rhs);
+}
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator<=(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    return !(rhs < lhs);
+}
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator>(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    return rhs < lhs;
+}
+
+template<class Key, typename Compare = less<Key>>
+bool
+operator>=(const set<Key, Compare>& lhs, const set<Key, Compare>& rhs)
+{
+    return !(lhs < rhs);
+}
+
+template<class Key, typename Compare = less<Key>>
+void
+swap(set<Key, Compare>& lhs, set<Key, Compare>& rhs) noexcept;
+
+} // namespace ctl
+
+#endif // CTL_SET_H_

ctl/string.h

@@ -1,7 +1,7 @@
 // -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
 // vi: set et ft=cpp ts=4 sts=4 sw=4 fenc=utf-8 :vi
-#ifndef COSMOPOLITAN_CTL_STRING_H_
-#define COSMOPOLITAN_CTL_STRING_H_
+#ifndef CTL_STRING_H_
+#define CTL_STRING_H_
 #include "string_view.h"
 
 namespace ctl {
@@ -397,4 +397,4 @@ operator"" s(const char* s, size_t n)
 }
 #pragma GCC diagnostic pop
 
-#endif // COSMOPOLITAN_CTL_STRING_H_
+#endif // CTL_STRING_H_