1 files changed, 157 insertions, 0 deletions
diff --git a/euler/include/std/list.hpp b/euler/include/std/list.hpp
new file mode 100644
index 0000000..77eaaec
--- /dev/null
+++ b/euler/include/std/list.hpp
@@ -0,0 +1,157 @@
+#pragma once
+
+#include <memory>
+
+namespace std {
+
+  template <class T, class Allocator = std::allocator<T>>
+  class list {
+
+  public:
+    struct node {
+      T value;
+      node *prev;
+      node *next;
+    };
+
+    template <class V>
+    struct generic_iterator {
+
+      node *the_node;
+
+      bool operator ==(const generic_iterator &other) {
+        return the_node == other.the_node;
+      }
+
+      bool operator !=(const generic_iterator &other) {
+        return the_node != other.the_node;
+      }
+
+      V &operator *() {
+        return the_node->value;
+      }
+
+      V *operator ->() {
+        return &the_node->value;
+      }
+
+      generic_iterator &operator ++() {
+        the_node = the_node->next;
+        return *this;
+      }
+
+    };
+
+    using iterator = generic_iterator<T>;
+    using const_iterator = generic_iterator<const T>;
+
+  private:
+    node *first_node;
+    node *last_node;
+    size_t count;
+
+  public:
+    void push_back(const T &value) {
+      node *n = new node { .value = value,
+        .prev = last_node, .next = 0 };
+      if (last_node) last_node->next = n;
+      else first_node = n;
+      last_node = n;
+      ++count;
+    }
+
+    void push_back(T &&value) {
+      node *n = new node {
+        .value = std::move(value),
+        .prev = last_node, .next = 0 };
+      if (last_node) last_node->next = n;
+      else first_node = n;
+      last_node = n;
+      ++count;
+    }
+
+    iterator erase(iterator pos) {
+      --count;
+      auto *n = pos.the_node;
+      auto *r = n->next;
+      if (n->prev) n->prev->next = n->next;
+      else            first_node = n->next;
+      if (n->next) n->next->prev = n->prev;
+      else             last_node = n->prev;
+      delete n;
+      return iterator { .the_node = r };
+    }
+
+    iterator begin() const noexcept {
+      return iterator { .the_node = first_node };
+    }
+
+    iterator end() const noexcept {
+      return iterator { .the_node = 0 };
+    }
+
+    size_t remove(const T &value) {
+      size_t removed = 0;
+      auto it = begin();
+      while (it != end())
+        if (*it == value) {
+          it = erase(it);
+          ++removed;
+        }
+        else
+          ++it;
+      count -= removed;
+      return removed;
+    }
+
+    list() : first_node(0), last_node(0), count(0) {}
+
+    list(const list &other) : first_node(0), last_node(0), count(0) {
+      for (node *n = other.first_node; n; n = n->next)
+        push_back(n->value);
+    }
+
+    list(list &&other) : first_node(other.first_node),
+      last_node(other.last_node), count(other.count) {
+      other.first_node = 0;
+      other.last_node = 0;
+      other.count = 0;
+    }
+
+    void clear() {
+
+      if (count == 0) return;
+
+      for (node *n = first_node->next; n; n = n->next)
+        delete n->prev;
+      delete last_node;
+
+      first_node = 0;
+      last_node = 0;
+      count = 0;
+
+    }
+
+    ~list() {
+      clear();
+    }
+
+    list &operator =(const list &other) {
+      clear();
+      for (node *n = other.first_node; n; n = n->next)
+        push_back(n->value);
+    }
+
+    list &operator =(list &&other) {
+      clear();
+      first_node = other.first_node;
+      last_node = other.last_node;
+      count = other.count;
+      other.first_node = 0;
+      other.last_node = 0;
+      other.count = 0;
+    }
+
+  };
+
+}