diff --git a/BlockingQueue.h b/BlockingQueue.h
new file mode 100644
index 0000000..0cccca5
--- /dev/null
+++ b/BlockingQueue.h
@@ -0,0 +1,54 @@
+//
+// A thread safe queue with a maximum capacity with blocking enqueue and dequeue calls.
+// enqueue blocks if the queue is full, dequeue blocks if the queue is empty.
+//
+
+#ifndef BLOCKINGQUEUE_H
+#define BLOCKINGQUEUE_H
+
+#include <chrono>
+#include <condition_variable>
+#include <mutex>
+#include <optional>
+#include <queue>
+
+template <typename T> class BlockingQueue {
+  public:
+    explicit BlockingQueue(const size_t capacity) : m_capacity(capacity) {
+    }
+
+    // Enqueue with timeout. Returns true on success, false on timeout.
+    bool enqueue(T &&item, std::chrono::milliseconds max_wait) {
+        std::unique_lock lock(m_mutex);
+        if (!m_cond_not_full.wait_for(lock, max_wait,
+                                      [this]() { return m_queue.size() < m_capacity; })) {
+            return false;
+        }
+
+        m_queue.push(std::move(item));
+        m_cond_not_empty.notify_one();
+        return true;
+    }
+
+    // Dequeue with timeout. Returns optional<T> (empty on timeout).
+    std::optional<T> dequeue(std::chrono::milliseconds max_wait) {
+        std::unique_lock lock(m_mutex);
+        if (!m_cond_not_empty.wait_for(lock, max_wait, [this]() { return !m_queue.empty(); })) {
+            return std::nullopt;
+        }
+
+        T item = std::move(m_queue.front());
+        m_queue.pop();
+        m_cond_not_full.notify_one();
+        return item;
+    }
+
+  private:
+    std::queue<T> m_queue;
+    size_t m_capacity;
+    std::mutex m_mutex;
+    std::condition_variable m_cond_not_empty;
+    std::condition_variable m_cond_not_full;
+};
+
+#endif // BLOCKINGQUEUE_H
diff --git a/Errno.h b/Errno.h
new file mode 100644
index 0000000..2a06a69
--- /dev/null
+++ b/Errno.h
@@ -0,0 +1,34 @@
+//
+// Print a detailed errno
+//
+
+#ifndef ERRNO_H
+#define ERRNO_H
+
+#include <string>
+
+#define ERRBUF_SIZE 300
+
+#ifdef _WIN32
+
+std::string get_errno() {
+    std::string errbuf;
+    errbuf.resize(ERRBUERRBUF_SIZE);
+    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, WSAGetLastError(), 0, errbuf.data(), ERERRBUF_SIZE,
+                  NULL);
+    return errbuf;
+}
+
+#else
+
+#include <errno.h>
+#include <string.h>
+
+std::string get_errno() {
+    std::string err = std::strerror(errno);
+    return err;
+}
+
+#endif
+
+#endif //ERRNO_H
diff --git a/Event.h b/Event.h
new file mode 100644
index 0000000..caf1c97
--- /dev/null
+++ b/Event.h
@@ -0,0 +1,55 @@
+
+//
+// An event/listener system.
+//
+
+#ifndef EVENT_H
+#define EVENT_H
+
+#include <functional>
+#include <unordered_map>
+
+class Event;
+
+class CallbackHandle {
+  public:
+    CallbackHandle(Event *evt, int id) : m_evt(evt), m_id(id) {
+    }
+    ~CallbackHandle();
+
+  private:
+    Event *m_evt;
+    int m_id;
+};
+
+class Event {
+  public:
+    using Callback = std::function<void()>;
+
+    CallbackHandle addListener(Callback cb) {
+        int id = m_nextId++;
+        m_callbacks[id] = std::move(cb);
+        return CallbackHandle(this, id);
+    }
+
+    void remove(int id) {
+        m_callbacks.erase(id);
+    }
+
+    void fire() {
+        for (auto &kv : m_callbacks)
+            kv.second();
+    }
+
+  private:
+    friend class CallbackHandle;
+    std::unordered_map<int, Callback> m_callbacks;
+    int m_nextId = 0;
+};
+
+CallbackHandle::~CallbackHandle() {
+    if (m_evt)
+        m_evt->remove(m_id);
+}
+
+#endif // EVENT_H
diff --git a/Map.h b/Map.h
new file mode 100644
index 0000000..2f46f0c
--- /dev/null
+++ b/Map.h
@@ -0,0 +1,19 @@
+
+#ifndef MAP_UTIL_H
+#define MAP_UTIL_H
+
+#include <unordered_map>
+#include <vector>
+
+// Get vector of values from an unordered_map
+template <typename K, typename V, typename H>
+std::vector<V> map_to_values(const std::unordered_map<K, V, H> &map) {
+    std::vector<V> out;
+    out.reserve(map.size());
+    for (auto const &[key, value] : map) {
+        out.push_back(value);
+    }
+    return out;
+}
+
+#endif // MAP_UTIL_H
diff --git a/Number.h b/Number.h
new file mode 100644
index 0000000..9e1b333
--- /dev/null
+++ b/Number.h
@@ -0,0 +1,19 @@
+
+#ifndef NUMBER_UTILS_H
+#define NUMBER_UTILS_H
+
+#include <iostream>
+#include <type_traits>
+
+// Map a value with range, to another range.
+template<typename T>
+T mapRange(T value, T inMin, T inMax, T outMin, T outMax) {
+    static_assert(std::is_arithmetic<T>::value, "Template parameter must be a numeric type");
+    if (inMin == inMax) {
+        return value;
+    }
+
+    return (value - inMin) * (outMax - outMin) / (inMax - inMin) + outMin;
+}
+
+#endif //NUMBER_UTILS_H
diff --git a/PairHash.h b/PairHash.h
new file mode 100644
index 0000000..6faffb6
--- /dev/null
+++ b/PairHash.h
@@ -0,0 +1,14 @@
+
+#ifndef PAIRHASH_H
+#define PAIRHASH_H
+
+#include <unordered_map>
+
+// Custom hash function for std::pair
+template <typename T> struct pair_hash {
+    std::size_t operator()(const std::pair<T, T> &p) const {
+        return std::hash<T>()(p.first) ^ (std::hash<T>()(p.second) << 1);
+    }
+};
+
+#endif // PAIRHASH_H
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4e1511b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# cpp-utils
+
+This repository contains a collection of C++ helper/utility functions I like to use in a lot of my projects.
diff --git a/String.h b/String.h
new file mode 100644
index 0000000..4c2040d
--- /dev/null
+++ b/String.h
@@ -0,0 +1,20 @@
+#ifndef STRING_H
+#define STRING_H
+#include <sstream>
+#include <string>
+#include <vector>
+
+// Split a string on a delimiter to a vector of strings
+inline std::vector<std::string> split(const std::string &str, const char delimiter) {
+    std::vector<std::string> result;
+    std::stringstream ss(str);
+    std::string token;
+
+    while (std::getline(ss, token, delimiter)) {
+        result.push_back(token);
+    }
+
+    return result;
+}
+
+#endif //STRING_H
diff --git a/Variant.h b/Variant.h
new file mode 100644
index 0000000..78cc3b3
--- /dev/null
+++ b/Variant.h
@@ -0,0 +1,23 @@
+
+// Helper to make it easier to use std::visit with std::variant
+// For example,
+// std::visit(
+//      overloaded{
+//          [](int i) { std::cout << "int: " << i << std::endl; },
+//          [](double d) { std::cout << "double: " << d << std::endl; },
+//      },
+//      variant
+// );
+
+#ifndef VARIANT_H
+#define VARIANT_H
+
+#include <variant> // NOLINT
+
+template <class... Ts> struct overloaded : Ts... {
+    using Ts::operator()...;
+};
+
+template <class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
+
+#endif // VARIANT_H
diff --git a/ip.h b/ip.h
new file mode 100644
index 0000000..52c2d47
--- /dev/null
+++ b/ip.h
@@ -0,0 +1,26 @@
+#ifndef IP_UTIL_H
+#define IP_UTIL_H
+
+#include <string>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#define CLOSE_SOCKET closesocket
+#pragma comment(lib, "ws2_32.lib")
+typedef SOCKET socket_t;
+#else
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#define CLOSE_SOCKET close
+typedef int socket_t;
+#endif
+
+bool is_valid_ipv4(const std::string &ip) {
+    struct in_addr addr;
+    return inet_pton(AF_INET, ip.c_str(), &addr) == 1;
+}
+
+#endif // IP_UTIL_H