Universal constexpr & runtime string hashing for C++17+ (User Mode & Kernel Mode)

oxhash is a lightweight, zero-dependency, single-header C++ library that provides fast and reliable string hashing at both compile-time and runtime. It is specifically designed to work in both User Mode and Kernel Mode environments on Windows, making it ideal for performance-critical and security-sensitive applications like loaders, drivers, anti-cheat systems, and malware analysis tools.

The library supports both char and wchar_t strings and is suitable for use in places where traditional function names or strings must be hidden — such as custom implementations of GetProcAddress, syscall resolution, or API lookup by hashed names.

• Compile-time hashing using constexpr functions
• Fast runtime hashing with minimal overhead
• Works in both User Mode and Kernel Mode
• No CRT, STL, or external dependencies
• Supports both char and wchar_t strings
• Single-header only, drop-in integration
• Suitable for anti-debugging and anti-reversing
• Compatible with both x86 and x64 architectures

oxhash provides two hashing functions:

1. Compile-time hash (HashCompileTime)
   Evaluates the hash entirely at compile-time using constexpr for string literals.

2. Runtime hash (HashRuntime)
   Provides the same hashing logic as HashCompileTime, but can evaluate strings at runtime — ideal for user input or dynamic strings.

Both functions implement a custom 64-bit hashing algorithm inspired by high-entropy prime-based mixing (similar in spirit to xxHash64) to produce hard-to-reverse and low-collision hash values.

Just include the oxhash.hpp file in your project:

#include "oxhash.hpp"