atticax / remodel

Data and class remodeling library

remodel library

remodel is a lightweight C++ library that allows interaction with applications that don't provide an official API. It can be used to create wrappers around the application's data structures and classes (with possibly many unknown fields), thereby avoiding messy casts and padding fields.

Core aspects

• Easy to use
• Modern (C++14, limited by what is already supported by MSVC 12)
• Lightweight
  • Header-only library
  • No RTTI required
  • Exceptionless
• Unit tests
• Completely documented public API
• CMake, cross-platform support, tested on:
  • MSVC 12 aka. 2013, 14 aka. 2015 (Windows)
  • clang 3.6, 3.7 (MSVC emulation mode on Windows, OS X)

Example

Imagine a scenario where you have instances of Dog in memory (let's say in your dog-simulator game that you intend to write mods for) that need be accessed.

class CustomString
{
  char* data;
  std::size_t length;
public:
  const char* str() const { return data; }
  std::size_t size() const { return length; }
};

class Dog
{
  CustomString name;
  CustomString* race;
  // ..
  // possibly many other unknown fields here
  // ..
  uint8_t age;
  bool hatesKittehz;
public:
  virtual int calculateFluffiness() const { /* ... */ }
  virtual void giveGoodie(int amount) { /* ... */ }
  // .. more methods ..
};

However, you obviously don't have that source code and only know a small subset of the whole thing that you found out through, let's say, reverse engineering with IDA. So here's the remodeled version:

class CustomString : public AdvancedClassWrapper<8 /* struct size */>
{
  REMODEL_ADV_WRAPPER(CustomString)
  // Note we omit the privates here because we decided we only need the methods.
public:
  MemberFunction<const char* (*)()> str{this, 0x12345678 /* function addr */};
  MemberFunction<std::size_t (*)()> size{this, 0x87654321};
};

// We don't create fields referring to `Dog`, so we don't have to know its
// size and can simply use `ClassWrapper` rather than `AdvancedClassWrapper`.
class Dog : public ClassWrapper
{
  REMODEL_WRAPPER(Dog)
  // We cheat and make the private fields public for our mod.
public:
  Field<CustomString> name{this, 4 /* struct offset */};
  Field<CustomString*> race{this, 12};
  // Note that we can just omit the unknown fields here without breaking
  // the integrity of the struct. No padding required.
  Field<uint8_t> age{this, 124};
  Field<bool> hatesKittehz{this, 125};
public:
  VirtualFunction<int (*)()> calculateFluffiness{this, 0 /* vftable index */};
  VirtualFunction<void (*)(int)> giveGoodie{this, 1};
};

And that's it! You can now use these wrappers pretty similar to how you would use the original class.

auto dog = wrapper_cast<Dog>(dogInstanceLocation);
// Don't give the bad dog too much of the good stuff!
dog.giveGoodie(dog.hatesKittehz ? 2 : 7);
// Year is over, +1 to age.
++dog.age;
// What was it's race again?
const char* race = dog.race->toStrong().str();

Note that this library is in an early stage, so some things might change in the future.

Cloning and dependencies

Please clone using the --recursive switch in order to automatically resolve the dependency on our core library.

git clone --recursive https://github.com/zyantific/remodel

Documentation

The HTML Doxygen documentation is automatically built from master every 12 hours.

License

remodel is released unter MIT license, dependencies are under their respective licenses.