Simple speed hack

#include <Windows.h>

#include "Detours/detours.h"

#pragma comment(lib, "Detours/detours.lib")

//#include "SpeedHack.h"
// TODO: put in another file, and rename to something better
template<class DataType>
class SpeedHack {
    DataType time_offset;
    DataType time_last_update;

    double speed_;

public:
    SpeedHack(DataType currentRealTime, double initialSpeed) {
        time_offset = currentRealTime;
        time_last_update = currentRealTime;

        speed_ = initialSpeed;
    }

    // TODO: put lock around for thread safety
    void setSpeed(DataType currentRealTime, double speed) {
        time_offset = getCurrentTime(currentRealTime);
        time_last_update = currentRealTime;

        speed_ = speed;
    }

    // TODO: put lock around for thread safety
    DataType getCurrentTime(DataType currentRealTime) {
        DataType difference = currentRealTime - time_last_update;

        return (DataType)(speed_ * difference) + time_offset;
    }
};


// function signature typedefs
typedef DWORD     (WINAPI *GetTickCountType)(void);
typedef ULONGLONG (WINAPI *GetTickCount64Type)(void);

typedef BOOL      (WINAPI *QueryPerformanceCounterType)(LARGE_INTEGER *lpPerformanceCount);

// globals
GetTickCountType   g_GetTickCountOriginal;
GetTickCount64Type g_GetTickCount64Original;
GetTickCountType   g_TimeGetTimeOriginal;    // Same function signature as GetTickCount

QueryPerformanceCounterType g_QueryPerformanceCounterOriginal;


const double kInitialSpeed = 1.0; // initial speed hack speed

//                                  (initialTime,      initialSpeed)
SpeedHack<DWORD>     g_speedHack    (GetTickCount(),   kInitialSpeed);
SpeedHack<ULONGLONG> g_speedHackULL (GetTickCount64(), kInitialSpeed);
SpeedHack<LONGLONG>  g_speedHackLL  (0,                kInitialSpeed); // Gets set properly in DllMain

// function prototypes

DWORD     WINAPI GetTickCountHacked(void);
ULONGLONG WINAPI GetTickCount64Hacked(void);

BOOL      WINAPI QueryPerformanceCounterHacked(LARGE_INTEGER *lpPerformanceCount);

DWORD     WINAPI KeysThread(LPVOID lpThreadParameter);

// functions

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD dwReason, LPVOID lpvReserved) {
    // TODO: split up this function for readability.

    if (dwReason == DLL_PROCESS_ATTACH) {
        DisableThreadLibraryCalls(hinstDLL);

        HMODULE kernel32 = GetModuleHandleA("Kernel32.dll");
        HMODULE winmm    = GetModuleHandleA("Winmm.dll");

        // TODO: check if the modules are even loaded.

        // Get all the original addresses of target functions
        g_GetTickCountOriginal   = (GetTickCountType)   GetProcAddress(kernel32, "GetTickCount");
        g_GetTickCount64Original = (GetTickCount64Type) GetProcAddress(kernel32, "GetTickCount64");

        g_TimeGetTimeOriginal = (GetTickCountType)GetProcAddress(winmm, "timeGetTime");

        g_QueryPerformanceCounterOriginal = (QueryPerformanceCounterType)GetProcAddress(kernel32, "QueryPerformanceCounter");

        // Setup the speed hack object for the Performance Counter
        LARGE_INTEGER performanceCounter;
        g_QueryPerformanceCounterOriginal(&performanceCounter);

        g_speedHackLL = SpeedHack<LONGLONG>(performanceCounter.QuadPart, kInitialSpeed);

        // Detour functions
        DetourTransactionBegin();

            DetourAttach((PVOID*)&g_GetTickCountOriginal,   (PVOID)GetTickCountHacked);
            DetourAttach((PVOID*)&g_GetTickCount64Original, (PVOID)GetTickCount64Hacked);

            // Detour timeGetTime to the hacked GetTickCount (same signature)
            DetourAttach((PVOID*)&g_TimeGetTimeOriginal, (PVOID)GetTickCountHacked);

            DetourAttach((PVOID*)&g_QueryPerformanceCounterOriginal, (PVOID)QueryPerformanceCounterHacked);

        DetourTransactionCommit();

        CreateThread(NULL, 0, KeysThread, NULL, 0, NULL);
    }

    return TRUE;
}

void setAllToSpeed(double speed) {
    g_speedHack.setSpeed(g_GetTickCountOriginal(), speed);

    g_speedHackULL.setSpeed(g_GetTickCount64Original(), speed);

    LARGE_INTEGER performanceCounter;
    g_QueryPerformanceCounterOriginal(&performanceCounter);

    g_speedHackLL.setSpeed(performanceCounter.QuadPart, speed);
}

DWORD WINAPI KeysThread(LPVOID lpThreadParameter) {
    while (true) {
        if (GetAsyncKeyState(VK_HOME) & 1) {
            setAllToSpeed(1.0);
        }
        if (GetAsyncKeyState(VK_END) & 1) {
            setAllToSpeed(5.0);
        }

        Sleep(1);
    }

    return 0;
}


DWORD WINAPI GetTickCountHacked(void) {
    return g_speedHack.getCurrentTime(g_GetTickCountOriginal());
}

ULONGLONG WINAPI GetTickCount64Hacked(void) {
    return g_speedHackULL.getCurrentTime(g_GetTickCount64Original());
}

BOOL WINAPI QueryPerformanceCounterHacked(LARGE_INTEGER *lpPerformanceCount) {
    LARGE_INTEGER performanceCounter;

    BOOL result = g_QueryPerformanceCounterOriginal(&performanceCounter);

    lpPerformanceCount->QuadPart = g_speedHackLL.getCurrentTime(performanceCounter.QuadPart);

    return result;
}