#include "Scan.h"

bool __fastcall INT_ComparePattern2(char * szSource, const char * szPattern, const char * szMask)
{
    while(*szMask)
    {
        if (*szMask <= '9')
        {
            szPattern   += ((*szMask) ^ 0x30);
            szSource    += ((*szMask) ^ 0x30);
        }
        else
        {
            for (int i = ((*szMask) ^ 0x60); i; --i)
                if (*(szSource++) != *(szPattern++))
                    return false;
        }
        ++szMask;
    }

    return true;
}

bool INT_ComparePattern(char * szSource, const char * szPattern, const char * szMask)
{
    for (; *szMask; ++szSource, ++szPattern, ++szMask)
        if (*szMask == 'x' && *szSource != *szPattern)
            return false;

    return true;
}

char * INT_PatternScan(char * pData, UINT_PTR RegionSize, const char * szPattern, const char * szMask, int Len)
{
    for (UINT i = 0; i != RegionSize - Len; ++i, ++pData)
        if (INT_ComparePattern(pData, szPattern, szMask))
            return pData;

    return nullptr;
}

char * PatternScan(char * pStart, UINT_PTR RegionSize, const char * szPattern, const char * szMask, int Len)
{
    char * pCurrent = pStart;

    while (pCurrent <= pStart + RegionSize - Len)
    {
        MEMORY_BASIC_INFORMATION MBI{ 0 };
        if (!VirtualQuery(pCurrent, &MBI, sizeof(MEMORY_BASIC_INFORMATION)))
            return nullptr;

        if (MBI.State == MEM_COMMIT && !(MBI.Protect & PAGE_NOACCESS || MBI.Protect & PAGE_GUARD))
        {
            if (pCurrent + MBI.RegionSize > pStart + RegionSize - Len)
                MBI.RegionSize = pStart + RegionSize - pCurrent + Len;

            char * Ret = INT_PatternScan(pCurrent, MBI.RegionSize, szPattern, szMask, Len);

            if (Ret)
                return Ret;
        }
        pCurrent += MBI.RegionSize;
    }

    return nullptr;
}

char * PatternScanEx(HANDLE hProc, char * pStart, UINT_PTR RegionSize, const char * szPattern, const char * szMask)
{
    DWORD Buffer = 0;
    if (!GetHandleInformation(hProc, &Buffer))
        return nullptr;

    char * pCurrent = pStart;
    auto Len = lstrlenA(szMask);

    SIZE_T BufferSize = 0x10000;
    char * Data = new char[BufferSize];

    while (pCurrent <= pStart + RegionSize - Len)
    {
        MEMORY_BASIC_INFORMATION MBI{ 0 };
        if (!VirtualQueryEx(hProc, pCurrent, &MBI, sizeof(MEMORY_BASIC_INFORMATION)))
            return nullptr;

        if (MBI.State == MEM_COMMIT && !(MBI.Protect & (PAGE_NOACCESS | PAGE_GUARD)))
        {
            if (BufferSize < MBI.RegionSize)
            {
                delete[] Data;
                BufferSize = MBI.RegionSize;
                Data = new char[BufferSize];
            }

            UINT_PTR Delta = pCurrent - reinterpret_cast<char*>(MBI.BaseAddress);
            MBI.RegionSize -= Delta;

            if (pCurrent + MBI.RegionSize > pStart + RegionSize - Len)
                MBI.RegionSize -= pCurrent + MBI.RegionSize - pStart - RegionSize + Len;

            if (!ReadProcessMemory(hProc, pCurrent, Data, MBI.RegionSize, nullptr))
            {
                pCurrent = pCurrent + MBI.RegionSize;
                continue;
            }

            char * Ret = INT_PatternScan(Data, MBI.RegionSize, szPattern, szMask, Len);

            if (Ret)
            {
                delete[] Data;
                return (Ret - Data + pCurrent);
            }
        }

        pCurrent = pCurrent + MBI.RegionSize;
    }

    delete[] Data;

    return nullptr;
}