// util/util.cc
// 8/23/2013 jichi
// Branch: ITH_Engine/engine.cpp, revision 133
// See: http://ja.wikipedia.org/wiki/プロジェクト:美少女ゲーム系/ゲームエンジン

#include "util/util.h"
#include "ithsys/ithsys.h"
#include "main.h"
#include <Psapi.h>

namespace { // unnamed

// jichi 4/19/2014: Return the integer that can mask the signature
// Artikash 8/4/2018: change implementation
DWORD SigMask(DWORD sig)
{
	DWORD count = 0;
	while (sig)
	{
		sig >>= 8;
		++count;
	}
	count -= 4;
	count = -count;
	return 0xffffffff >> (count << 3);
}

uint64_t SafeSearchMemory(uint64_t startAddr, uint64_t endAddr, const BYTE* bytes, short length)
{
	__try
	{
		for (int i = 0; i < endAddr - startAddr - length; ++i)
			for (int j = 0; j <= length; ++j)
				if (j == length) return startAddr + i; // not sure about this algorithm...
				else if (*((BYTE*)startAddr + i + j) != *(bytes + j) && *(bytes + j) != XX) break;
	}
	__except (EXCEPTION_EXECUTE_HANDLER)
	{
		ConsoleOutput("SearchMemory ERROR");
	}
	return 0;
}

} // namespace unnamed

namespace Util
{

#ifndef _WIN64
// jichi 8/24/2013: binary search?
DWORD GetCodeRange(DWORD hModule,DWORD *low, DWORD *high)
{
  IMAGE_DOS_HEADER *DosHdr;
  IMAGE_NT_HEADERS *NtHdr;
  DWORD dwReadAddr;
  IMAGE_SECTION_HEADER *shdr;
  DosHdr = (IMAGE_DOS_HEADER *)hModule;
  if (IMAGE_DOS_SIGNATURE == DosHdr->e_magic) {
    dwReadAddr = hModule + DosHdr->e_lfanew;
    NtHdr = (IMAGE_NT_HEADERS *)dwReadAddr;
    if (IMAGE_NT_SIGNATURE == NtHdr->Signature) {
      shdr = (PIMAGE_SECTION_HEADER)((DWORD)(&NtHdr->OptionalHeader) + NtHdr->FileHeader.SizeOfOptionalHeader);
      while ((shdr->Characteristics & IMAGE_SCN_CNT_CODE) == 0)
        shdr++;
      *low = hModule + shdr->VirtualAddress;
      *high = *low + (shdr->Misc.VirtualSize & 0xfffff000) + 0x1000;
    }
  }
  return 0;
}

DWORD FindCallAndEntryBoth(DWORD fun, DWORD size, DWORD pt, DWORD sig)
{
  //WCHAR str[0x40];
  enum { reverse_length = 0x800 };
  DWORD t, l;
  DWORD mask = SigMask(sig);
  bool flag2;
  for (DWORD i = 0x1000; i < size-4; i++) {
    bool flag1 = false;
    if (*(BYTE *)(pt + i) == 0xe8) {
      flag1 = flag2 = true;
      t = *(DWORD *)(pt + i + 1);
    } else if (*(WORD *)(pt + i) == 0x15ff) {
      flag1 = true;
      flag2 = false;
      t = *(DWORD *)(pt + i + 2);
    }
    if (flag1) {
      if (flag2) {
        flag1 = (pt + i + 5 + t == fun);
        l = 5;
      } else if (t >= pt && t <= pt + size - 4) {
        flag1 = fun == *(DWORD *)t;
        l = 6;
      } else
        flag1 = false;
      if (flag1)
        //swprintf(str,L"CALL addr: 0x%.8X",pt + i);
        //OutputConsole(str);
        for (DWORD j = i; j > i - reverse_length; j--)
          if ((*(WORD *)(pt + j)) == (sig & mask))  //Fun entry 1.
            //swprintf(str,L"Entry: 0x%.8X",pt + j);
            //OutputConsole(str);
            return pt + j;
      else
        i += l;
    }
  }
  //OutputConsole(L"Find call and entry failed.");
  return 0;
}

DWORD FindCallOrJmpRel(DWORD fun, DWORD size, DWORD pt, bool jmp)
{
  BYTE sig = (jmp) ? 0xe9 : 0xe8;
  for (DWORD i = 0x1000; i < size - 4; i++)
    if (sig == *(BYTE *)(pt + i)) {
      DWORD t = *(DWORD *)(pt + i + 1);
      if(fun == pt + i + 5 + t)
        //OutputDWORD(pt + i);
        return pt + i;
      else
        i += 5;
    }
  return 0;
}

DWORD FindCallOrJmpAbs(DWORD fun, DWORD size, DWORD pt, bool jmp)
{
  WORD sig = jmp ? 0x25ff : 0x15ff;
  for (DWORD i = 0x1000; i < size - 4; i++)
    if (sig == *(WORD *)(pt + i)) {
      DWORD t = *(DWORD *)(pt + i + 2);
      if (t > pt && t < pt + size) {
        if (fun == *(DWORD *)t)
          return pt + i;
        else
          i += 5;
      }
    }
  return 0;
}

DWORD FindCallBoth(DWORD fun, DWORD size, DWORD pt)
{
  for (DWORD i = 0x1000; i < size - 4; i++) {
    if (*(BYTE *)(pt + i) == 0xe8) {
      DWORD t = *(DWORD *)(pt + i + 1) + pt + i + 5;
      if (t == fun)
        return i;
    }
    if (*(WORD *)(pt + i) == 0x15ff) {
      DWORD t = *(DWORD *)(pt + i + 2);
      if (t >= pt && t <= pt + size - 4) {
        if (*(DWORD *)t == fun)
          return i;
        else
          i += 6;
      }
    }
  }
  return 0;
}

DWORD FindCallAndEntryAbs(DWORD fun, DWORD size, DWORD pt, DWORD sig)
{
  //WCHAR str[0x40];
  enum { reverse_length = 0x800 };
  DWORD mask = SigMask(sig);
  for (DWORD i = 0x1000; i < size - 4; i++)
    if (*(WORD *)(pt + i) == 0x15ff) {
      DWORD t = *(DWORD *)(pt + i + 2);
      if (t >= pt && t <= pt + size - 4) {
        if (*(DWORD *)t == fun)
          //swprintf(str,L"CALL addr: 0x%.8X",pt + i);
          //OutputConsole(str);
          for (DWORD j = i ; j > i - reverse_length; j--)
            if ((*(DWORD *)(pt + j) & mask) == sig) // Fun entry 1.
              //swprintf(str,L"Entry: 0x%.8X",pt + j);
              //OutputConsole(str);
              return pt + j;

      } else
        i += 6;
    }
  //OutputConsole(L"Find call and entry failed.");
  return 0;
}

DWORD FindCallAndEntryRel(DWORD fun, DWORD size, DWORD pt, DWORD sig)
{
  //WCHAR str[0x40];
  enum { reverse_length = 0x800 };
  if (DWORD i = FindCallOrJmpRel(fun, size, pt, false)) {
    DWORD mask = SigMask(sig);
    for (DWORD j = i; j > i - reverse_length; j--)
      if (((*(DWORD *)j) & mask) == sig)  //Fun entry 1.
        //swprintf(str,L"Entry: 0x%.8X",j);
        //OutputConsole(str);
        return j;
      //OutputConsole(L"Find call and entry failed.");
  }
  return 0;
} 

DWORD FindImportEntry(DWORD hModule, DWORD fun)
{
  IMAGE_DOS_HEADER *DosHdr;
  IMAGE_NT_HEADERS *NtHdr;
  DWORD IAT, end, pt, addr;
  DosHdr = (IMAGE_DOS_HEADER *)hModule;
  if (IMAGE_DOS_SIGNATURE == DosHdr->e_magic) {
    NtHdr = (IMAGE_NT_HEADERS *)(hModule + DosHdr->e_lfanew);
    if (IMAGE_NT_SIGNATURE == NtHdr->Signature) {
      IAT = NtHdr->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IAT].VirtualAddress;
      end = NtHdr->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IAT].Size;
      IAT += hModule;
      end += IAT;
      for (pt = IAT; pt < end; pt += 4) {
        addr = *(DWORD *)pt;
        if (addr == fun)
          return pt;
      }
    }
  }
  return 0;
}
#endif

bool CheckFile(LPCWSTR name)
{
	WIN32_FIND_DATAW unused;
	HANDLE file = FindFirstFileW(name, &unused);
	if (file != INVALID_HANDLE_VALUE)
	{
		FindClose(file);
		return true;
	}
	wchar_t path[MAX_PATH * 2];
	wchar_t* end = path + GetModuleFileNameW(nullptr, path, MAX_PATH);
	while (*(--end) != L'\\');
	wcscpy_s(end + 1, MAX_PATH, name);
	file = FindFirstFileW(path, &unused);
	if (file != INVALID_HANDLE_VALUE)
	{
		FindClose(file);
		return true;
	}
	return false;
}

// Search string in rsrc section. This section usually contains version and copyright info.
bool SearchResourceString(LPCWSTR str)
{
  uintptr_t hModule = (uintptr_t)GetModuleHandleW(nullptr);
  IMAGE_DOS_HEADER *DosHdr;
  IMAGE_NT_HEADERS *NtHdr;
  DosHdr = (IMAGE_DOS_HEADER *)hModule;
  uintptr_t rsrc, size;
  if (IMAGE_DOS_SIGNATURE == DosHdr->e_magic) {
    NtHdr = (IMAGE_NT_HEADERS *)(hModule + DosHdr->e_lfanew);
    if (IMAGE_NT_SIGNATURE == NtHdr->Signature) {
      rsrc = NtHdr->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_RESOURCE].VirtualAddress;
      if (rsrc) {
        rsrc += hModule;
        if (IthGetMemoryRange((LPVOID)rsrc, &rsrc ,&size) &&
            SearchPattern(rsrc, size - 4, str, wcslen(str) << 1))
          return true;
      }
    }
  }
  return false;
}

std::pair<uintptr_t, uintptr_t> QueryModuleLimits(HMODULE module,uintptr_t addition,DWORD protect)
{
	uintptr_t moduleStartAddress = (uintptr_t)module + addition;
	uintptr_t moduleStopAddress = moduleStartAddress;
	MEMORY_BASIC_INFORMATION info;
	do
	{
		VirtualQuery((void*)moduleStopAddress, &info, sizeof(info));
		moduleStopAddress = (uintptr_t)info.BaseAddress + info.RegionSize;
	} while (info.Protect>=protect);
	moduleStopAddress -= info.RegionSize;
	return { moduleStartAddress, moduleStopAddress };
}

std::vector<uintptr_t> SearchMemory(const void* bytes, short length, DWORD protect, uintptr_t minAddr, uintptr_t maxAddr)
{
	SYSTEM_INFO systemInfo;
	GetNativeSystemInfo(&systemInfo);
	std::vector<std::pair<uintptr_t, uintptr_t>> validMemory;
	for (BYTE* probe = NULL; probe < systemInfo.lpMaximumApplicationAddress;)
	{
		MEMORY_BASIC_INFORMATION info = {};
		if (!VirtualQuery(probe, &info, sizeof(info)))
		{
			probe += systemInfo.dwPageSize;
			continue;
		}
		else
		{
			if ((uintptr_t)info.BaseAddress + info.RegionSize >= minAddr && info.Protect >= protect && !(info.Protect & PAGE_GUARD))
				validMemory.push_back({ (uintptr_t)info.BaseAddress, info.RegionSize });
			probe += info.RegionSize;
		}
	}

	std::vector<uintptr_t> ret;
	for (auto memory : validMemory)
		for (uintptr_t addr = max(memory.first, minAddr); true;)
			if (addr < maxAddr && (addr = SafeSearchMemory(addr, memory.first + memory.second, (const BYTE*)bytes, length)))
				ret.push_back(addr++);
			else break;

	return ret;
}

uintptr_t FindFunction(const char* function)
{
    static HMODULE modules[300] = {};
    static auto _ = EnumProcessModules(GetCurrentProcess(), modules, sizeof(modules), DUMMY);
    for (auto module : modules) if (auto addr = GetProcAddress(module, function)) return (uintptr_t)addr;
    return 0;
}

}

#ifndef _WIN64

ULONG SafeFindEnclosingAlignedFunction(DWORD addr, DWORD range)
{
  ULONG r = 0;
  __try{
    r = MemDbg::findEnclosingAlignedFunction(addr, range); // this function might raise if failed
  }__except(EXCEPTION_EXECUTE_HANDLER) {}
  return r;
}

ULONG SafeFindBytes(LPCVOID pattern, DWORD patternSize, DWORD lowerBound, DWORD upperBound)
{
  ULONG r = 0;
  __try{
    r = MemDbg::findBytes(pattern, patternSize, lowerBound, upperBound);
  }__except(EXCEPTION_EXECUTE_HANDLER) {}
  return r;
}
// jichi 7/17/2014: Search mapped memory for emulators
ULONG _SafeMatchBytesInMappedMemory(LPCVOID pattern, DWORD patternSize, BYTE wildcard,
                                   ULONG start, ULONG stop, ULONG step)
{
  for (ULONG i = start; i < stop; i += step) // + patternSize to avoid overlap
    if (ULONG r = SafeFindBytes(pattern, patternSize, i, i + step + patternSize + 1))
      return r;
  return 0;
}
ULONG SafeMatchBytesInGCMemory(LPCVOID pattern, DWORD patternSize)
{
  enum : ULONG {
    start = MemDbg::MappedMemoryStartAddress // 0x01000000
    , stop = MemDbg::MemoryStopAddress // 0x7ffeffff
    , step = start
  };
  return _SafeMatchBytesInMappedMemory(pattern, patternSize, XX, start, stop, step);
}
#endif


#ifndef _WIN64

std::vector<DWORD> findrelativecall(const BYTE* pattern ,int length,DWORD calladdress,DWORD start, DWORD end)
{
  std::vector<DWORD> save;
  for (; start < end;start+=1 ) { 
    DWORD addr=MemDbg::findBytes(pattern, length, start, end); 
    start = addr;
    if (!addr)return save;
    
    BYTE callop = 0xE8;
    
    union little {
      DWORD _dw;
      BYTE _bytes[4]; 
    }relative;
    relative._dw = (calladdress - addr -length- 5);
    DWORD calladdr = addr + length;
    if (*((BYTE*)calladdr) == callop) {

      calladdr += 1;
      BYTE* _b = (BYTE*)calladdr;
      BYTE* _a = relative._bytes;
      /*ConsoleOutput("%p", addr);
      ConsoleOutput("%p %x", calladdress, relative._dw);
      ConsoleOutput("%02x%02x%02x%02x %02x%02x%02x%02x", _a[0], _a[1], _a[2], _a[3], _b[0], _b[1], _b[2], _b[3]);*/
      if ((_a[0] == _b[0]) && (_a[1] == _b[1]) && (_a[2] == _b[2]) && (_a[3] == _b[3])) {
        save.push_back(start);
      }
    } 
  }
  return save;
}
std::vector<DWORD> findxref_reverse_checkcallop(DWORD addr, DWORD from, DWORD to,BYTE op) {
  //op可以为E8 call E9 jump
  //上面的版本其实就应该checkcallop的，之前忘了，但不敢乱改破坏之前的了，不然还要重新测试。
  std::vector<DWORD> res;
  if (addr == 0)return res;
  DWORD now = to;
  while (now > from) {
    DWORD calladdr = now - 5;
    if(IsBadReadPtr((LPVOID)(calladdr + 1),4)==0){
      DWORD relative = *(DWORD*)(calladdr + 1);
      if (now + relative == addr) {
        if(*(BYTE*)calladdr==op)
          res.push_back(calladdr);
      }
    }
    
    now -= 1;
  }
  return res;
}
uintptr_t finddllfunctioncall(uintptr_t funcptr,uintptr_t start, uintptr_t end,WORD sig,bool reverse){
  auto entry=Util::FindImportEntry(start,funcptr);  
  if(entry==0)return 0;
  BYTE bytes[]={0xFF,0x15,XX4};
  memcpy(bytes+2,&entry,4);  
  memcpy(bytes,&sig,2);
  if(reverse)
    return reverseFindBytes(bytes,sizeof(bytes),start,end);
  else
    return MemDbg::findBytes(bytes,sizeof(bytes),start,end);
}
uintptr_t findfuncstart(uintptr_t addr,uintptr_t range){
  const BYTE funcstart[] = {
    0x55,0x8b,0xec
  };
  addr = reverseFindBytes(funcstart, sizeof(funcstart), addr-range, addr);
  return addr;
}

#endif


uintptr_t reverseFindBytes(const BYTE* pattern, int length, uintptr_t start, uintptr_t end) {
  for (end -= length; end >= start; end -= 1) {
    bool success=true;
    for(int i=0;i<length;i++){
      if(pattern[i]!=*(BYTE*)(end+i) && pattern[i]!=XX){
        success=false;break;
      }
    }
    if(success)return end;
    // if (memcmp(pattern, (const BYTE*)(end), length) == 0) {
    //   return end;
    // }
  }
  return 0;
} 
std::vector<uintptr_t> findxref_reverse(uintptr_t addr, uintptr_t from, uintptr_t to) {
  std::vector<uintptr_t> res;
  if (addr == 0)return res;
  uintptr_t now = to;
  while (now > from) {
    uintptr_t calladdr = now - 5;
    uintptr_t relative = *(int*)(calladdr + 1);
    if (now + relative == addr) {
      res.push_back(calladdr);
    }
    now -= 1;
  }
  return res;
} 
int hexCharToValue(char c) {
    if (c >= '0' && c <= '9') {
        return c - '0';
    } else if (c >= 'A' && c <= 'F') {
        return c - 'A' + 10;
    } else if (c >= 'a' && c <= 'f') {
        return c - 'a' + 10;
    } else if(c=='?'){
        return -1;
      }
    else{
        return -2;
    }
}
uintptr_t find_pattern(const char* pattern,uintptr_t start,uintptr_t end){
  std::vector<int> check;
   bool ignore=false;
   for(int i=0;i<strlen(pattern);i++){
    auto c=pattern[i];
    switch (c)
    {
    case '\n':
      ignore=false; //注释，直到换行
    case ' ':   //忽略空格，制表，回车
    case '\t':
      break;
    case '/': //注释
      ignore=true;
      break;
    default:{ //? 0-9A-Fa-f
        auto _i=hexCharToValue(c);
        if(_i==-2)return 0;
        check.push_back(_i);
      }
    }
  } 
  if(check.size()%2!=0)return 0;
  std::vector<BYTE>_type,_pattern;
  for(int j=0;j<check.size();j+=2){
    if(check[j]!=-1&&check[j+1]!=-1){
      _type.push_back(0);
      _pattern.push_back(check[j]*0x10+check[j+1]);
    }
    else if(check[j]==-1&&check[j+1]==-1){ //??
      _type.push_back(1);
      _pattern.push_back(0);
    }
    else if(check[j]==-1){ //?_
      _type.push_back(2);
      _pattern.push_back(check[j+1]);
    }
    else{// _?
      _type.push_back(3);
      _pattern.push_back(check[j]*0x10);
    }
  }
  for(uintptr_t i=start;i<end;i++){
    bool succ=true;
    for(int j=0;succ&&(j<_pattern.size());j+=1){
      switch (_type[j])
      {
        case 0:{
          if(_pattern[j]!=*(BYTE*)(i+j)){
            succ=false;
          }
          break;
        }
        case 1:{
          break;
        }
        case 2:{
          if(((*(BYTE*)(i+j))&0xf)!=_pattern[j]){
            succ=false;
          }
          break;
        }
        case 3:{
          if(((*(BYTE*)(i+j))&0xf0)!=_pattern[j]){
            succ=false;
          }
          break;
        }
      }
    }
    if(succ)
      return i;
  }
  return 0;
}

bool Engine::isAddressReadable(const uintptr_t *p)
{ return p && !::IsBadReadPtr(p, sizeof(*p)); }

bool Engine::isAddressReadable(const char *p, size_t count)
{ return p && count && !::IsBadReadPtr(p, sizeof(*p) * count); }

bool Engine::isAddressReadable(const wchar_t *p, size_t count)
{ return p && count && !::IsBadReadPtr(p, sizeof(*p) * count); }

bool Engine::isAddressWritable(const uintptr_t *p)
{ return p && !::IsBadWritePtr((LPVOID)p, sizeof(*p)); }

bool Engine::isAddressWritable(const char *p, size_t count)
{ return p && count && !::IsBadWritePtr((LPVOID)p, sizeof(*p) * count); }

bool Engine::isAddressWritable(const wchar_t *p, size_t count)
{ return p && count && !::IsBadWritePtr((LPVOID)p, sizeof(*p) * count); }