CODEWITHSUNDEEP
c++delphitemplatespascal
paulohr
paulohr

Reputation: 586

Delphi Templates like C++?

Please, can anyone convert this code for me?

I don't know so much about C++, so I need to convert this code from C++ to delphi:

template <typename DestType, typename SrcType>
DestType* ByteOffset(SrcType* ptr, ptrdiff_t offset)
{
        return reinterpret_cast<DestType*>(reinterpret_cast<unsigned char*>(ptr) + offset);
}

Thank you...

Upvotes: 2

Views: 4411

Answers (2)

Remy Lebeau
Remy Lebeau

Reputation: 596101

Delphi Generics is the closest equivilent to C++ templates, eg:

type
  ByteOffset<DestType, SrcType> = class
  public
    type
      PSrcType = ^SrcType;
      PDestType = ^DestType;

    class function At(ptr: PSrcType; offset: NativeInt): PDestType;
  end;

class function ByteOffset<DestType, SrcType>.At(ptr: PSrcType; offset: NativeInt): PDestType;
begin
  Result := PDestType(PByte(ptr) + offset);
end;

.

var
  I: Integer;
  W: PWord;
begin
  I := $11223344;
  W := ByteOffset<Word, Integer>.At(@I, 2);
end;

Upvotes: 3

David Heffernan
David Heffernan

Reputation: 612954

It's actually pretty simple to convert, but you can't use templates in Delphi. It is merely adding an offset to a pointer, but the offset is specified in bytes rather than multiples of the pointer base type.

So convert

ByteOffset<IMAGE_NT_HEADERS>(DosHeader, DosHeader->e_lfanew)

into

PIMAGE_NT_HEADERS(PAnsiChar(DosHeader)+DosHeader.e_lfanew)

Some more examples:

ExportDirectory := PIMAGE_EXPORT_DIRECTORY(PAnsiChar(DosHeader)+
    NtHeader.OptionalHeader.
    DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress);

functions := PDWORD(PAnsiChar(DosHeader)+ExportDirectory->AddressOfFunctions);

and so on.

Upvotes: 4

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