var
  data: Integer;                    // int -> Integer
  m_Strtag: string;                 // m_Strtag is CString, I guess
  sz: array[0..3] of Byte;          // unsigned char sz[4] -> array[0..3] of Byte
begin
  data := StrToInt(m_Strtag);       // _ttoi -> StrToInt
  FillChar(sz, 4, 0);               // memset(sz, 0, 4) -> no direct equivalent; the same with different param. order does e.g. FillChar

  sz[0] := (data shr 24) and $FF;   // (data >> 24) & 0xFF
  sz[1] := (data shr 16) and $FF;   // (data >> 16) & 0xFF
  sz[2] := (data shr 8) and $FF;    // (data >> 8) & 0xFF
  sz[3] := data and $FF;            // data & 0xFF
end;