TZStreamRec = packed record
  next_in: PChar;
  avail_in: Integer;
  total_in: Integer;
  next_out: PChar;
  avail_out: Integer;
  total_out: Integer;
  msg: PChar;
  internal: Pointer;
  zalloc: TAlloc;
  zfree: TFree;
  AppData: Pointer;
  data_type: Integer;
  adler: Integer;
  reserved: Integer;
end;

struct TZStreamRec {
  const char * next_in;
  int avail_in;
  int total_in;
  const char * next_out;
  int avail_out;
  int total_out;
  const char * msg;
  void * internal;
  TAlloc zalloc;
  TFree zfree;
  void * AppData;
  int data_type;
  int adler;
  int reserved;
};