小编Jun*_*orD的帖子

我需要扩展TFileStream,以便它可以使用不是0偏移量的文件,而是来自用户定义的偏移量.我的意思是它必须将用户定义的偏移解释为流开始.我的代码是:

type
  TSuFileStream = class(TFileStream)
  protected
    FOffset : int64;

    procedure SetOffset(Offset : int64);

    procedure SetSize(NewSize: Longint); override;
    procedure SetSize(const NewSize: Int64); override;
  public
    constructor Create(const AFileName: string; Mode: Word); overload;
    constructor Create(const AFileName: string; Mode: Word; Rights: Cardinal); overload;

    function Seek(Offset: Longint; Origin: Word): Longint; override;
    function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;

    property Offset : int64 read FOffset write SetOffset;
  end;
...
constructor TSuFileStream.Create(const AFileName: string; Mode: Word);
begin
  inherited Create(AFileName, Mode);
  FOffset := 0;
end;

constructor TSuFileStream.Create(const …