/packages/fcl-db/src/dbase/dbf_cursor.pas

 1unit dbf_cursor;
 2
 3interface
 4
 5{$I dbf_common.inc}
 6
 7uses
 8  SysUtils,
 9  Classes,
10  dbf_pgfile,
11  dbf_common;
12
13type
14
15//====================================================================
16  TVirtualCursor = class(TObject)
17  private
18    FFile: TPagedFile;
19
20  protected
21    function GetPhysicalRecNo: Integer; virtual; abstract;
22    function GetSequentialRecNo: Integer; virtual; abstract;
23    function GetSequentialRecordCount: Integer; virtual; abstract;
24    procedure SetPhysicalRecNo(RecNo: Integer); virtual; abstract;
25    procedure SetSequentialRecNo(RecNo: Integer); virtual; abstract;
26
27  public
28    constructor Create(pFile: TPagedFile);
29    destructor Destroy; override;
30
31    function  RecordSize: Integer;
32
33    function  Next: Boolean; virtual; abstract;
34    function  Prev: Boolean; virtual; abstract;
35    procedure First; virtual; abstract;
36    procedure Last; virtual; abstract;
37
38    property PagedFile: TPagedFile read FFile;
39    property PhysicalRecNo: Integer read GetPhysicalRecNo write SetPhysicalRecNo;
40    property SequentialRecNo: Integer read GetSequentialRecNo write SetSequentialRecNo;
41    property SequentialRecordCount: Integer read GetSequentialRecordCount;
42  end;
43
44implementation
45
46constructor TVirtualCursor.Create(pFile: TPagedFile);
47begin
48  FFile := pFile;
49end;
50
51destructor TVirtualCursor.Destroy; {override;}
52begin
53end;
54
55function TVirtualCursor.RecordSize : Integer;
56begin
57  if FFile = nil then
58    Result := 0
59  else
60    Result := FFile.RecordSize;
61end;
62
63end.
64