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

https://github.com/slibre/freepascal · Pascal · 64 lines · 46 code · 16 blank · 2 comment · 1 complexity · 4ff6329c2568f633ed3164b54778675e MD5 · raw file 

    

  1. unit dbf_cursor;
    2. 

  2. 

  3. interface
    4. 

  4. 

  5. {$I dbf_common.inc}
    6. 

  6. 

  7. uses
    8. 

  8.   SysUtils,
    9. 

  9.   Classes,
    10. 

  10.   dbf_pgfile,
    11. 

  11.   dbf_common;
    12. 

  12. 

  13. type
    14. 

  14. 

  15. //====================================================================
    16. 

  16.   TVirtualCursor = class(TObject)
    17. 

  17.   private
    18. 

  18.     FFile: TPagedFile;
    19. 

  19. 

  20.   protected
    21. 

  21.     function GetPhysicalRecNo: Integer; virtual; abstract;
    22. 

  22.     function GetSequentialRecNo: Integer; virtual; abstract;
    23. 

  23.     function GetSequentialRecordCount: Integer; virtual; abstract;
    24. 

  24.     procedure SetPhysicalRecNo(RecNo: Integer); virtual; abstract;
    25. 

  25.     procedure SetSequentialRecNo(RecNo: Integer); virtual; abstract;
    26. 

  26. 

  27.   public
    28. 

  28.     constructor Create(pFile: TPagedFile);
    29. 

  29.     destructor Destroy; override;
    30. 

  30. 

  31.     function  RecordSize: Integer;
    32. 

  32. 

  33.     function  Next: Boolean; virtual; abstract;
    34. 

  34.     function  Prev: Boolean; virtual; abstract;
    35. 

  35.     procedure First; virtual; abstract;
    36. 

  36.     procedure Last; virtual; abstract;
    37. 

  37. 

  38.     property PagedFile: TPagedFile read FFile;
    39. 

  39.     property PhysicalRecNo: Integer read GetPhysicalRecNo write SetPhysicalRecNo;
    40. 

  40.     property SequentialRecNo: Integer read GetSequentialRecNo write SetSequentialRecNo;
    41. 

  41.     property SequentialRecordCount: Integer read GetSequentialRecordCount;
    42. 

  42.   end;
    43. 

  43. 

  44. implementation
    45. 

  45. 

  46. constructor TVirtualCursor.Create(pFile: TPagedFile);
    47. 

  47. begin
    48. 

  48.   FFile := pFile;
    49. 

  49. end;
    50. 

  50. 

  51. destructor TVirtualCursor.Destroy; {override;}
    52. 

  52. begin
    53. 

  53. end;
    54. 

  54. 

  55. function TVirtualCursor.RecordSize : Integer;
    56. 

  56. begin
    57. 

  57.   if FFile = nil then
    58. 

  58.     Result := 0
    59. 

  59.   else
    60. 

  60.     Result := FFile.RecordSize;
    61. 

  61. end;
    62. 

  62. 

  63. end.
    64.