1 | unit Storage;
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2 |
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3 | interface
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4 |
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5 | uses
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6 | Classes, SysUtils, Device, Channel, Int;
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7 |
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8 | type
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9 |
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10 | { TStorage }
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11 |
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12 | TStorage = class(TDevice)
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13 | private
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14 | FFileName: string;
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15 | function GetSize: Integer;
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16 | procedure SetFileName(AValue: string);
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17 | procedure SetSize(AValue: Integer);
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18 | public
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19 | FFile: TFileStream;
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20 | Position: Integer;
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21 | function ReadByte(Address: TInt): Byte;
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22 | function ReadData(Size: TIntSize): TInt;
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23 | function ReadPosition(Size: TIntSize): TInt;
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24 | function ReadSize(Size: TIntSize): TInt;
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25 | procedure WriteData(Size: TIntSize; Value: TInt);
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26 | procedure WritePosition(Size: TIntSize; Value: TInt);
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27 | procedure WriteSize(Size: TIntSize; Value: TInt);
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28 | function GetHandlers: THandlers; override;
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29 | constructor Create;
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30 | destructor Destroy; override;
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31 | property FileName: string read FFileName write SetFileName;
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32 | property Size: Integer read GetSize write SetSize;
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33 | end;
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34 |
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35 |
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36 | implementation
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37 |
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38 | { TStorage }
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39 |
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40 | procedure TStorage.SetFileName(AValue: string);
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41 | begin
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42 | if FFileName = AValue then Exit;
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43 | if AValue = '' then FreeAndNil(FFile);
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44 | FFileName := AValue;
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45 | if FFileName <> '' then begin
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46 | if FileExists(FFileName) then FFile := TFileStream.Create(FFileName, fmOpenReadWrite)
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47 | else FFile := TFileStream.Create(FFileName, fmCreate);
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48 | end;
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49 | end;
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50 |
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51 | function TStorage.GetSize: Integer;
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52 | begin
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53 | Result := FFile.Size;
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54 | end;
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55 |
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56 | procedure TStorage.SetSize(AValue: Integer);
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57 | begin
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58 | FFile.Size := AValue;
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59 | end;
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60 |
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61 | function TStorage.ReadByte(Address: TInt): Byte;
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62 | begin
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63 | Result := 0;
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64 | FFile.Position := Address;
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65 | FFile.Read(Result, 1);
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66 | end;
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67 |
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68 | function TStorage.ReadData(Size: TIntSize): TInt;
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69 | begin
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70 | FFile.Position := Position;
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71 | FFile.Read(Result, Size);
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72 | Inc(Position, Size);
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73 | end;
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74 |
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75 | function TStorage.ReadPosition(Size: TIntSize): TInt;
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76 | begin
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77 | Result := Position;
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78 | end;
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79 |
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80 | function TStorage.ReadSize(Size: TIntSize): TInt;
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81 | begin
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82 | Result := FFile.Size;
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83 | end;
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84 |
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85 | procedure TStorage.WriteData(Size: TIntSize; Value: TInt);
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86 | begin
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87 | FFile.Position := Position;
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88 | FFile.Write(Value, Size);
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89 | Inc(Position, Size);
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90 | end;
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91 |
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92 | procedure TStorage.WritePosition(Size: TIntSize; Value: TInt);
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93 | begin
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94 | Position := Value;
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95 | end;
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96 |
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97 | procedure TStorage.WriteSize(Size: TIntSize; Value: TInt);
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98 | begin
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99 | FFile.Size := Value;
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100 | end;
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101 | function TStorage.GetHandlers: THandlers;
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102 | begin
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103 | Result := THandlers.Create;
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104 | Result.ReadHandlers.Add(ReadData);
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105 | Result.ReadHandlers.Add(ReadPosition);
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106 | Result.ReadHandlers.Add(ReadSize);
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107 | Result.WriteHandlers.Add(WriteData);
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108 | Result.WriteHandlers.Add(WritePosition);
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109 | Result.WriteHandlers.Add(WriteSize);
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110 | end;
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111 |
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112 | constructor TStorage.Create;
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113 | begin
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114 | FileName := 'Storage.dat';
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115 | Position := 0;
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116 | end;
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117 |
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118 | destructor TStorage.Destroy;
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119 | begin
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120 | FreeAndNil(FFile);
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121 | inherited;
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122 | end;
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123 |
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124 | end.
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125 |
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