rsvk/Component/ofile.pas

unit Ofile;
{$I-}
{Object file unit.
 Copyright (C) 1995 F-inc.
 rev 2.1 5/July/1996

 Borland Delphi Object Pascal compatible.
 Do not use with BP7.
}

(**) interface (**)
uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls, Buttons;

    (***************************************************************************

    General Notes:
    If you want to override any of the functions, only do so
    for those that are virtual.
    Do not override non virtual methods!

    Notes v2.0:
    - Many virtual methods have been taken out for faster execution.
      For faster, buffered saving of delphi data types, use TWriter or TBufferedFileStream.
      See unit buffered_file_stream_unit (F-inc).
    - To check for errors, use the Error function (this calls IOResult) or IOResult method.

    v2.1:
    - Took out AssignFile. Directly pass the file name in create. This is more inline
      with Borland's own TStreamFile creation procedure and is less confusing.

    ***************************************************************************)



Type
  PFile = ^File;
  TErrorFlag = Integer;

  TOFile = Class
  private
    procedure AssignFile(const AFilePath : string);   {Accepts : A file path. The path to the file}

  public
    Constructor Create(const file_path: string);
    Destructor  Destroy; Override;

    function  Error: Boolean;           {Returns true if there is an error}
    function IOResult: integer;         {wraps the system's IOResult}

    {Wrapper methods}
    procedure Reset(Const aSize : Word);
    procedure ResetReadOnly(Const aSize : Word);
    procedure Rewrite(Const aSize : Word); //virtual;
    procedure Close; //virtual;

    function  FilePos : LongInt; //virtual;
    procedure Seek(Const aPos : LongInt); //virtual;
    procedure SeekEOF;                  {Seeks to the end of file}

    {Block read/write support
     Returns number of bytes read/written}
    function BlockRead(Var Buf; Const Count : longint): longint; {virtual;}
    function BlockWrite(Var Buf; Const Count : longint): longint; {virtual;}

    {Writes/reads a string
     String is stored in the format [StringLength][...String...]}
    procedure ReadString(Var rString : String);
    procedure WriteString(aString : String);
    function  GetString : string;

    {Writes/reads a byte}
    procedure ReadByte(Var rByte : Byte);
    procedure WriteByte(aByte : Byte);
    function  GetByte : byte;

    {Writes/reads a integer}
    procedure ReadInteger(Var rInteger : Integer);
    procedure WriteInteger(aInteger : Integer);
    function  GetInteger : Integer;

    {Writes/reads a integer}
    procedure ReadLongint(Var rLongint : Longint);
    procedure WriteLongint(aLongint : Longint);
    function  GetLongint : Longint;

    function  EOF : Boolean;             {True if end of file reached}
    function  Exists : Boolean;          {True if file exists}

    function  FileSize : LongInt;

  protected

    F : File;                           {The actual file variable}
    FName : String;                      {The actual file name}
    FPath : String;                      {The actual file path}
    FOpen : Boolean;                     {True if file is open}

    //BlockResult : longint;              {BlockRead/Write result stored here}
    //ErrorFlag   : TErrorFlag;           {The error flag. 0 - no error.}

    //procedure UpdateErrorFlag;          {Assigns IOError to ErrorFlag}
    //function  GetErrorFlag : TErrorFlag; {Returns the value of the error flag}

    procedure _Reset(Const aSize : Word); virtual;       {Real reset}
    //procedure _BlockRead(Var Buf; Const Count : word);   {Default BlockRead procedure}
    //procedure _BlockWrite(Var Buf; Const Count : word);  {Default BlockWrite prrocedure}

  published
    property Handle: File read F;        {Returns a pointer to the file handle}
    property IsOpen: boolean read FOpen;   {True if file is open}
    property FileName: string read FName;
    property FilePath: string read FPath;
  end;


(**) implementation (**)
//Uses EDosu;

{/////////////////////////////////////////////////////////////}
{Constructor/Destructor}
{/////////////////////////////////////////////////////////////}
Constructor TOFile.Create(const file_path: string);
//Constructor TOFile.Create;
begin
  Inherited Create;

  FOpen := False;
  AssignFile(file_path);
end;

Destructor TOFile.Destroy;
begin
  Close;
  Inherited  Destroy;
end;

{/////////////////////////////////////////////////////////////}
{Misc functions}
{/////////////////////////////////////////////////////////////}
{function TOFile.GetHandle: PFile;
begin
  result := @F;
end;}

{/////////////////////////////////////////////////////////////}
{Wrapper functions}
{/////////////////////////////////////////////////////////////}
procedure TOFile.AssignFile(const AFilePath : String);
begin
  Close;

  {Init fields}
  FName := ExtractFileName(AFilePath);
  FPath := ExtractFilePath(AFilePath);
  Assign(f, AFilePath);
end;

procedure TOFile.Reset;
begin
  FileMode := 2;
  _Reset(aSize);
end;

procedure TOFile.ResetReadOnly;
begin
  FileMode := 0;
  _Reset(aSize);
end;

procedure TOFile._Reset;
begin
  Close;
  System.Reset(f, aSize);
  FOpen := True;
end;

procedure TOFile.Rewrite;
begin
  Close;
  System.Rewrite(f, aSize);
  FOpen := True;
end;

procedure TOFile.Close;
begin
  If IsOpen then
  begin
    System.Close(f);
    FOpen := False;
  end;
end;

function  TOFile.FilePos : LongInt;
begin
  FilePos := System.FilePos(f);
end;

procedure TOFile.Seek;
begin
  System.Seek(f, aPos);
end;

procedure TOFile.SeekEOF;
begin
  Seek(FileSize);
end;

function  TOFile.EOF;
begin
  Result := System.EOF(f);
end;

function TOFile.Exists;
begin
  Result := FileExists(FPath + FName);
end;

Function TOFile.FileSize;
begin
  Result := System.FileSize(f);
end;

{/////////////////////////////////////////////////////////////}
{BlockRead / BlockWrite wrappers}
{/////////////////////////////////////////////////////////////}
{The procedurers call the virtual BlockRead and BlockWrite.
 These can be overriden. _BlockRead and _BlockWrite cannot.}

function TOFile.BlockRead(Var Buf; Const Count: longint): longint;
begin
  System.BlockRead(f, Buf, Count, result);
end;

function TOFile.BlockWrite(Var Buf; Const Count: longint): longint;
begin
  System.BlockWrite(f, Buf, Count, result);
end;


{/////////////////////////////////////////////////////////////}
{Write data types support}
{/////////////////////////////////////////////////////////////}

{/////////////////////////////////////////////////////////////}
{String support}
{/////////////////////////////////////////////////////////////}
procedure TOFile.WriteString(aString : String);
begin
  {Write Length + 1 bytes because the length byte is also written}
  BlockWrite(aString, Length(aString));
end;

procedure TOFile.ReadString(Var rString : String);
begin
  {Read length,
   Read string data if length is  > 0}

  If length(rString) > 0 then
    BlockRead(rString, length(rString));
end;

function TOFile.GetString : string;
var
  s : string;
begin
  ReadString(s);
  GetString := s;
end;

{/////////////////////////////////////////////////////////////}
{Byte support}
{/////////////////////////////////////////////////////////////}
procedure TOFile.WriteByte(aByte : Byte);
begin
  BlockWrite(aByte, SizeOf(Byte));
end;

procedure TOFile.ReadByte(Var rByte : Byte);
begin
  BlockRead(rByte, SizeOf(Byte));
end;

function TOFile.GetByte : byte;
var
  b : byte;
begin
  ReadByte(b);
  GetByte := b;
end;

{/////////////////////////////////////////////////////////////}
{Integer support}
{/////////////////////////////////////////////////////////////}
procedure TOFile.WriteInteger(aInteger : Integer);
begin
  BlockWrite(aInteger, SizeOf(Integer));
end;

procedure TOFile.ReadInteger(Var rInteger : Integer);
begin
  BlockRead(rInteger, SizeOf(Integer));
end;

function TOFile.GetInteger : Integer;
var
  i : Integer;
begin
  ReadInteger(i);
  GetInteger := i;
end;

{/////////////////////////////////////////////////////////////}
{Long Integer support}
{/////////////////////////////////////////////////////////////}
procedure TOFile.WriteLongInt(aLongint : Longint);
begin
  BlockWrite(aLongint, SizeOf(Longint));
end;

procedure TOFile.ReadLongint(Var rLongint : Longint);
begin
  BlockRead(rLongint, SizeOf(Longint));
end;

function TOFile.GetLongint : Longint;
var
  i : Longint;
begin
  ReadLongint(i);
  GetLongint := i;
end;

{/////////////////////////////////////////////////////////////}
{Error support}
{/////////////////////////////////////////////////////////////}
function TOFile.Error;
begin
  Result := (IOResult = 0);
end;

function TOFile.IOResult: integer;
begin
  result := system.IOResult;
end;




end.