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| unit sharedmm;
interface
uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
type TSharedMemory = class(TComponent) private FMappingHandle :THandle; FMemory :Pointer; Fsize :Longint; fblockexists :boolean; Fname :String; protected Procedure Alloc; Procedure Dealloc; Procedure setfSize (size:Longint); Procedure Setfname (const name:String); public constructor Create(AOwner: TComponent);override; destructor Destroy; override;
property Memory :Pointer read FMemory;
published
Property BlockSize :Longint read fsize write setfSize default 0; Property BlockName :String read fname write setfname; Property BlockExists : Boolean read fblockexists; end;
procedure Register;
implementation
{$R sharedmm.DCR}
Procedure tsharedmemory.setfSize(size:Longint); begin Dealloc; Fsize:=size; Alloc; end;
Procedure Tsharedmemory.Setfname (const name:String); begin Dealloc; fname:=name; Alloc; end;
Procedure TSharedmemory.Dealloc; begin if csdesigning in componentstate then exit;
fblockexists:=False;
if ( FMemory <> Nil ) then begin if not UnmapViewOfFile( FMemory ) then raise Exception.Create( 'TFilemapping unmapview error'); FMemory := Nil; end;
if ( FMappingHandle <> 0 ) then if not CloseHandle( FMappingHandle ) then raise Exception.Create('TFileMapping close handle error' ); end;
constructor Tsharedmemory.Create(AOwner: TComponent); begin inherited create(aowner); fmemory:=NIL; fmappingHandle:=0; fsize:=0; fblockexists:=False; fname:=''; end;
procedure TSharedMemory.alloc; VAR i:integer; begin if csdesigning in componentstate then exit; if (fsize=0) or (fname='') then exit;
FMappingHandle := CreateFileMapping( $FFFFFFFF, nil, page_readwrite, 0, fsize, pchar(fName));
i:=getlasterror; fblockExists:=(i=error_already_exists);
if ( FMappingHandle = 0 ) then raise Exception.Create( 'TSharedmemory.create handle error' );
FMemory := MapViewOfFile( FMappingHandle, FILE_MAP_write, 0, 0, 0 );
if ( FMemory = Nil ) then raise Exception.Create('Tfilemapping map view error' ); end;
destructor TSharedMemory.Destroy; begin inherited Destroy; end;
procedure Register; begin RegisterComponents('MULTI', [TSharedMemory]); end;
end. |