Copy a file using a TFileStream (Views: 712)
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Problem/Question/Abstract: How to copy a file using a TFileStream Answer: { ... } type TFileCopyUpdateEvent = procedure(const SrcFile, DestFile: string; CurrentPos, MaxSize: Integer) of object; function Min(Val1, Val2: Integer): Integer; begin Result := Val1; if Val2 < Val1 then Result := Val2; end; {SrcFile and DestFile are the fully qualified filenames to the files to copy function} MyFileCopy(SrcFile, DestFile: TFilename; OnUpdate: TFileCopyUpdateEvent = nil): Boolean; const StreamBuf = 4096; var Src, Dst: TFileStream; BufCount: Integer; begin Src := nil; Dst := nil; {prevents .Free problems on exception} {allow everyone else any access} Src := TFileStream.Create(SrcFile, fmOpenRead or fmShareDenyNone); if FileExists(DestFile) then {this could cause an error if a user has the file open} Dst := TFileStream.Create(DestFile, fmOpenWrite or fmShareExclusive) else Dst := TFileStream.Create(DestFile, fmCreate or fmShareExclusive); try while Dst.Position < Dst.Size do begin BufCount := Min(StreamBuf, Dst.Size - Dst.Position); Src.CopyFrom(Dst, BufCount); if Assigned(OnUpdate) then {report progress every 4k} OnUpdate(SrcFile, DestFile, Dst.Position, Dst.Size); end; finally Src.Free; Dst.Free; end; end; |