(*// 标题:搜索字符串在流中的位置 说明:适用于文件搜索等 设计:Zswang 支持:[email protected] 日期:2004-03-21 //*)
(*//============================================================================ 设计思路: 从流中将数据取到缓冲中 再逐一对缓冲进行搜索 ============================================================================//*)
function ScanStream(mStream: TStream; mStr: string): Integer; const cBufferSize = $8000; var S: string; T: string; I: Integer; L: Integer; begin Result := -1; if not Assigned(mStream) then Exit; if mStr = '' then Exit; L := Length(mStr); mStream.Position := 0; SetLength(S, cBufferSize); T := ''; for I := 1 to mStream.Size div cBufferSize do begin mStream.Read(S[1], cBufferSize); Result := Pos(mStr, T + S) - 1; //保留上次搜索的尾部字符～～ T := Copy(S, cBufferSize - L, MaxInt); if Result >= 0 then begin Result := Result + Pred(I) * cBufferSize - Length(T); Exit; end; end; I := mStream.Size mod cBufferSize; SetLength(S, I); if I > 0 then begin mStream.Read(S[1], I); Result := Pos(mStr, T + S) - 1; if Result >= 0 then begin Result := Result + mStream.Size - I - Length(T); Exit; end; end; end; { ScanStream }
//Example procedure TForm1.Button1Click(Sender: TObject); var vFileStream: TFileStream; begin vFileStream := TFileStream.Create('C:\temp\temp.exe', fmShareDenyNone); try Label1.Caption := IntToStr(ScanStream(vFileStream, Edit1.Text)); finally vFileStream.Free; end; end;
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