Поиск строки в файле

unit Unit1;
 
interface
 
uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    OpenDialog1: TOpenDialog;
    Button2: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
  fbuf:TFileStream;
 
implementation
 
{$R *.dfm}
{$SETPEFLAGS $0020}
 
function BMFind(szSubStr, buf: PAnsiChar; iBufSize: integer): integer;
  { Returns -1 if substring not found,
  or zero-based index into buffer if substring found }
var
  iSubStrLen: integer;
  skip: array [char] of integer;
  found: boolean;
  iMaxSubStrIdx: integer;
  iSubStrIdx: integer;
  iBufIdx: integer;
  iScanSubStr: integer;
  mismatch: boolean;
  iBufScanStart: integer;
  ch: char;
begin
  { Initialisations }
  found := False;
  Result := -1;
  { Check if trivial scan for empty string }
  iSubStrLen := StrLen(szSubStr);
  if iSubStrLen = 0 then
  begin
    Result := 0;
    Exit
  end;
 
  iMaxSubStrIdx := iSubStrLen - 1;
  { Initialise the skip table }
  for ch := Low(skip) to High(skip) do skip[ch] := iSubStrLen;
  for iSubStrIdx := 0 to (iMaxSubStrIdx - 1) do
    skip[szSubStr[iSubStrIdx]] := iMaxSubStrIdx - iSubStrIdx;
 
  { Scan the buffer, starting comparisons at the end of the substring }
  iBufScanStart := iMaxSubStrIdx;
  while (not found) and (iBufScanStart < iBufSize) do
  begin
    iBufIdx := iBufScanStart;
    iScanSubStr := iMaxSubStrIdx;
    repeat
      mismatch := (szSubStr[iScanSubStr] <> buf[iBufIdx]);
      if not mismatch then
        if iScanSubStr > 0 then
        begin // more characters to scan
          Dec(iBufIdx); Dec(iScanSubStr)
        end
      else
        found := True;
    until mismatch or found;
    if found then
      Result := iBufIdx
    else
      iBufScanStart := iBufScanStart + skip[buf[iBufScanStart]];
  end;
end;
 
function StringInFile(strFind: string; fstm: TFileStream): boolean;
const
  BUFSIZE = 8192;
var
  numread: Longint;
  buffer: array [0..BUFSIZE-1] of AnsiChar;
  szFind: array [0..255] of AnsiChar;
  found: boolean;
begin
  StrPCopy(szFind, strFind);
  found := False;
  repeat
    numread := fstm.Read(Buffer, BUFSIZE);
    if BMFind(szFind, Buffer, numread) >= 0 then
      found := True
    else if numread = BUFSIZE then // more to scan
     fstm.Position := fstm.Position - (Length(strFind)-1);
  until found or (numread < BUFSIZE);
  //fstm.Free;
  Result := found;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
var
tmp:widestring;
begin
if opendialog1.Execute then
fbuf := TFileStream.Create(opendialog1.FileName, fmOpenRead);
end;
 
procedure TForm1.Button2Click(Sender: TObject);
begin
if StringInFile('найдименя', fbuf) then
memo1.Lines.Add('Found');
end;
 
end.

procedure TestBufferedFileStream(const sFileName: String; 
                                 const iBufferSize: Integer);
var
  fs: TBufferedFileStream;
  sr: TStreamReader;
  sw: TStopwatch;
  st: String;
begin
  sw := TStopwatch.StartNew;
  fs := TBufferedFileStream.Create(sFileName, fmOpenRead, iBufferSize);
  try
    sr := TStreamReader.Create(fs);
    try
      while not sr.EndOfStream do
        st := sr.ReadLine;
[COLOR="Red"]   if st='Я ищу это' then[/COLOR]
////////////////////
    finally
      sr.Free
    end;
  finally
    fs.Free;
  end;
  sw.Stop;
  WriteLn(st.Chars[0], ' ', sw.Elapsed.ToString);
end;

uses
..., bufferedfilestream;
 
function TestBufferedFileStream(const sFileName: String; Search: string;
                                 const iBufferSize: Integer):boolean;
var
  fs: TReadOnlyCachedFileStream;
  sr: TStreamReader;
  res:boolean;
begin
  res:=false;
  fs := TReadOnlyCachedFileStream.Create(sFileName, iBufferSize);
  try
    sr := TStreamReader.Create(fs);
    try
      while not sr.EndOfStream do
        if sr.ReadLine=Search then begin
        res:=true;
        Break;
        end;
    finally
      sr.Free
    end;
  finally
    fs.Free;
  end;
  Result:=res;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
if opendialog1.Execute then
if TestBufferedFileStream(opendialog1.filename,'Я ищу именно тебя моя строка',8192) then
memo1.Lines.Add('Found')
else
memo1.Lines.Add('NOT Found');
end;