delphi读取文本文件的最后一行

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls;

type

TForm1 = class(TForm)

Button1: TButton;

Edit1: TEdit;

Button2: TButton;

procedure Button1Click(Sender: TObject);

procedure Button2Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);

var

LFindHandle: THandle;

LFindData: TWin32FindData;

LSearchFullPath, LFileName: String;

LFileList: TStringList;

LLines: TStringList;

I: Integer;

LFile: TextFile;

LLine, LLastLine: string;

begin

// 对于大文件，速度很慢

LFileList := TStringList.Create;

LLines := TStringList.Create;

LSearchFullPath := Edit1.Text;

FillChar(LFindData, SizeOf(LFindData), 0);

LFindHandle := FindFirstFile(PChar(LSearchFullPath), LFindData);

if LFindHandle <> INVALID_HANDLE_VALUE then

begin

try

repeat

if LFindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY <> 0 then

begin

Continue;

end;

if LFindData.dwFileAttributes and FILE_ATTRIBUTE_HIDDEN <> 0 then

Continue;

LFileName := LFindData.cFileName;

LFileList.Add(LFileName);

until not FindNextFile(LFindHandle, LFindData);

finally

Windows.FindClose(LFindHandle);

end;

for I := 0 to LFileList.Count - 1 do

begin

AssignFile(LFile, LFileList.Strings[I]);

Reset(LFile);

LLastLine := '';

while not Eof(LFile) do

begin

Readln(LFile, LLine);

if Length(LLine) > 0 then

begin

LLastLine := LLine;

end;

if Length(LLastLine) > 0 then

LLines.Add(LLastLine);

end;

LLines.SaveToFile('1.dat');

LFileList.Free;

LLines.Free;

end;

function TextSeek(var f: Text; position: Int64; FromPos: DWORD = FILE_BEGIN): Int64;

var pos64: Int64Rec absolute position;

resHi: cardinal;

resLow: Cardinal;

begin

result := 0;

with TTextRec(f) do

begin

if mode<>fmInput then

exit;

resHi := pos64.Hi;

resLow := SetFilePointer(handle,pos64.Lo,@resHi,FromPos);

BufEnd := 0; // flush internal reading buffer

BufPos := 0;

// 返回当前文件的位置

if (resHi = INVALID_HANDLE_VALUE) and (resLow = INVALID_HANDLE_VALUE) then

Result := -1

else

result := resHi shl 32 + resLow;

end;

procedure TForm1.Button2Click(Sender: TObject);

var

LFindHandle: THandle;

LFindData: TWin32FindData;

LSearchFullPath, LFileName: String;

LFileList: TStringList;

LLines: TStringList;

I: Integer;

LEndIndex: Integer;

LFile: TextFile;

LLine, LLastLine: string;

begin

LFileList := TStringList.Create;

LLines := TStringList.Create;

LSearchFullPath := Edit1.Text;

FillChar(LFindData, SizeOf(LFindData), 0);

LFindHandle := FindFirstFile(PChar(LSearchFullPath), LFindData);

if LFindHandle <> INVALID_HANDLE_VALUE then

begin

try

repeat

if LFindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY <> 0 then

begin

Continue;

end;

if LFindData.dwFileAttributes and FILE_ATTRIBUTE_HIDDEN <> 0 then

Continue;

LFileName := LFindData.cFileName;

LFileList.Add(LFileName);

until not FindNextFile(LFindHandle, LFindData);

finally

Windows.FindClose(LFindHandle);

end;

for I := 0 to LFileList.Count - 1 do

begin

AssignFile(LFile, LFileList.Strings[I]);

Reset(LFile);

LLastLine := '';

// 先去掉最后的空行

LEndIndex := 1;

while True do

begin

if TextSeek(LFile, -LEndIndex, FILE_END) < 0 then

Break;

Readln(LFile, LLine);

if Length(LLine) > 0 then

Break;

Inc(LEndIndex);

end;

// 读取最后一行

Inc(LEndIndex);

while True do

begin

if TextSeek(LFile, -LEndIndex, FILE_END) < 0 then

Break;

Readln(LFile, LLine);

if Length(LLine) = 0 then

Break;

LLastLine := LLine;

Inc(LEndIndex);

end;

if Length(LLastLine) > 0 then

LLines.Add(LLastLine);

CloseFile(LFile);

end;

LLines.SaveToFile('1.dat');

LFileList.Free;

LLines.Free;

end;

end.

来源：https://blog.csdn.net/xiuzhentianting/article/details/48472969

推荐分享