比较两个文件是否相同

function CompareStream(// 比较两个流是否相等

mStream1, mStream2: TStream // 两个流

): Boolean;// 返回两个流是否相等

var

vBuffer1, vBuffer2: array[0..$1000-1] of Char;

vLength1, vLength2: Integer;

begin

Result := mStream1 = mStream2;

if Result then Exit;

if not Assigned(mStream1) or not Assigned(mStream2) then Exit;// 其中一个为空

while True do

begin

vLength1 := mStream1.Read(vBuffer1, SizeOf(vBuffer1));

vLength2 := mStream2.Read(vBuffer2, SizeOf(vBuffer2));

if vLength1 <> vLength2 then Exit;

if vLength1 =0 then Break;

if not CompareMem(@vBuffer1[0],@vBuffer2[0], vLength1) then Exit;

end;

Result := True;

end;{ CompareStream }

function CompareFile(// 比较两个文件是否相等

mFileName1, mFileName2: string // 两个文件

): Boolean;// 返回两个文件是否相等

var

vFileHandle1, vFileHandle2: THandle;

vFileStream1, vFileStream2: TFileStream;

vShortPath1, vShortPath2: array[0..MAX_PATH] of Char;

begin

Result := False;

if not FileExists(mFileName1) or not FileExists(mFileName2) then Exit;// 其中一个文件不存在

GetShortPathName(PChar(mFileName1), vShortPath1, SizeOf(vShortPath1));

GetShortPathName(PChar(mFileName2), vShortPath2, SizeOf(vShortPath2));

Result := SameText(vShortPath1, vShortPath2);// 两个文件名是否相同

if Result then Exit;

vFileHandle1 := _lopen(PChar(mFileName1), OF_READ or OF_SHARE_DENY_NONE);

vFileHandle2 := _lopen(PChar(mFileName2), OF_READ or OF_SHARE_DENY_NONE);

Result :=(Integer(vFileHandle1)>0) and (Integer(vFileHandle2)>0);// 文件是否可以访问

if not Result then

begin

_lclose(vFileHandle1);

_lclose(vFileHandle2);

Exit;

end;

Result := GetFileSize(vFileHandle1, nil)= GetFileSize(vFileHandle2, nil);// 文件大小是否一致

if not Result then

begin

_lclose(vFileHandle1);

_lclose(vFileHandle2);

Exit;

end;

vFileStream1 := TFileStream.Create(vFileHandle1);

vFileStream2 := TFileStream.Create(vFileHandle2);

try

Result := CompareStream(vFileStream1, vFileStream2);// 比较两个文件内容是否相同

finally

vFileStream1.Free;

vFileStream2.Free;

end;

end;{ CompareFile }

procedure TForm1.FormCreate(Sender: TObject);

begin

Caption := BoolToStr(

CompareFile('c:/temp/temp1.txt','c:/temp/temp2.txt'), True);

end;