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;
http://blog.csdn.net/zswang/article/details/1807693