GPL许可证.代码重用

我正在根据GPL许可证撰写申请.我在GPL下的另一个项目中找到了一些有用的代码.我想知道我是否可以使用它.

我想Foo从A项目中选择一个类并将其添加到我自己的项目中.接下来,我想在Foo类中进行更改(重命名类名和函数名,更改代码格式,删除一些函数,更改一些算法,添加我自己的函数等).

它允许吗？如何标记这个类是A项目的一部分？像这样？

All original material Copyright (C) 2009-2010 author

Original file from A: A/foo/foo.h
Copyright (C) 1997-2001 author.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

Or http://www.softwarefreedom.org/resources/2007/gpl-non-gpl-collaboration.html#x1-40002.2?

接下来,我想在B项目中添加一个函数到我的Foo类版本.如何标记该功能来自B项目？

谢谢,