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/cvs/gvpe/src/callback.h
Revision: 1.1
Committed: Wed Apr 2 03:06:22 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Log Message:
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File Contents

# User Rev Content
1 pcg 1.1 /*
2     callback.h -- C++ callback mechanism
3    
4     This program is free software; you can redistribute it and/or modify
5     it under the terms of the GNU General Public License as published by
6     the Free Software Foundation; either version 2 of the License, or
7     (at your option) any later version.
8    
9     This program is distributed in the hope that it will be useful,
10     but WITHOUT ANY WARRANTY; without even the implied warranty of
11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12     GNU General Public License for more details.
13    
14     You should have received a copy of the GNU General Public License
15     along with this program; if not, write to the Free Software
16     Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17     */
18    
19     #ifndef VPE_CALLBACK_H__
20     #define VPE_CALLBACK_H__
21    
22     template<class R, class A>
23     class callback {
24     struct object { };
25    
26     void *obj;
27     R (object::*meth)(A arg);
28    
29     // a proxy is a kind of recipe on how to call a specific class method
30     struct proxy_base {
31     virtual R call (void *obj, R (object::*meth)(A), A arg) = 0;
32     };
33     template<class O1, class O2>
34     struct proxy : proxy_base {
35     virtual R call (void *obj, R (object::*meth)(A), A arg)
36     {
37     ((reinterpret_cast<O1 *>(obj)) ->* (reinterpret_cast<R (O2::*)(A)>(meth)))
38     (arg);
39     }
40     };
41    
42     proxy_base *prxy;
43    
44     public:
45     template<class O1, class O2>
46     callback (O1 *object, R (O2::*method)(A))
47     {
48     static proxy<O1,O2> p;
49     obj = reinterpret_cast<void *>(object);
50     meth = reinterpret_cast<R (object::*)(A)>(method);
51     prxy = &p;
52     }
53    
54     R call(A arg) const
55     {
56     return prxy->call (obj, meth, arg);
57     }
58    
59     R operator ()(A arg) const
60     {
61     return call (arg);
62     }
63     };
64    
65     #endif
66