1 /*
 2  * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24 
25 #ifndef SHARE_UTILITIES_CHECKEDCAST_HPP
26 #define SHARE_UTILITIES_CHECKEDCAST_HPP
27 
28 #include "utilities/debug.hpp"
29 
30 // In many places we've added C-style casts to silence compiler
31 // warnings, for example when truncating a size_t to an int when we
32 // know the size_t is a small struct. Such casts are risky because
33 // they effectively disable useful compiler warnings. We can make our
34 // lives safer with this function, which ensures that any cast is
35 // reversible without loss of information. It doesn't check
36 // everything: it isn't intended to make sure that pointer types are
37 // compatible, for example.
38 template <typename T2, typename T1>
39 constexpr T2 checked_cast(T1 thing) {
40   T2 result = static_cast<T2>(thing);
41   assert(static_cast<T1>(result) == thing, "must be");
42   return result;
43 }
44 
45 #endif // SHARE_UTILITIES_CHECKEDCAST_HPP
46