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https://github.com/quizhizhe/LiteLoaderBDS-1.16.40.git
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67 lines
1.7 KiB
C++
67 lines
1.7 KiB
C++
// Copyright 2016 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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////////////////////////////////////////////////////////////////////////////////
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#ifndef UTIL_VARSETTER_H_
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#define UTIL_VARSETTER_H_
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//
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// Use a VarSetter object to temporarily set an object of some sort to
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// a particular value. When the VarSetter object is destructed, the
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// underlying object will revert to its former value.
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//
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// Sample code:
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//
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#if 0
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{
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bool b = true;
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{
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VarSetter<bool> bool_setter(&b, false);
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// Now b == false.
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}
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// Now b == true again.
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}
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#endif
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template <class C>
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class VarSetter {
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public:
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// Constructor that just sets the object to a fixed value
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VarSetter(C* object, const C& value) : object_(object), old_value_(*object) {
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*object = value;
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}
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~VarSetter() { *object_ = old_value_; }
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private:
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C*const object_;
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C old_value_;
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// Disallow
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VarSetter(const VarSetter&);
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VarSetter& operator=(const VarSetter&);
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// VarSetters always live on the stack
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static void* operator new (size_t);
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static void* operator new[](size_t); // Redundant, no default ctor
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static void operator delete (void*);
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static void operator delete[](void*);
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};
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#endif // UTIL_VARSETTER_H_
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