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rippled/modules/beast_core/containers/beast_ScopedValueSetter.h
2013-08-30 17:33:33 -07:00

94 lines
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C++

//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
Portions of this file are from JUCE.
Copyright (c) 2013 - Raw Material Software Ltd.
Please visit http://www.juce.com
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef BEAST_SCOPEDVALUESETTER_H_INCLUDED
#define BEAST_SCOPEDVALUESETTER_H_INCLUDED
//==============================================================================
/**
Helper class providing an RAII-based mechanism for temporarily setting and
then re-setting a value.
E.g. @code
int x = 1;
{
ScopedValueSetter setter (x, 2);
// x is now 2
}
// x is now 1 again
{
ScopedValueSetter setter (x, 3, 4);
// x is now 3
}
// x is now 4
@endcode
*/
template <typename ValueType>
class ScopedValueSetter : public Uncopyable
{
public:
/** Creates a ScopedValueSetter that will immediately change the specified value to the
given new value, and will then reset it to its original value when this object is deleted.
*/
ScopedValueSetter (ValueType& valueToSet,
ValueType newValue)
: value (valueToSet),
originalValue (valueToSet)
{
valueToSet = newValue;
}
/** Creates a ScopedValueSetter that will immediately change the specified value to the
given new value, and will then reset it to be valueWhenDeleted when this object is deleted.
*/
ScopedValueSetter (ValueType& valueToSet,
ValueType newValue,
ValueType valueWhenDeleted)
: value (valueToSet),
originalValue (valueWhenDeleted)
{
valueToSet = newValue;
}
~ScopedValueSetter()
{
value = originalValue;
}
private:
//==============================================================================
ValueType& value;
const ValueType originalValue;
};
#endif // BEAST_SCOPEDVALUESETTER_H_INCLUDED