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/*
* Copyright (C) 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef MoveOnly_h
#define MoveOnly_h
#include <wtf/HashFunctions.h>
#include <wtf/HashTraits.h>
class MoveOnly {
public:
MoveOnly()
: m_value(0)
{
}
MoveOnly(unsigned value)
: m_value(value)
{
}
unsigned value() const
{
return m_value;
}
MoveOnly(MoveOnly&& other)
: m_value(other.m_value)
{
other.m_value = 0;
}
MoveOnly& operator=(MoveOnly&& other)
{
if (this == &other)
return *this;
m_value = other.m_value;
other.m_value = 0;
return *this;
}
friend bool operator==(const MoveOnly& a, const MoveOnly& b)
{
return a.m_value == b.m_value;
}
private:
unsigned m_value;
};
namespace WTF {
template<> struct HashTraits<MoveOnly> : public GenericHashTraits<MoveOnly> {
static void constructDeletedValue(MoveOnly& slot) { slot = MoveOnly(std::numeric_limits<unsigned>::max()); }
static bool isDeletedValue(const MoveOnly& slot) { return slot.value() == std::numeric_limits<unsigned>::max(); }
};
template<> struct DefaultHash<MoveOnly> {
struct Hash {
static unsigned hash(const MoveOnly& key)
{
return intHash(key.value());
}
static bool equal(const MoveOnly& a, const MoveOnly& b)
{
return a == b;
}
static const bool safeToCompareToEmptyOrDeleted = true;
};
};
} // namespace WTF
#endif // MoveOnly_h
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