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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
* Copyright (C) 2020 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 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 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.
*/
#pragma once
#ifndef NDEBUG
#include <wtf/text/TextStream.h>
#endif
namespace WebCore {
// Class template representing a closed interval which can hold arbitrary
// endpoints and a piece of user data. Ordering and equality are defined
// including the UserData, except in the special case of WeakPtr.
//
// Both the T and UserData types must support a copy constructor, operator<,
// operator==, and operator=, except that this does not depend on operator<
// or operator== for WeakPtr.
//
// In debug mode, printing of intervals and the data they contain is
// enabled. This uses WTF::TextStream.
//
// Note that this class supplies a copy constructor and assignment
// operator in order so it can be stored in the red-black tree.
// FIXME: The prefix "POD" here isn't correct; this works with non-POD types.
template<class T, class UserData> class PODIntervalBase {
public:
const T& low() const { return m_low; }
const T& high() const { return m_high; }
const UserData& data() const { return m_data; }
bool overlaps(const T& low, const T& high) const
{
return !(m_high < low || high < m_low);
}
bool overlaps(const PODIntervalBase& other) const
{
return overlaps(other.m_low, other.m_high);
}
const T& maxHigh() const { return m_maxHigh; }
void setMaxHigh(const T& maxHigh) { m_maxHigh = maxHigh; }
protected:
PODIntervalBase(const T& low, const T& high, UserData&& data)
: m_low(low)
, m_high(high)
, m_data(WTFMove(data))
, m_maxHigh(high)
{
}
#if COMPILER(MSVC)
// Work around an MSVC bug.
PODIntervalBase(const T& low, const T& high, const UserData& data)
: m_low(low)
, m_high(high)
, m_data(data)
, m_maxHigh(high)
{
}
#endif
private:
T m_low;
T m_high;
UserData m_data { };
T m_maxHigh;
};
template<class T, class UserData> class PODInterval : public PODIntervalBase<T, UserData> {
public:
PODInterval(const T& low, const T& high, UserData&& data = { })
: PODIntervalBase<T, UserData>(low, high, WTFMove(data))
{
}
PODInterval(const T& low, const T& high, const UserData& data)
: PODIntervalBase<T, UserData>(low, high, UserData { data })
{
}
bool operator<(const PODInterval& other) const
{
if (Base::low() < other.Base::low())
return true;
if (other.Base::low() < Base::low())
return false;
if (Base::high() < other.Base::high())
return true;
if (other.Base::high() < Base::high())
return false;
return Base::data() < other.Base::data();
}
bool operator==(const PODInterval& other) const
{
return Base::low() == other.Base::low()
&& Base::high() == other.Base::high()
&& Base::data() == other.Base::data();
}
private:
using Base = PODIntervalBase<T, UserData>;
};
template<class T, class U> class PODInterval<T, WeakPtr<U>> : public PODIntervalBase<T, WeakPtr<U>> {
public:
PODInterval(const T& low, const T& high, WeakPtr<U>&& data)
: PODIntervalBase<T, WeakPtr<U>>(low, high, WTFMove(data))
{
}
bool operator<(const PODInterval& other) const
{
if (Base::low() < other.Base::low())
return true;
if (other.Base::low() < Base::low())
return false;
return Base::high() < other.Base::high();
}
private:
using Base = PODIntervalBase<T, WeakPtr<U>>;
};
#ifndef NDEBUG
template<class T, class UserData>
TextStream& operator<<(TextStream& stream, const PODInterval<T, UserData>& interval)
{
return stream << "[PODInterval (" << interval.low() << ", " << interval.high() << "), data=" << *interval.data() << ", maxHigh=" << interval.maxHigh() << ']';
}
#endif
} // namespace WebCore