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/*
* Copyright (C) 2015-2024 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. ``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
* 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
#include <limits.h>
#include <wtf/Assertions.h>
#include <wtf/TZoneMalloc.h>
namespace JSC {
// A mixin for creating the various kinds of variable offsets that our engine supports.
template<typename T>
class GenericOffset {
WTF_MAKE_TZONE_ALLOCATED_TEMPLATE(GenericOffset);
public:
static constexpr unsigned invalidOffset = UINT_MAX;
GenericOffset()
: m_offset(invalidOffset)
{
}
explicit GenericOffset(unsigned offset)
: m_offset(offset)
{
}
bool operator!() const { return m_offset == invalidOffset; }
unsigned offsetUnchecked() const
{
return m_offset;
}
unsigned offset() const
{
ASSERT(m_offset != invalidOffset);
return m_offset;
}
friend auto operator<=>(const GenericOffset&, const GenericOffset&) = default;
T operator+(int value) const
{
return T(offset() + value);
}
T operator-(int value) const
{
return T(offset() - value);
}
T& operator+=(int value)
{
return *static_cast<T*>(this) = *this + value;
}
T& operator-=(int value)
{
return *static_cast<T*>(this) = *this - value;
}
private:
unsigned m_offset;
};
WTF_MAKE_TZONE_ALLOCATED_TEMPLATE_IMPL(template<typename T>, GenericOffset<T>);
} // namespace JSC
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