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/*
* Copyright (C) 2014-2016 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.
*/
#ifndef SmallPage_h
#define SmallPage_h
#include "BAssert.h"
#include "List.h"
#include "Mutex.h"
#include "VMAllocate.h"
#include <mutex>
namespace bmalloc {
class SmallPage : public ListNode<SmallPage> {
public:
SmallPage()
: m_hasFreeLines(true)
{
}
void ref(std::lock_guard<StaticMutex>&);
bool deref(std::lock_guard<StaticMutex>&);
unsigned refCount(std::lock_guard<StaticMutex>&) { return m_refCount; }
size_t sizeClass() { return m_sizeClass; }
void setSizeClass(size_t sizeClass) { m_sizeClass = sizeClass; }
bool hasFreeLines(std::lock_guard<StaticMutex>&) const { return m_hasFreeLines; }
void setHasFreeLines(std::lock_guard<StaticMutex>&, bool hasFreeLines) { m_hasFreeLines = hasFreeLines; }
SmallLine* begin();
unsigned char slide() const { return m_slide; }
void setSlide(unsigned char slide) { m_slide = slide; }
private:
unsigned char m_hasFreeLines: 1;
unsigned char m_refCount: 7;
unsigned char m_sizeClass;
unsigned char m_slide;
static_assert(
sizeClassCount <= std::numeric_limits<decltype(m_sizeClass)>::max(),
"Largest size class must fit in SmallPage metadata");
};
inline void SmallPage::ref(std::lock_guard<StaticMutex>&)
{
BASSERT(!m_slide);
++m_refCount;
BASSERT(m_refCount);
}
inline bool SmallPage::deref(std::lock_guard<StaticMutex>&)
{
BASSERT(!m_slide);
BASSERT(m_refCount);
--m_refCount;
return !m_refCount;
}
} // namespace bmalloc
#endif // SmallPage_h
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