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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 SmallLine_h
#define SmallLine_h
#include "BAssert.h"
#include "Mutex.h"
#include "ObjectType.h"
#include <mutex>
namespace bmalloc {
class SmallLine {
public:
void ref(std::lock_guard<StaticMutex>&, unsigned char = 1);
bool deref(std::lock_guard<StaticMutex>&);
unsigned refCount(std::lock_guard<StaticMutex>&) { return m_refCount; }
char* begin();
char* end();
private:
unsigned char m_refCount;
static_assert(
smallLineSize / alignment <= std::numeric_limits<decltype(m_refCount)>::max(),
"maximum object count must fit in SmallLine::m_refCount");
};
inline void SmallLine::ref(std::lock_guard<StaticMutex>&, unsigned char refCount)
{
BASSERT(!m_refCount);
m_refCount = refCount;
}
inline bool SmallLine::deref(std::lock_guard<StaticMutex>&)
{
BASSERT(m_refCount);
--m_refCount;
return !m_refCount;
}
} // namespace bmalloc
#endif // SmallLine_h
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