| /* |
| * 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 |