JavaScriptCore-1097.3.tar.gz

[apple/javascriptcore.git] / heap / CopiedAllocator.h

diff --git a/heap/CopiedAllocator.h b/heap/CopiedAllocator.h
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+/*
+ * Copyright (C) 2011 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 CopiedAllocator_h
+#define CopiedAllocator_h
+
+#include "CopiedBlock.h"
+
+namespace JSC {
+
+class CopiedAllocator {
+    friend class JIT;
+public:
+    CopiedAllocator();
+    void* allocate(size_t);
+    bool fitsInCurrentBlock(size_t);
+    bool wasLastAllocation(void*, size_t);
+    void startedCopying();
+    void resetCurrentBlock(CopiedBlock*);
+    size_t currentCapacity();
+
+private:
+    CopiedBlock* currentBlock() { return m_currentBlock; }
+
+    char* m_currentOffset;
+    CopiedBlock* m_currentBlock; 
+};
+
+inline CopiedAllocator::CopiedAllocator()
+    : m_currentOffset(0)
+    , m_currentBlock(0)
+{
+}
+
+inline void* CopiedAllocator::allocate(size_t bytes)
+{
+    ASSERT(m_currentOffset);
+    ASSERT(is8ByteAligned(reinterpret_cast<void*>(bytes)));
+    ASSERT(fitsInCurrentBlock(bytes));
+    void* ptr = static_cast<void*>(m_currentOffset);
+    m_currentOffset += bytes;
+    ASSERT(is8ByteAligned(ptr));
+    return ptr;
+}
+
+inline bool CopiedAllocator::fitsInCurrentBlock(size_t bytes)
+{
+    return m_currentOffset + bytes < reinterpret_cast<char*>(m_currentBlock) + HeapBlock::s_blockSize && m_currentOffset + bytes > m_currentOffset;
+}
+
+inline bool CopiedAllocator::wasLastAllocation(void* ptr, size_t size)
+{
+    return static_cast<char*>(ptr) + size == m_currentOffset && ptr > m_currentBlock && ptr < reinterpret_cast<char*>(m_currentBlock) + HeapBlock::s_blockSize;
+}
+
+inline void CopiedAllocator::startedCopying()
+{
+    if (m_currentBlock)
+        m_currentBlock->m_offset = static_cast<void*>(m_currentOffset);
+    m_currentOffset = 0;
+    m_currentBlock = 0;
+}
+
+inline void CopiedAllocator::resetCurrentBlock(CopiedBlock* newBlock)
+{
+    if (m_currentBlock)
+        m_currentBlock->m_offset = static_cast<void*>(m_currentOffset);
+    m_currentBlock = newBlock;
+    m_currentOffset = static_cast<char*>(newBlock->m_offset);
+}
+
+inline size_t CopiedAllocator::currentCapacity()
+{
+    return m_currentBlock->capacity();
+}
+
+} // namespace JSC
+
+#endif