diff options
Diffstat (limited to 'Source/WebCore/platform/graphics/gpu/PODArena.h')
-rw-r--r-- | Source/WebCore/platform/graphics/gpu/PODArena.h | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/Source/WebCore/platform/graphics/gpu/PODArena.h b/Source/WebCore/platform/graphics/gpu/PODArena.h new file mode 100644 index 0000000..f68baef --- /dev/null +++ b/Source/WebCore/platform/graphics/gpu/PODArena.h @@ -0,0 +1,211 @@ +/* + * Copyright (C) 2010 Google 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 AND ITS CONTRIBUTORS "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 OR ITS 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 PODArena_h +#define PODArena_h + +#include <stdint.h> +#include <wtf/Assertions.h> +#include <wtf/FastMalloc.h> +#include <wtf/Noncopyable.h> +#include <wtf/OwnPtr.h> +#include <wtf/PassOwnPtr.h> +#include <wtf/RefCounted.h> +#include <wtf/Vector.h> + +namespace WebCore { + +// An arena which allocates only Plain Old Data (POD), or classes and +// structs bottoming out in Plain Old Data. NOTE: the constructors of +// the objects allocated in this arena are called, but _not_ their +// destructors. + +class PODArena : public RefCounted<PODArena> { +public: + // The arena is configured with an allocator, which is responsible + // for allocating and freeing chunks of memory at a time. + class Allocator : public RefCounted<Allocator> { + public: + virtual void* allocate(size_t size) = 0; + virtual void free(void* ptr) = 0; + protected: + virtual ~Allocator() { } + friend class WTF::RefCounted<Allocator>; + }; + + // The Arena's default allocator, which uses fastMalloc and + // fastFree to allocate chunks of storage. + class FastMallocAllocator : public Allocator { + public: + static PassRefPtr<FastMallocAllocator> create() + { + return adoptRef(new FastMallocAllocator); + } + + virtual void* allocate(size_t size) { return fastMalloc(size); } + virtual void free(void* ptr) { fastFree(ptr); } + + protected: + FastMallocAllocator() { } + }; + + // Creates a new PODArena configured with a FastMallocAllocator. + static PassRefPtr<PODArena> create() + { + return adoptRef(new PODArena); + } + + // Creates a new PODArena configured with the given Allocator. + static PassRefPtr<PODArena> create(PassRefPtr<Allocator> allocator) + { + return adoptRef(new PODArena(allocator)); + } + + // Allocates an object from the arena. + template<class T> T* allocateObject() + { + void* ptr = allocateBase<T>(); + if (ptr) { + // Use placement operator new to allocate a T at this location. + new(ptr) T(); + } + return static_cast<T*>(ptr); + } + + // Allocates an object from the arena, calling a single-argument constructor. + template<class T, class Argument1Type> T* allocateObject(const Argument1Type& argument1) + { + void* ptr = allocateBase<T>(); + if (ptr) { + // Use placement operator new to allocate a T at this location. + new(ptr) T(argument1); + } + return static_cast<T*>(ptr); + } + + // The initial size of allocated chunks; increases as necessary to + // satisfy large allocations. Mainly public for unit tests. + enum { + DefaultChunkSize = 16384 + }; + +protected: + ~PODArena() { } + friend class WTF::RefCounted<PODArena>; + +private: + PODArena() + : m_allocator(FastMallocAllocator::create()) + , m_current(0) + , m_currentChunkSize(DefaultChunkSize) { } + + explicit PODArena(PassRefPtr<Allocator> allocator) + : m_allocator(allocator) + , m_current(0) + , m_currentChunkSize(DefaultChunkSize) { } + + // Returns the alignment requirement for classes and structs on the + // current platform. + template <class T> static size_t minAlignment() + { + return WTF_ALIGN_OF(T); + } + + template<class T> void* allocateBase() + { + void* ptr = 0; + size_t roundedSize = roundUp(sizeof(T), minAlignment<T>()); + if (m_current) + ptr = m_current->allocate(roundedSize); + + if (!ptr) { + if (roundedSize > m_currentChunkSize) + m_currentChunkSize = roundedSize; + m_chunks.append(adoptPtr(new Chunk(m_allocator.get(), m_currentChunkSize))); + m_current = m_chunks.last().get(); + ptr = m_current->allocate(roundedSize); + } + return ptr; + } + + // Rounds up the given allocation size to the specified alignment. + size_t roundUp(size_t size, size_t alignment) + { + ASSERT(!(alignment % 2)); + return (size + alignment - 1) & ~(alignment - 1); + } + + // Manages a chunk of memory and individual allocations out of it. + class Chunk : public Noncopyable { + public: + // Allocates a block of memory of the given size from the passed + // Allocator. + Chunk(Allocator* allocator, size_t size) + : m_allocator(allocator) + , m_size(size) + , m_currentOffset(0) + { + m_base = static_cast<uint8_t*>(m_allocator->allocate(size)); + } + + // Frees the memory allocated from the Allocator in the + // constructor. + ~Chunk() + { + m_allocator->free(m_base); + } + + // Returns a pointer to "size" bytes of storage, or 0 if this + // Chunk could not satisfy the allocation. + void* allocate(size_t size) + { + // Check for overflow + if (m_currentOffset + size < m_currentOffset) + return 0; + + if (m_currentOffset + size > m_size) + return 0; + + void* result = m_base + m_currentOffset; + m_currentOffset += size; + return result; + } + + private: + Allocator* m_allocator; + uint8_t* m_base; + size_t m_size; + size_t m_currentOffset; + }; + + RefPtr<Allocator> m_allocator; + Chunk* m_current; + size_t m_currentChunkSize; + Vector<OwnPtr<Chunk> > m_chunks; +}; + +} // namespace WebCore + +#endif // PODArena_h |