asiva@google.com
690b823195
Review URL: https://codereview.chromium.org//10967044 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@12820 260f80e4-7a28-3924-810f-c04153c831b5
78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_MEMORY_REGION_H_
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#define VM_MEMORY_REGION_H_
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#include "platform/assert.h"
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#include "vm/globals.h"
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namespace dart {
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// Memory regions are useful for accessing memory with bounds check in
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// debug mode. They can be safely passed by value and do not assume ownership
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// of the region.
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class MemoryRegion {
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public:
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MemoryRegion() : pointer_(NULL), size_(0) { }
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MemoryRegion(void* pointer, uword size) : pointer_(pointer), size_(size) { }
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void* pointer() const { return pointer_; }
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uword size() const { return size_; }
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uword size_in_bits() const { return size_ * kBitsPerByte; }
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static uword pointer_offset() { return OFFSET_OF(MemoryRegion, pointer_); }
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uword start() const { return reinterpret_cast<uword>(pointer_); }
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uword end() const { return start() + size_; }
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template<typename T> T Load(uword offset) const {
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return *ComputeInternalPointer<T>(offset);
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}
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template<typename T> void Store(uword offset, T value) const {
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*ComputeInternalPointer<T>(offset) = value;
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}
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template<typename T> T* PointerTo(uword offset) const {
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return ComputeInternalPointer<T>(offset);
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}
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bool Contains(uword address) const {
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return (address >= start()) && (address < end());
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}
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void CopyFrom(uword offset, const MemoryRegion& from) const;
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// Compute a sub memory region based on an existing one.
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void Subregion(const MemoryRegion& from, uword offset, uword size) {
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ASSERT(from.size() >= size);
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ASSERT(offset <= (from.size() - size));
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pointer_ = reinterpret_cast<void*>(from.start() + offset);
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size_ = size;
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}
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// Compute an extended memory region based on an existing one.
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void Extend(const MemoryRegion& region, uword extra) {
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pointer_ = region.pointer();
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size_ = (region.size() + extra);
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}
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private:
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template<typename T> T* ComputeInternalPointer(uword offset) const {
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ASSERT(size() >= sizeof(T));
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ASSERT(offset <= size() - sizeof(T));
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return reinterpret_cast<T*>(start() + offset);
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}
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void* pointer_;
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uword size_;
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DISALLOW_COPY_AND_ASSIGN(MemoryRegion);
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};
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} // namespace dart
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#endif // VM_MEMORY_REGION_H_
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