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+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_MEMORY_DEALER_H
+#define ANDROID_MEMORY_DEALER_H
+
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <binder/IMemory.h>
+#include <utils/threads.h>
+#include <binder/MemoryHeapBase.h>
+
+namespace android {
+// ----------------------------------------------------------------------------
+class String8;
+
+/*
+ * interface for implementing a "heap". A heap basically provides
+ * the IMemoryHeap interface for cross-process sharing and the
+ * ability to map/unmap pages within the heap.
+ */
+class HeapInterface : public virtual BnMemoryHeap
+{
+public:
+ // all values must be page-aligned
+ virtual sp<IMemory> mapMemory(size_t offset, size_t size) = 0;
+
+ HeapInterface();
+protected:
+ virtual ~HeapInterface();
+};
+
+// ----------------------------------------------------------------------------
+
+/*
+ * interface for implementing an allocator. An allocator provides
+ * methods for allocating and freeing memory blocks and dumping
+ * its state.
+ */
+class AllocatorInterface : public RefBase
+{
+public:
+ enum {
+ PAGE_ALIGNED = 0x00000001
+ };
+
+ virtual size_t allocate(size_t size, uint32_t flags = 0) = 0;
+ virtual status_t deallocate(size_t offset) = 0;
+ virtual size_t size() const = 0;
+ virtual void dump(const char* what, uint32_t flags = 0) const = 0;
+ virtual void dump(String8& res,
+ const char* what, uint32_t flags = 0) const = 0;
+
+ AllocatorInterface();
+protected:
+ virtual ~AllocatorInterface();
+};
+
+// ----------------------------------------------------------------------------
+
+/*
+ * concrete implementation of HeapInterface on top of mmap()
+ */
+class SharedHeap : public HeapInterface, public MemoryHeapBase
+{
+public:
+ SharedHeap();
+ SharedHeap(size_t size, uint32_t flags = 0, char const * name = NULL);
+ virtual ~SharedHeap();
+ virtual sp<IMemory> mapMemory(size_t offset, size_t size);
+};
+
+// ----------------------------------------------------------------------------
+
+/*
+ * A simple templatized doubly linked-list implementation
+ */
+
+template <typename NODE>
+class LinkedList
+{
+ NODE* mFirst;
+ NODE* mLast;
+
+public:
+ LinkedList() : mFirst(0), mLast(0) { }
+ bool isEmpty() const { return mFirst == 0; }
+ NODE const* head() const { return mFirst; }
+ NODE* head() { return mFirst; }
+ NODE const* tail() const { return mLast; }
+ NODE* tail() { return mLast; }
+
+ void insertAfter(NODE* node, NODE* newNode) {
+ newNode->prev = node;
+ newNode->next = node->next;
+ if (node->next == 0) mLast = newNode;
+ else node->next->prev = newNode;
+ node->next = newNode;
+ }
+
+ void insertBefore(NODE* node, NODE* newNode) {
+ newNode->prev = node->prev;
+ newNode->next = node;
+ if (node->prev == 0) mFirst = newNode;
+ else node->prev->next = newNode;
+ node->prev = newNode;
+ }
+
+ void insertHead(NODE* newNode) {
+ if (mFirst == 0) {
+ mFirst = mLast = newNode;
+ newNode->prev = newNode->next = 0;
+ } else {
+ insertBefore(mFirst, newNode);
+ }
+ }
+
+ void insertTail(NODE* newNode) {
+ if (mLast == 0) insertBeginning(newNode);
+ else insertAfter(mLast, newNode);
+ }
+
+ NODE* remove(NODE* node) {
+ if (node->prev == 0) mFirst = node->next;
+ else node->prev->next = node->next;
+ if (node->next == 0) mLast = node->prev;
+ else node->next->prev = node->prev;
+ return node;
+ }
+};
+
+
+/*
+ * concrete implementation of AllocatorInterface using a simple
+ * best-fit allocation scheme
+ */
+class SimpleBestFitAllocator : public AllocatorInterface
+{
+public:
+
+ SimpleBestFitAllocator(size_t size);
+ virtual ~SimpleBestFitAllocator();
+
+ virtual size_t allocate(size_t size, uint32_t flags = 0);
+ virtual status_t deallocate(size_t offset);
+ virtual size_t size() const;
+ virtual void dump(const char* what, uint32_t flags = 0) const;
+ virtual void dump(String8& res,
+ const char* what, uint32_t flags = 0) const;
+
+private:
+
+ struct chunk_t {
+ chunk_t(size_t start, size_t size)
+ : start(start), size(size), free(1), prev(0), next(0) {
+ }
+ size_t start;
+ size_t size : 28;
+ int free : 4;
+ mutable chunk_t* prev;
+ mutable chunk_t* next;
+ };
+
+ ssize_t alloc(size_t size, uint32_t flags);
+ chunk_t* dealloc(size_t start);
+ void dump_l(const char* what, uint32_t flags = 0) const;
+ void dump_l(String8& res, const char* what, uint32_t flags = 0) const;
+
+ static const int kMemoryAlign;
+ mutable Mutex mLock;
+ LinkedList<chunk_t> mList;
+ size_t mHeapSize;
+};
+
+// ----------------------------------------------------------------------------
+
+class MemoryDealer : public RefBase
+{
+public:
+
+ enum {
+ READ_ONLY = MemoryHeapBase::READ_ONLY,
+ PAGE_ALIGNED = AllocatorInterface::PAGE_ALIGNED
+ };
+
+ // creates a memory dealer with the SharedHeap and SimpleBestFitAllocator
+ MemoryDealer(size_t size, uint32_t flags = 0, const char* name = 0);
+
+ // provide a custom heap but use the SimpleBestFitAllocator
+ MemoryDealer(const sp<HeapInterface>& heap);
+
+ // provide both custom heap and allocotar
+ MemoryDealer(
+ const sp<HeapInterface>& heap,
+ const sp<AllocatorInterface>& allocator);
+
+ virtual ~MemoryDealer();
+
+ virtual sp<IMemory> allocate(size_t size, uint32_t flags = 0);
+ virtual void deallocate(size_t offset);
+ virtual void dump(const char* what, uint32_t flags = 0) const;
+
+
+ sp<IMemoryHeap> getMemoryHeap() const { return heap(); }
+ sp<AllocatorInterface> getAllocator() const { return allocator(); }
+
+private:
+ const sp<HeapInterface>& heap() const;
+ const sp<AllocatorInterface>& allocator() const;
+
+ class Allocation : public BnMemory {
+ public:
+ Allocation(const sp<MemoryDealer>& dealer,
+ ssize_t offset, size_t size, const sp<IMemory>& memory);
+ virtual ~Allocation();
+ virtual sp<IMemoryHeap> getMemory(ssize_t* offset, size_t* size) const;
+ private:
+ sp<MemoryDealer> mDealer;
+ ssize_t mOffset;
+ size_t mSize;
+ sp<IMemory> mMemory;
+ };
+
+ sp<HeapInterface> mHeap;
+ sp<AllocatorInterface> mAllocator;
+};
+
+
+// ----------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_MEMORY_DEALER_H
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