1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/GrMemoryPool.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,80 @@
1.4 +/*
1.5 + * Copyright 2012 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrMemoryPool_DEFINED
1.12 +#define GrMemoryPool_DEFINED
1.13 +
1.14 +#include "GrTypes.h"
1.15 +
1.16 +/**
1.17 + * Allocates memory in blocks and parcels out space in the blocks for allocation
1.18 + * requests. It is optimized for allocate / release speed over memory
1.19 + * effeciency. The interface is designed to be used to implement operator new
1.20 + * and delete overrides. All allocations are expected to be released before the
1.21 + * pool's destructor is called. Allocations will be 8-byte aligned.
1.22 + */
1.23 +class GrMemoryPool {
1.24 +public:
1.25 + /**
1.26 + * Prealloc size is the amount of space to make available at pool creation
1.27 + * time and keep around until pool destruction. The min alloc size is the
1.28 + * smallest allowed size of additional allocations.
1.29 + */
1.30 + GrMemoryPool(size_t preallocSize, size_t minAllocSize);
1.31 +
1.32 + ~GrMemoryPool();
1.33 +
1.34 + /**
1.35 + * Allocates memory. The memory must be freed with release().
1.36 + */
1.37 + void* allocate(size_t size);
1.38 +
1.39 + /**
1.40 + * p must have been returned by allocate()
1.41 + */
1.42 + void release(void* p);
1.43 +
1.44 + /**
1.45 + * Returns true if there are no unreleased allocations.
1.46 + */
1.47 + bool isEmpty() const { return fTail == fHead && !fHead->fLiveCount; }
1.48 +
1.49 +private:
1.50 + struct BlockHeader;
1.51 +
1.52 + static BlockHeader* CreateBlock(size_t size);
1.53 +
1.54 + static void DeleteBlock(BlockHeader* block);
1.55 +
1.56 + void validate();
1.57 +
1.58 + struct BlockHeader {
1.59 + BlockHeader* fNext; ///< doubly-linked list of blocks.
1.60 + BlockHeader* fPrev;
1.61 + int fLiveCount; ///< number of outstanding allocations in the
1.62 + ///< block.
1.63 + intptr_t fCurrPtr; ///< ptr to the start of blocks free space.
1.64 + intptr_t fPrevPtr; ///< ptr to the last allocation made
1.65 + size_t fFreeSize; ///< amount of free space left in the block.
1.66 + };
1.67 +
1.68 + enum {
1.69 + // We assume this alignment is good enough for everybody.
1.70 + kAlignment = 8,
1.71 + kHeaderSize = GR_CT_ALIGN_UP(sizeof(BlockHeader), kAlignment),
1.72 + kPerAllocPad = GR_CT_ALIGN_UP(sizeof(BlockHeader*), kAlignment),
1.73 + };
1.74 + size_t fPreallocSize;
1.75 + size_t fMinAllocSize;
1.76 + BlockHeader* fHead;
1.77 + BlockHeader* fTail;
1.78 +#ifdef SK_DEBUG
1.79 + int fAllocationCnt;
1.80 +#endif
1.81 +};
1.82 +
1.83 +#endif
