1 2 /* 3 * Copyright 2006 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef SkChunkAlloc_DEFINED 11 #define SkChunkAlloc_DEFINED 12 13 #include "SkTypes.h" 14 15 class SkChunkAlloc : SkNoncopyable { 16 public: 17 SkChunkAlloc(size_t minSize); 18 ~SkChunkAlloc(); 19 20 /** 21 * Free up all allocated blocks. This invalidates all returned 22 * pointers. 23 */ 24 void reset(); 25 /** 26 * Reset to 0 used bytes preserving as much memory as possible. 27 * This invalidates all returned pointers. 28 */ 29 void rewind(); 30 31 enum AllocFailType { 32 kReturnNil_AllocFailType, 33 kThrow_AllocFailType 34 }; 35 36 /** 37 * Allocates a memory block of size bytes. 38 * On success: returns a pointer to beginning of memory block that is 39 * 8 byte aligned. The content of allocated block is not initialized. 40 * On failure: calls abort() if called with kThrow_AllocFailType, 41 * otherwise returns NULL pointer. 42 */ 43 void* alloc(size_t bytes, AllocFailType); 44 45 /** 46 * Shortcut for calling alloc with kThrow_AllocFailType. 47 */ allocThrow(size_t bytes)48 void* allocThrow(size_t bytes) { 49 return this->alloc(bytes, kThrow_AllocFailType); 50 } 51 52 /** Call this to unalloc the most-recently allocated ptr by alloc(). On 53 success, the number of bytes freed is returned, or 0 if the block could 54 not be unallocated. This is a hint to the underlying allocator that 55 the previous allocation may be reused, but the implementation is free 56 to ignore this call (and return 0). 57 */ 58 size_t unalloc(void* ptr); 59 totalCapacity()60 size_t totalCapacity() const { return fTotalCapacity; } totalUsed()61 size_t totalUsed() const { return fTotalUsed; } 62 SkDEBUGCODE(int blockCount() const { return fBlockCount; }) 63 SkDEBUGCODE(size_t totalLost() const { return fTotalLost; }) 64 65 /** 66 * Returns true if the specified address is within one of the chunks, and 67 * has at least 1-byte following the address (i.e. if addr points to the 68 * end of a chunk, then contains() will return false). 69 */ 70 bool contains(const void* addr) const; 71 72 private: 73 struct Block; 74 75 Block* fBlock; 76 size_t fMinSize; 77 size_t fChunkSize; 78 size_t fTotalCapacity; 79 size_t fTotalUsed; // will be <= fTotalCapacity 80 SkDEBUGCODE(int fBlockCount;) 81 SkDEBUGCODE(size_t fTotalLost;) // will be <= fTotalCapacity 82 83 Block* newBlock(size_t bytes, AllocFailType ftype); 84 Block* addBlockIfNecessary(size_t bytes, AllocFailType ftype); 85 86 SkDEBUGCODE(void validate();) 87 }; 88 89 #endif 90