1 2 /* 3 * Copyright 2011 Google Inc. 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 SkBitSet_DEFINED 11 #define SkBitSet_DEFINED 12 13 #include "SkTypes.h" 14 #include "SkTDArray.h" 15 16 class SkBitSet { 17 public: 18 /** NumberOfBits must be greater than zero. 19 */ 20 explicit SkBitSet(int numberOfBits); 21 explicit SkBitSet(const SkBitSet& source); 22 23 SkBitSet& operator=(const SkBitSet& rhs); 24 bool operator==(const SkBitSet& rhs); 25 bool operator!=(const SkBitSet& rhs); 26 27 /** Clear all data. 28 */ 29 void clearAll(); 30 31 /** Set the value of the index-th bit. 32 */ 33 void setBit(int index, bool value) { 34 uint32_t mask = 1 << (index & 31); 35 uint32_t* chunk = this->internalGet(index); 36 if (value) { 37 *chunk |= mask; 38 } else { 39 *chunk &= ~mask; 40 } 41 } 42 43 /** Test if bit index is set. 44 */ 45 bool isBitSet(int index) const { 46 uint32_t mask = 1 << (index & 31); 47 return SkToBool(*this->internalGet(index) & mask); 48 } 49 50 /** Or bits from source. false is returned if this doesn't have the same 51 * bit count as source. 52 */ 53 bool orBits(const SkBitSet& source); 54 55 /** Export indices of set bits to T array. 56 */ 57 template<typename T> 58 void exportTo(SkTDArray<T>* array) const { 59 SkASSERT(array); 60 uint32_t* data = reinterpret_cast<uint32_t*>(fBitData.get()); 61 for (unsigned int i = 0; i < fDwordCount; ++i) { 62 uint32_t value = data[i]; 63 if (value) { // There are set bits 64 unsigned int index = i * 32; 65 for (unsigned int j = 0; j < 32; ++j) { 66 if (0x1 & (value >> j)) { 67 array->push(index + j); 68 } 69 } 70 } 71 } 72 } 73 74 private: 75 SkAutoFree fBitData; 76 // Dword (32-bit) count of the bitset. 77 size_t fDwordCount; 78 size_t fBitCount; 79 80 uint32_t* internalGet(int index) const { 81 SkASSERT((size_t)index < fBitCount); 82 size_t internalIndex = index / 32; 83 SkASSERT(internalIndex < fDwordCount); 84 return reinterpret_cast<uint32_t*>(fBitData.get()) + internalIndex; 85 } 86 }; 87 88 89 #endif 90
