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      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     const 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 
     35     /** Test if bit index is set.
     36      */
     37     bool isBitSet(int index) const;
     38 
     39     /** Or bits from source.  false is returned if this doesn't have the same
     40      *  bit count as source.
     41      */
     42     bool orBits(const SkBitSet& source);
     43 
     44     /** Export indices of set bits to T array.
     45      */
     46     template<typename T>
     47     void exportTo(SkTDArray<T>* array) const {
     48         SkASSERT(array);
     49         uint32_t* data = reinterpret_cast<uint32_t*>(fBitData.get());
     50         for (unsigned int i = 0; i < fDwordCount; ++i) {
     51             uint32_t value = data[i];
     52             if (value) {  // There are set bits
     53                 unsigned int index = i * 32;
     54                 for (unsigned int j = 0; j < 32; ++j) {
     55                     if (0x1 & (value >> j)) {
     56                         array->push(index + j);
     57                     }
     58                 }
     59             }
     60         }
     61     }
     62 
     63 private:
     64     SkAutoFree fBitData;
     65     // Dword (32-bit) count of the bitset.
     66     size_t fDwordCount;
     67     size_t fBitCount;
     68 
     69     uint32_t* internalGet(int index) const {
     70         SkASSERT((size_t)index < fBitCount);
     71         size_t internalIndex = index / 32;
     72         SkASSERT(internalIndex < fDwordCount);
     73         return reinterpret_cast<uint32_t*>(fBitData.get()) + internalIndex;
     74     }
     75 };
     76 
     77 
     78 #endif
     79