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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 #ifndef VM_BITMAP_H_ |
| 6 #define VM_BITMAP_H_ |
| 7 |
| 8 #include "vm/allocation.h" |
| 9 |
| 10 namespace dart { |
| 11 |
| 12 // Forward declarations. |
| 13 class RawStackmap; |
| 14 class Stackmap; |
| 15 |
| 16 |
| 17 // BitmapBuilder is used to build a bitmap. The implementation is optimized for |
| 18 // a dense set of small bit maps without an upper bound (e.g: a pointer map |
| 19 // description of a stack). |
| 20 class BitmapBuilder : public ZoneAllocated { |
| 21 public: |
| 22 BitmapBuilder() : size_in_bytes_(kInitialSizeInBytes), |
| 23 bit_list_(bit_list_data_) { |
| 24 memset(bit_list_data_, 0, kInitialSizeInBytes); |
| 25 } |
| 26 |
| 27 intptr_t SizeInBits() const { return (size_in_bytes_ * kBitsPerByte); } |
| 28 intptr_t SizeInBytes() const { return size_in_bytes_; } |
| 29 |
| 30 // Get/Set individual bits in the bitmap, set expands the underlying bitmap |
| 31 // if needed. |
| 32 bool Get(intptr_t bit_offset) const; |
| 33 void Set(intptr_t bit_offset, bool value); |
| 34 |
| 35 // Return the bit offset of the highest bit set. |
| 36 intptr_t Maximum() const; |
| 37 |
| 38 // Return the bit offset of the lowest bit set. |
| 39 intptr_t Minimum() const; |
| 40 |
| 41 // Sets min..max (inclusive) to value. |
| 42 void SetRange(intptr_t min, intptr_t max, bool value); |
| 43 |
| 44 // Replicates the bit map setting of the passed in Stackmap object. |
| 45 void SetBits(const Stackmap& bitmap); |
| 46 |
| 47 private: |
| 48 static const intptr_t kInitialSizeInBytes = 16; |
| 49 static const intptr_t kIncrementSizeInBytes = 16; |
| 50 |
| 51 bool InRange(intptr_t offset) const { |
| 52 return (offset >= 0) && (offset < SizeInBits()); |
| 53 } |
| 54 |
| 55 bool GetBit(intptr_t bit_offset) const; |
| 56 void SetBit(intptr_t bit_offset, bool value); |
| 57 |
| 58 intptr_t size_in_bytes_; |
| 59 uint8_t bit_list_data_[kInitialSizeInBytes]; |
| 60 uint8_t* bit_list_; |
| 61 |
| 62 DISALLOW_COPY_AND_ASSIGN(BitmapBuilder); |
| 63 }; |
| 64 |
| 65 } // namespace dart |
| 66 |
| 67 #endif // VM_BITMAP_H_ |
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