| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #ifndef VM_BITMAP_H_ |
| #define VM_BITMAP_H_ |
| |
| #include "vm/allocation.h" |
| #include "vm/isolate.h" |
| #include "vm/zone.h" |
| |
| namespace dart { |
| |
| // Forward declarations. |
| class RawStackmap; |
| class Stackmap; |
| |
| |
| // BitmapBuilder is used to build a bitmap. The implementation is optimized |
| // for a dense set of small bit maps without a fixed upper bound (e.g: a |
| // pointer map description of a stack). |
| class BitmapBuilder : public ZoneAllocated { |
| public: |
| BitmapBuilder() |
| : length_(0), |
| data_size_in_bytes_(kInitialSizeInBytes), |
| data_(Isolate::Current()->current_zone()->Alloc<uint8_t>( |
| kInitialSizeInBytes)) { |
| memset(data_, 0, kInitialSizeInBytes); |
| } |
| |
| intptr_t Length() const { return length_; } |
| void SetLength(intptr_t length); |
| |
| // Get/Set individual bits in the bitmap, setting bits beyond the bitmap's |
| // length increases the length and expands the underlying bitmap if |
| // needed. |
| bool Get(intptr_t bit_offset) const; |
| void Set(intptr_t bit_offset, bool value); |
| |
| // Return the bit offset of the highest bit set. |
| intptr_t Maximum() const; |
| |
| // Return the bit offset of the lowest bit set. |
| intptr_t Minimum() const; |
| |
| // Sets min..max (inclusive) to value. |
| void SetRange(intptr_t min, intptr_t max, bool value); |
| |
| private: |
| static const intptr_t kInitialSizeInBytes = 16; |
| static const intptr_t kIncrementSizeInBytes = 16; |
| |
| bool InRange(intptr_t offset) const { |
| return (offset >= 0) && (offset < length_); |
| } |
| |
| // Get/Set a bit that is known to be covered by the backing store. |
| bool GetBit(intptr_t bit_offset) const; |
| void SetBit(intptr_t bit_offset, bool value); |
| |
| intptr_t length_; |
| |
| // Backing store for the bitmap. Reading bits beyond the backing store |
| // (up to length_) is allowed and they are assumed to be false. |
| intptr_t data_size_in_bytes_; |
| uint8_t* data_; |
| |
| DISALLOW_COPY_AND_ASSIGN(BitmapBuilder); |
| }; |
| |
| } // namespace dart |
| |
| #endif // VM_BITMAP_H_ |