| // 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 RUNTIME_VM_BITMAP_H_ |
| #define RUNTIME_VM_BITMAP_H_ |
| |
| #include "vm/allocation.h" |
| #include "vm/datastream.h" |
| #include "vm/thread_state.h" |
| #include "vm/zone.h" |
| |
| namespace dart { |
| |
| // 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_(kInlineCapacityInBytes) { |
| memset(data_.inline_, 0, data_size_in_bytes_); |
| } |
| |
| BitmapBuilder(const BitmapBuilder& other) |
| : ZoneAllocated(), |
| length_(other.length_), |
| data_size_in_bytes_(other.data_size_in_bytes_) { |
| if (data_size_in_bytes_ == kInlineCapacityInBytes) { |
| memmove(data_.inline_, other.data_.inline_, kInlineCapacityInBytes); |
| } else { |
| data_.ptr_ = AllocBackingStore(data_size_in_bytes_); |
| memmove(data_.ptr_, other.data_.ptr_, data_size_in_bytes_); |
| } |
| } |
| |
| 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); |
| |
| void Print() const; |
| void AppendAsBytesTo(BaseWriteStream* stream) const; |
| |
| void Write(BaseWriteStream* stream) const; |
| void Read(ReadStream* stream); |
| |
| private: |
| static constexpr intptr_t kIncrementSizeInBytes = 16; |
| static constexpr intptr_t kInlineCapacityInBytes = 16; |
| |
| bool InRange(intptr_t offset) const { |
| if (offset < 0) { |
| FATAL( |
| "Fatal error in BitmapBuilder::InRange :" |
| " invalid bit_offset, %" Pd "\n", |
| offset); |
| } |
| return (offset < length_); |
| } |
| |
| bool InBackingStore(intptr_t bit_offset) { |
| intptr_t byte_offset = bit_offset >> kBitsPerByteLog2; |
| return byte_offset < data_size_in_bytes_; |
| } |
| |
| uint8_t* BackingStore() { |
| return data_size_in_bytes_ == kInlineCapacityInBytes ? &data_.inline_[0] |
| : data_.ptr_; |
| } |
| |
| const uint8_t* BackingStore() const { |
| return data_size_in_bytes_ == kInlineCapacityInBytes ? &data_.inline_[0] |
| : data_.ptr_; |
| } |
| |
| static uint8_t* AllocBackingStore(intptr_t size_in_bytes) { |
| return ThreadState::Current()->zone()->Alloc<uint8_t>(size_in_bytes); |
| } |
| |
| // 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_; |
| union { |
| uint8_t* ptr_; |
| uint8_t inline_[kInlineCapacityInBytes]; |
| } data_; |
| }; |
| |
| } // namespace dart |
| |
| #endif // RUNTIME_VM_BITMAP_H_ |