dart-sdk/runtime/vm/bit_vector.h

121 lines
2.8 KiB
C++

// 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_BIT_VECTOR_H_
#define RUNTIME_VM_BIT_VECTOR_H_
#include "vm/allocation.h"
#include "vm/isolate.h"
#include "vm/zone.h"
namespace dart {
// Bit vector implementation.
class BitVector : public ZoneAllocated {
public:
// Iterator for the elements of this BitVector.
class Iterator : public ValueObject {
public:
explicit Iterator(BitVector* target)
: target_(target),
bit_index_(-1),
word_index_(0),
current_word_(target->data_[0]) {
ASSERT(target->data_length_ > 0);
Advance();
}
~Iterator() {}
bool Done() const { return word_index_ >= target_->data_length_; }
void Advance();
intptr_t Current() const {
ASSERT(!Done());
return bit_index_;
}
private:
BitVector* target_;
intptr_t bit_index_;
intptr_t word_index_;
uword current_word_;
friend class BitVector;
};
BitVector(Zone* zone, intptr_t length)
: length_(length),
data_length_(SizeFor(length)),
data_(zone->Alloc<uword>(data_length_)) {
Clear();
}
void CopyFrom(const BitVector* other) {
Clear();
AddAll(other);
}
static intptr_t SizeFor(intptr_t length) {
return 1 + ((length - 1) / kBitsPerWord);
}
void Add(intptr_t i) {
ASSERT(i >= 0 && i < length());
data_[i / kBitsPerWord] |= (static_cast<uword>(1) << (i % kBitsPerWord));
}
void Remove(intptr_t i) {
ASSERT(i >= 0 && i < length());
data_[i / kBitsPerWord] &= ~(static_cast<uword>(1) << (i % kBitsPerWord));
}
bool Equals(const BitVector& other) const;
// Add all elements that are in the bitvector from.
bool AddAll(const BitVector* from);
// Remove all elements that are in the bitvector from.
bool RemoveAll(const BitVector* from);
// From the bitvector gen add those elements that are not in the
// bitvector kill.
bool KillAndAdd(BitVector* kill, BitVector* gen);
void Intersect(const BitVector* other);
bool IsEmpty() const;
bool Contains(intptr_t i) const {
ASSERT(i >= 0 && i < length());
uword block = data_[i / kBitsPerWord];
return (block & (static_cast<uword>(1) << (i % kBitsPerWord))) != 0;
}
void Clear() {
for (intptr_t i = 0; i < data_length_; i++) {
data_[i] = 0;
}
}
void SetAll() {
for (intptr_t i = 0; i < data_length_; i++) {
data_[i] = static_cast<uword>(-1);
}
}
intptr_t length() const { return length_; }
void Print() const;
private:
intptr_t length_;
intptr_t data_length_;
uword* data_;
DISALLOW_COPY_AND_ASSIGN(BitVector);
};
} // namespace dart
#endif // RUNTIME_VM_BIT_VECTOR_H_