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351 lines
9.4 KiB
C++
351 lines
9.4 KiB
C++
//===-- sanitizer_bitvector.h -----------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Specializer BitVector implementation.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SANITIZER_BITVECTOR_H
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#define SANITIZER_BITVECTOR_H
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#include "sanitizer_common.h"
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namespace __sanitizer {
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// Fixed size bit vector based on a single basic integer.
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template <class basic_int_t = uptr>
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class BasicBitVector {
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public:
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enum SizeEnum : uptr { kSize = sizeof(basic_int_t) * 8 };
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uptr size() const { return kSize; }
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// No CTOR.
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void clear() { bits_ = 0; }
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void setAll() { bits_ = ~(basic_int_t)0; }
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bool empty() const { return bits_ == 0; }
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// Returns true if the bit has changed from 0 to 1.
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bool setBit(uptr idx) {
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basic_int_t old = bits_;
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bits_ |= mask(idx);
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return bits_ != old;
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}
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// Returns true if the bit has changed from 1 to 0.
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bool clearBit(uptr idx) {
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basic_int_t old = bits_;
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bits_ &= ~mask(idx);
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return bits_ != old;
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}
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bool getBit(uptr idx) const { return (bits_ & mask(idx)) != 0; }
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uptr getAndClearFirstOne() {
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CHECK(!empty());
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uptr idx = LeastSignificantSetBitIndex(bits_);
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clearBit(idx);
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return idx;
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}
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// Do "this |= v" and return whether new bits have been added.
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bool setUnion(const BasicBitVector &v) {
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basic_int_t old = bits_;
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bits_ |= v.bits_;
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return bits_ != old;
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}
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// Do "this &= v" and return whether any bits have been removed.
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bool setIntersection(const BasicBitVector &v) {
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basic_int_t old = bits_;
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bits_ &= v.bits_;
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return bits_ != old;
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}
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// Do "this &= ~v" and return whether any bits have been removed.
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bool setDifference(const BasicBitVector &v) {
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basic_int_t old = bits_;
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bits_ &= ~v.bits_;
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return bits_ != old;
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}
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void copyFrom(const BasicBitVector &v) { bits_ = v.bits_; }
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// Returns true if 'this' intersects with 'v'.
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bool intersectsWith(const BasicBitVector &v) const {
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return (bits_ & v.bits_) != 0;
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}
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// for (BasicBitVector<>::Iterator it(bv); it.hasNext();) {
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// uptr idx = it.next();
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// use(idx);
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// }
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class Iterator {
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public:
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Iterator() { }
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explicit Iterator(const BasicBitVector &bv) : bv_(bv) {}
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bool hasNext() const { return !bv_.empty(); }
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uptr next() { return bv_.getAndClearFirstOne(); }
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void clear() { bv_.clear(); }
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private:
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BasicBitVector bv_;
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};
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private:
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basic_int_t mask(uptr idx) const {
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CHECK_LT(idx, size());
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return (basic_int_t)1UL << idx;
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}
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basic_int_t bits_;
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};
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// Fixed size bit vector of (kLevel1Size*BV::kSize**2) bits.
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// The implementation is optimized for better performance on
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// sparse bit vectors, i.e. the those with few set bits.
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template <uptr kLevel1Size = 1, class BV = BasicBitVector<> >
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class TwoLevelBitVector {
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// This is essentially a 2-level bit vector.
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// Set bit in the first level BV indicates that there are set bits
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// in the corresponding BV of the second level.
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// This structure allows O(kLevel1Size) time for clear() and empty(),
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// as well fast handling of sparse BVs.
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public:
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enum SizeEnum : uptr { kSize = BV::kSize * BV::kSize * kLevel1Size };
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// No CTOR.
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uptr size() const { return kSize; }
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void clear() {
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for (uptr i = 0; i < kLevel1Size; i++)
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l1_[i].clear();
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}
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void setAll() {
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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l1_[i0].setAll();
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for (uptr i1 = 0; i1 < BV::kSize; i1++)
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l2_[i0][i1].setAll();
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}
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}
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bool empty() const {
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for (uptr i = 0; i < kLevel1Size; i++)
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if (!l1_[i].empty())
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return false;
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return true;
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}
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// Returns true if the bit has changed from 0 to 1.
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bool setBit(uptr idx) {
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check(idx);
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uptr i0 = idx0(idx);
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uptr i1 = idx1(idx);
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uptr i2 = idx2(idx);
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if (!l1_[i0].getBit(i1)) {
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l1_[i0].setBit(i1);
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l2_[i0][i1].clear();
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}
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bool res = l2_[i0][i1].setBit(i2);
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// Printf("%s: %zd => %zd %zd %zd; %d\n", __func__,
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// idx, i0, i1, i2, res);
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return res;
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}
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bool clearBit(uptr idx) {
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check(idx);
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uptr i0 = idx0(idx);
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uptr i1 = idx1(idx);
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uptr i2 = idx2(idx);
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bool res = false;
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if (l1_[i0].getBit(i1)) {
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res = l2_[i0][i1].clearBit(i2);
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if (l2_[i0][i1].empty())
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l1_[i0].clearBit(i1);
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}
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return res;
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}
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bool getBit(uptr idx) const {
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check(idx);
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uptr i0 = idx0(idx);
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uptr i1 = idx1(idx);
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uptr i2 = idx2(idx);
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// Printf("%s: %zd => %zd %zd %zd\n", __func__, idx, i0, i1, i2);
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return l1_[i0].getBit(i1) && l2_[i0][i1].getBit(i2);
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}
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uptr getAndClearFirstOne() {
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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if (l1_[i0].empty()) continue;
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uptr i1 = l1_[i0].getAndClearFirstOne();
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uptr i2 = l2_[i0][i1].getAndClearFirstOne();
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if (!l2_[i0][i1].empty())
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l1_[i0].setBit(i1);
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uptr res = i0 * BV::kSize * BV::kSize + i1 * BV::kSize + i2;
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// Printf("getAndClearFirstOne: %zd %zd %zd => %zd\n", i0, i1, i2, res);
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return res;
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}
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CHECK(0);
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return 0;
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}
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// Do "this |= v" and return whether new bits have been added.
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bool setUnion(const TwoLevelBitVector &v) {
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bool res = false;
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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BV t = v.l1_[i0];
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while (!t.empty()) {
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uptr i1 = t.getAndClearFirstOne();
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if (l1_[i0].setBit(i1))
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l2_[i0][i1].clear();
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if (l2_[i0][i1].setUnion(v.l2_[i0][i1]))
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res = true;
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}
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}
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return res;
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}
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// Do "this &= v" and return whether any bits have been removed.
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bool setIntersection(const TwoLevelBitVector &v) {
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bool res = false;
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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if (l1_[i0].setIntersection(v.l1_[i0]))
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res = true;
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if (!l1_[i0].empty()) {
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BV t = l1_[i0];
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while (!t.empty()) {
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uptr i1 = t.getAndClearFirstOne();
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if (l2_[i0][i1].setIntersection(v.l2_[i0][i1]))
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res = true;
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if (l2_[i0][i1].empty())
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l1_[i0].clearBit(i1);
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}
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}
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}
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return res;
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}
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// Do "this &= ~v" and return whether any bits have been removed.
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bool setDifference(const TwoLevelBitVector &v) {
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bool res = false;
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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BV t = l1_[i0];
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t.setIntersection(v.l1_[i0]);
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while (!t.empty()) {
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uptr i1 = t.getAndClearFirstOne();
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if (l2_[i0][i1].setDifference(v.l2_[i0][i1]))
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res = true;
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if (l2_[i0][i1].empty())
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l1_[i0].clearBit(i1);
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}
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}
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return res;
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}
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void copyFrom(const TwoLevelBitVector &v) {
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clear();
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setUnion(v);
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}
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// Returns true if 'this' intersects with 'v'.
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bool intersectsWith(const TwoLevelBitVector &v) const {
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for (uptr i0 = 0; i0 < kLevel1Size; i0++) {
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BV t = l1_[i0];
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t.setIntersection(v.l1_[i0]);
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while (!t.empty()) {
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uptr i1 = t.getAndClearFirstOne();
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if (!v.l1_[i0].getBit(i1)) continue;
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if (l2_[i0][i1].intersectsWith(v.l2_[i0][i1]))
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return true;
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}
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}
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return false;
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}
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// for (TwoLevelBitVector<>::Iterator it(bv); it.hasNext();) {
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// uptr idx = it.next();
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// use(idx);
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// }
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class Iterator {
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public:
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Iterator() { }
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explicit Iterator(const TwoLevelBitVector &bv) : bv_(bv), i0_(0), i1_(0) {
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it1_.clear();
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it2_.clear();
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}
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bool hasNext() const {
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if (it1_.hasNext()) return true;
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for (uptr i = i0_; i < kLevel1Size; i++)
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if (!bv_.l1_[i].empty()) return true;
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return false;
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}
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uptr next() {
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// Printf("++++: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),
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// it2_.hasNext(), kSize);
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if (!it1_.hasNext() && !it2_.hasNext()) {
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for (; i0_ < kLevel1Size; i0_++) {
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if (bv_.l1_[i0_].empty()) continue;
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it1_ = typename BV::Iterator(bv_.l1_[i0_]);
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// Printf("+i0: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),
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// it2_.hasNext(), kSize);
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break;
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}
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}
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if (!it2_.hasNext()) {
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CHECK(it1_.hasNext());
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i1_ = it1_.next();
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it2_ = typename BV::Iterator(bv_.l2_[i0_][i1_]);
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// Printf("++i1: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),
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// it2_.hasNext(), kSize);
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}
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CHECK(it2_.hasNext());
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uptr i2 = it2_.next();
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uptr res = i0_ * BV::kSize * BV::kSize + i1_ * BV::kSize + i2;
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// Printf("+ret: %zd %zd; %d %d; size %zd; res: %zd\n", i0_, i1_,
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// it1_.hasNext(), it2_.hasNext(), kSize, res);
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if (!it1_.hasNext() && !it2_.hasNext())
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i0_++;
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return res;
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}
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private:
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const TwoLevelBitVector &bv_;
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uptr i0_, i1_;
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typename BV::Iterator it1_, it2_;
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};
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private:
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void check(uptr idx) const { CHECK_LE(idx, size()); }
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uptr idx0(uptr idx) const {
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uptr res = idx / (BV::kSize * BV::kSize);
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CHECK_LE(res, kLevel1Size);
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return res;
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}
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uptr idx1(uptr idx) const {
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uptr res = (idx / BV::kSize) % BV::kSize;
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CHECK_LE(res, BV::kSize);
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return res;
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}
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uptr idx2(uptr idx) const {
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uptr res = idx % BV::kSize;
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CHECK_LE(res, BV::kSize);
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return res;
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}
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BV l1_[kLevel1Size];
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BV l2_[kLevel1Size][BV::kSize];
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};
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} // namespace __sanitizer
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#endif // SANITIZER_BITVECTOR_H
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