pastk/organicmaps
1
Fork 0
forked from organicmaps/organicmaps
Code Pull requests Activity

[coding] Added CBV::LeaveFirstSetNBits().

Browse source
This commit is contained in:
Yuri Gorshenin 2016-02-09 12:46:53 +03:00 • committed by Sergey Yershov
parent cb3fe67baa
commit 004b63425f
3 changed files with 124 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

80
coding/coding_tests/compressed_bit_vector_test.cpp
View file

@ -387,3 +387,83 @@ UNIT_TEST(CompressedBitVector_DenseOneBit)
TEST_EQUAL(pos, 0, ());
});
}
UNIT_TEST(CompressedBitVector_LeaveFirstNBitsSmoke)
{
auto cbv = coding::CompressedBitVectorBuilder::FromBitPositions(vector<uint64_t>{});
TEST_EQUAL(cbv->PopCount(), 0, ());
cbv = cbv->LeaveFirstSetNBits(0);
TEST_EQUAL(cbv->PopCount(), 0, ());
cbv = cbv->LeaveFirstSetNBits(200);
TEST_EQUAL(cbv->PopCount(), 0, ());
}
UNIT_TEST(CompressedBitVector_DenseLeaveFirstNBits)
{
{
vector<uint64_t> setBits;
setBits.assign(coding::DenseCBV::kBlockSize * 4, 1);
auto cbv = coding::CompressedBitVectorBuilder::FromBitPositions(setBits);
TEST_EQUAL(cbv->PopCount(), coding::DenseCBV::kBlockSize * 4, ());
TEST_EQUAL(cbv->GetStorageStrategy(), coding::CompressedBitVector::StorageStrategy::Dense, ());
cbv = cbv->LeaveFirstSetNBits(0);
TEST_EQUAL(cbv->PopCount(), 0, ());
}
{
vector<uint64_t> setBits;
for (int i = 0; i < 100; ++i)
setBits.push_back(2 * i);
auto cbv = coding::CompressedBitVectorBuilder::FromBitPositions(setBits);
TEST_EQUAL(cbv->PopCount(), 100, ());
TEST_EQUAL(cbv->GetStorageStrategy(), coding::CompressedBitVector::StorageStrategy::Dense, ());
cbv = cbv->LeaveFirstSetNBits(50);
TEST_EQUAL(cbv->PopCount(), 50, ());
TEST_EQUAL(cbv->GetStorageStrategy(), coding::CompressedBitVector::StorageStrategy::Dense, ());
for (int i = 0; i < 50; ++i)
{
TEST(cbv->GetBit(2 * i), ());
TEST(!cbv->GetBit(2 * i + 1), ());
}
}
}
UNIT_TEST(CompressedBitVector_SparseLeaveFirstNBits)
{
vector<uint64_t> setBits;
for (int p = 0; p < 20; ++p)
setBits.push_back(static_cast<uint64_t>(1) << p);
auto cbv = coding::CompressedBitVectorBuilder::FromBitPositions(setBits);
TEST_EQUAL(cbv->PopCount(), 20, ());
TEST_EQUAL(cbv->GetStorageStrategy(), coding::CompressedBitVector::StorageStrategy::Sparse, ());
cbv = cbv->LeaveFirstSetNBits(100);
TEST_EQUAL(cbv->PopCount(), 20, ());
for (uint64_t bit = 0; bit < (1 << 20); ++bit)
{
if (bit != 0 && (bit & (bit - 1)) == 0)
TEST(cbv->GetBit(bit), (bit));
else
TEST(!cbv->GetBit(bit), (bit));
}
cbv = cbv->LeaveFirstSetNBits(10);
TEST_EQUAL(cbv->PopCount(), 10, ());
for (uint64_t bit = 0; bit < (1 << 20); ++bit)
{
if (bit != 0 && (bit & (bit - 1)) == 0 && bit < (1 << 10))
TEST(cbv->GetBit(bit), (bit));
else
TEST(!cbv->GetBit(bit), (bit));
}
cbv = cbv->LeaveFirstSetNBits(0);
TEST_EQUAL(cbv->PopCount(), 0, ());
for (uint64_t bit = 0; bit < (1 << 20); ++bit)
TEST(!cbv->GetBit(bit), (bit));
}

44
coding/compressed_bit_vector.cpp
View file

@ -309,6 +309,36 @@ bool DenseCBV::GetBit(uint64_t pos) const
return ((bitGroup >> (pos % kBlockSize)) & 1) > 0;
}
unique_ptr<CompressedBitVector> DenseCBV::LeaveFirstSetNBits(uint64_t n) const
{
if (PopCount() <= n)
return Clone();
vector<uint64_t> groups;
for (size_t i = 0; i < m_bitGroups.size() && n != 0; ++i)
{
uint64_t group = m_bitGroups[i];
uint32_t const bits = bits::PopCount(group);
if (bits <= n)
{
n -= bits;
groups.push_back(group);
}
else
{
uint64_t part = 0;
while (n != 0)
{
part = part | (group & -group);
group = group & (group - 1);
--n;
}
groups.push_back(part);
}
}
return CompressedBitVectorBuilder::FromBitGroups(move(groups));
}
CompressedBitVector::StorageStrategy DenseCBV::GetStorageStrategy() const
{
return CompressedBitVector::StorageStrategy::Dense;
@ -352,6 +382,14 @@ bool SparseCBV::GetBit(uint64_t pos) const
return binary_search(m_positions.begin(), m_positions.end(), pos);
}
unique_ptr<CompressedBitVector> SparseCBV::LeaveFirstSetNBits(uint64_t n) const
{
if (PopCount() <= n)
return Clone();
vector<uint64_t> positions(m_positions.begin(), m_positions.begin() + n);
return CompressedBitVectorBuilder::FromBitPositions(move(positions));
}
CompressedBitVector::StorageStrategy SparseCBV::GetStorageStrategy() const
{
return CompressedBitVector::StorageStrategy::Sparse;
@ -420,10 +458,8 @@ string DebugPrint(CompressedBitVector::StorageStrategy strat)
{
switch (strat)
{
case CompressedBitVector::StorageStrategy::Dense:
return "Dense";
case CompressedBitVector::StorageStrategy::Sparse:
return "Sparse";
case CompressedBitVector::StorageStrategy::Dense: return "Dense";
case CompressedBitVector::StorageStrategy::Sparse: return "Sparse";
}
}

4
coding/compressed_bit_vector.hpp
View file

@ -58,6 +58,8 @@ public:
// Would operator[] look better?
virtual bool GetBit(uint64_t pos) const = 0;
virtual unique_ptr<CompressedBitVector> LeaveFirstSetNBits(uint64_t n) const = 0;
// Returns the strategy used when storing this bit vector.
virtual StorageStrategy GetStorageStrategy() const = 0;
@ -114,6 +116,7 @@ public:
// CompressedBitVector overrides:
uint64_t PopCount() const override;
bool GetBit(uint64_t pos) const override;
unique_ptr<CompressedBitVector> LeaveFirstSetNBits(uint64_t n) const override;
StorageStrategy GetStorageStrategy() const override;
void Serialize(Writer & writer) const override;
unique_ptr<CompressedBitVector> Clone() const override;
@ -148,6 +151,7 @@ public:
// CompressedBitVector overrides:
uint64_t PopCount() const override;
bool GetBit(uint64_t pos) const override;
unique_ptr<CompressedBitVector> LeaveFirstSetNBits(uint64_t n) const override;
StorageStrategy GetStorageStrategy() const override;
void Serialize(Writer & writer) const override;
unique_ptr<CompressedBitVector> Clone() const override;