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#include "indexer/features_offsets_table.hpp"
#include "indexer/features_vector.hpp"
#include "platform/local_country_file.hpp"
#include "platform/local_country_file_utils.hpp"
#include "platform/platform.hpp"
#include "coding/file_container.hpp"
#include "coding/internal/file_data.hpp"
#include "base/assert.hpp"
#include "base/logging.hpp"
#include "std/string.hpp"
using namespace platform;
namespace feature
{
void FeaturesOffsetsTable::Builder::PushOffset(uint32_t const offset)
{
ASSERT(m_offsets.empty() || m_offsets.back() < offset, ());
m_offsets.push_back(offset);
}
FeaturesOffsetsTable::FeaturesOffsetsTable(succinct::elias_fano::elias_fano_builder & builder)
: m_table(&builder)
{
}
FeaturesOffsetsTable::FeaturesOffsetsTable(string const & filePath)
{
m_pReader.reset(new MmapReader(filePath));
succinct::mapper::map(m_table, reinterpret_cast<char const *>(m_pReader->Data()));
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::Build(Builder & builder)
{
vector<uint32_t> const & offsets = builder.m_offsets;
size_t const numOffsets = offsets.size();
uint32_t const maxOffset = offsets.empty() ? 0 : offsets.back();
succinct::elias_fano::elias_fano_builder elias_fano_builder(maxOffset, numOffsets);
for (uint32_t offset : offsets)
elias_fano_builder.push_back(offset);
return unique_ptr<FeaturesOffsetsTable>(new FeaturesOffsetsTable(elias_fano_builder));
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::LoadImpl(string const & filePath)
{
return unique_ptr<FeaturesOffsetsTable>(new FeaturesOffsetsTable(filePath));
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::Load(string const & filePath)
{
if (!GetPlatform().IsFileExistsByFullPath(filePath))
return unique_ptr<FeaturesOffsetsTable>();
return LoadImpl(filePath);
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::CreateImpl(
platform::LocalCountryFile const & localFile,
FilesContainerR const & cont, string const & storePath)
{
LOG(LINFO, ("Creating features offset table file", storePath));
VERIFY(CountryIndexes::PreparePlaceOnDisk(localFile), ());
Builder builder;
FeaturesVector::ForEachOffset(cont.GetReader(DATA_FILE_TAG), [&builder] (uint32_t offset)
{
builder.PushOffset(offset);
});
unique_ptr<FeaturesOffsetsTable> table(Build(builder));
table->Save(storePath);
return table;
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::CreateIfNotExistsAndLoad(
LocalCountryFile const & localFile, FilesContainerR const & cont)
{
string const offsetsFilePath = CountryIndexes::GetPath(localFile, CountryIndexes::Index::Offsets);
if (Platform::IsFileExistsByFullPath(offsetsFilePath))
return LoadImpl(offsetsFilePath);
return CreateImpl(localFile, cont, offsetsFilePath);
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::CreateIfNotExistsAndLoad(
LocalCountryFile const & localFile)
{
string const offsetsFilePath = CountryIndexes::GetPath(localFile, CountryIndexes::Index::Offsets);
if (Platform::IsFileExistsByFullPath(offsetsFilePath))
return LoadImpl(offsetsFilePath);
return CreateImpl(localFile, FilesContainerR(localFile.GetPath(MapOptions::Map)), offsetsFilePath);
}
// static
unique_ptr<FeaturesOffsetsTable> FeaturesOffsetsTable::CreateIfNotExistsAndLoad(FilesContainerR const & cont)
{
return CreateIfNotExistsAndLoad(LocalCountryFile::MakeTemporary(cont.GetFileName()), cont);
}
void FeaturesOffsetsTable::Save(string const & filePath)
{
LOG(LINFO, ("Saving features offsets table to ", filePath));
string const fileNameTmp = filePath + EXTENSION_TMP;
succinct::mapper::freeze(m_table, fileNameTmp.c_str());
my::RenameFileX(fileNameTmp, filePath);
}
uint32_t FeaturesOffsetsTable::GetFeatureOffset(size_t index) const
{
ASSERT_LESS(index, size(), ("Index out of bounds", index, size()));
return static_cast<uint32_t>(m_table.select(index));
}
size_t FeaturesOffsetsTable::GetFeatureIndexbyOffset(uint32_t offset) const
{
ASSERT_GREATER(size(), 0, ("We must not ask empty table"));
ASSERT_LESS_OR_EQUAL(offset, m_table.select(size() - 1), ("Offset out of bounds", offset,
m_table.select(size() - 1)));
ASSERT_GREATER_OR_EQUAL(offset, m_table.select(0), ("Offset out of bounds", offset,
m_table.select(size() - 1)));
//Binary search in elias_fano list
size_t leftBound = 0, rightBound = size();
while (leftBound + 1 < rightBound) {
size_t middle = leftBound + (rightBound - leftBound) / 2;
if (m_table.select(middle) <= offset)
leftBound = middle;
else
rightBound = middle;
}
ASSERT_EQUAL(offset, m_table.select(leftBound), ("Can't find offset", offset, "in the table"));
return leftBound;
}
} // namespace feature
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