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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Dictionary.hh"
namespace orc {
// insert a new string into dictionary, return its insertion order
size_t SortedStringDictionary::insert(const char* str, size_t len) {
size_t index = flatDict_.size();
auto it = keyToIndex_.find(std::string_view{str, len});
if (it != keyToIndex_.end()) {
return it->second;
} else {
flatDict_.emplace_back(str, len, index);
totalLength_ += len;
const auto& lastEntry = flatDict_.back().entry;
keyToIndex_.emplace(std::string_view{lastEntry.data->data(), lastEntry.data->size()}, index);
return index;
}
}
// write dictionary data & length to output buffer
void SortedStringDictionary::flush(AppendOnlyBufferedStream* dataStream,
RleEncoder* lengthEncoder) const {
std::sort(flatDict_.begin(), flatDict_.end(), LessThan());
for (const auto& entryWithIndex : flatDict_) {
dataStream->write(entryWithIndex.entry.data->data(), entryWithIndex.entry.data->size());
lengthEncoder->write(static_cast<int64_t>(entryWithIndex.entry.data->size()));
}
}
/**
* Reorder input index buffer from insertion order to dictionary order
*
* We require this function because string values are buffered by indexes
* in their insertion order. Until the entire dictionary is complete can
* we get their sorted indexes in the dictionary in that ORC specification
* demands dictionary should be ordered. Therefore this function transforms
* the indexes from insertion order to dictionary value order for final
* output.
*/
void SortedStringDictionary::reorder(std::vector<int64_t>& idxBuffer) const {
// iterate the dictionary to get mapping from insertion order to value order
std::vector<size_t> mapping(flatDict_.size());
for (size_t i = 0; i < flatDict_.size(); ++i) {
mapping[flatDict_[i].index] = i;
}
// do the transformation
for (size_t i = 0; i != idxBuffer.size(); ++i) {
idxBuffer[i] = static_cast<int64_t>(mapping[static_cast<size_t>(idxBuffer[i])]);
}
}
// get dict entries in insertion order
void SortedStringDictionary::getEntriesInInsertionOrder(
std::vector<const DictEntry*>& entries) const {
/// flatDict_ is sorted in insertion order before [[SortedStringDictionary::flush]] is invoked.
entries.resize(flatDict_.size());
for (size_t i = 0; i < flatDict_.size(); ++i) {
entries[i] = &(flatDict_[i].entry);
}
}
// return count of entries
size_t SortedStringDictionary::size() const {
return flatDict_.size();
}
// return total length of strings in the dictioanry
uint64_t SortedStringDictionary::length() const {
return totalLength_;
}
void SortedStringDictionary::clear() {
totalLength_ = 0;
keyToIndex_.clear();
flatDict_.clear();
}
} // namespace orc
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