mirror of https://github.com/facebook/rocksdb.git
118 lines
3.2 KiB
C++
118 lines
3.2 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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#pragma once
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#include <algorithm>
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#include <string>
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#include <vector>
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#include "db/dbformat.h"
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#include "rocksdb/iterator.h"
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#include "rocksdb/slice.h"
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#include "table/internal_iterator.h"
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namespace ROCKSDB_NAMESPACE {
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// Iterator over a vector of keys/values
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class VectorIterator : public InternalIterator {
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public:
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VectorIterator(std::vector<std::string> keys, std::vector<std::string> values,
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const Comparator* icmp = nullptr)
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: keys_(std::move(keys)),
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values_(std::move(values)),
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current_(keys_.size()),
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indexed_cmp_(icmp, &keys_) {
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assert(keys_.size() == values_.size());
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indices_.reserve(keys_.size());
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for (size_t i = 0; i < keys_.size(); i++) {
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indices_.push_back(i);
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}
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if (icmp != nullptr) {
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std::sort(indices_.begin(), indices_.end(), indexed_cmp_);
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}
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}
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virtual bool Valid() const override {
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return !indices_.empty() && current_ < indices_.size();
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}
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virtual void SeekToFirst() override { current_ = 0; }
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virtual void SeekToLast() override { current_ = indices_.size() - 1; }
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virtual void Seek(const Slice& target) override {
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if (indexed_cmp_.cmp != nullptr) {
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current_ = std::lower_bound(indices_.begin(), indices_.end(), target,
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indexed_cmp_) -
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indices_.begin();
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} else {
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current_ =
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std::lower_bound(keys_.begin(), keys_.end(), target.ToString()) -
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keys_.begin();
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}
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}
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virtual void SeekForPrev(const Slice& target) override {
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if (indexed_cmp_.cmp != nullptr) {
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current_ = std::upper_bound(indices_.begin(), indices_.end(), target,
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indexed_cmp_) -
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indices_.begin();
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} else {
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current_ =
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std::upper_bound(keys_.begin(), keys_.end(), target.ToString()) -
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keys_.begin();
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}
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if (!Valid()) {
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SeekToLast();
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} else {
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Prev();
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}
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}
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virtual void Next() override { current_++; }
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virtual void Prev() override { current_--; }
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virtual Slice key() const override {
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return Slice(keys_[indices_[current_]]);
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}
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virtual Slice value() const override {
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return Slice(values_[indices_[current_]]);
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}
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virtual Status status() const override { return Status::OK(); }
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virtual bool IsKeyPinned() const override { return true; }
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virtual bool IsValuePinned() const override { return true; }
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protected:
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std::vector<std::string> keys_;
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std::vector<std::string> values_;
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size_t current_;
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private:
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struct IndexedKeyComparator {
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IndexedKeyComparator(const Comparator* c,
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const std::vector<std::string>* ks)
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: cmp(c), keys(ks) {}
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bool operator()(size_t a, size_t b) const {
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return cmp->Compare((*keys)[a], (*keys)[b]) < 0;
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}
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bool operator()(size_t a, const Slice& b) const {
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return cmp->Compare((*keys)[a], b) < 0;
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}
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bool operator()(const Slice& a, size_t b) const {
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return cmp->Compare(a, (*keys)[b]) < 0;
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}
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const Comparator* cmp;
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const std::vector<std::string>* keys;
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};
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IndexedKeyComparator indexed_cmp_;
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std::vector<size_t> indices_;
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};
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} // namespace ROCKSDB_NAMESPACE
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