leveldb::FilterBlockBuilder Class Reference

#include <filter_block.h>

Collaboration diagram for leveldb::FilterBlockBuilder:

Public Member Functions
	FilterBlockBuilder (const FilterPolicy *)
void	StartBlock (uint64_t block_offset)
void	AddKey (const Slice &key)
Slice	Finish ()

Private Member Functions
void	GenerateFilter ()
	FilterBlockBuilder (const FilterBlockBuilder &)
void	operator= (const FilterBlockBuilder &)

Private Attributes
const FilterPolicy *	policy_
std::string	keys_
std::vector< size_t >	start_
std::string	result_
std::vector< Slice >	tmp_keys_
std::vector< uint32_t >	filter_offsets_

Detailed Description

Definition at line 29 of file filter_block.h.

Constructor & Destructor Documentation

FilterBlockBuilder() [1/2]

leveldb::FilterBlockBuilder::FilterBlockBuilder ( const FilterPolicy *  policy )

explicit

Definition at line 18 of file filter_block.cc.

    : policy_(policy) {
}

FilterBlockBuilder() [2/2]

leveldb::FilterBlockBuilder::FilterBlockBuilder ( const FilterBlockBuilder &  )

private

Member Function Documentation

AddKey()

void leveldb::FilterBlockBuilder::AddKey

(

const Slice &

key

)

Definition at line 30 of file filter_block.cc.

                                                {
  Slice k = key;
  start_.push_back(keys_.size());
  keys_.append(k.data(), k.size());
}

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Finish()

Slice leveldb::FilterBlockBuilder::Finish

(

)

Definition at line 36 of file filter_block.cc.

                                 {
  if (!start_.empty()) {
    GenerateFilter();
  }

  // Append array of per-filter offsets
  const uint32_t array_offset = result_.size();
  for (size_t i = 0; i < filter_offsets_.size(); i++) {
    PutFixed32(&result_, filter_offsets_[i]);
  }

  PutFixed32(&result_, array_offset);
  result_.push_back(kFilterBaseLg);  // Save encoding parameter in result
  return Slice(result_);
}

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GenerateFilter()

void leveldb::FilterBlockBuilder::GenerateFilter ( )

private

Definition at line 52 of file filter_block.cc.

                                        {
  const size_t num_keys = start_.size();
  if (num_keys == 0) {
    // Fast path if there are no keys for this filter
    filter_offsets_.push_back(result_.size());
    return;
  }

  // Make list of keys from flattened key structure
  start_.push_back(keys_.size());  // Simplify length computation
  tmp_keys_.resize(num_keys);
  for (size_t i = 0; i < num_keys; i++) {
    const char* base = keys_.data() + start_[i];
    size_t length = start_[i+1] - start_[i];
    tmp_keys_[i] = Slice(base, length);
  }

  // Generate filter for current set of keys and append to result_.
  filter_offsets_.push_back(result_.size());
  policy_->CreateFilter(&tmp_keys_[0], static_cast<int>(num_keys), &result_);

  tmp_keys_.clear();
  keys_.clear();
  start_.clear();
}

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operator=()

void leveldb::FilterBlockBuilder::operator= ( const FilterBlockBuilder &  )

private

StartBlock()

void leveldb::FilterBlockBuilder::StartBlock

(

uint64_t

block_offset

)

Definition at line 22 of file filter_block.cc.

                                                         {
  uint64_t filter_index = (block_offset / kFilterBase);
  assert(filter_index >= filter_offsets_.size());
  while (filter_index > filter_offsets_.size()) {
    GenerateFilter();
  }
}

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Member Data Documentation

filter_offsets_

std::vector<uint32_t> leveldb::FilterBlockBuilder::filter_offsets_

private

Definition at line 45 of file filter_block.h.

keys_

std::string leveldb::FilterBlockBuilder::keys_

private

Definition at line 41 of file filter_block.h.

policy_

const FilterPolicy* leveldb::FilterBlockBuilder::policy_

private

Definition at line 40 of file filter_block.h.

result_

std::string leveldb::FilterBlockBuilder::result_

private

Definition at line 43 of file filter_block.h.

start_

std::vector<size_t> leveldb::FilterBlockBuilder::start_

private

Definition at line 42 of file filter_block.h.

tmp_keys_

std::vector<Slice> leveldb::FilterBlockBuilder::tmp_keys_

private

Definition at line 44 of file filter_block.h.

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The documentation for this class was generated from the following files:

• table/filter_block.h
• table/filter_block.cc