leveldb::BlockBuilder Class Reference

#include <block_builder.h>

Collaboration diagram for leveldb::BlockBuilder:

Public Member Functions
	BlockBuilder (const Options *options)
void	Reset ()
void	Add (const Slice &key, const Slice &value)
Slice	Finish ()
size_t	CurrentSizeEstimate () const
bool	empty () const

Private Member Functions
	BlockBuilder (const BlockBuilder &)
void	operator= (const BlockBuilder &)

Private Attributes
const Options *	options_
std::string	buffer_
std::vector< uint32_t >	restarts_
int	counter_
bool	finished_
std::string	last_key_

Detailed Description

Definition at line 17 of file block_builder.h.

Constructor & Destructor Documentation

BlockBuilder() [1/2]

leveldb::BlockBuilder::BlockBuilder ( const Options *  options )

explicit

Definition at line 39 of file block_builder.cc.

    : options_(options),
      restarts_(),
      counter_(0),
      finished_(false) {
  assert(options->block_restart_interval >= 1);
  restarts_.push_back(0);       // First restart point is at offset 0
}

BlockBuilder() [2/2]

leveldb::BlockBuilder::BlockBuilder ( const BlockBuilder &  )

private

Member Function Documentation

Add()

void leveldb::BlockBuilder::Add	(	const Slice &	key,
		const Slice &	value
	)

Definition at line 73 of file block_builder.cc.

                                                           {
  Slice last_key_piece(last_key_);
  assert(!finished_);
  assert(counter_ <= options_->block_restart_interval);
  assert(buffer_.empty() // No values yet?
         || options_->comparator->Compare(key, last_key_piece) > 0);
  size_t shared = 0;
  if (counter_ < options_->block_restart_interval) {
    // See how much sharing to do with previous string
    const size_t min_length = std::min(last_key_piece.size(), key.size());
    while ((shared < min_length) && (last_key_piece[shared] == key[shared])) {
      shared++;
    }
  } else {
    // Restart compression
    restarts_.push_back(buffer_.size());
    counter_ = 0;
  }
  const size_t non_shared = key.size() - shared;

  // Add "<shared><non_shared><value_size>" to buffer_
  PutVarint32(&buffer_, shared);
  PutVarint32(&buffer_, non_shared);
  PutVarint32(&buffer_, value.size());

  // Add string delta to buffer_ followed by value
  buffer_.append(key.data() + shared, non_shared);
  buffer_.append(value.data(), value.size());

  // Update state
  last_key_.resize(shared);
  last_key_.append(key.data() + shared, non_shared);
  assert(Slice(last_key_) == key);
  counter_++;
}

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CurrentSizeEstimate()

size_t leveldb::BlockBuilder::CurrentSizeEstimate

(

)

const

Definition at line 57 of file block_builder.cc.

                                               {
  return (buffer_.size() +                        // Raw data buffer
          restarts_.size() * sizeof(uint32_t) +   // Restart array
          sizeof(uint32_t));                      // Restart array length
}

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empty()

bool leveldb::BlockBuilder::empty ( ) const

inline

Definition at line 38 of file block_builder.h.

                     {
    return buffer_.empty();
  }

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Finish()

Slice leveldb::BlockBuilder::Finish

(

)

Definition at line 63 of file block_builder.cc.

                           {
  // Append restart array
  for (size_t i = 0; i < restarts_.size(); i++) {
    PutFixed32(&buffer_, restarts_[i]);
  }
  PutFixed32(&buffer_, restarts_.size());
  finished_ = true;
  return Slice(buffer_);
}

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operator=()

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

private

Reset()

void leveldb::BlockBuilder::Reset

(

)

Definition at line 48 of file block_builder.cc.

                         {
  buffer_.clear();
  restarts_.clear();
  restarts_.push_back(0);       // First restart point is at offset 0
  counter_ = 0;
  finished_ = false;
  last_key_.clear();
}

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Member Data Documentation

buffer_

std::string leveldb::BlockBuilder::buffer_

private

Definition at line 44 of file block_builder.h.

counter_

int leveldb::BlockBuilder::counter_

private

Definition at line 46 of file block_builder.h.

finished_

bool leveldb::BlockBuilder::finished_

private

Definition at line 47 of file block_builder.h.

last_key_

std::string leveldb::BlockBuilder::last_key_

private

Definition at line 48 of file block_builder.h.

options_

const Options* leveldb::BlockBuilder::options_

private

Definition at line 43 of file block_builder.h.

restarts_

std::vector<uint32_t> leveldb::BlockBuilder::restarts_

private

Definition at line 45 of file block_builder.h.

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

• table/block_builder.h
• table/block_builder.cc