aitools::bighashmap::core::external_map< T > Class Template Reference

#include <external_map.hpp>

List of all members.

Public Types
typedef cmph_map< T >	base_type
typedef base_type::key_type	key_type
typedef base_type::value_type	value_type
typedef base_type::checksum_type	checksum_type
Public Member Functions
	~external_map ()
bool	find (const key_type &key, value_type &value)
Static Public Member Functions
static external_map *	open (const bfs::path &idx_file)
Private Types
typedef value::pair < checksum_type, value_type >	entry_type
typedef value::value_traits < entry_type >	entry_traits
Private Member Functions
	external_map ()
	external_map (const bfs::path &mph_file, const bfs::path &dat_file)
Private Attributes
FILE *	data_

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Detailed Description

template<typename T>
class aitools::bighashmap::core::external_map< T >

This class implements a hash table with a minimal perfect hash function for addressing buckets. The hash function itself is hold in memory, whereas the table data is stored on disk. Together with the wrapper class big_hash_map this makes it possible to build very large hash maps with millions of keys. Note that this class is designed to build hash maps completely in memory as required by the CMPH library. Also filling the hash table happens in memory, because writing value to disk randomly takes too much time due to seek operations. The class big_hash_map applies a hierarchical approach on very large key sets that cannot be constructed in memory. It first subdivides the key set to smaller key sets and builds a hash map for each of these sets. Although this construction schema is a build-in feature of the CMPH library it turns out that the BRZ algorithm is much more memory consuming.

Author:

martin.trenkmann@uni-weimar.de

Version:

Id

external_map.hpp,v 1.2 2011/09/21 01:00:50 trenkman Exp

Definition at line 43 of file external_map.hpp.

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Member Typedef Documentation

template<typename T >

typedef cmph_map<T> aitools::bighashmap::core::external_map< T >::base_type

Definition at line 47 of file external_map.hpp.

template<typename T >

typedef base_type::checksum_type aitools::bighashmap::core::external_map< T >::checksum_type

Reimplemented from aitools::bighashmap::core::cmph_map< T >.

Definition at line 50 of file external_map.hpp.

template<typename T >

typedef value::value_traits<entry_type> aitools::bighashmap::core::external_map< T >::entry_traits [private]

Definition at line 55 of file external_map.hpp.

template<typename T >

typedef value::pair<checksum_type, value_type> aitools::bighashmap::core::external_map< T >::entry_type [private]

Definition at line 54 of file external_map.hpp.

template<typename T >

typedef base_type::key_type aitools::bighashmap::core::external_map< T >::key_type

Reimplemented from aitools::bighashmap::core::cmph_map< T >.

Definition at line 48 of file external_map.hpp.

template<typename T >

typedef base_type::value_type aitools::bighashmap::core::external_map< T >::value_type

Reimplemented from aitools::bighashmap::core::cmph_map< T >.

Definition at line 49 of file external_map.hpp.

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Constructor & Destructor Documentation

template<typename T >

aitools::bighashmap::core::external_map< T >::external_map

(

)

[inline, private]

Definition at line 59 of file external_map.hpp.

Referenced by aitools::bighashmap::core::external_map< T >::open().

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template<typename T >

aitools::bighashmap::core::external_map< T >::external_map	(	const bfs::path &	mph_file,
		const bfs::path &	dat_file
	)			[inline, private]

Definition at line 62 of file external_map.hpp.

References aitools::bighashmap::core::external_map< T >::data_, and aitools::util::fopen().

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template<typename T >

aitools::bighashmap::core::external_map< T >::~external_map

(

)

[inline]

Definition at line 70 of file external_map.hpp.

References aitools::bighashmap::core::external_map< T >::data_, and aitools::util::fclose().

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Member Function Documentation

template<typename T >

bool aitools::bighashmap::core::external_map< T >::find	(	const key_type &	key,
		value_type &	value
	)			[inline, virtual]

Implements aitools::bighashmap::core::cmph_map< T >.

Definition at line 96 of file external_map.hpp.

References aitools::bighashmap::core::external_map< T >::data_, aitools::value::pair< T1, T2 >::e1(), aitools::value::pair< T1, T2 >::e2(), aitools::util::fseek(), aitools::bighashmap::core::cmph_map< T >::hash(), aitools::util::log_debug(), aitools::util::log_error(), aitools::value::value_traits< T >::read_from(), aitools::value::value_traits< T >::size_of(), and aitools::util::throw_runtime_error().

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template<typename T >

static external_map* aitools::bighashmap::core::external_map< T >::open

(

const bfs::path &

idx_file

)

[inline, static]

Definition at line 78 of file external_map.hpp.

References aitools::bighashmap::core::external_map< T >::external_map(), and aitools::util::throw_runtime_error().

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Member Data Documentation

template<typename T >

FILE* aitools::bighashmap::core::external_map< T >::data_ [private]

Definition at line 131 of file external_map.hpp.

Referenced by aitools::bighashmap::core::external_map< T >::external_map(), aitools::bighashmap::core::external_map< T >::find(), and aitools::bighashmap::core::external_map< T >::~external_map().

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

• include/core/external_map.hpp