62 lines
1.9 KiB
C++
62 lines
1.9 KiB
C++
#ifndef __CXXMPH_MPHTABLE_H__
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#define __CXXMPH_MPHTABLE_H__
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// Minimal perfect hash abstraction implementing the BDZ algorithm
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#include <vector>
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#include "randomly_seeded_hash.h"
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#include "stringpiece.h"
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#include "trigraph.h"
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namespace cxxmph {
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template <class Key, class NewRandomlySeededHashFcn = RandomlySeededMurmur2>
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class MPHTable {
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public:
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typedef Key key_type;
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typedef NewRandomlySeededHashFcn hasher;
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MPHTable(double c = 1.23, cmph_uint8 b = 7) : c_(c), b_(b) { }
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~MPHTable();
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template <class ForwardIterator>
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bool Reset(ForwardIterator begin, ForwardIterator end);
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cmph_uint32 index(const key_type& x) const;
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private:
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template <class ForwardIterator>
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bool Mapping(ForwardIterator begin, ForwardIterator end,
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vector<Edge>* edges, vector<cmph_uint32> queue);
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bool GenerateQueue(TriGraph* graph, vector<cmph_uint32>* queue);
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void Assigning(TriGraph* graph_builder, Queue* queue);
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void Ranking(TriGraph* graph_builder, Queue* queue);
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cmph_uint32 Search(const StringPiece& key);
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cmph_uint32 Rank(const StringPiece& key);
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// Algorithm parameters
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cmph_uint8 b_; // Number of bits of the kth index in the ranktable
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double c_; // Number of bits per key (? is it right)
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// Values used during generation
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cmph_uint32 m_; // edges count
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cmph_uint32 n_; // vertex count
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cmph_uint32 k_ // kth index in ranktable, $k = log_2(n=3r)\varepsilon$
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// Values used during search
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// Partition vertex count, derived from c parameter.
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cmph_uint32 r_;
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// The array containing the minimal perfect hash function graph.
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std::vector<cmph_uint8> g_;
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// The table used for the rank step of the minimal perfect hash function
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std::vector<cmph_uint32> ranktable_;
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// The selected hash function triplet for finding the edges in the minimal
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// perfect hash function graph.
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hasher hash_function_[3];
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};
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} // namespace cxxmph
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#define // __CXXMPH_MPHTABLE_H__
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