114 lines
4.2 KiB
C++
114 lines
4.2 KiB
C++
/*
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Copyright (c) Marshall Clow 2010-2012.
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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For more information, see http://www.boost.org
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*/
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#ifndef BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP
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#define BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP
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#include <climits> // for CHAR_BIT
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#include <vector>
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#include <iterator> // for std::iterator_traits
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#include <boost/type_traits/make_unsigned.hpp>
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#include <boost/type_traits/is_integral.hpp>
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#include <boost/type_traits/remove_pointer.hpp>
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#include <boost/type_traits/remove_const.hpp>
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#include <boost/array.hpp>
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#ifdef BOOST_NO_CXX11_HDR_UNORDERED_MAP
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#include <boost/unordered_map.hpp>
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#else
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#include <unordered_map>
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#endif
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#include <boost/algorithm/searching/detail/debugging.hpp>
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namespace boost { namespace algorithm { namespace detail {
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//
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// Default implementations of the skip tables for B-M and B-M-H
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//
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template<typename key_type, typename value_type, bool /*useArray*/> class skip_table;
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// General case for data searching other than bytes; use a map
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template<typename key_type, typename value_type>
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class skip_table<key_type, value_type, false> {
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private:
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#ifdef BOOST_NO_CXX11_HDR_UNORDERED_MAP
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typedef boost::unordered_map<key_type, value_type> skip_map;
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#else
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typedef std::unordered_map<key_type, value_type> skip_map;
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#endif
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const value_type k_default_value;
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skip_map skip_;
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public:
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skip_table ( std::size_t patSize, value_type default_value )
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: k_default_value ( default_value ), skip_ ( patSize ) {}
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void insert ( key_type key, value_type val ) {
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skip_ [ key ] = val; // Would skip_.insert (val) be better here?
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}
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value_type operator [] ( key_type key ) const {
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typename skip_map::const_iterator it = skip_.find ( key );
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return it == skip_.end () ? k_default_value : it->second;
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}
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void PrintSkipTable () const {
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std::cout << "BM(H) Skip Table <unordered_map>:" << std::endl;
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for ( typename skip_map::const_iterator it = skip_.begin (); it != skip_.end (); ++it )
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if ( it->second != k_default_value )
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std::cout << " " << it->first << ": " << it->second << std::endl;
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std::cout << std::endl;
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}
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};
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// Special case small numeric values; use an array
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template<typename key_type, typename value_type>
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class skip_table<key_type, value_type, true> {
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private:
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typedef typename boost::make_unsigned<key_type>::type unsigned_key_type;
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typedef boost::array<value_type, 1U << (CHAR_BIT * sizeof(key_type))> skip_map;
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skip_map skip_;
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const value_type k_default_value;
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public:
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skip_table ( std::size_t /*patSize*/, value_type default_value ) : k_default_value ( default_value ) {
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std::fill_n ( skip_.begin(), skip_.size(), default_value );
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}
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void insert ( key_type key, value_type val ) {
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skip_ [ static_cast<unsigned_key_type> ( key ) ] = val;
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}
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value_type operator [] ( key_type key ) const {
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return skip_ [ static_cast<unsigned_key_type> ( key ) ];
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}
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void PrintSkipTable () const {
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std::cout << "BM(H) Skip Table <boost:array>:" << std::endl;
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for ( typename skip_map::const_iterator it = skip_.begin (); it != skip_.end (); ++it )
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if ( *it != k_default_value )
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std::cout << " " << std::distance (skip_.begin (), it) << ": " << *it << std::endl;
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std::cout << std::endl;
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}
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};
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template<typename Iterator>
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struct BM_traits {
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typedef typename std::iterator_traits<Iterator>::difference_type value_type;
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typedef typename std::iterator_traits<Iterator>::value_type key_type;
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typedef boost::algorithm::detail::skip_table<key_type, value_type,
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boost::is_integral<key_type>::value && (sizeof(key_type)==1)> skip_table_t;
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};
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}}} // namespaces
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#endif // BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP
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