Chris@16: /* 
Chris@16:    Copyright (c) Marshall Clow 2010-2012.
Chris@16: 
Chris@16:    Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16:     For more information, see http://www.boost.org
Chris@16: */
Chris@16: 
Chris@16: #ifndef BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP
Chris@16: #define BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP
Chris@16: 
Chris@16: #include <climits>      // for CHAR_BIT
Chris@16: #include <vector>
Chris@16: #include <iterator>     // for std::iterator_traits
Chris@16: 
Chris@16: #include <boost/type_traits/make_unsigned.hpp>
Chris@16: #include <boost/type_traits/is_integral.hpp>
Chris@16: #include <boost/type_traits/remove_pointer.hpp>
Chris@16: #include <boost/type_traits/remove_const.hpp>
Chris@16: 
Chris@16: #include <boost/array.hpp>
Chris@101: #ifdef BOOST_NO_CXX11_HDR_UNORDERED_MAP
Chris@101: #include <boost/unordered_map.hpp>
Chris@101: #else
Chris@101: #include <unordered_map>
Chris@101: #endif
Chris@16: 
Chris@16: #include <boost/algorithm/searching/detail/debugging.hpp>
Chris@16: 
Chris@16: namespace boost { namespace algorithm { namespace detail {
Chris@16: 
Chris@16: //
Chris@16: //  Default implementations of the skip tables for B-M and B-M-H
Chris@16: //
Chris@16:     template<typename key_type, typename value_type, bool /*useArray*/> class skip_table;
Chris@16: 
Chris@16: //  General case for data searching other than bytes; use a map
Chris@16:     template<typename key_type, typename value_type>
Chris@16:     class skip_table<key_type, value_type, false> {
Chris@16:     private:
Chris@101: #ifdef BOOST_NO_CXX11_HDR_UNORDERED_MAP
Chris@101:         typedef boost::unordered_map<key_type, value_type> skip_map;
Chris@101: #else
Chris@101:         typedef std::unordered_map<key_type, value_type> skip_map;
Chris@101: #endif
Chris@16:         const value_type k_default_value;
Chris@16:         skip_map skip_;
Chris@16:         
Chris@16:     public:
Chris@16:         skip_table ( std::size_t patSize, value_type default_value ) 
Chris@16:             : k_default_value ( default_value ), skip_ ( patSize ) {}
Chris@16:         
Chris@16:         void insert ( key_type key, value_type val ) {
Chris@16:             skip_ [ key ] = val;    // Would skip_.insert (val) be better here?
Chris@16:             }
Chris@16: 
Chris@16:         value_type operator [] ( key_type key ) const {
Chris@16:             typename skip_map::const_iterator it = skip_.find ( key );
Chris@16:             return it == skip_.end () ? k_default_value : it->second;
Chris@16:             }
Chris@16:             
Chris@16:         void PrintSkipTable () const {
Chris@16:             std::cout << "BM(H) Skip Table <unordered_map>:" << std::endl;
Chris@16:             for ( typename skip_map::const_iterator it = skip_.begin (); it != skip_.end (); ++it )
Chris@16:                 if ( it->second != k_default_value )
Chris@16:                     std::cout << "  " << it->first << ": " << it->second << std::endl;
Chris@16:             std::cout << std::endl;
Chris@16:             }
Chris@16:         };
Chris@16:         
Chris@16:     
Chris@16: //  Special case small numeric values; use an array
Chris@16:     template<typename key_type, typename value_type>
Chris@16:     class skip_table<key_type, value_type, true> {
Chris@16:     private:
Chris@16:         typedef typename boost::make_unsigned<key_type>::type unsigned_key_type;
Chris@16:         typedef boost::array<value_type, 1U << (CHAR_BIT * sizeof(key_type))> skip_map;
Chris@16:         skip_map skip_;
Chris@16:         const value_type k_default_value;
Chris@16:     public:
Chris@16:         skip_table ( std::size_t patSize, value_type default_value ) : k_default_value ( default_value ) {
Chris@16:             std::fill_n ( skip_.begin(), skip_.size(), default_value );
Chris@16:             }
Chris@16:         
Chris@16:         void insert ( key_type key, value_type val ) {
Chris@16:             skip_ [ static_cast<unsigned_key_type> ( key ) ] = val;
Chris@16:             }
Chris@16: 
Chris@16:         value_type operator [] ( key_type key ) const {
Chris@16:             return skip_ [ static_cast<unsigned_key_type> ( key ) ];
Chris@16:             }
Chris@16: 
Chris@16:         void PrintSkipTable () const {
Chris@16:             std::cout << "BM(H) Skip Table <boost:array>:" << std::endl;
Chris@16:             for ( typename skip_map::const_iterator it = skip_.begin (); it != skip_.end (); ++it )
Chris@16:                 if ( *it != k_default_value )
Chris@16:                     std::cout << "  " << std::distance (skip_.begin (), it) << ": " << *it << std::endl;
Chris@16:             std::cout << std::endl;
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:     template<typename Iterator>
Chris@16:     struct BM_traits {
Chris@16:         typedef typename std::iterator_traits<Iterator>::difference_type value_type;
Chris@16:         typedef typename std::iterator_traits<Iterator>::value_type key_type;
Chris@16:         typedef boost::algorithm::detail::skip_table<key_type, value_type, 
Chris@16:                 boost::is_integral<key_type>::value && (sizeof(key_type)==1)> skip_table_t;
Chris@16:         };
Chris@16: 
Chris@16: }}} // namespaces
Chris@16: 
Chris@16: #endif  //  BOOST_ALGORITHM_SEARCH_DETAIL_BM_TRAITS_HPP