BadCharacterShiftTable.h

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#pragma once
 
#include <alib/set>
#include <alib/map>
 
#include <string/LinearString.h>
 
namespace string {
 
namespace properties {
 
class BadCharacterShiftTable {
public:
    template < class SymbolType >
    static ext::map < SymbolType, size_t > bcs ( const string::LinearString < SymbolType > & pattern );
 
};
 
template < class SymbolType >
ext::map<SymbolType, size_t> BadCharacterShiftTable::bcs(const string::LinearString < SymbolType >& pattern) {
    const ext::set<SymbolType>& alphabet = pattern.getAlphabet();
    ext::map<SymbolType, size_t> bcs;
 
    /* Initialization of BCS to the length of the needle. */
    for(const auto& symbol : alphabet)
        bcs.insert(std::make_pair(symbol, pattern.getContent().size()));
 
    /* Filling out BCS, ignoring last character. */
    for(size_t i = 0; i < pattern.getContent().size() - 1; i++)
        bcs[pattern.getContent().at(i)] = pattern.getContent().size() - i - 1;
 
    /*
    for(const auto& kv: bcs)
        common::Streams::out << std::string(kv.first) << " " << kv.second << std::endl;
    for(const auto& s: string.getContent())
        common::Streams::out << std::string(s);common::Streams::out << std::endl;
    */
 
    return bcs;
}
 
} /* namespace properties */
 
} /* namespace string */