string_match_reproduction.cpp

#include <cstdio>

int main()
{
    auto badmatch = []( unsigned char cName, unsigned char cQuery ) {
        if ( cName == cQuery )
            return true;
        else if ( cName - 'A' <= (unsigned char)'Z' - 'A' && cName - 'A' + 'a' == cQuery )
            return true;
        else if ( cName - 'a' <= (unsigned char)'z' - 'a' && cName - 'a' + 'A' == cQuery )
            return true;
            
        return false;
    };
    
    auto goodmatch = []( unsigned char cName, unsigned char cQuery ) {
        if ( cName == cQuery )
            return true;
        else if ( (unsigned char)(cName - 'A') <= 'Z' - 'A' && cName - 'A' + 'a' == cQuery )
            return true;
        else if ( (unsigned char)(cName - 'a') <= 'z' - 'a' && cName - 'a' + 'A' == cQuery )
            return true;
            
        return false;
    };
    
    auto fastermatch = []( unsigned char cName, unsigned char cQuery ) {
        if ( cName == cQuery )
            return true;
        else if ( (cName | 32) == cQuery )
            return true;
        else if ( (cQuery | 32) == cName )
            return true;
            
        return false;
    };

    // Loop through all characters.
    for ( auto i = 32; i <= 126; i++ )
    {
        auto cQuery = (unsigned char)i;
        for ( auto j = 32; j <= 126; j++ )
        {
            auto cName = (unsigned char)j;
            
            if ( badmatch( cName, cQuery ) )
            //if ( goodmatch( cName, cQuery ) )
            //if ( fastermatch( cName, cQuery ) )
            {
                printf("%c=%c\n", cName, cQuery );
            }
        }
    }
}