// ==========================================================================
//                 SeqAn - The Library for Sequence Analysis
// ==========================================================================
// Copyright (c) 2006-2024, Knut Reinert, FU Berlin
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
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//     * Neither the name of Knut Reinert or the FU Berlin nor the names of
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// ==========================================================================
// Helpers for the test_modifier tests.
// ==========================================================================

#ifndef TESTS_MODIFIER_HELPERS_H_
#define TESTS_MODIFIER_HELPERS_H_

#include <functional>

// Cesar Chiffre as a test functor.
template <typename TArgChar, typename TResultChar = TArgChar>
struct CaesarChiffre : public std::function<TResultChar(TArgChar)>
{
    TArgChar _delta;

    CaesarChiffre() : _delta(0) {}
    CaesarChiffre(CaesarChiffre const &other) = default;
    CaesarChiffre & operator=(CaesarChiffre const &) = default;

    CaesarChiffre(TArgChar delta) {
        if (delta < 0)
            _delta = ('z' - 'a' + 1) - (-delta) % ('z' - 'a' + 1);
        else
            _delta = delta;
    }

    inline TResultChar operator()(TArgChar const & x) const {
        if (('a' <= x) && (x <= 'z'))
            return (x - 'a' + _delta) % ('z' - 'a' + 1) + 'a';
        if (('A' <= x) && (x <= 'Z'))
            return (x - 'A' + _delta) % ('Z' - 'A' + 1) + 'A';
        return x;
    }
};


#endif  // TESTS_MODIFIER_HELPERS_H_
