expansion_base.h

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#ifndef EXPANSION_BASE_H
#define EXPANSION_BASE_H
#pragma once
/***************************************************************************
 *   Copyright (C) 2007-2013 Mike Kinghan, imk@burroingroingjoing.com      *
 *   All rights reserved.                                                  *
 *                                                                         *
 *   Contributed originally by Mike Kinghan, imk@burroingroingjoing.com    *
 *                                                                         *
 *   Redistribution and use in source and binary forms, with or without    *
 *   modification, are permitted provided that the following conditions    *
 *   are met:                                                              *
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 *   Redistributions of source code must retain the above copyright        *
 *   notice, this list of conditions and the following disclaimer.         *
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 *   Redistributions in binary form must reproduce the above copyright     *
 *   notice, this list of conditions and the following disclaimer in the   *
 *   documentation and/or other materials provided with the distribution.  *
 *                                                                         *
 *   Neither the name of Mike Kinghan nor the names of its contributors    *
 *   may be used to endorse or promote products derived from this software *
 *   without specific prior written permission.                            *
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 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS   *
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#include "reference.h"
#include <string>
#include <memory>

struct expansion_base : reference
{
        explicit expansion_base(reference const & ref);

        std::string const & value() const {
        return _value;
        }

        virtual unsigned expand() = 0;

        virtual void throw_self() const = 0;

        std::string const & invocation() const override {
        static std::string s;
        s = id();
        if (args()) {
            s += args().str();
        }
                return s;
        }

        static std::unique_ptr<expansion_base>
        factory(bool explain, reference const & ref);

        static constexpr unsigned max_expansion_size() {
            return 4196;
        }

protected:

        void set_expansion_flags();

        size_t seek_expandable_arg() {
                for (   ;_cur_arg < args().size() && !args().is_expandable(_cur_arg);
                        ++_cur_arg){}
                return _cur_arg;
        }

    void edit(  std::string & str,
                    size_t at, size_t len,
                    std::string const & replacement) {
        size_t next_size = str.size() - len + replacement.size();
        if (next_size > max_expansion_size()) {
            throw_self();
        }
        str.replace(at,len,replacement);
    }

        unsigned edit_buf(
                std::string & str,
                expansion_base const & e,
                size_t off = 0);

        unsigned edit_trailing_args(
                expansion_base const & e,
                size_t start = 0);

        bool args_expansion_done() const {
                return _cur_arg == args().size();
        }

        virtual unsigned expand(std::string & str) = 0;

        bool substitute();


        std::string _value;
        size_t _cur_arg = 0;
};

#endif // EOF