foot/emulator/include/elfio/elfio_modinfo.hpp

/*
Copyright (C) 2001-present by Serge Lamikhov-Center

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#ifndef ELFIO_MODINFO_HPP
#define ELFIO_MODINFO_HPP

#include <string_view>
#include <vector>

namespace ELFIO {

//------------------------------------------------------------------------------
/**
 * @class modinfo_section_accessor_template
 * @brief A template class to access modinfo section.
 * 
 * @tparam S The section type.
 */
template <class S> class modinfo_section_accessor_template
{
  public:
    //------------------------------------------------------------------------------
    /**
     * @brief Construct a new modinfo section accessor template object.
     * 
     * @param section The section to be accessed.
     */
    explicit modinfo_section_accessor_template( S* section )
        : modinfo_section( section )
    {
        process_section();
    }

    //------------------------------------------------------------------------------
    /**
     * @brief Get the number of attributes.
     * 
     * @return Elf_Word The number of attributes.
     */
    Elf_Word get_attribute_num() const { return (Elf_Word)content.size(); }

    //------------------------------------------------------------------------------
    /**
     * @brief Get the attribute by index.
     * 
     * @param no The index of the attribute.
     * @param field The field name of the attribute.
     * @param value The value of the attribute.
     * @return true If the attribute is found.
     * @return false If the attribute is not found.
     */
    bool
    get_attribute( Elf_Word no, std::string& field, std::string& value ) const
    {
        if ( no < content.size() ) {
            field = content[no].first;
            value = content[no].second;
            return true;
        }

        return false;
    }

    //------------------------------------------------------------------------------
    /**
     * @brief Get the attribute by field name.
     * 
     * @param field_name The field name of the attribute.
     * @param value The value of the attribute.
     * @return true If the attribute is found.
     * @return false If the attribute is not found.
     */
    bool get_attribute( const std::string_view& field_name,
                        std::string&            value ) const
    {
        for ( const auto& [first, second] : content ) {
            if ( field_name == first ) {
                value = second;
                return true;
            }
        }

        return false;
    }

    //------------------------------------------------------------------------------
    /**
     * @brief Add a new attribute.
     * 
     * @param field The field name of the attribute.
     * @param value The value of the attribute.
     * @return Elf_Word The position of the new attribute.
     */
    Elf_Word add_attribute( const std::string& field, const std::string& value )
    {
        Elf_Word current_position = 0;

        if ( modinfo_section ) {
            // Strings are addeded to the end of the current section data
            current_position = (Elf_Word)modinfo_section->get_size();

            std::string attribute = field + "=" + value;

            modinfo_section->append_data( attribute + '\0' );
            content.emplace_back( field, value );
        }

        return current_position;
    }

    //------------------------------------------------------------------------------
  private:
    /**
     * @brief Process the section to extract attributes.
     */
    void process_section()
    {
        const char* pdata = modinfo_section->get_data();
        if ( pdata ) {
            ELFIO::Elf_Xword i = 0;
            while ( i < modinfo_section->get_size() ) {
                while ( i < modinfo_section->get_size() && !pdata[i] )
                    i++;
                if ( i < modinfo_section->get_size() ) {
                    std::string info = pdata + i;
                    size_t      loc  = info.find( '=' );
                    content.emplace_back( info.substr( 0, loc ),
                                          info.substr( loc + 1 ) );

                    i += info.length();
                }
            }
        }
    }

    //------------------------------------------------------------------------------
  private:
    S* modinfo_section; ///< The section to be accessed.
    std::vector<std::pair<std::string, std::string>>
        content; ///< The list of attributes.
};

using modinfo_section_accessor = modinfo_section_accessor_template<section>;
using const_modinfo_section_accessor =
    modinfo_section_accessor_template<const section>;

} // namespace ELFIO

#endif // ELFIO_MODINFO_HPP