names_values.hpp

#include <sstream>
#include <string>

namespace witherspoon
{
namespace power
{
namespace util
{

/**
 * @class NamesValues
 *
 * Builds up a string of name=value pairs for use in
 * situations like error log metadata.
 *
 * Names and values can be added to an instance of this
 * class, and then calling get() will return a string
 * that appends them all together.
 *
 * Currently, just uint64_t values that will be displayed
 * in hex are supported.
 *
 * For example:
 *     NamesValues m;
 *     uint8_t d = 0xFF;
 *
 *     m.add("STATUS_VOUT", d);
 *     m.add("STATUS_WORD", 0xABCD);
 *
 *     m.get() //returns: "STATUS_VOUT=0xFF|STATUS_WORD=0xABCD"
 */
class NamesValues
{
    public:

        NamesValues() = default;
        NamesValues(const NamesValues&) = default;
        NamesValues& operator=(const NamesValues&) = default;
        NamesValues(NamesValues&&) = default;
        NamesValues& operator=(NamesValues&&) = default;

        /**
         * Adds a name/value pair to the object
         *
         * @param name - the name to add
         * @param value - the value to add
         */
        void add(const std::string& name, uint64_t value)
        {
            addDivider();
            addName(name);
            addValue(value);
        }

        /**
         * Returns a formatted concatenation of all of the names and
         * their values.
         *
         * @return string - "<name1>=<value1>|<name2>=<value2>..etc"
         */
        const std::string& get() const
        {
            return all;
        }

    private:

        /**
         * Adds a name to the object
         *
         * @param name - the name to add
         */
        void addName(const std::string& name)
        {
            all += name + '=';
        }

        /**
         * Adds a value to the object
         *
         * @param value - the value to add
         */
        void addValue(uint64_t value)
        {
            std::ostringstream stream;
            stream << "0x" << std::hex << value;
            all += stream.str();
        }

        /**
         * Adds a divider to the summary string to
         * break up the name/value pairs
         */
        void addDivider()
        {
           if (!all.empty())
           {
                all += '|';
           }
        }

        /**
         * The string containing all name/value pairs
         */
        std::string all;
};

}
}
}