libcruft-util/cruft/util/stats.hpp

/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Copyright 2010 Danny Robson <danny@nerdcruft.net>
 */

#pragma once

#include <iosfwd>
#include <fmt/core.h>


namespace cruft {
    namespace stats {
        // Undefined until at least one value has been added.

        template <typename T>
        struct accumulator {
            accumulator ();

            void reset (void);

            void add (T);
            void add (const accumulator<T> &);

            size_t count;

            T min;
            T max;
            T sum;

            T range (void) const;
            T mean  (void) const;
        };

        template <typename T>
        std::ostream&
        operator<< (std::ostream&, const accumulator<T>&);
    }
}


template <typename T>
struct fmt::formatter<cruft::stats::accumulator<T>> {
    constexpr format_parse_context::iterator
    parse (format_parse_context &ctx)
    {
        return ctx.begin ();
    }

    format_context::iterator
    format (cruft::stats::accumulator<T> const&, format_context &ctx) const;
};