iteration_parameter_formatter.h

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/*
 * Copyright 2022 MusicScience37 (Kenta Kabashima)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#pragma once
 
#include <iterator>
#include <optional>
#include <string_view>
 
#include <fmt/base.h>
#include <fmt/format.h>
 
#include "num_collect/base/concepts/formattable.h"
#include "num_collect/base/exception.h"
#include "num_collect/base/index_type.h"
#include "num_collect/logging/concepts/formattable_iteration_parameter_value.h"  // IWYU pragma: keep
#include "num_collect/logging/concepts/formattable_real_scalar.h"
#include "num_collect/logging/iterations/iteration_parameter_formatter_decl.h"
 
namespace num_collect::logging::iterations {
 
namespace impl {
 
constexpr index_type iteration_parameter_formatter_default_precision = 4;
 
}  // namespace impl
 
template <base::concepts::formattable Value>
class iteration_parameter_formatter<Value> {
public:
    iteration_parameter_formatter() noexcept = default;
 
    void format(const Value& value, fmt::memory_buffer& buffer) const {
        fmt::format_to(std::back_inserter(buffer), "{0}", value);
    }
 
    void format_with_alignment(const Value& value, index_type width,
        fmt::memory_buffer& buffer) const {
        fmt::format_to(std::back_inserter(buffer), "{0: >{1}}", value, width);
    }
};
 
template <concepts::formattable_real_scalar Value>
class iteration_parameter_formatter<Value> {
public:
    iteration_parameter_formatter() noexcept = default;
 
    void format(const Value& value, fmt::memory_buffer& buffer) const {
        fmt::format_to(
            std::back_inserter(buffer), "{0:.{1}}", value, precision_);
    }
 
    void format_with_alignment(const Value& value, index_type width,
        fmt::memory_buffer& buffer) const {
        fmt::format_to(std::back_inserter(buffer), "{0: >{1}.{2}}", value,
            width, precision_);
    }
 
    auto precision(index_type value) -> iteration_parameter_formatter& {
        if (value <= 0) [[unlikely]] {
            throw invalid_argument("Precision must be a positive number.");
        }
        precision_ = value;
        return *this;
    }
 
    [[nodiscard]] auto precision() const -> index_type { return precision_; }
 
private:
    index_type precision_{
        impl::iteration_parameter_formatter_default_precision};
};
 
template <concepts::formattable_iteration_parameter_value Value>
class iteration_parameter_formatter<std::optional<Value>>
    : public iteration_parameter_formatter<Value> {
public:
    iteration_parameter_formatter() noexcept = default;
 
    void format(
        const std::optional<Value>& value, fmt::memory_buffer& buffer) const {
        if (value) {
            iteration_parameter_formatter<Value>::format(*value, buffer);
        } else {
            buffer.append(null_string);
        }
    }
 
    void format_with_alignment(const std::optional<Value>& value,
        index_type width, fmt::memory_buffer& buffer) const {
        if (value) {
            iteration_parameter_formatter<Value>::format_with_alignment(
                *value, width, buffer);
        } else {
            fmt::format_to(
                std::back_inserter(buffer), "{0: >{1}}", null_string, width);
        }
    }
 
private:
    static constexpr std::string_view null_string{"null"};
};
 
}  // namespace num_collect::logging::iterations