101 lines
4.3 KiB
C++
101 lines
4.3 KiB
C++
#pragma once
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#include "../string/reinterpret.hpp"
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#include <string>
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#include <array>
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#include <type_traits>
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#include <charconv>
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#include <stdexcept>
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#define NS_YYCC_STRING_REINTERPRET ::yycc::string::reinterpret
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/**
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* @brief Provides stringify utilities for converting numeric and boolean values to strings.
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* @details
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* This namespace contains functions for stringifying various numeric types (integer, floating point)
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* and boolean values into string. It uses \c std::to_chars internally for efficient stringify.
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* @remarks
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* See https://en.cppreference.com/w/cpp/utility/to_chars for underlying called functions.
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* Default float precision = 6 is gotten from: https://en.cppreference.com/w/c/io/fprintf
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*/
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namespace yycc::num::stringify {
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/// @private
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/// @brief Size of the internal buffer used for string conversion.
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inline constexpr size_t STRINGIFY_BUFFER_SIZE = 64u;
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/// @private
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/// @brief Type alias for the buffer used in string conversion.
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using StringifyBuffer = std::array<char8_t, STRINGIFY_BUFFER_SIZE>;
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/**
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* @brief Return the string representation of given floating point value.
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* @tparam T The type derived from floating point type.
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* @param[in] num The value need to get string representation.
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* @param[in] fmt The floating point format used when getting string representation.
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* @param[in] precision The floating point precision used when getting string representation.
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* @return The string representation of given value.
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*/
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template<typename T>
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requires(std::is_floating_point_v<T>)
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std::u8string stringify(T num, std::chars_format fmt = std::chars_format::general, int precision = 6) {
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namespace reinterpret = NS_YYCC_STRING_REINTERPRET;
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StringifyBuffer buffer;
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auto [ptr, ec] = std::to_chars(reinterpret::as_ordinary(buffer.data()),
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reinterpret::as_ordinary(buffer.data() + buffer.size()),
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num,
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fmt,
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precision);
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if (ec == std::errc()) {
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return std::u8string(buffer.data(), reinterpret::as_utf8(ptr) - buffer.data());
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} else if (ec == std::errc::value_too_large) {
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// Too short buffer. This should not happen.
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throw std::out_of_range("stringify() buffer is not sufficient.");
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} else {
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// Unreachable
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throw std::runtime_error("unreachable code.");
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}
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}
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/**
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* @brief Return the string representation of given integral value.
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* @tparam T The type derived from integral type except bool type.
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* @param[in] num The value need to get string representation.
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* @param[in] base Integer base used when getting string representation: a value between 2 and 36 (inclusive).
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* @return The string representation of given value.
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*/
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template<typename T>
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requires(std::is_integral_v<T> && !std::is_same_v<T, bool>)
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std::u8string stringify(T num, int base = 10) {
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namespace reinterpret = NS_YYCC_STRING_REINTERPRET;
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StringifyBuffer buffer;
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auto [ptr, ec] = std::to_chars(reinterpret::as_ordinary(buffer.data()),
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reinterpret::as_ordinary(buffer.data() + buffer.size()),
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num,
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base);
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if (ec == std::errc()) {
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return std::u8string(buffer.data(), reinterpret::as_utf8(ptr) - buffer.data());
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} else if (ec == std::errc::value_too_large) {
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// Too short buffer. This should not happen.
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throw std::out_of_range("stringify() buffer is not sufficient.");
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} else {
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// Unreachable
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throw std::runtime_error("unreachable code.");
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}
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}
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/**
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* @brief Return the string representation of given bool value.
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* @tparam T The type derived from bool type.
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* @param[in] num The value need to get string representation.
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* @return The string representation of given value ("true" or "false").
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*/
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template<typename T>
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requires(std::is_same_v<T, bool>)
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std::u8string stringify(T num) {
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if (num) return std::u8string(u8"true");
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else return std::u8string(u8"false");
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}
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} // namespace yycc::num::stringify
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#undef NS_YYCC_STRING_REINTERPRET
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