StringUtil.cpp

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* ANTIKERNEL                                                                                                           *
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* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
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/**
	@file
	@author Frederic BORRY
	@brief Implementation of string utility functions
 */
#include "StringUtil.h"

#include <string>
#include <cwchar>
#include <clocale>
#include <cstdlib>

#ifdef _WIN32
#include <locale.h>
#endif

static void EnsureUtf8LocaleForCurrentThread()
{
#ifdef _WIN32
    static thread_local bool initialized = false;

    if (!initialized)
    {
        _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
        std::setlocale(LC_CTYPE, ".UTF-8");
        initialized = true;
    }
#else
    static bool initialized = false;

    if (!initialized)
    {
        std::setlocale(LC_CTYPE, "");
        initialized = true;
    }
#endif
}

/**
 * @brief Convert a std::wstring into an std::string
 * @param wstr the wstring to convert
 * @return the converted string
 */
std::string WstringToString(const std::wstring &wstr)
{
    EnsureUtf8LocaleForCurrentThread();

	std::mbstate_t state{};
	const wchar_t* src = wstr.c_str();
	std::size_t len = std::wcsrtombs(nullptr, &src, 0, &state);

	if (len == static_cast<std::size_t>(-1))
	return "Invalid wide-character string or invalid locale";

	std::string result(len, '\0');
	state = std::mbstate_t{};
	src = wstr.c_str();
	std::size_t converted = std::wcsrtombs(result.data(), &src, result.size(), &state);

	if (converted == static_cast<std::size_t>(-1))
	return "Wstring to string conversion failed";

	return result;
}

/**
 * @brief Convert a std::string into an std::wstring
 * @param wstr the string to convert
 * @return the converted wstring
 */
std::wstring StringToWstring(const std::string &str)
{
    EnsureUtf8LocaleForCurrentThread();

    std::mbstate_t state{};
    const char* src = str.c_str();
    std::size_t len = std::mbsrtowcs(nullptr, &src, 0, &state);

	if (len == static_cast<std::size_t>(-1))
        return L"Invalid UTF-8 string or invalid locale";

    std::wstring result(len, L'\0');
    state = std::mbstate_t{};
    src = str.c_str();
    std::size_t converted = std::mbsrtowcs(result.data(), &src, result.size(), &state);

    if (converted == static_cast<std::size_t>(-1))
        return L"String to wstring conversion failed";

    return result;
}