IoHelper.h

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/*
 * IoHelper.h - helper functions for file I/O
 *
 * Copyright (c) 2018 Hyunjin Song <tteu.ingog/at/gmail.com>
 *
 * This file is part of LMMS - https://lmms.io
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
// NOTE: The LMMS/zynaddsubfx repo contains a copy of this header.
//       If you modify this file, consider modifying it there as well.
 
#ifndef LMMS_IO_HELPER_H
#define LMMS_IO_HELPER_H
 
#include <cstdio>
#include <limits>
#include <memory>
#include <stdexcept>
#include <string>
#include <string_view>
 
#ifdef _WIN32
#   ifndef NOMINMAX
#       define NOMINMAX
#   endif
#   include <windows.h>
#endif
 
#if defined(_WIN32) && !defined(__WINE__)
#   include <io.h>
#elif __has_include(<unistd.h>)
#   include <unistd.h>
#endif
 
namespace lmms
{
 
 
#ifdef _WIN32

inline std::unique_ptr<wchar_t[]> toWString(std::string_view utf8)
{
    std::unique_ptr<wchar_t[]> ret;
    if (utf8.empty())
    {
        ret = std::make_unique<wchar_t[]>(1);
        return ret;
    }
 
    if (utf8.length() > static_cast<std::size_t>(std::numeric_limits<int>::max()))
    {
        throw std::overflow_error{"toWString: input string is too long"};
    }
    const auto utf8Len = static_cast<int>(utf8.length());
 
    int result = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8.data(), utf8Len, nullptr, 0);
    if (result <= 0)
    {
        const DWORD error = ::GetLastError();
        throw std::invalid_argument{"toWString: failed to get size of result string. error code: " + std::to_string(error)};
    }
 
    ret = std::make_unique<wchar_t[]>(result + 1); // includes null terminator
    result = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, utf8.data(), utf8Len, ret.get(), result);
    if (result <= 0)
    {
        const DWORD error = ::GetLastError();
        throw std::invalid_argument{"toWString: failed to convert. error code: " + std::to_string(error)};
    }
 
    return ret;
}
 
#endif // _WIN32

inline std::FILE* fopenUtf8(const std::string& filename, const char* mode)
{
#if defined(_WIN32) && !defined(__WINE__)
    return _wfopen(toWString(filename).get(), toWString(mode).get());
#else
    return std::fopen(filename.c_str(), mode);
#endif
}

inline int fileToDescriptor(std::FILE* file, bool closeFile = true)
{
    if (file == nullptr) { return -1; }
 
#if defined(_WIN32) && !defined(__WINE__)
    int fh = _dup(_fileno(file));
#else
    int fh = dup(fileno(file));
#endif
 
    if (closeFile) { std::fclose(file); }
    return fh;
}
 
 
} // namespace lmms
 
#endif // LMMS_IO_HELPER_H