if (fullCheck)
    {
        path = path.TrimEnd(Path.TrimEndChars);
        Path.CheckInvalidPathChars(path);
    }
    int i = 0;
    PathHelper pathHelper = null;
    if (path.Length <= Path.MaxPath)
    {
        char* charArrayPtr = stackalloc char[(UIntPtr)Path.MaxPath];
        pathHelper = new PathHelper(charArrayPtr, Path.MaxPath);
    }
    else
    {
        pathHelper = new PathHelper(path.Length + Path.MaxPath, maxPathLength);
    }
    uint num = 0u;
    uint num2 = 0u;
    bool flag = false;
    uint num3 = 0u;
    int num4 = -1;
    bool flag2 = false;
    bool flag3 = true;
    bool flag4 = false;
    int num5 = 0;
    if (path.Length > 0 && (path[0] == Path.DirectorySeparatorChar || path[0] == Path.AltDirectorySeparatorChar))
    {
        pathHelper.Append('\\');
        i++;
        num4 = 0;
    }
    while (i < path.Length)
    {
        char c = path[i];
        if (c == Path.DirectorySeparatorChar || c == Path.AltDirectorySeparatorChar)
        {
            if (num3 == 0u)
            {
                if (num2 > 0u)
                {
                    int num6 = num4 + 1;
                    if (path[num6] != '.')
                    {
                        throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                    }
                    if (num2 >= 2u)
                    {
                        if (flag2 && num2 > 2u)
                        {
                            throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                        }
                        if (path[num6 + 1] == '.')
                        {
                            int num7 = num6 + 2;
                            while ((long)num7 < (long)num6 + (long)((ulong)num2))
                            {
                                if (path[num7] != '.')
                                {
                                    throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                                }
                                num7++;
                            }
                            num2 = 2u;
                        }
                        else
                        {
                            if (num2 > 1u)
                            {
                                throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                            }
                            num2 = 1u;
                        }
                    }
                    if (num2 == 2u)
                    {
                        pathHelper.Append('.');
                    }
                    pathHelper.Append('.');
                    flag = false;
                }
                if (num > 0u && flag3 && i + 1 < path.Length && (path[i + 1] == Path.DirectorySeparatorChar || path[i + 1] == Path.AltDirectorySeparatorChar))
                {
                    pathHelper.Append(Path.DirectorySeparatorChar);
                }
            }
            num2 = 0u;
            num = 0u;
            if (!flag)
            {
                flag = true;
                pathHelper.Append(Path.DirectorySeparatorChar);
            }
            num3 = 0u;
            num4 = i;
            flag2 = false;
            flag3 = false;
            if (flag4)
            {
                pathHelper.TryExpandShortFileName();
                flag4 = false;
            }
            int num8 = pathHelper.Length - 1;
            if (num8 - num5 > Path.MaxDirectoryLength)
            {
                throw new PathTooLongException(Environment.GetResourceString("IO.PathTooLong"));
            }
            num5 = num8;
        }
        else
        {
            if (c == '.')
            {
                num2 += 1u;
            }
            else
            {
                if (c == ' ')
                {
                    num += 1u;
                }
                else
                {
                    if (c == '~')
                    {
                        flag4 = true;
                    }
                    flag = false;
                    if (flag3 && c == Path.VolumeSeparatorChar)
                    {
                        char c2 = (i > 0) ? path[i - 1] : ' ';
                        if (num2 != 0u || num3 < 1u || c2 == ' ')
                        {
                            throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                        }
                        flag2 = true;
                        if (num3 > 1u)
                        {
                            int num9 = 0;
                            while (num9 < pathHelper.Length && pathHelper[num9] == ' ')
                            {
                                num9++;
                            }
                            if ((ulong)num3 - (ulong)((long)num9) == 1uL)
                            {
                                pathHelper.Length = 0;
                                pathHelper.Append(c2);
                            }
                        }
                        num3 = 0u;
                    }
                    else
                    {
                        num3 += 1u + num2 + num;
                    }
                    if (num2 > 0u || num > 0u)
                    {
                        int num10 = (num4 >= 0) ? (i - num4 - 1) : i;
                        if (num10 > 0)
                        {
                            for (int j = 0; j < num10; j++)
                            {
                                pathHelper.Append(path[num4 + 1 + j]);
                            }
                        }
                        num2 = 0u;
                        num = 0u;
                    }
                    pathHelper.Append(c);
                    num4 = i;
                }
            }
        }
        i++;
    }
    if (pathHelper.Length - 1 - num5 > Path.MaxDirectoryLength)
    {
        throw new PathTooLongException(Environment.GetResourceString("IO.PathTooLong"));
    }
    if (num3 == 0u && num2 > 0u)
    {
        int num11 = num4 + 1;
        if (path[num11] != '.')
        {
            throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
        }
        if (num2 >= 2u)
        {
            if (flag2 && num2 > 2u)
            {
                throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
            }
            if (path[num11 + 1] == '.')
            {
                int num12 = num11 + 2;
                while ((long)num12 < (long)num11 + (long)((ulong)num2))
                {
                    if (path[num12] != '.')
                    {
                        throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                    }
                    num12++;
                }
                num2 = 2u;
            }
            else
            {
                if (num2 > 1u)
                {
                    throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
                }
                num2 = 1u;
            }
        }
        if (num2 == 2u)
        {
            pathHelper.Append('.');
        }
        pathHelper.Append('.');
    }
    if (pathHelper.Length == 0)
    {
        throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegal"));
    }
    if (fullCheck && (pathHelper.OrdinalStartsWith("http:", false) || pathHelper.OrdinalStartsWith("file:", false)))
    {
        throw new ArgumentException(Environment.GetResourceString("Argument_PathUriFormatNotSupported"));
    }
    if (flag4)
    {
        pathHelper.TryExpandShortFileName();
    }
    int num13 = 1;
    if (fullCheck)
    {
        num13 = pathHelper.GetFullPathName();
        flag4 = false;
        int num14 = 0;
        while (num14 < pathHelper.Length && !flag4)
        {
            if (pathHelper[num14] == '~')
            {
                flag4 = true;
            }
            num14++;
        }
        if (flag4 && !pathHelper.TryExpandShortFileName())
        {
            int num15 = -1;
            for (int k = pathHelper.Length - 1; k >= 0; k--)
            {
                if (pathHelper[k] == Path.DirectorySeparatorChar)
                {
                    num15 = k;
                    break;
                }
            }
            if (num15 >= 0)
            {
                if (pathHelper.Length >= maxPathLength)
                {
                    throw new PathTooLongException(Environment.GetResourceString("IO.PathTooLong"));
                }
                int lenSavedName = pathHelper.Length - num15 - 1;
                pathHelper.Fixup(lenSavedName, num15);
            }
        }
    }
    if (num13 != 0 && pathHelper.Length > 1 && pathHelper[0] == '\\' && pathHelper[1] == '\\')
    {
        int l;
        for (l = 2; l < num13; l++)
        {
            if (pathHelper[l] == '\\')
            {
                l++;
                break;
            }
        }
        if (l == num13)
        {
            throw new ArgumentException(Environment.GetResourceString("Arg_PathIllegalUNC"));
        }
        if (pathHelper.OrdinalStartsWith("\\\\?\\globalroot", true))
        {
            throw new ArgumentException(Environment.GetResourceString("Arg_PathGlobalRoot"));
        }
    }
    if (pathHelper.Length >= maxPathLength)
    {
        throw new PathTooLongException(Environment.GetResourceString("IO.PathTooLong"));
    }
    if (num13 == 0)
    {
        int num16 = Marshal.GetLastWin32Error();
        if (num16 == 0)
        {
            num16 = 161;
        }
        __Error.WinIOError(num16, path);
        return null;
    }
    string text = pathHelper.ToString();
    if (string.Equals(text, path, StringComparison.Ordinal))
    {
        text = path;
    }
    return text;