String manipulation helper methods.

StringHelperUtil.cs

/// <summary>
///     String manipulation helper methods.
/// </summary>
internal static class StringHelperUtil
{
    /// <summary>
    ///     Converts an array of <see cref="string" /> into a double-null-terminated multi-byte character memory block.
    /// </summary>
    /// <param name="instances">Source array of strings.</param>
    /// <param name="length">The length of the resulting byte array.</param>
    /// <returns>The allocated memory buffer.</returns>
    public static IntPtr StringArrayToMultiSzPointer(this IEnumerable<string> instances, out int length)
    {
        // Temporary byte array
        IEnumerable<byte> multiSz = new List<byte>();

        // Convert each string into wide multi-byte and add NULL-terminator in between
        multiSz = instances.Aggregate(multiSz,
            (current, entry) => current.Concat(Encoding.Unicode.GetBytes(entry))
                .Concat(Encoding.Unicode.GetBytes(new[] {char.MinValue})));

        // Add another NULL-terminator to signal end of the list
        multiSz = multiSz.Concat(Encoding.Unicode.GetBytes(new[] {char.MinValue}));

        // Convert expression to array
        var multiSzArray = multiSz.ToArray();

        // Convert array to managed native buffer
        var buffer = Marshal.AllocHGlobal(multiSzArray.Length);
        Marshal.Copy(multiSzArray, 0, buffer, multiSzArray.Length);

        length = multiSzArray.Length;

        // Return usable buffer, don't forget to free!
        return buffer;
    }

    /// <summary>
    ///     Converts a double-null-terminated multi-byte character memory block into a string array.
    /// </summary>
    /// <param name="buffer">The memory buffer.</param>
    /// <param name="length">The size in bytes of the memory buffer.</param>
    /// <returns>The extracted string array.</returns>
    public static IEnumerable<string> MultiSzPointerToStringArray(this IntPtr buffer, int length)
    {
        // Temporary byte array
        var rawBuffer = new byte[length];

        // Grab data from buffer
        Marshal.Copy(buffer, rawBuffer, 0, length);

        // Trims away potential redundant NULL-characters and splits at NULL-terminator
        return Encoding.Unicode.GetString(rawBuffer).TrimEnd(char.MinValue).Split(char.MinValue);
    }
}