namespace System.Net
{
	/// <summary>
	/// Provides extension methods for <see cref="IPAddress"/>es.
	/// </summary>
	public static class IPAddressExtensions
	{
		/// <summary>
		/// Increments the <see cref="IPAddress"/> by one and returns a new instance.
		/// </summary>
		/// <param name="address">The <see cref="IPAddress"/> to increment.</param>
		public static IPAddress Increment(this IPAddress address)
		{
			byte[] bytes = address.GetAddressBytes();
			int bytePos = bytes.Length - 1;

			while (bytes[bytePos] == byte.MaxValue)
			{
				bytes[bytePos] = 0;
				bytePos--;

				if (bytePos < 0)
					return new IPAddress(bytes);
			}
			bytes[bytePos]++;

			return new IPAddress(bytes);
		}

		/// <summary>
		/// Decrements the <see cref="IPAddress"/> by one and returns a new instance.
		/// </summary>
		/// <param name="address">The <see cref="IPAddress"/> to decrement.</param>
		public static IPAddress Decrement(this IPAddress address)
		{
			byte[] bytes = address.GetAddressBytes();
			int bytePos = bytes.Length - 1;

			while (bytes[bytePos] == 0)
			{
				bytes[bytePos] = byte.MaxValue;
				bytePos--;

				if (bytePos < 0)
					return new IPAddress(bytes);
			}
			bytes[bytePos]--;

			return new IPAddress(bytes);
		}
	}
}