Convert an integer to a string IP address

IPIntegerToString.cs

// Follow up of the discussion https://twitter.com/stebets/status/739563007202758656

public static unsafe string IntegerToIPAddress(uint input)
{
	var text = stackalloc char[15];
	var ptext = text + 15;
	for (int i = 0; i < 4; i++)
	{
		if (i > 0)
		{
			*--ptext = '.';
		}
		var value = input & 0xFF;
		input = input >> 8;
		var index = value >= 100 ? 2 : value >= 10 ? 1 : 0;
		while (index >= 0)
		{
			*--ptext = (char)('0' + (value % 10));
			value = value / 10;
			index--;
		}
	}
	return new string(ptext, 0, 15 - (int)(ptext - text));
}

//                   Method |      Median |    StdDev |    Gen 0 | Gen 1 | Gen 2 | Bytes Allocated/Op |
// ------------------------ |------------ |---------- |--------- |------ |------ |------------------- |
//  BenchIP2LocationHelper7 | 181.6422 ns | 2.3263 ns | 1,222.71 |     - |     - |              60.24 |
//    BenchIP2Locationxoofx |  95.9410 ns | 0.7456 ns |   278.00 |     - |     - |              14.06 |