How to convert an Ip Address Instance[generateed by using IPAddress.Parse method] back to a IP string

Swapnasagar Panda

How to convert an Ip Address Instance[generateed by using IPAddress.Parse method] back to a IP string.

Observation:--
The ToString() method is not working..

6 Replies

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Vulpes14y ago
Well, I don't see how you can use IPAddress if it's behaving differently in OS's.

However, it's not difficult to change my latest code so that it now deals with abbreviated addresses - it still prints them out in expanded form but I imagine that's not a problem:

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;

class Program
{
static void Main()
{
string address1 = "2001:0db8:85a3::8a2e:0370:7334";
string address2 = "2001:0db8:85a3::8a2e:0370:7383";
List pool = GetIPv6AddressBlock(address1, address2);
foreach(string address in pool) Console.WriteLine(address);
Console.ReadKey();
}

static List GetIPv6AddressBlock(string from, string to)
{
List addresses = new List();

ushort[] words1 = GetAddressWords(from);
ushort[] words2 = GetAddressWords(to);

addresses.Add(ToAddress(words1));

while(!AreEqual(words1, words2))
{
AddOne(words1);
addresses.Add(ToAddress(words1));
}
return addresses;
}

static void AddOne(ushort[] words)
{
for(int i = words.Length - 1; i >= 0; i--)
{
if (words[i] < 65535)
{
words[i]++;
return;
}

words[i] = 0;
}

}

static bool AreEqual(ushort[] words1, ushort[] words2)
{
if (words1.Length != words2.Length) return false;

for(int i = 0; i < words1.Length; i++)
{
if (words1[i] != words2[i]) return false;
}

return true;
}

static ushort[] GetAddressWords(string address)
{
int index = address.IndexOf("::");

if (index > -1)
{
int count = 0;
foreach(char c in address)
{
if (c == ':') count++;
}
int number = 9 - count;

if (index == 0)
{
address = address.Replace("::", Repeat("0000:", number));
}
else if(index == address.Length - 2)
{
address = address.Replace("::", Repeat(":0000", number));
}
else
{
address = address.Replace("::", Repeat(":0000", number - 1) + ":");
}
}

string[] wordStrs = address.Split(':');
ushort[] words = new ushort[8];

for(int i = 0; i < 8; i++)
{
words[i] = Convert.ToUInt16(wordStrs[i], 16);
}

return words;
}

static string ToAddress(ushort[] words)
{
string[] wordStrs = new string[8];

for(int i = 0; i < 8; i++)
{
wordStrs[i] = words[i].ToString("x4");
}

return String.Join(":", wordStrs);
}

static string Repeat(string s, int number)
{
StringBuilder sb = new StringBuilder();
int count = 0;

while (count < number)
{
sb.Append(s);
count++;
}

return sb.ToString();
}
}
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Swapnasagar Panda14y ago
I checked your code, that is working only if the IP is this following format:-- "2001:0db8:85a3:0000:0000:8a2e:0370:7334"..

But the same IP i can write like 2001:0db8:85a3::8a2e:0370:7334

And the code fail in this case, as u r spliting : only. So the first approach is the better approach as that is a more generalised way. Apart from the O.S problem. Actually i chked the diff. also. The IPAddress.Parse() methos is behaving diff. for both the OS. Please suggest if any.

Thanx
Swapnasagar
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Vulpes14y ago
The code in my latest post to your previous thread:

http://www.c-sharpcorner.com/forums/thread/182052/generating-the-next-value-of-a-valid-ipv6-format-ip-add.aspx

should work under any OS because I'm not using the IPAddress class at all.
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Swapnasagar Panda14y ago
yes vulpes,
U r absolutely right. I checked in windows 7 O.S and found that the code is working properly.But can u suggest me any way, so that it ll work in every O.S.
Thanks a lot for ur help till now. Please suggest any alternative.
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Swapnasagar Panda14y ago
Hi,
I am using .net framework 4.0 , but os is windows xp sp3. So is there any problem with it, because in the ipv6 generation code what u ve given , there i am not getting this desired o/p.my last 32 bits are coming as ipv4 format.
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Vulpes14y ago
As mentioned in your other thread about IPv6 addresses, I'm not seeing any problem here.

If I run this code:

string address = "2001:0db8:85a3:0000:0000:8a2e:0370:7334";
IPAddress ipa = IPAddress.Parse(address);
string ipaStr = ipa.ToString();
Console.WriteLine(ipaStr);

then the output is:

2001:db8:85a3::8a2e:370:7334

Whilst leading zeros and the 0000's have been been removed in the standard way, this is exactly the same address.

If you're seeing something different, then it could conceivably be an OS or .NET version problem. I'm using Windows 7 and .NET 4.0.
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