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//
// System.Net.IPv6AddressFormatter.cs
//
// Author:
// Lawrence Pit (loz@cable.a2000.nl)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Globalization;
using System.Text;
namespace System.Net {
struct IPv6AddressFormatter
{
ushort [] address;
long scopeId;
public IPv6AddressFormatter (ushort[] addr, long scopeId)
{
this.address = addr;
this.scopeId = scopeId;
}
static ushort SwapUShort (ushort number)
{
return (ushort) ( ((number >> 8) & 0xFF) + ((number << 8) & 0xFF00) );
}
// Convert the address into a format expected by the IPAddress (long) ctor
// This needs to be unsigned to satisfy the '> 1' test in IsIPv4Compatible()
uint AsIPv4Int ()
{
return (uint)(SwapUShort (address [7]) << 16) + SwapUShort (address [6]);
}
bool IsIPv4Compatible ()
{
for (int i = 0; i < 6; i++)
if (address [i] != 0)
return false;
/* MS .net only seems to format the last 4
* bytes as an IPv4 address if address[6] is
* non-zero
*/
if (address[6] == 0)
return false;
return (AsIPv4Int () > 1);
}
bool IsIPv4Mapped ()
{
for (int i = 0; i < 5; i++)
if (address [i] != 0)
return false;
/* MS .net only seems to format the last 4
* bytes as an IPv4 address if address[6] is
* non-zero
*/
if (address[6] == 0)
return false;
return address [5] == 0xffff;
}
public override string ToString ()
{
StringBuilder s = new StringBuilder ();
if(IsIPv4Compatible() || IsIPv4Mapped())
{
s.Append("::");
if(IsIPv4Mapped())
s.Append("ffff:");
s.Append(new IPAddress( AsIPv4Int ()).ToString ());
return s.ToString ();
}
int bestChStart = -1; // Best chain start
int bestChLen = 0; // Best chain length
int currChLen = 0; // Current chain length
// Looks for the longest zero chain
for (int i=0; i<8; i++)
{
if (address[i] != 0)
{
if ((currChLen > bestChLen)
&& (currChLen > 1))
{
bestChLen = currChLen;
bestChStart = i - currChLen;
}
currChLen = 0;
}
else
currChLen++;
}
if ((currChLen > bestChLen)
&& (currChLen > 1))
{
bestChLen = currChLen;
bestChStart = 8 - currChLen;
}
// makes the string
if (bestChStart == 0)
s.Append(":");
for (int i=0; i<8; i++)
{
if (i == bestChStart)
{
s.Append (":");
i += (bestChLen - 1);
continue;
}
s.AppendFormat("{0:x}", address [i]);
if (i < 7) s.Append (':');
}
if (scopeId != 0)
s.Append ('%').Append (scopeId);
return s.ToString ();
}
}
}
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