//
// System.Web.SessionState.SessionId
//
// Author(s):
// Jackson Harper (jackson@ximian.com)
//
// Copyright (C) 2003,2006 Novell, Inc (http://www.novell.com)
//
// 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.Text;
using System.Security.Cryptography;
namespace System.Web.SessionState{
internal class SessionId {
static char [] allowed = { '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', 'A', 'B',
'C', 'D', 'E', 'F' };
internal const int IdLength = 24;
const int half_len = IdLength / 2;
static RandomNumberGenerator rng = RandomNumberGenerator.Create ();
internal static string Create ()
{
byte[] key = new byte [half_len];
lock (rng) {
rng.GetBytes (key);
}
return Encode (key);
}
internal static string Encode (byte[] key)
{
if (key == null)
throw new ArgumentNullException ("key");
if (key.Length != half_len)
throw new ArgumentException (String.Concat ("key must be ", half_len.ToString (), " bytes long."));
// Just a standard hex conversion
char[] res = new char [IdLength];
for (int i=0; i < half_len; i++) {
int b = key [i];
res [i * 2] = allowed [b >> 4];
res [(i * 2) + 1] = allowed [b & 0xF];
}
return new String (res);
}
#if !NET_2_0
internal static string Lookup (HttpRequest request, bool cookieless)
{
if (cookieless)
return (string) request.Headers [SessionStateModule.HeaderName];
HttpCookie cookie = request.Cookies [SessionStateModule.CookieName];
if (cookie == null)
return null;
return cookie.Value;
}
#endif
}
}
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