Import lwIP contrib rep

... from http://git.savannah.gnu.org/cgit/lwip/lwip-contrib.git/ into contrib/ subdir, STABLE-2_1_0_RELEASE tag
lwIP contrib is now officially frozen
TODO: Fix build

contrib/apps/LwipMibCompiler/SharpSnmpLib/Mib/SymbolList.cs

@@ -0,0 +1,146 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Lextm.SharpSnmpLib.Mib
+{
+    public class SymbolList : List<Symbol>
+    {
+        public class SymbolEnumerator : ISymbolEnumerator
+        {
+            private SymbolList _list  = null;
+            private int        _index = -1;
+
+            internal SymbolEnumerator(SymbolList list)
+            {
+                if (list == null)
+                {
+                    throw new ArgumentNullException("lexer");
+                }
+
+                _list = list;
+            }
+
+            #region ISymbolEnumerator Member
+
+            public bool PutBack(Symbol item)
+            {
+                if ((_index < 0) || (_index >= _list.Count) || (item != _list[_index]))
+                {
+                    throw new ArgumentException(@"wrong last symbol", "last");
+                    //return false;
+                }
+
+                _index--;
+                return true;
+            }
+
+            #endregion
+
+            #region IEnumerator<Symbol> Member
+
+            public Symbol Current
+            {
+                get
+                {
+                    if ((_index >= 0) && (_index <= _list.Count))
+                    {
+                        return _list[_index];
+                    }
+
+                    return null;
+                }
+            }
+
+            #endregion
+
+            #region IDisposable Member
+
+            public void Dispose()
+            {
+            }
+
+            #endregion
+
+            #region IEnumerator Member
+
+            object System.Collections.IEnumerator.Current
+            {
+                get { return this.Current; }
+            }
+
+            public bool MoveNext()
+            {
+                _index++;
+                return (_index >= 0) && (_index < _list.Count);
+            }
+
+            public void Reset()
+            {
+                _index = -1;
+            }
+
+            #endregion
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SymbolList"/> class.
+        /// </summary>
+        public SymbolList()
+        {
+        }
+
+        public ISymbolEnumerator GetSymbolEnumerator()
+        {
+            return new SymbolEnumerator(this);
+        }
+
+        public string Join(string separator)
+        {
+            if (separator == null)
+                separator = "";
+
+            StringBuilder result = new StringBuilder();
+
+            foreach (Symbol s in this)
+            {
+                result.Append(s);
+                result.Append(separator);
+            }
+
+            if (result.Length > 0)
+            {
+                result.Length -= separator.Length;
+            }
+
+            return result.ToString();
+        }
+    }
+
+    public static class SymbolEnumeratorExtension
+    {
+        public static Symbol NextSymbol(this IEnumerator<Symbol> enumerator)
+        {
+            if (enumerator.MoveNext())
+            {
+                return enumerator.Current;
+            }
+
+            return null;
+        }
+
+        public static Symbol NextNonEOLSymbol(this IEnumerator<Symbol> enumerator)
+        {
+            while (enumerator.MoveNext())
+            {
+                if (enumerator.Current != Symbol.EOL)
+                {
+                    return enumerator.Current;
+                }
+            }
+
+            return null;
+        }
+    }
+}