System.ComponentModel.AttributeCollection.this C# (CSharp) Method

        public virtual Attribute this[Type attributeType] 
        {
            get 
            {
                lock (internalSyncObject) {
                    // 2 passes here for perf.  Really!  first pass, we just 
                    // check equality, and if we don't find it, then we
                    // do the IsAssignableFrom dance.   Turns out that's
                    // a relatively expensive call and we try to avoid it
                    // since we rarely encounter derived attribute types
                    // and this list is usually short. 
                    //
                    if (_foundAttributeTypes == null)
                    {
                        _foundAttributeTypes = new AttributeEntry[FOUND_TYPES_LIMIT];
                    }

                    int ind = 0;
     
                    for (; ind < FOUND_TYPES_LIMIT; ind++)
                    {
                        if (_foundAttributeTypes[ind].type == attributeType)
                        {
                           int index = _foundAttributeTypes[ind].index;
                           if (index != -1)
                           {
                               return _attributes[index];
                           }
                           else{
                               return GetDefaultAttribute(attributeType);
                           }   
                        }
                        if (_foundAttributeTypes[ind].type == null)
                            break;
                    }

                    ind = _index++;

                    if (_index >= FOUND_TYPES_LIMIT)
                    {
    	                _index = 0;
                    }

                    _foundAttributeTypes[ind].type = attributeType; 

                    int count = _attributes.Length;
                    

                    for (int i = 0; i < count; i++)
                    {
                        Attribute attribute = _attributes[i];
                        Type aType = attribute.GetType();
                        if (aType == attributeType)
                        {        
                            _foundAttributeTypes[ind].index = i;
                            return attribute;
                        }
                    }

                    // now check the hierarchies.
                    for (int i = 0; i < count; i++)
                    {
                        Attribute attribute = _attributes[i];
                        Type aType = attribute.GetType();
                        if (attributeType.IsAssignableFrom(aType))
                        {
                            _foundAttributeTypes[ind].index = i;
                            return attribute;
                        }
                    }
                    
                    _foundAttributeTypes[ind].index = -1;
                    return GetDefaultAttribute(attributeType);
                }
            }
        }