Dictionary源碼解析（未完）

private void Insert(TKey key, TValue value, bool add)
{
if (key == null)
    {
        ThrowHelper.ThrowArgumentNullException(ExceptionArgument.key);
    }
if (this.buckets == null)
    {
this.Initialize(0);
    }
int num = this.comparer.GetHashCode(key) & 2147483647;
int num2 = num % this.buckets.Length;
for (int i = this.buckets[num2]; i >= 0; i = this.entries[i].next)
    {
if (this.entries[i].hashCode == num && this.comparer.Equals(this.entries[i].key, key))
        {
if (add)
            {
                ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_AddingDuplicate);
            }
this.entries[i].value = value;
this.version++;
return;
        }
    }
int num3;
if (this.freeCount > 0)
    {
        num3 = this.freeList;
this.freeList = this.entries[num3].next;
this.freeCount--;
    }
else
    {
if (this.count == this.entries.Length)
        {
this.Resize();
            num2 = num % this.buckets.Length;
        }
        num3 = this.count;
this.count++;
    }
this.entries[num3].hashCode = num;
this.entries[num3].next = this.buckets[num2];
this.entries[num3].key = key;
this.entries[num3].value = value;
this.buckets[num2] = num3;
this.version++;
}

1.如果傳入的是字串的話，GetHashCode的演算法和字串的長度成正比。這導致了有時這個O(1)的時間複雜度在具體使用時可能比log(n)複雜度的還有久。

2. 如果直接重寫equals方法，可能會對實值型別裝箱。這樣就不能體現實值型別在調用完就立刻回收，不會增加GC壓力的這個好處了。

3.memecached

解決增加節點後的緩衝失效問題，hash consistence演算法。

 http://blog.csdn.net/sparkliang/article/details/5279393

 

3.安全執行緒