/// <summary>
/// 获取或设置指定索引处的元素。
/// </summary>
/// <param name="index">要获得或设置的元素从零开始的索引。</param>
/// <value>指定索引处的元素。</value>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> 不是
/// <see cref="ListBase{T}"/> 中的有效索引。</exception>
/// <exception cref="ArgumentException">设置属性，且 <paramref name="value"/> 不能赋值给
/// <typeparamref name="T"/> 类型。</exception>
object IList.this[int index]
{
get
{
if (index < 0)
{
throw CommonExceptions.ArgumentNegative("index", index);
}
if (index > this.Count)
{
throw CommonExceptions.ArgumentOutOfRange("index", index);
}
Contract.EndContractBlock();
return(this.GetItemAt(index));
}
set
{
if (index < 0)
{
throw CommonExceptions.ArgumentNegative("index", index);
}
if (index > this.Count)
{
throw CommonExceptions.ArgumentOutOfRange("index", index);
}
Contract.EndContractBlock();
try
{
this.SetItemAt(index, (T)value);
}
catch (InvalidCastException)
{
throw CommonExceptions.ArgumentWrongType("value", value, typeof(T));
}
}
}
/// <summary>
/// 将指定集合的元素插入到当前列表的指定索引处。
/// </summary>
/// <typeparam name="T">列表中元素的类型。</typeparam>
/// <param name="list">要插入到的列表。</param>
/// <param name="index">从零开始的索引，在此处开始插入新元素。</param>
/// <param name="collection">要插入的元素集合。</param>
/// <exception cref="ArgumentNullException"><paramref name="list"/> 为 <c>null</c>。</exception>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> 为 <c>null</c>。</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> 不是
/// <paramref name="list"/> 中的有效索引。</exception>
public static void InsertRange <T>(this IList <T> list, int index, IEnumerable <T> collection)
{
if (list == null)
{
throw CommonExceptions.ArgumentNull("list");
}
if (collection == null)
{
throw CommonExceptions.ArgumentNull("collection");
}
if (index < 0)
{
throw CommonExceptions.ArgumentNegative("index", index);
}
if (index >= list.Count)
{
throw CommonExceptions.ArgumentOutOfRange("index", index);
}
Contract.EndContractBlock();
foreach (T item in collection)
{
list.Insert(index++, item);
}
}
/// <summary>
/// 从 <see cref="BitList"/> 中移除一定范围的元素。
/// </summary>
/// <param name="index">要移除的元素的范围从零开始的起始索引。</param>
/// <param name="length">要移除的元素数。</param>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="index"/> 小于 <c>0</c>。</exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="length"/> 小于 <c>0</c>。</exception>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="index"/> 和 <paramref name="length"/> 不表示
/// <see cref="BitList"/> 中元素的有效范围。</exception>
public void RemoveRange(int index, int length)
{
if (index < 0)
{
throw CommonExceptions.ArgumentNegative("index", index);
}
if (length < 0)
{
throw CommonExceptions.ArgumentNegative("length", length);
}
if (index + length > this.count)
{
throw CommonExceptions.ArgumentOutOfRange("length", length);
}
Contract.EndContractBlock();
if (length <= 0)
{
return;
}
if (length == 1)
{
this.RemoveItem(index);
return;
}
int valueIdx = (index + length) >> IndexShift;
int idx = index >> IndexShift;
int tailSize = index & IndexMask;
int rSize = (index + length) & IndexMask;
if (rSize > 0)
{
uint value = this.items[valueIdx];
int highSize = tailSize == 0 ? 0 : UnitSize - tailSize;
int restSize = UnitSize - rSize;
if (highSize > restSize)
{
highSize = restSize;
}
if (highSize > 0)
{
uint tailMask = GetMask(tailSize);
this.items[idx] = (this.items[idx] & tailMask) |
((value >> rSize) << tailSize);
tailSize += highSize;
if (tailSize == UnitSize)
{
idx++;
tailSize = 0;
}
}
if (restSize > highSize)
{
tailSize = restSize - highSize;
items[idx] = value >> (UnitSize - tailSize);
}
valueIdx++;
}
// 计算要复制的长度。
int len = this.count - (valueIdx << IndexShift) + tailSize;
if (len > 0)
{
this.CopyItems(this.items, valueIdx, idx, tailSize, len);
}
this.count -= length;
}