/// <summary>
/// adds elements from <paramref name="sourceList"/>
/// in range [<paramref name="startIndex"/>,<paramref name="endIndex"/>)
/// to end of <paramref name="destinationList"/>.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="destinationList"></param>
/// <param name="startIndex"></param>
/// <param name="endIndex"></param>
/// <param name="sourceList"></param>
public static void AddRange <T>(
this List <T> destinationList,
int startIndex,
int endIndex,
IList <T> sourceList)
{
ListUtils.AssertRangeIndicesValid(startIndex, endIndex, sourceList);
int numberOfItemsToBeAddedToList = (endIndex - startIndex);
int numberOfItemsInListAfterAdd = destinationList.Count + numberOfItemsToBeAddedToList;
// number of items in list after add is greater than current list capacity,
// and doubling list capacity fails to allocate enough space for added items
if (destinationList.Capacity * 2 < numberOfItemsInListAfterAdd)
{
// manually allocate additional memory to list
destinationList.Capacity = numberOfItemsInListAfterAdd;
}
// add items from sourceList in range [beginIndex - endIndex) to destinationList
for (int i = startIndex; i < endIndex; i++)
{
T sourceListItem = sourceList[i];
destinationList.Add(sourceListItem);
}
}
/// <summary>
/// represents an <paramref name="array"/> range of
/// [<paramref name="startIndex"/>, <paramref name="endIndex"/>).
/// </summary>
/// <param name="list"></param>
/// <param name="startIndex"></param>
/// <param name="endIndex"></param>
/// <exception cref="IndexOutOfRangeException">
/// <seealso cref="ListUtils.AssertRangeIndicesValid{T}(int, int, IList{T})"/>
/// </exception>
public ArrayRange(T[] array, int startIndex, int endIndex)
{
ListUtils.AssertRangeIndicesValid(startIndex, endIndex, array);
this.startIndex = startIndex;
this.endIndex = endIndex;
this.subArray = array.GetRange(startIndex, endIndex);
}
/// <summary>
/// returns subarray of <paramref name="sourceArray"/> containing items in range
/// [<paramref name="startIndex"/>, <paramref name="endIndex"/>).
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="sourceArray"></param>
/// <param name="startIndex"></param>
/// <param name="endIndex"></param>
/// <returns>
/// subarray of <paramref name="sourceArray"/> containing items in range
/// [<paramref name="startIndex"/>, <paramref name="endIndex"/>)
/// </returns>
/// <exception cref="IndexOutOfRangeException">
/// <seealso cref="ListUtils.AssertRangeIndicesValid{T}(int, int, IList{T})"/>
/// </exception>
public static T[] Subarray <T>(this T[] sourceArray, int startIndex, int endIndex)
{
ListUtils.AssertRangeIndicesValid(startIndex, endIndex, sourceArray);
T[] subarray;
// allocate memory for subArray
int subarrayLength = endIndex - startIndex;
subarray = new T[subarrayLength];
// copy element from sourceArray into subArray
Array.Copy(sourceArray, startIndex, subarray, 0, subarrayLength);
return(subarray);
}
/// <summary>
/// returns a subarray containing elements from <paramref name="sourceList"/> in
/// range [<paramref name="startIndex"/>, <paramref name="endIndex"/>).
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="sourceList"></param>
/// <param name="startIndex"></param>
/// <param name="endIndex"></param>
/// <returns>
/// subarray containing elements from <paramref name="sourceList"/> in
/// range [<paramref name="startIndex"/>, <paramref name="endIndex"/>).
/// </returns>
/// <exception cref="IndexOutOfRangeException">
/// <seealso cref="ListUtils.AssertRangeIndicesValid{T}(int, int, IList{T})"/>
/// </exception>
public static T[] GetRange <T>(
this IList <T> sourceList,
int startIndex,
int endIndex)
{
ListUtils.AssertRangeIndicesValid(startIndex, endIndex, sourceList);
int numberOfItemsInRange = endIndex - startIndex;
T[] resultArray = new T[numberOfItemsInRange];
// copy elements in range [startIndex, endIndex) in sourceList to resultArray
for (int i = startIndex; i < endIndex; i++)
{
T sourceListItem = sourceList[i];
int resultArrayIndex = i - startIndex;
resultArray[resultArrayIndex] = sourceListItem;
}
return(resultArray);
}
