/// <summary>
/// Projects each element of a <paramref name="indexedSequence"/> into a form provided by the given <paramref name="selector"/>.
/// In addition to the element of the sequence the action also gets index of it during this processing. Note that
/// the given index must no be equal to its real index within the underlying collection.
/// </summary>
/// <typeparam name="TResult">Type of object resulting the transform function</typeparam>
/// <param name="indexedSequence">Collection of items</param>
/// <param name="selector">Transform function</param>
/// <returns>Collection of transformed items</returns>
public static IEnumerable <TResult> Select <TResult>(this IIndexedEnumerable indexedSequence,
Func <int, object, TResult> selector)
{
int i = -1;
for (IEnumerator itr = indexedSequence.GetEnumerator(); itr.MoveNext();)
{
yield return(selector(++i, itr.Current));
}
}
/// <summary>
/// Applies the given strong-typed <paramref name="action"/> to each element of the given <paramref name="indexedSequence"/>.
/// In addition to the element of the sequence the action also gets index of it during this processing. Note that
/// the given index must no be equal to its real index within the underlying collection.
/// </summary>
/// <typeparam name="TItem">Type of elements to iterate</typeparam>
/// <param name="indexedSequence">Collection of items</param>
/// <param name="action">Action to apply to each element</param>
public static void ForEach <TItem>(this IIndexedEnumerable <TItem> indexedSequence, Action <int, TItem> action)
{
int i = -1;
using (IEnumerator <TItem> itr = indexedSequence.GetEnumerator()) {
while (itr.MoveNext())
{
action(++i, itr.Current);
}
}
}
/// <summary>
/// Projects each strong-typed element a <paramref name="indexedSequence"/> into a form provided by the given <paramref name="selector"/>.
/// In addition to the element of the sequence the action also gets index of it during this processing. Note that
/// the given index must no be equal to its real index within the underlying collection.
/// </summary>
/// <typeparam name="TItem">Type of elements to iterate</typeparam>
/// <typeparam name="TResult">Type of object resulting the transform function</typeparam>
/// <param name="indexedSequence">Collection of items</param>
/// <param name="selector">Transform function</param>
/// <returns>Collection of transformed items</returns>
public static IEnumerable <TResult> Select <TItem, TResult>(this IIndexedEnumerable <TItem> indexedSequence,
Func <int, TItem, TResult> selector)
{
int i = -1;
using (IEnumerator <TItem> itr = indexedSequence.GetEnumerator()) {
while (itr.MoveNext())
{
yield return(selector(++i, itr.Current));
}
}
}
/// <summary>
/// Applies the given <paramref name="action"/> to each element of the given <paramref name="indexedSequence"/>.
/// In addition to the element of the sequence the action also gets index of it during this processing. Note that
/// the given index must no be equal to its real index within the underlying collection.
/// </summary>
/// <param name="indexedSequence">Collection of items</param>
/// <param name="action">Action to apply to each element</param>
public static void ForEach(this IIndexedEnumerable indexedSequence, Action <int, object> action)
{
if (indexedSequence == null)
{
throw new NullReferenceException();
}
IEnumerator itr = indexedSequence.GetEnumerator();
try {
int i = -1;
while (itr.MoveNext())
{
action(++i, itr.Current);
}
} finally {
(itr as IDisposable)?.Dispose();
}
}