public static TSource First <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
{
if (source == null)
{
throw Error.ArgumentNull("source");
}
if (predicate == null)
{
throw Error.ArgumentNull("predicate");
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.First(predicate));
}
foreach (TSource element in source)
{
if (predicate(element))
{
return(element);
}
}
throw Error.NoMatch();
}
internal static TSource TryGetFirst <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate, out bool found)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (predicate == null)
{
throw Error.ArgumentNull(nameof(predicate));
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.TryGetFirst(predicate, out found));
}
foreach (TSource element in source)
{
if (predicate(element))
{
found = true;
return(element);
}
}
found = false;
return(default(TSource));
}
IOrderedEnumerable <TElement> IOrderedEnumerable <TElement> .CreateOrderedEnumerable <TKey>(Func <TElement, TKey> keySelector, IComparer <TKey> comparer, bool descending)
{
OrderedEnumerable <TElement, TKey> result = new OrderedEnumerable <TElement, TKey>(source, keySelector, comparer, descending);
result.parent = this;
return(result);
}
public static TSource FirstOrDefault <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (predicate == null)
{
throw Error.ArgumentNull(nameof(predicate));
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.FirstOrDefault(predicate));
}
foreach (TSource element in source)
{
if (predicate(element))
{
return(element);
}
}
return(default(TSource));
}
public static TSource Last <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (predicate == null)
{
throw Error.ArgumentNull(nameof(predicate));
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.Last(predicate));
}
IList <TSource> list = source as IList <TSource>;
if (list != null)
{
for (int i = list.Count - 1; i >= 0; --i)
{
TSource result = list[i];
if (predicate(result))
{
return(result);
}
}
}
else
{
using (IEnumerator <TSource> e = source.GetEnumerator())
{
while (e.MoveNext())
{
TSource result = e.Current;
if (predicate(result))
{
while (e.MoveNext())
{
TSource element = e.Current;
if (predicate(element))
{
result = element;
}
}
return(result);
}
}
}
}
throw Error.NoMatch();
}
public static TSource LastOrDefault <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (predicate == null)
{
throw Error.ArgumentNull(nameof(predicate));
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.LastOrDefault(predicate));
}
IList <TSource> list = source as IList <TSource>;
if (list != null)
{
for (int i = list.Count - 1; i >= 0; --i)
{
TSource element = list[i];
if (predicate(element))
{
return(element);
}
}
return(default(TSource));
}
else
{
TSource result = default(TSource);
foreach (TSource element in source)
{
if (predicate(element))
{
result = element;
}
}
return(result);
}
}
internal OrderedEnumerable(IEnumerable <TElement> source, Func <TElement, TKey> keySelector, IComparer <TKey> comparer, bool descending)
{
if (source == null)
{
throw Error.ArgumentNull("source");
}
if (keySelector == null)
{
throw Error.ArgumentNull("keySelector");
}
base.source = source;
this.parent = null;
this.keySelector = keySelector;
this.comparer = (comparer != null) ? comparer : ((IComparer <TKey>)Comparer <TKey> .Default);
this.descending = descending;
}
internal OrderedSequence(OrderedEnumerable <TElement> parent, IEnumerable <TElement> source, Func <TElement, TKey> keySelector, IComparer <TKey> comparer, SortDirection direction)
: this(source, keySelector, comparer, direction)
{
this.parent = parent;
}
public OrderedPartition(OrderedEnumerable <TElement> source, int minIdxInclusive, int maxIdxInclusive)
{
_source = source;
_minIndexInclusive = minIdxInclusive;
_maxIndexInclusive = maxIdxInclusive;
}
public OrderedPartition(OrderedEnumerable <TElement> source, int minIdx, int maxIdx)
{
_source = source;
_minIndex = minIdx;
_maxIndex = maxIdx;
}
internal static TSource TryGetLast <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate, out bool found)
{
if (source == null)
{
throw Error.ArgumentNull(nameof(source));
}
if (predicate == null)
{
throw Error.ArgumentNull(nameof(predicate));
}
OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;
if (ordered != null)
{
return(ordered.TryGetLast(predicate, out found));
}
IList <TSource> list = source as IList <TSource>;
if (list != null)
{
for (int i = list.Count - 1; i >= 0; --i)
{
TSource result = list[i];
if (predicate(result))
{
found = true;
return(result);
}
}
}
else
{
using (IEnumerator <TSource> e = source.GetEnumerator())
{
while (e.MoveNext())
{
TSource result = e.Current;
if (predicate(result))
{
while (e.MoveNext())
{
TSource element = e.Current;
if (predicate(element))
{
result = element;
}
}
found = true;
return(result);
}
}
}
}
found = false;
return(default(TSource));
}
