public TElement First(Func <TElement, bool> predicate)
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = source.GetEnumerator())
{
TElement value;
do
{
if (!e.MoveNext())
{
throw Error.NoMatch();
}
value = e.Current;
} while (!predicate(value));
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (predicate(x) && comparer.Compare(x, true) < 0)
{
value = x;
}
}
return(value);
}
}
public TElement LastOrDefault(Func <TElement, bool> predicate)
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = source.GetEnumerator())
{
TElement value;
do
{
if (!e.MoveNext())
{
return(default(TElement));
}
value = e.Current;
} while (!predicate(value));
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (predicate(x) && comparer.Compare(x, false) > 0)
{
value = x;
}
}
return(value);
}
}
private bool TryGetFirst(out TElement result)
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
result = default(TElement);
return(false);
}
TElement value = e.Current;
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (comparer.Compare(x, true) < 0)
{
value = x;
}
}
result = value;
return(true);
}
}
public TElement TryGetLast(Func <TElement, bool> predicate, out bool found)
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = _source.GetEnumerator())
{
TElement value;
do
{
if (!e.MoveNext())
{
found = false;
return(default(TElement));
}
value = e.Current;
}while (!predicate(value));
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (predicate(x) && comparer.Compare(x, false) >= 0)
{
value = x;
}
}
found = true;
return(value);
}
}
public TElement TryGetLast(out bool found)
{
using (IEnumerator <TElement> e = _source.GetEnumerator())
{
if (!e.MoveNext())
{
found = false;
return(default(TElement));
}
CachingComparer <TElement> comparer = GetComparer();
TElement value = e.Current;
comparer.SetElement(value);
while (e.MoveNext())
{
TElement current = e.Current;
if (comparer.Compare(current, false) >= 0)
{
value = current;
}
}
found = true;
return(value);
}
}
public TElement TryGetFirst(out bool found)
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = _source.GetEnumerator())
{
if (!e.MoveNext())
{
found = false;
return(default(TElement));
}
TElement value = e.Current;
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (comparer.Compare(x, true) < 0)
{
value = x;
}
}
found = true;
return(value);
}
}
private TElement Last(Buffer <TElement> buffer)
{
CachingComparer <TElement> comparer = GetComparer();
TElement[] items = buffer.items;
int count = buffer.count;
TElement value = items[0];
comparer.SetElement(value);
for (int i = 1; i != count; ++i)
{
TElement x = items[i];
if (comparer.Compare(x, false) >= 0)
{
value = x;
}
}
return(value);
}
public TElement LastOrDefault()
{
CachingComparer <TElement> comparer = GetComparer();
using (IEnumerator <TElement> e = source.GetEnumerator())
{
if (!e.MoveNext())
{
return(default(TElement));
}
TElement value = e.Current;
comparer.SetElement(value);
while (e.MoveNext())
{
TElement x = e.Current;
if (comparer.Compare(x, false) >= 0)
{
value = x;
}
}
return(value);
}
}
public CachingComparerWithChild(Func <TElement, TKey> keySelector, IComparer <TKey> comparer, bool descending, CachingComparer <TElement> child)
: base(keySelector, comparer, descending)
{
_child = child;
}
internal abstract CachingComparer <TElement> GetComparer(CachingComparer <TElement> childComparer);