public static readonly Func<T, bool> Always = (t) => true;
}
+ class Function<T> {
+ public static readonly Func<T, T> Identity = (t) => t;
+ }
+
#region Aggregate
public static TSource Aggregate<TSource> (this IEnumerable<TSource> source, Func<TSource, TSource, TSource> func)
{
Check.Source (source);
+ var collection = source as ICollection<TSource>;
+ if (collection != null)
+ return collection.Count > 0;
+
using (var enumerator = source.GetEnumerator ())
return enumerator.MoveNext ();
}
{
Check.Source (source);
- return source.AverageNullable<long, long, double> ((a, b) => a + b, (a, b) => a / b);
+ return source.AverageNullable<long, long, double> ((a, b) => a + b, (a, b) => (double) a / b);
}
public static double? Average (this IEnumerable<double?> source)
static IEnumerable<TResult> CreateCastIterator<TResult> (IEnumerable source)
{
- foreach (object element in source)
- yield return (TResult) element;
+ foreach (TResult element in source)
+ yield return element;
}
#endregion
{
Check.Source (source);
- return source.First (PredicateOf<TSource>.Always, Fallback.Throw);
+ var list = source as IList<TSource>;
+ if (list != null) {
+ if (list.Count != 0)
+ return list [0];
+
+ throw new InvalidOperationException ();
+ } else {
+ using (var enumerator = source.GetEnumerator ()) {
+ if (enumerator.MoveNext ())
+ return enumerator.Current;
+ }
+ }
+
+ throw new InvalidOperationException ();
}
public static TSource First<TSource> (this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
Check.Source (source);
+ var collection = source as ICollection<TSource>;
+ if (collection != null && collection.Count == 0)
+ throw new InvalidOperationException ();
+
+ var list = source as IList<TSource>;
+ if (list != null)
+ return list [list.Count - 1];
+
return source.Last (PredicateOf<TSource>.Always, Fallback.Throw);
}
static T? IterateNullable<T> (IEnumerable<T?> source, T initValue, Func<T?, T?, bool> selector) where T : struct
{
- int counter = 0;
+ bool empty = true;
T? value = initValue;
foreach (var element in source) {
if (!element.HasValue)
if (selector (element.Value, value))
value = element;
- ++counter;
+
+ empty = false;
}
- if (counter == 0)
+ if (empty)
return null;
return value;
static U Iterate<T, U> (IEnumerable<T> source, U initValue, Func<T, U, U> selector)
{
- int counter = 0;
+ bool empty = true;
foreach (var element in source) {
initValue = selector (element, initValue);
- ++counter;
+ empty = false;
}
- if (counter == 0)
+ if (empty)
throw new InvalidOperationException ();
return initValue;
static U? IterateNullable<T, U> (IEnumerable<T> source, U initialValue, Func<T, U?, U?> selector) where U : struct
{
- int counter = 0;
+ bool empty = true;
U? value = initialValue;
foreach (var element in source) {
value = selector (element, value);
if (!value.HasValue)
continue;
- ++counter;
+ empty = false;
}
- if (counter == 0)
+ if (empty)
return null;
return value;
{
Check.Source (source);
- return Sum<int, int> (source, (a, b) => a + b);
+ return Sum<int, int> (source, (a, b) => checked (a + b));
}
public static int? Sum (this IEnumerable<int?> source)
{
Check.Source (source);
- return source.SumNullable<int?, int?> (0, (a, b) => a.HasValue ? a + b : a);
+ return source.SumNullable<int?, int?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
public static int Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
{
Check.SourceAndSelector (source, selector);
- return Sum<TSource, int> (source, (a, b) => a + selector (b));
+ return Sum<TSource, int> (source, (a, b) => checked (a + selector (b)));
}
public static int? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int?> selector)
return source.SumNullable<TSource, int?> (0, (a, b) => {
var value = selector (b);
- return value.HasValue ? a + value.Value : a;
+ return value.HasValue ? checked (a + value.Value) : a;
});
}
{
Check.Source (source);
- return Sum<long, long> (source, (a, b) => a + b);
+ return Sum<long, long> (source, (a, b) => checked (a + b));
}
public static long? Sum (this IEnumerable<long?> source)
{
Check.Source (source);
- return source.SumNullable<long?, long?> (0, (a, b) => a.HasValue ? a + b : a);
+ return source.SumNullable<long?, long?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
public static long Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, long> selector)
{
Check.SourceAndSelector (source, selector);
- return Sum<TSource, long> (source, (a, b) => a + selector (b));
+ return Sum<TSource, long> (source, (a, b) => checked (a + selector (b)));
}
public static long? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, long?> selector)
return source.SumNullable<TSource, long?> (0, (a, b) => {
var value = selector (b);
- return value.HasValue ? a + value.Value : a;
+ return value.HasValue ? checked (a + value.Value) : a;
});
}
{
Check.Source (source);
- return Sum<double, double> (source, (a, b) => a + b);
+ return Sum<double, double> (source, (a, b) => checked (a + b));
}
public static double? Sum (this IEnumerable<double?> source)
{
Check.Source (source);
- return source.SumNullable<double?, double?> (0, (a, b) => a.HasValue ? a + b : a);
+ return source.SumNullable<double?, double?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
public static double Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, double> selector)
{
Check.SourceAndSelector (source, selector);
- return Sum<TSource, double> (source, (a, b) => a + selector (b));
+ return Sum<TSource, double> (source, (a, b) => checked (a + selector (b)));
}
public static double? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, double?> selector)
return source.SumNullable<TSource, double?> (0, (a, b) => {
var value = selector (b);
- return value.HasValue ? a + value.Value : a;
+ return value.HasValue ? checked (a + value.Value) : a;
});
}
{
Check.Source (source);
- return Sum<float, float> (source, (a, b) => a + b);
+ return Sum<float, float> (source, (a, b) => checked (a + b));
}
public static float? Sum (this IEnumerable<float?> source)
{
Check.Source (source);
- return source.SumNullable<float?, float?> (0, (a, b) => a.HasValue ? a + b : a);
+ return source.SumNullable<float?, float?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
public static float Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, float> selector)
{
Check.SourceAndSelector (source, selector);
- return Sum<TSource, float> (source, (a, b) => a + selector (b));
+ return Sum<TSource, float> (source, (a, b) => checked (a + selector (b)));
}
public static float? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, float?> selector)
return source.SumNullable<TSource, float?> (0, (a, b) => {
var value = selector (b);
- return value.HasValue ? a + value.Value : a;
+ return value.HasValue ? checked (a + value.Value) : a;
});
}
{
Check.Source (source);
- return Sum<decimal, decimal> (source, (a, b) => a + b);
+ return Sum<decimal, decimal> (source, (a, b) => checked (a + b));
}
public static decimal? Sum (this IEnumerable<decimal?> source)
{
Check.Source (source);
- return source.SumNullable<decimal?, decimal?> (0, (a, b) => a.HasValue ? a + b : a);
+ return source.SumNullable<decimal?, decimal?> (0, (total, element) => element.HasValue ? checked (total + element) : total);
}
public static decimal Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal> selector)
{
Check.SourceAndSelector (source, selector);
- return Sum<TSource, decimal> (source, (a, b) => a + selector (b));
+ return Sum<TSource, decimal> (source, (a, b) => checked (a + selector (b)));
}
public static decimal? Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, decimal?> selector)
return source.SumNullable<TSource, decimal?> (0, (a, b) => {
var value = selector (b);
- return value.HasValue ? a + value.Value : a;
+ return value.HasValue ? checked (a + value.Value) : a;
});
}
int counter = 0;
foreach (TSource element in source) {
- if (counter++ == count)
- yield break;
-
yield return element;
+
+ if (++counter == count)
+ yield break;
}
}
public static Dictionary<TKey, TSource> ToDictionary<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
{
- Check.SourceAndKeySelector (source, keySelector);
-
- if (comparer == null)
- comparer = EqualityComparer<TKey>.Default;
-
- var dict = new Dictionary<TKey, TSource> (comparer);
- foreach (var e in source)
- dict.Add (keySelector (e), e);
-
- return dict;
+ return ToDictionary<TSource, TKey, TSource> (source, keySelector, Function<TSource>.Identity, comparer);
}
#endregion
public static ILookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
{
- return ToLookup<TSource, TKey> (source, keySelector, null);
+ return ToLookup<TSource, TKey, TSource> (source, keySelector, Function<TSource>.Identity, null);
}
public static ILookup<TKey, TSource> ToLookup<TSource, TKey> (this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
{
- Check.SourceAndKeySelector (source, keySelector);
-
- var dictionary = new Dictionary<TKey, List<TSource>> (comparer ?? EqualityComparer<TKey>.Default);
- foreach (TSource element in source) {
- TKey key = keySelector (element);
- if (key == null)
- throw new ArgumentNullException ();
- if (!dictionary.ContainsKey (key))
- dictionary.Add (key, new List<TSource> ());
- dictionary [key].Add (element);
- }
- return new Lookup<TKey, TSource> (dictionary);
+ return ToLookup<TSource, TKey, TSource> (source, keySelector, element => element, comparer);
}
public static ILookup<TKey, TElement> ToLookup<TSource, TKey, TElement> (this IEnumerable<TSource> source,
{
Check.SourceAndKeyElementSelectors (source, keySelector, elementSelector);
- Dictionary<TKey, List<TElement>> dictionary = new Dictionary<TKey, List<TElement>> (comparer ?? EqualityComparer<TKey>.Default);
- foreach (TSource element in source) {
- TKey key = keySelector (element);
+ var dictionary = new Dictionary<TKey, List<TElement>> (comparer ?? EqualityComparer<TKey>.Default);
+ foreach (var element in source) {
+ var key = keySelector (element);
if (key == null)
- throw new ArgumentNullException ();
- if (!dictionary.ContainsKey (key))
- dictionary.Add (key, new List<TElement> ());
- dictionary [key].Add (elementSelector (element));
+ throw new ArgumentNullException ("key");
+
+ List<TElement> list;
+ if (!dictionary.TryGetValue (key, out list)) {
+ list = new List<TElement> ();
+ dictionary.Add (key, list);
+ }
+
+ list.Add (elementSelector (element));
}
+
return new Lookup<TKey, TElement> (dictionary);
}
if (comparer == null)
comparer = EqualityComparer<TSource>.Default;
- var first_enumerator = first.GetEnumerator ();
- var second_enumerator = second.GetEnumerator ();
+ using (IEnumerator<TSource> first_enumerator = first.GetEnumerator (),
+ second_enumerator = second.GetEnumerator ()) {
- while (first_enumerator.MoveNext ()) {
- if (!second_enumerator.MoveNext ())
- return false;
+ while (first_enumerator.MoveNext ()) {
+ if (!second_enumerator.MoveNext ())
+ return false;
- if (!comparer.Equals (first_enumerator.Current, second_enumerator.Current))
- return false;
- }
+ if (!comparer.Equals (first_enumerator.Current, second_enumerator.Current))
+ return false;
+ }
- return !second_enumerator.MoveNext ();
+ return !second_enumerator.MoveNext ();
+ }
}
#endregion
projects / mono.git / blobdiff