LastIndexOf() [4/4]

int System.Collections.Immutable.ImmutableArray< T >.LastIndexOf ( T item, int startIndex, int count, IEqualityComparer< T >? equalityComparer )

inline

Implements System.Collections.Immutable.IImmutableList< T >.

Definition at line 1003 of file ImmutableArray.cs.

    {
        ImmutableArray<T> immutableArray = this;
        immutableArray.ThrowNullRefIfNotInitialized();
        if (startIndex == 0 && count == 0)
        {
            return -1;
        }
        Requires.Range(startIndex >= 0 && startIndex < immutableArray.Length, "startIndex");
        Requires.Range(count >= 0 && startIndex - count + 1 >= 0, "count");
        equalityComparer = equalityComparer ?? EqualityComparer<T>.Default;
        if (equalityComparer == EqualityComparer<T>.Default)
        {
            return Array.LastIndexOf(immutableArray.array, item, startIndex, count);
        }
        for (int num = startIndex; num >= startIndex - count + 1; num--)
        {
            if (equalityComparer.Equals(item, immutableArray.array[num]))
            {
                return num;
            }
        }
        return -1;
    }

References System.count, System.Default, System.item, System.Array.LastIndexOf(), System.Collections.Immutable.Requires.Range(), and System.startIndex.