public static ILiveList<int> Range(ILiveValue<int> startValue, ILiveValue<int> countValue)
{
LiveObserver<IValueState<int>> startObserver = null;
LiveObserver<IValueState<int>> countObserver = null;
return LiveListObservable<int>.Create(
innerChanged =>
{
countValue.Subscribe(countObserver = countValue.CreateObserver(innerChanged));
startValue.Subscribe(startObserver = startValue.CreateObserver(innerChanged));
return Lockers.Empty;
},
(innerChanged, notified, stateLock, oldState) =>
{
// get state
var count = countObserver.GetState();
var start = startObserver.GetState();
var newStatus = count.Status.And(start.Status);
// work out delta
ListDelta<int> delta = null;
if (newStatus.IsDeltaRelevant() && (count.HasChange || start.HasChange))
{
delta = new ListDelta<int>();
// adjust head
var head = Math.Min(Math.Max(start.OldValue - start.NewValue, -count.OldValue), count.NewValue);
if (head < 0)
delta.Delete(0, Enumerable.Range(start.OldValue, -head));
else if (head > 0)
delta.Insert(0, Enumerable.Range(start.NewValue, head));
var currentCount = count.OldValue + head;
var leftoverCount = count.OldValue + Math.Min(0, head);
// adjust tail
var tail = count.NewValue - currentCount;
if (tail > 0)
delta.Insert(currentCount, Enumerable.Range(start.NewValue + currentCount, tail));
else if (tail < 0)
delta.Delete(count.NewValue, Enumerable.Range(start.OldValue + count.OldValue + tail, -tail));
}
// work out new state
var result = new CollectionState<int, IListDelta<int>, IList<int>>();
result.SetState(
oldState.GetStatus().Add(newStatus),
delta,
Enumerable.Range(start.NewValue, count.NewValue),
Math.Max(count.LastUpdated, start.LastUpdated),
stateLock);
return result;
},
() =>
{
startObserver.Dispose();
countObserver.Dispose();
});
}
public void TestListDeltaSimple()
{
// single delete
{
var d = new ListDelta<int>();
d.Delete(3, new[] { 1 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
DeleteItems = new[] { 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// subsequent deletes
{
var d = new ListDelta<int>();
d.Delete(3, new[] { 1 });
d.Delete(3, new[] { 2 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
DeleteItems = new[] { 1, 2 },
},
},
}, new IndexNodeComparer<int>()));
}
// subsequent deletes
{
var d = new ListDelta<int>();
d.Delete(1, new[] { 1 });
d.Delete(0, new[] { 0 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 0,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
DeleteItems = new[] { 0, 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// single insert
{
var d = new ListDelta<int>();
d.Insert(3, new[] { 1 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// subsequent inserts
{
var d = new ListDelta<int>();
d.Insert(3, new[] { 1 });
d.Insert(3, new[] { 2 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 2, 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// insert and delete complementing (update)
{
var d = new ListDelta<int>();
d.Delete(3, new[] { 1 });
d.Insert(3, new[] { 2 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 2 },
DeleteItems = new[] { 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// multiple updates
{
var d = new ListDelta<int>();
d.Update(3, 1, 2);
d.Update(3, 2, 3);
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 3,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 3 },
DeleteItems = new[] { 1 },
},
},
}, new IndexNodeComparer<int>()));
}
// insert and delete offsetting
{
var d = new ListDelta<int>();
d.Insert(3, new[] { 1 });
d.Delete(3, new[] { 1 });
Assert.IsTrue(!d.IndexDeltas.Any());
}
// interleaved offsetting delete/inserts
{
var d = new ListDelta<int>();
d.Delete(0, new[] { 1, 2, 3, 4, 5, 7 });
d.Insert(0, new[] { 1, 2, 4, 5, 6, 7 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 2,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
DeleteItems = new[] { 3 },
},
},
new IndexNode<int>
{
Index = 4,
DenseIndex = 1,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 6 },
},
}
}, new IndexNodeComparer<int>()));
}
}
public void TestListDeltaCanonical()
{
{
var d = new ListDelta<int>();
d.Insert(0, new[] { 100 });
d.Insert(1, new[] { 101 });
d.Delete(2, new[] { 0, 1 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 0,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 100, 101 },
DeleteItems = new[] { 0, 1 },
},
},
}, new IndexNodeComparer<int>()));
}
{
var d = new ListDelta<int>();
d.Delete(0, new[] { 0, 1 });
d.Insert(0, new[] { 100 });
d.Insert(1, new[] { 101 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 0,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 100, 101 },
DeleteItems = new[] { 0, 1 },
},
},
}, new IndexNodeComparer<int>()));
}
{
var d = new ListDelta<int>();
d.Delete(0, new[] { 100 });
d.Delete(2, new[] { 102 });
d.Delete(1, new[] { 101 });
var indexDeltas = d.IndexDeltas.ToArray();
Assert.IsTrue(indexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 0,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new int[] { },
DeleteItems = new[] { 100 },
},
},
new IndexNode<int>
{
Index = 1,
DenseIndex = 1,
Data = new ListIndexDelta<int>
{
InsertItems = new int[] { },
DeleteItems = new[] { 101, 102 },
},
},
}, new IndexNodeComparer<int>()));
}
// case where the root node gets canonicalized away
{
var d = new ListDelta<int>();
d.Update(4, 4, 104);
d.Update(6, 6, 106);
d.Update(2, 2, 102);
d.Update(8, 8, 108);
d.Update(3, 3, 103); // <== root changed from 104 to 106
var indexDeltas = d.IndexDeltas.ToArray();
Assert.IsTrue(indexDeltas.SequenceEqual(new[]
{
new IndexNode<int>
{
Index = 2,
DenseIndex = 0,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 102, 103, 104 },
DeleteItems = new[] { 2, 3, 4 },
},
},
new IndexNode<int>
{
Index = 6,
DenseIndex = 1,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 106 },
DeleteItems = new[] { 6 },
},
},
new IndexNode<int>
{
Index = 8,
DenseIndex = 2,
Data = new ListIndexDelta<int>
{
InsertItems = new[] { 108 },
DeleteItems = new[] { 8 },
},
},
}, new IndexNodeComparer<int>()));
}
}
public void TestListDeltaEmpty()
{
{
var d = new ListDelta<int>();
d.Insert(0, new[] { 1 });
d.Delete(0, new[] { 1 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(
new IndexNode<int>[0],
new IndexNodeComparer<int>()));
}
{
var d = new ListDelta<int>();
d.Delete(0, new[] { 1 });
d.Insert(0, new[] { 1 });
Assert.IsTrue(d.IndexDeltas.SequenceEqual(
new IndexNode<int>[0],
new IndexNodeComparer<int>()));
}
}