public static Progressor <T> CreateDistinct(Progressor <T> wrapped)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
var control = 0;
SafeDictionary <T, bool> buffer = new SafeDictionary <T, bool>();
Predicate <T> newFilter = item => Thread.VolatileRead(ref control) == 0;
var proxy = new ProxyObservable <T>();
Progressor <T> result = new Progressor <T>(
(out T value) =>
{
Interlocked.Increment(ref control);
try
{
again:
foreach (KeyValuePair <T, bool> item in buffer)
{
if (!item.Value)
{
value = item.Key;
buffer.Set(value, true);
proxy.OnNext(value);
return(true);
}
}
if (wrapped.TryTake(out value))
{
bool seen;
if (!buffer.TryGetValue(value, out seen) || !seen)
{
buffer.Set(value, true);
proxy.OnNext(value);
return(true);
}
else
{
goto again;
}
}
else
{
return(false);
}
}
finally
{
Interlocked.Decrement(ref control);
}
},
proxy
);
wrapped.Subscribe
(
new CustomObserver <T>
(
() => result._done = true,
exception => result._done = true,
item =>
{
if (newFilter(item))
{
buffer.TryAdd(item, false);
}
}
)
);
return(result);
}
public static Progressor <T> CreatedFilteredConverted <TInput>(Progressor <TInput> wrapped, Predicate <TInput> filter, Converter <TInput, T> converter)
{
if (wrapped == null)
{
throw new ArgumentNullException("wrapped");
}
if (filter == null)
{
throw new ArgumentNullException("filter");
}
if (converter == null)
{
throw new ArgumentNullException("converter");
}
var control = 0;
Predicate <TInput> newFilter = item => Thread.VolatileRead(ref control) == 0 && filter(item);
var buffer = new SafeQueue <T>();
var proxy = new ProxyObservable <T>();
var result = new Progressor <T>(
(out T value) =>
{
Interlocked.Increment(ref control);
try
{
TInput item;
again:
if (buffer.TryTake(out value))
{
proxy.OnNext(value);
return(true);
}
else if (wrapped.TryTake(out item))
{
if (filter(item))
{
value = converter(item);
proxy.OnNext(value);
return(true);
}
else
{
goto again;
}
}
value = default(T);
return(false);
}
finally
{
Interlocked.Decrement(ref control);
}
},
proxy
);
wrapped.Subscribe
(
new CustomObserver <TInput>
(
() => result._done = true,
exception => result._done = true,
item =>
{
if (newFilter(item))
{
buffer.Add(converter(item));
}
}
)
);
return(result);
}