具有延时的简单输入输出

Question

Let's say I have an input signal, could be a random double:

while(true){
  double t; // = current time, let's assume I know that
  double input = rand();
}

I want to generate an output signal that simply applies a 0.5 sec time delay (a 0.5sec dead time in signal processing terms.)

while(true){
  double input = rand();
  // in pseudocode double output(t) = input(t-0.5)
}

I was thinking about storing the input in a vector, along with a time stamp in another vector, and then look up output = input(0.5sec ago). However, that seems very inefficient.

What's an appropriate data structure for this type of problem? (A buffer that let's me recall a value that was stored 0.5 sec ago and discards recorded values that are further in the past than the chosen time delay)

Answer 1

The struct you use to store data should have a timestamp (either expiry or the moment it was enqueued) along with the double value.

The data structure to store the structs should be a priority queue (sorted on timestamp).

The consumer thread should sleep for n milliseconds where n is initialized to 500ms.

When the consumer pops the first item, it can check the second item and calculate n (the amount of time to sleep for the next iteration). Else it can sleep again for 500 ms.

Let me know if I should write code for it.

Answer 2

What immediately comes to mind is the Producer-Consumer Pattern .

Have the producer push the input to a std::queue and every 0.5 seconds (using a std::thread ) have the consumer pop from it.