cmsketch.zig

An implementation of the count-min sketch data structures.

Estimator

An Estimator can be used to count the occurrences of different keys:

const testing = @import("std").testing;

test {
  var est = Estimator.init();
  try testing.expect(est.increment("foo", 1) == 1);
  try testing.expect(est.incrementBy("bar", 17) == 17);

  try testing.expect(est.get("foo") == 1);
  try testing.expect(est.get("bar") == 17);
}

Rate

A Rate can be used to count the estimated occurrences of keys within a given time interval.

const testing = @import("std").testing;

test {
  // Initialize a new Rate, with the given time interval in milliseconds.
  // Here, we are using a 1h interval.
  var rate = Rate.init(3600000);

  // You can observe the number of events for a given key.
  try testing.expect(rate.observe("foo", 70) == 70);
  try testing.expect(rate.observe("foo", 70) == 140);

  // ...after an hour, the time window for the observed events will
  // have elapsed, and the number of observations would be reset.
  try testing.expect(rate.get("foo") == 0);
}

Shout-outs

The code in this package was ported from/inspired by ryanfowler/limits.