b2histogram

A fast and efficient 64-bit integer histogram with power-of-2 spaced buckets.

• Fixed memory footprint (520 bytes) with no dynamic allocations
• Constant time record and retrieve operations that compile down to a few instructions
• no_std support
• Work in progress: Compact binary serialization

• Documentation
• Release Notes

Usage

Add this to your Cargo.toml:

[dependencies]
b2histogram = "1.0.1"

and this to your crate root:

extern crate b2histogram;

Quick Example

extern crate b2histogram;

use b2histogram::Base2Histogram;

fn main() {
  let mut hist = Base2Histogram::new();

  hist.record(0); // Record a single observation of '0'
  hist.record(11); //
  hist.record(11); // Two observations of '11'
  hist.record_n(300_000, 6); // Six observations of 300,000

  // Retrieve counts directly
  println!("Observations for 300,000: {}", hist.observations(300_000));

  // Retrieve the `Bucket` covering a given value
  println!("Bucket corresponding to '11': {:?}", hist.bucket_for(11));

  // Iterate buckets that have observations
  for bucket in hist.iter().filter(|b| b.count > 0) {
      println!("({:5}, {:5}): {}", bucket.begin, bucket.end, bucket.count);
  }
}

See the documentation for more.