Skip to content
master
Go to file
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

README.md

gocroaring Build Status GoDoc

Go wrapper for CRoaring (a C/C++ implementation at https://github.com/RoaringBitmap/CRoaring)

Roaring bitmaps are used by several important systems:

Roaring bitmaps are found to work well in many important applications:

Use Roaring for bitmap compression whenever possible. Do not use other bitmap compression methods (Wang et al., SIGMOD 2017)

The original java version can be found at https://github.com/RoaringBitmap/RoaringBitmap

There is a native Go version at https://github.com/RoaringBitmap/roaring

This code is licensed under Apache License, Version 2.0 (ASL2.0).

Copyright 2016 by the authors.

Benchmarking

See https://github.com/lemire/gobitmapbenchmark for a comparison between this wrapper and the Go native version.

References

  • Daniel Lemire, Owen Kaser, Nathan Kurz, Luca Deri, Chris O'Hara, François Saint-Jacques, Gregory Ssi-Yan-Kai, Roaring Bitmaps: Implementation of an Optimized Software Library arXiv:1709.07821
  • Samy Chambi, Daniel Lemire, Owen Kaser, Robert Godin, Better bitmap performance with Roaring bitmaps, Software: Practice and Experience Volume 46, Issue 5, pages 709–719, May 2016 http://arxiv.org/abs/1402.6407 This paper used data from http://lemire.me/data/realroaring2014.html
  • Daniel Lemire, Gregory Ssi-Yan-Kai, Owen Kaser, Consistently faster and smaller compressed bitmaps with Roaring, Software: Practice and Experience (accepted in 2016, to appear) http://arxiv.org/abs/1603.06549

Dependencies

None in particular.

Naturally, you also need to grab the roaring code itself:

  • go get github.com/RoaringBitmap/gocroaring

Example

Here is a simplified but complete example:

package main

import (
	"fmt"

	"github.com/RoaringBitmap/gocroaring"
)

func main() {
	// example inspired by https://github.com/fzandona/goroar
	fmt.Println("==roaring==")
	rb1 := gocroaring.New(1, 2, 3, 4, 5, 100, 1000)
	rb1.RunOptimize() // improves compression
	fmt.Println("Cardinality: ", rb1.Cardinality())
	fmt.Println("Contains 3? ", rb1.Contains(3))

	rb2 := gocroaring.New()
	rb2.Add(3, 4, 1000)
	rb2.RunOptimize() // improves compression

	rb1.And(rb2)
	// prints {3,4,1000}
	fmt.Println(rb1)

	rb3 := gocroaring.New(1, 5)
	rb3.Or(rb1)

        // prints 1, 3, 4, 5, 1000
        i := rb3.Iterator()
        for i.HasNext() {
          fmt.Println(i.Next())
        }
        fmt.Println()

	fmt.Println(rb3.ToArray())
	fmt.Println(rb3)

	rb4 := gocroaring.FastOr(rb1, rb2, rb3) // optimized way to compute unions between many bitmaps
	fmt.Println(rb4)

	// next we include an example of serialization
	buf := make([]byte, rb1.SerializedSizeInBytes())
	rb1.Write(buf) // we omit error handling
	newrb, _ := gocroaring.Read(buf)
	if rb1.Equals(newrb) {
		fmt.Println("I wrote the content to a byte stream and read it back.")
	}

	fmt.Println(rb1.Stats()) // show the cardinality and the numbers of each type of container used.
}

Documentation

Current documentation is available at http://godoc.org/github.com/RoaringBitmap/gocroaring

Mailing list/discussion group

https://groups.google.com/forum/#!forum/roaring-bitmaps

Compatibility with Java RoaringBitmap library

You can read bitmaps in Go, Java, C, C++ that have been serialized in Go, Java, C, C++.

You can’t perform that action at this time.