fifo

go.fifo

Description

go.fifo provides a simple FIFO thread-safe queue. *fifo.Queue supports pushing an item at the end with Add(), and popping an item from the front with Next(). There is no intermediate type for the stored data. Data is directly added and retrieved as type interface{} The queue itself is implemented as a single-linked list of chunks containing max 64 items each.

Installation

go get github.com/foize/go.fifo

Usage

package main

import (
	"github.com/foize/go.fifo"
	"fmt"
)

func main() {
	// create a new queue
	numbers := fifo.NewQueue()

	// add items to the queue
	numbers.Add(42)
	numbers.Add(123)
	numbers.Add(456)

	// retrieve items from the queue
	fmt.Println(numbers.Next()) // 42
	fmt.Println(numbers.Next()) // 123
	fmt.Println(numbers.Next()) // 456
}

package main

import (
	"github.com/foize/go.fifo"
	"fmt"
)

type thing struct {
	Text string
	Number int
}

func main() {
	// create a new queue
	things := fifo.NewQueue()

	// add items to the queue
	things.Add(&thing{
		Text: "one thing",
		Number: 1,
	})
	things.Add(&thing {
		Text: "another thing",
		Number: 2,
	})

	// retrieve items from the queue
	for  {
		// get a new item from the things queue
		item := things.Next();

		// check if there was an item
		if item == nil {
			fmt.Println("queue is empty")
			return
		}

		// assert the type for the item
		someThing := item.(*thing)

		// print the fields
		fmt.Println(someThing.Text)
		fmt.Printf("with number: %d\n", someThing.Number)
	}
}

/* output: */
// one thing
// with number: 1
// another thing
// with number: 2
// queue is empty

Documentation

Documentation can be found at godoc.org/github.com/foize/go.fifo. For more detailed documentation, read the source.

History

This package is based on github.com/yasushi-saito/fifo_queue There are several differences:

• renamed package to fifo to make usage simpler
• removed intermediate type Item and now directly using interface{} instead.
• renamed (*Queue).PushBack() to (*Queue).Add()
• renamed (*Queue).PopFront() to (*Queue).Next()
• Next() will not panic on empty queue, will just return nil interface{}
• Add() does not accept nil interface{} and will panic when trying to add nil interface{}.
• Made fifo.Queue thread/goroutine-safe (sync.Mutex)
• Added a lot of comments
• renamed internal variable/field names