laney

laney

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Laney package provides queue, priority queue, stack and deque data structures implementations. Its was designed with simplicity, performance, and concurrent usage in mind.

Priority Queue

Pqueue is a heap priority queue data structure implementation. It can be whether max or min ordered, is synchronized and is safe for concurrent operations. It performs insertion and max/min removal in O(log N) time.

Priority Queue Example

 // Let's create a new max ordered priority queue
 var priorityQueue = NewPQueue[string](MINPQ)

 // And push some prioritized content into it
 priorityQueue.Push("easy as", 3)
 priorityQueue.Push("123", 2)
 priorityQueue.Push("do re mi", 4)
 priorityQueue.Push("abc", 1)

 // Now let's take a look at the min element in
 // the priority queue
 headValue, headPriority := priorityQueue.Head()
 fmt.Println(headValue)    // "abc"
 fmt.Println(headPriority) // 1

 // Okay the song order seems to be preserved, let's
 // roll
 var jacksonFive = make([]string, priorityQueue.Size())

 for i := 0; i < len(jacksonFive); i++ {
  value, _ := priorityQueue.Pop()

  jacksonFive[i] = value
 }

 fmt.Println(strings.Join(jacksonFive, " "))

Deque

Deque is a head-tail linked list data structure implementation. It is based on a doubly-linked list container, so that every operations time complexity is O(1). All operations over an instiated Deque are synchronized and safe for concurrent usage.

Deques can optionally be created with a limited capacity, whereby the return value of the Append and Prepend return false if the Deque was full and the item was not added.

Deque Example

 // Let's create a new deque data structure
 deque := NewDeque[string]()

 // And push some content into it using the Append
 // and Prepend methods
 deque.Append("easy as")
 deque.Prepend("123")
 deque.Append("do re mi")
 deque.Prepend("abc")

 // Now let's take a look at what are the first and
 // last element stored in the Deque
 firstValue := deque.First()
 lastValue := deque.Last()
 fmt.Println(firstValue) // "abc"
 fmt.Println(lastValue)  // 1

 // Okay now let's play with the Pop and Shift
 // methods to bring the song words together
 jacksonFive := make([]string, deque.Size())

 for i := 0; i < len(jacksonFive); i++ {
  value := deque.Shift()
  jacksonFive[i] = value
 }

 // abc 123 easy as do re mi
 fmt.Println(strings.Join(jacksonFive, " "))

 // Let's create a new musical quartet
 quartet := NewCappedDeque[string](4)

 // List of young hopeful musicians
 musicians := []string{"John", "Paul", "George", "Ringo", "Stuart"}

 // Add as many of them to the band as we can.
 for _, name := range musicians {
  if quartet.Append(name) {
   fmt.Printf("%s is in the band!\n", name)
  } else {
   fmt.Printf("Sorry - %s is not in the band.\n", name)
  }
 }

 // Assemble our new rock sensation
 beatles := make([]string, quartet.Size())

 for i := 0; i < len(beatles); i++ {
  beatles[i] = quartet.Shift()
 }

 fmt.Println("The Beatles are:", strings.Join(beatles, ", "))

Queue

Queue is a FIFO ( First in first out ) data structure implementation. It is based on a deque container and focuses its API on core functionalities: Enqueue, Dequeue, Head, Size, Empty. Every operations time complexity is O(1). As it is implemented using a Deque container, every operations over an instiated Queue are synchronized and safe for concurrent usage.

Queue Example

    import (
        "fmt"
        "github.com/oleiade/laney"
        "sync"
    )

    func worker(item string, wg *sync.WaitGroup) {
        fmt.Println(item)
        wg.Done()
    }


    func main() {

        queue := laney.NewQueue[string]()
        queue.Enqueue("grumpyClient")
        queue.Enqueue("happyClient")
        queue.Enqueue("ecstaticClient")

        var wg sync.WaitGroup

        // Let's handle the clients asynchronously
        for queue.Head() != nil {
            item := queue.Dequeue()

            wg.Add(1)
            go worker(item, &wg)
        }

        // Wait until everything is printed
        wg.Wait()
    }

Stack

Stack is a LIFO ( Last in first out ) data structure implementation. It is based on a deque container and focuses its API on core functionalities: Push, Pop, Head, Size, Empty. Every operations time complexity is O(1). As it is implemented using a Deque container, every operations over an instiated Stack are synchronized and safe for concurrent usage.

Stack Example

 // Create a new stack and put some plates over it
 stack := NewStack[string]()

 // Let's put some plates on the stack
 stack.Push("redPlate")
 stack.Push("bluePlate")
 stack.Push("greenPlate")

 fmt.Println(stack.Head) // greenPlate

 // What's on top of the stack?
 value := stack.Pop()
 fmt.Println(value) // greenPlate

 stack.Push("yellowPlate")
 value = stack.Pop()
 fmt.Println(value) // yellowPlate

 // What's on top of the stack?
 value = stack.Pop()
 fmt.Println(value) // bluePlate

 // What's on top of the stack?
 value = stack.Pop()
 fmt.Println(value) // redPlate

Documentation

For a more detailled overview of laney, please refer to Documentation