initial commit

.gitignore

@@ -19,3 +19,5 @@
 
 # Go workspace file
 go.work
+
+.idea

README.md

@@ -1,2 +1,47 @@
 # go-prioritize
-Priority Queue for Go
+Priority Queue for Go with Generic support
+
+## Installation
+
+```bash
+go get github.com/jinwoo1225/go-prioritize
+```
+
+## Usage
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/jinwoo1225/go-prioritize"
+)
+
+func main() {
+	    // Create a new priority queue
+    pq := prioritize.NewPriorityQueue[string](nil)
+
+    // Add some items
+    pq.Push(prioritize.NewItem[string]("foo", 1))
+    pq.Push(prioritize.NewItem[string]("bar", 2))
+    pq.Push(prioritize.NewItem[string]("baz", 3))
+
+    // Pop the highest priority item
+    item := pq.Pop()
+    fmt.Println(item) // "baz"
+
+    // Pop the next highest priority item
+    item = pq.Pop()
+    fmt.Println(item) // "bar"
+
+    // Pop the next highest priority item
+    item = pq.Pop()
+    fmt.Println(item) // "foo"
+
+    // Pop the next highest priority item
+    item = pq.Pop()
+    fmt.Println(item) // nil (queue is empty)
+}
+
+```
+

go.mod

@@ -0,0 +1,11 @@
+module github.com/jinwoo1225/go-prioritize
+
+go 1.21.0
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal_heap.go

@@ -0,0 +1,41 @@
+package prioritize
+
+import "container/heap"
+
+type internalHeap[T any] struct {
+	items []Item[T]
+}
+
+var _ heap.Interface = &internalHeap[any]{}
+
+func (h *internalHeap[T]) Len() int {
+	return len(h.items)
+}
+
+func (h *internalHeap[T]) Less(i, j int) bool {
+	return h.items[i].Priority > h.items[j].Priority
+}
+
+func (h *internalHeap[T]) Swap(i, j int) {
+	h.items[i], h.items[j] = h.items[j], h.items[i]
+	h.items[i].index = i
+	h.items[j].index = j
+}
+
+func (h *internalHeap[T]) Push(x interface{}) {
+	item := x.(Item[T])
+	item.index = len(h.items)
+	h.items = append(h.items, item)
+}
+
+func (h *internalHeap[T]) Pop() interface{} {
+	old := h.items
+	n := len(old)
+	item := old[0]
+	h.items = old[1:n]
+	return item
+}
+
+func (h *internalHeap[T]) Fix(i int) {
+	heap.Fix(h, i)
+}

item.go

@@ -0,0 +1,20 @@
+package prioritize
+
+// Item for generic support
+type Item[T any] struct {
+	// The Value of the item; arbitrary.
+	Value T
+	// The Priority of the item in the queue.
+	Priority int64
+	// The index of the item in the heap.
+	// This is needed by update and is maintained by the heap.Interface methods.
+	index int
+}
+
+func NewItem[T any](value T, priority int64) Item[T] {
+	return Item[T]{
+		Value:    value,
+		Priority: priority,
+		index:    -1,
+	}
+}

priority_queue.go

@@ -0,0 +1,85 @@
+package prioritize
+
+import (
+	"container/heap"
+	"sync"
+)
+
+type PriorityQueuer[T any] interface {
+	Pop() Item[T]
+	Push(x Item[T])
+	Update(item Item[T], value T, priority int64)
+	Peek() Item[T]
+	Range() []Item[T]
+}
+
+type PriorityQueue[T any] struct {
+	mu           sync.RWMutex
+	internalHeap *internalHeap[T]
+}
+
+func NewPriorityQueue[T any](items []Item[T]) *PriorityQueue[T] {
+	for i := range items {
+		items[i].index = i
+	}
+
+	iHeap := &internalHeap[T]{
+		items: items,
+	}
+
+	heap.Init(iHeap)
+
+	return &PriorityQueue[T]{
+		mu:           sync.RWMutex{},
+		internalHeap: iHeap,
+	}
+}
+
+func (h *PriorityQueue[T]) Push(x Item[T]) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	h.internalHeap.Push(x)
+	h.internalHeap.Fix(h.internalHeap.Len() - 1)
+}
+
+func (h *PriorityQueue[T]) Pop() Item[T] {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	return h.internalHeap.Pop().(Item[T])
+}
+
+func (h *PriorityQueue[T]) Peek() Item[T] {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+
+	if h.internalHeap.Len() == 0 {
+		return Item[T]{}
+	}
+
+	return h.internalHeap.items[0]
+}
+
+func (h *PriorityQueue[T]) Update(item Item[T], value T, priority int64) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	item.Value = value
+	item.Priority = priority
+
+	h.internalHeap.items[item.index] = item
+	h.internalHeap.Fix(item.index)
+}
+
+func (h *PriorityQueue[T]) Range() []Item[T] {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+
+	var items []Item[T]
+	for _, item := range h.internalHeap.items {
+		items = append(items, item)
+	}
+
+	return items
+}