Add iterators for mq and npq.

.gitea/workflows/build.yaml

@@ -17,12 +17,12 @@ jobs:
       name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: 1.21.5
+        go-version: 1.23.0
     -
       name: Run linter
       uses: golangci/golangci-lint-action@v3
       with:
-        version: v1.54
+        version: v1.60.2
     -
       name: Run tests
       run: go test ./...

go.mod

@@ -1,5 +1,5 @@
 module gogs.humancabbage.net/sam/priorityq
 
-go 1.20
+go 1.23
 
 require golang.org/x/exp v0.0.0-20230224173230-c95f2b4c22f2

mq/lib.go

@@ -28,6 +28,7 @@
 package mq
 
 import (
+	"iter"
 	"sync"
 
 	"gogs.humancabbage.net/sam/priorityq"
@@ -199,3 +200,18 @@ func (s *state[T]) trySend(value T, buf *queue.Q[T]) error {
 	s.canRecv.Broadcast()
 	return nil
 }
+
+// Iter returns an iterator that consumes values until the queue is closed.
+func (s *state[T]) Iter() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for {
+			t, ok := s.Recv()
+			if !ok {
+				return
+			}
+			if !yield(t) {
+				return
+			}
+		}
+	}
+}

mq/lib_test.go

@@ -164,6 +164,30 @@ func TestConcProducerConsumer(t *testing.T) {
 	wg.Wait()
 }
 
+func TestIter(t *testing.T) {
+	t.Parallel()
+	q := mq.Make[int](4)
+	q.Send(1)
+	q.Send(2)
+	q.Send(3)
+	q.SendHigh(0)
+	q.Close()
+	i := 0
+	for v := range q.Iter() {
+		if v != i {
+			t.Errorf("expected %d, got %d", i, v)
+		}
+		i++
+	}
+
+	// to test yield() returning false
+	q = mq.Make[int](4)
+	q.Send(3)
+	for _ = range q.Iter() {
+		break
+	}
+}
+
 func BenchmarkSend(b *testing.B) {
 	q := mq.Make[int](b.N)
 	b.ResetTimer()

npq/lib.go

@@ -38,6 +38,7 @@ package npq
 
 import (
 	"fmt"
+	"iter"
 	"sync"
 
 	"gogs.humancabbage.net/sam/priorityq"
@@ -212,3 +213,18 @@ func (s *state[P, T]) validatePriority(priority P) {
 			priority, s.min, s.max))
 	}
 }
+
+// Iter returns an iterator that consumes values until the queue is closed.
+func (s *state[P, T]) Iter() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for {
+			t, ok := s.Recv()
+			if !ok {
+				return
+			}
+			if !yield(t) {
+				return
+			}
+		}
+	}
+}

npq/lib_test.go

@@ -186,6 +186,30 @@ func TestConcProducerConsumer(t *testing.T) {
 	wg.Wait()
 }
 
+func TestIter(t *testing.T) {
+	t.Parallel()
+	q := npq.Make[int, int](4, 0, 16)
+	q.Send(4, 0)
+	q.Send(3, 1)
+	q.Send(2, 2)
+	q.Send(1, 3)
+	q.Close()
+	i := 0
+	for v := range q.Iter() {
+		if v != i {
+			t.Errorf("expected %d, got %d", i, v)
+		}
+		i++
+	}
+
+	// to test yield() returning false
+	q = npq.Make[int, int](4, 0, 16)
+	q.Send(1, 3)
+	for _ = range q.Iter() {
+		break
+	}
+}
+
 const highPriority = 2
 
 func BenchmarkSend(b *testing.B) {

pq/lib.go

@@ -24,6 +24,7 @@
 package pq
 
 import (
+	"iter"
 	"sync"
 
 	"gogs.humancabbage.net/sam/priorityq"
@@ -153,3 +154,18 @@ func (s *state[P, T]) TrySend(priority P, value T) error {
 	s.canRecv.Broadcast()
 	return nil
 }
+
+// Iter returns an iterator that consumes values until the queue is closed.
+func (s *state[P, T]) Iter() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for {
+			_, t, ok := s.Recv()
+			if !ok {
+				return
+			}
+			if !yield(t) {
+				return
+			}
+		}
+	}
+}

pq/lib_test.go

@@ -147,6 +147,30 @@ func TestConcProducerConsumer(t *testing.T) {
 	wg.Wait()
 }
 
+func TestIter(t *testing.T) {
+	t.Parallel()
+	q := pq.Make[int, int](4)
+	q.Send(4, 0)
+	q.Send(3, 1)
+	q.Send(2, 2)
+	q.Send(1, 3)
+	q.Close()
+	i := 0
+	for v := range q.Iter() {
+		if v != i {
+			t.Errorf("expected %d, got %d", i, v)
+		}
+		i++
+	}
+
+	// to test yield() returning false
+	q = pq.Make[int, int](4)
+	q.Send(1, 3)
+	for _ = range q.Iter() {
+		break
+	}
+}
+
 func BenchmarkSend(b *testing.B) {
 	q := pq.Make[int, int](b.N)
 	// randomize priorities to get amortized cost per op

queue/lib.go

@@ -6,6 +6,8 @@
 // makes determining whether the queue is full or empty trivial.
 package queue
 
+import "iter"
+
 // Q is a non-concurrent queue.
 type Q[T any] struct {
 	buf  []T
@@ -73,3 +75,32 @@ func (b *Q[T]) PushBack(value T) {
 		b.tail = 0
 	}
 }
+
+// Iter returns an iterator over all items in the queue.
+//
+// This does not pop items off the queue.
+func (b *Q[T]) Iter() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		remaining := b.len
+		i := b.head
+		for remaining > 0 {
+			yield(b.buf[i])
+			remaining--
+			i++
+			if i == b.len {
+				i = 0
+			}
+		}
+	}
+}
+
+// IterPop returns an iterator that pops each item off the queue.
+func (b *Q[T]) IterPop() iter.Seq[T] {
+	return func(yield func(T) bool) {
+		for b.CanPop() {
+			if !yield(b.PopFront()) {
+				break
+			}
+		}
+	}
+}

queue/lib_test.go

@@ -73,6 +73,51 @@ func TestFullPushPanic(t *testing.T) {
 	q.PushBack(2)
 }
 
+func TestIter(t *testing.T) {
+	q := queue.Make[int](4)
+	q.PushBack(1)
+	q.PushBack(2)
+	q.PushBack(3)
+	q.PushBack(4)
+	i := 0
+	for v := range q.Iter() {
+		expected := i + 1
+		if v != expected {
+			t.Errorf("iter %d should have value %d, not %d",
+				i, expected, v)
+		}
+		i++
+	}
+	if q.Len() != 4 {
+		t.Errorf("wrong length")
+	}
+}
+
+func TestIterPop(t *testing.T) {
+	t.Parallel()
+	q := queue.Make[int](4)
+	q.PushBack(1)
+	q.PushBack(2)
+	q.PushBack(3)
+	q.PushBack(4)
+	i := 0
+	for v := range q.IterPop() {
+		expected := i + 1
+		if v != expected {
+			t.Errorf("iter %d should have value %d, not %d",
+				i, expected, v)
+		}
+		i++
+		// to test yield() returning false
+		if i == 4 {
+			break
+		}
+	}
+	if q.Len() != 0 {
+		t.Errorf("wrong length")
+	}
+}
+
 func BenchmarkPush(b *testing.B) {
 	q := queue.Make[int](b.N)
 	rs := rand.NewSource(0)