From 7bb55be855270fd6a0ab74a4c07c31687758b5ba Mon Sep 17 00:00:00 2001
From: cnderrauber <zengjie9004@gmail.com>
Date: Mon, 1 Jul 2024 15:36:57 +0800
Subject: [PATCH] Remove third-party dequeue

Remove third-party dequeue
---
 go.mod           |  1 -
 go.sum           |  2 --
 payload_queue.go |  6 ++--
 queue.go         | 78 ++++++++++++++++++++++++++++++++++++++++++++++++
 queue_test.go    | 48 +++++++++++++++++++++++++++++
 5 files changed, 128 insertions(+), 7 deletions(-)
 create mode 100644 queue.go
 create mode 100644 queue_test.go

diff --git a/go.mod b/go.mod
index 42fa5eb4..2f004cae 100644
--- a/go.mod
+++ b/go.mod
@@ -1,7 +1,6 @@
 module github.com/pion/sctp
 
 require (
-	github.com/gammazero/deque v0.2.1
 	github.com/pion/logging v0.2.2
 	github.com/pion/randutil v0.1.0
 	github.com/pion/transport/v3 v3.0.2
diff --git a/go.sum b/go.sum
index 92a3c047..25392e78 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,6 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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/gammazero/deque v0.2.1 h1:qSdsbG6pgp6nL7A0+K/B7s12mcCY/5l5SIUpMOl+dC0=
-github.com/gammazero/deque v0.2.1/go.mod h1:LFroj8x4cMYCukHJDbxFCkT+r9AndaJnFMuZDV34tuU=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
diff --git a/payload_queue.go b/payload_queue.go
index 7ee8820a..92eacecd 100644
--- a/payload_queue.go
+++ b/payload_queue.go
@@ -3,15 +3,13 @@
 
 package sctp
 
-import "github.com/gammazero/deque"
-
 type payloadQueue struct {
-	chunks *deque.Deque[*chunkPayloadData]
+	chunks *queue[*chunkPayloadData]
 	nBytes int
 }
 
 func newPayloadQueue() *payloadQueue {
-	return &payloadQueue{chunks: deque.New[*chunkPayloadData](128)}
+	return &payloadQueue{chunks: newQueue[*chunkPayloadData](128)}
 }
 
 func (q *payloadQueue) pushNoCheck(p *chunkPayloadData) {
diff --git a/queue.go b/queue.go
new file mode 100644
index 00000000..e089973a
--- /dev/null
+++ b/queue.go
@@ -0,0 +1,78 @@
+package sctp
+
+import "fmt"
+
+type queue[T any] struct {
+	buf   []T
+	head  int
+	tail  int
+	count int
+}
+
+const minCap = 16
+
+func newQueue[T any](capacity int) *queue[T] {
+	queueCap := minCap
+	for queueCap < capacity {
+		queueCap <<= 1
+	}
+
+	return &queue[T]{
+		buf: make([]T, queueCap),
+	}
+}
+
+func (q *queue[T]) Len() int {
+	return q.count
+}
+
+func (q *queue[T]) PushBack(ele T) {
+	q.growIfFull()
+	q.buf[q.tail] = ele
+	q.tail = (q.tail + 1) % len(q.buf)
+	q.count++
+}
+
+func (q *queue[T]) PopFront() T {
+	if q.count <= 0 {
+		panic("PopFront() called on empty queue")
+	}
+	ele := q.buf[q.head]
+	var zeroVal T
+	q.buf[q.head] = zeroVal
+	q.head = (q.head + 1) % len(q.buf)
+	q.count--
+	return ele
+}
+
+func (q *queue[T]) Front() T {
+	if q.count <= 0 {
+		panic("Front() called on empty queue")
+	}
+	return q.buf[q.head]
+}
+
+func (q *queue[T]) At(i int) T {
+	if i < 0 || i >= q.count {
+		panic(fmt.Sprintf("index %d out of range %d", i, q.count))
+	}
+	return q.buf[(q.head+i)%(len(q.buf))]
+}
+
+func (q *queue[T]) growIfFull() {
+	if q.count < len(q.buf) {
+		return
+	}
+
+	newBuf := make([]T, q.count<<1)
+	if q.tail > q.head {
+		copy(newBuf, q.buf[q.head:q.tail])
+	} else {
+		n := copy(newBuf, q.buf[q.head:])
+		copy(newBuf[n:], q.buf[:q.tail])
+	}
+
+	q.head = 0
+	q.tail = q.count
+	q.buf = newBuf
+}
diff --git a/queue_test.go b/queue_test.go
new file mode 100644
index 00000000..522ab15c
--- /dev/null
+++ b/queue_test.go
@@ -0,0 +1,48 @@
+package sctp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestQueue(t *testing.T) {
+	q := newQueue[int](32)
+	assert.Panics(t, func() { q.PopFront() })
+	assert.Panics(t, func() { q.Front() })
+	assert.Zero(t, q.Len())
+
+	// test push & pop
+	for i := 1; i < 33; i++ {
+		q.PushBack(i)
+	}
+	assert.Equal(t, 32, q.Len())
+	assert.Equal(t, 5, q.At(4))
+	for i := 1; i < 33; i++ {
+		assert.Equal(t, i, q.Front())
+		assert.Equal(t, i, q.PopFront())
+	}
+	assert.Zero(t, q.Len())
+
+	q.PushBack(10)
+	q.PushBack(11)
+	assert.Equal(t, 2, q.Len())
+	assert.Equal(t, 11, q.At(1))
+	assert.Equal(t, 10, q.Front())
+	assert.Panics(t, func() {
+		q.At(33)
+	})
+	assert.Equal(t, 10, q.PopFront())
+	assert.Equal(t, 11, q.PopFront())
+
+	// test grow capacity
+	for i := 0; i < 64; i++ {
+		q.PushBack(i)
+	}
+	assert.Equal(t, 64, q.Len())
+	assert.Equal(t, 2, q.At(2))
+	for i := 0; i < 64; i++ {
+		assert.Equal(t, i, q.Front())
+		assert.Equal(t, i, q.PopFront())
+	}
+}