add v2, a new version built with generics

README.md

@@ -1,19 +1,21 @@
 # Overview
 Deque is a highly optimized double-ended queue.
 
+**Please use [v2](v2/README.md), the generic version, if you have golang 1.18 or above.** 
+
 # Benchmark
 ```
-PushBack/Deque<harden>       100000000       10.3 ns/op       9 B/op      0 allocs/op
-PushBack/Deque                20000000       81.3 ns/op      24 B/op      1 allocs/op
-PushBack/list.List             5000000      281   ns/op      56 B/op      2 allocs/op
+PushBack/Deque<harden>       100000000       12.0 ns/op       8 B/op      0 allocs/op
+PushBack/Deque                20000000       55.5 ns/op      24 B/op      1 allocs/op
+PushBack/list.List             5000000      158.7 ns/op      56 B/op      1 allocs/op
 
-PushFront/Deque<harden>      195840157        8.0 ns/op       9 B/op      0 allocs/op
-PushFront/Deque               30000000       70.6 ns/op      24 B/op      1 allocs/op
-PushFront/list.List            5000000      276   ns/op      56 B/op      2 allocs/op
+PushFront/Deque<harden>      195840157        9.2 ns/op       8 B/op      0 allocs/op
+PushFront/Deque               30000000       49.2 ns/op      24 B/op      1 allocs/op
+PushFront/list.List            5000000      159.2 ns/op      56 B/op      1 allocs/op
 
-Random/Deque<harden>          65623633       17.3 ns/op       0 B/op      0 allocs/op
-Random/Deque                  50000000       32.1 ns/op       4 B/op      0 allocs/op
-Random/list.List              30000000      123   ns/op      28 B/op      1 allocs/op
+Random/Deque<harden>          65623633       15.1 ns/op       0 B/op      0 allocs/op
+Random/Deque                  50000000       24.7 ns/op       4 B/op      0 allocs/op
+Random/list.List              30000000       46.9 ns/op      28 B/op      1 allocs/op
 ```
 
 # Usage

deque.go

@@ -311,6 +311,9 @@ func (dq *deque) Range(f func(i int, v Elem) bool) {
 func (dq *deque) Peek(idx int) Elem {
 	i := idx
 	for _, c := range dq.chunks {
+		if i < 0 {
+			break
+		}
 		n := c.e - c.s
 		if i < n {
 			return c.data[c.s+i]
@@ -323,6 +326,9 @@ func (dq *deque) Peek(idx int) Elem {
 func (dq *deque) Replace(idx int, v Elem) {
 	i := idx
 	for _, c := range dq.chunks {
+		if i < 0 {
+			break
+		}
 		n := c.e - c.s
 		if i < n {
 			c.data[c.s+i] = v

interface.go

@@ -38,8 +38,8 @@ type Deque interface {
 	// Range iterates all the values in Deque.
 	Range(f func(i int, v Elem) bool)
 
-	// Peek returns the value at idx
+	// Peek returns the value at idx.
 	Peek(idx int) Elem
-	// Replace replaces the value at idx
+	// Replace replaces the value at idx.
 	Replace(idx int, v Elem)
 }

v2/README.md

@@ -0,0 +1,42 @@
+# Overview
+Deque is a highly optimized double-ended queue.
+
+# Benchmark
+```
+PushBack/Deque                20000000       13.6 ns/op       8 B/op      0 allocs/op
+PushBack/list.List             5000000      158.7 ns/op      56 B/op      1 allocs/op
+
+PushFront/Deque               30000000        9.8 ns/op       8 B/op      0 allocs/op
+PushFront/list.List            5000000      159.2 ns/op      56 B/op      1 allocs/op
+
+Random/Deque                  50000000       13.9 ns/op       0 B/op      0 allocs/op
+Random/list.List              30000000       46.9 ns/op      28 B/op      1 allocs/op
+```
+
+# Usage
+``` go
+import "github.com/edwingeng/deque/v2"
+
+dq := NewDeque[int]()
+dq.PushBack(100)
+dq.PushBack(200)
+dq.PushBack(300)
+for !dq.IsEmpty() {
+    fmt.Println(dq.PopFront())
+}
+
+dq.PushFront(100)
+dq.PushFront(200)
+dq.PushFront(300)
+for i, n := 0, dq.Len(); i < n; i++ {
+    fmt.Println(dq.PopFront())
+}
+
+// Output:
+// 100
+// 200
+// 300
+// 300
+// 200
+// 100
+```

v2/benchmark_test.go

@@ -0,0 +1,80 @@
+package deque
+
+import (
+	"container/list"
+	"math/rand"
+	"testing"
+)
+
+func BenchmarkPushBack(b *testing.B) {
+	b.Run("Deque", func(b *testing.B) {
+		dq := NewDeque[int]()
+		for i := 0; i < b.N; i++ {
+			dq.PushBack(i)
+		}
+	})
+	b.Run("list.List", func(b *testing.B) {
+		lst := list.New()
+		for i := 0; i < b.N; i++ {
+			lst.PushBack(i)
+		}
+	})
+}
+
+func BenchmarkPushFront(b *testing.B) {
+	b.Run("Deque", func(b *testing.B) {
+		dq := NewDeque[int]()
+		for i := 0; i < b.N; i++ {
+			dq.PushFront(i)
+		}
+	})
+	b.Run("list.List", func(b *testing.B) {
+		lst := list.New()
+		for i := 0; i < b.N; i++ {
+			lst.PushFront(i)
+		}
+	})
+}
+
+func BenchmarkRandom(b *testing.B) {
+	const nn = 10000
+	a := make([]int, nn)
+	for i := 0; i < nn; i++ {
+		a[i] = rand.Int()
+	}
+
+	b.Run("Deque", func(b *testing.B) {
+		dq := NewDeque[int]()
+		for i := 0; i < b.N; i++ {
+			switch a[i%nn] % 4 {
+			case 0:
+				dq.PushBack(i)
+			case 1:
+				dq.PushFront(i)
+			case 2:
+				dq.TryPopBack()
+			case 3:
+				dq.TryPopFront()
+			}
+		}
+	})
+	b.Run("list.List", func(b *testing.B) {
+		lst := list.New()
+		for i := 0; i < b.N; i++ {
+			switch a[i%nn] % 4 {
+			case 0:
+				lst.PushBack(i)
+			case 1:
+				lst.PushFront(i)
+			case 2:
+				if v := lst.Back(); v != nil {
+					lst.Remove(v)
+				}
+			case 3:
+				if v := lst.Front(); v != nil {
+					lst.Remove(v)
+				}
+			}
+		}
+	})
+}

v2/coverage.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+
+[[ "$TRACE" ]] && set -x
+pushd `dirname "$0"` > /dev/null
+trap __EXIT EXIT
+
+colorful=false
+tput setaf 7 > /dev/null 2>&1
+if [[ $? -eq 0 ]]; then
+    colorful=true
+fi
+
+function __EXIT() {
+    popd > /dev/null
+}
+
+function printError() {
+    $colorful && tput setaf 1
+    >&2 echo "Error: $@"
+    $colorful && tput setaf 7
+}
+
+function printImportantMessage() {
+    $colorful && tput setaf 3
+    >&2 echo "$@"
+    $colorful && tput setaf 7
+}
+
+function printUsage() {
+    $colorful && tput setaf 3
+    >&2 echo "$@"
+    $colorful && tput setaf 7
+}
+
+go test -cover -coverprofile=c.out -v "$@" && go tool cover -html=c.out