From 8467ce7abc9c39dcb05f260a1934cbe184e05f4c Mon Sep 17 00:00:00 2001
From: Bo-Yi Wu <appleboy.tw@gmail.com>
Date: Sun, 17 May 2020 15:24:08 +0800
Subject: [PATCH] chore: improve countParams performance

---
 tree.go      | 35 +++++++++++++++++++++++++----------
 tree_test.go | 14 ++++++++++++++
 2 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/tree.go b/tree.go
index 24f14060..2e0c4478 100644
--- a/tree.go
+++ b/tree.go
@@ -5,13 +5,20 @@
 package gin
 
 import (
+	"bytes"
 	"net/url"
+	"reflect"
 	"strings"
 	"unicode"
 	"unicode/utf8"
 	"unsafe"
 )
 
+var (
+	strColon = []byte(":")
+	strStar  = []byte("*")
+)
+
 // Param is a single URL parameter, consisting of a key and a value.
 type Param struct {
 	Key   string
@@ -41,10 +48,6 @@ func (ps Params) ByName(name string) (va string) {
 	return
 }
 
-func bytesToStr(b []byte) string {
-	return *(*string)(unsafe.Pointer(&b))
-}
-
 type methodTree struct {
 	method string
 	root   *node
@@ -77,14 +80,26 @@ func longestCommonPrefix(a, b string) int {
 	return i
 }
 
+func bytesToStr(b []byte) string {
+	return *(*string)(unsafe.Pointer(&b))
+}
+
+func strToBytes(s string) (b []byte) {
+	/* #nosec G103 */
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	/* #nosec G103 */
+	sh := *(*reflect.StringHeader)(unsafe.Pointer(&s))
+	bh.Data = sh.Data
+	bh.Len = sh.Len
+	bh.Cap = sh.Len
+	return b
+}
+
 func countParams(path string) uint16 {
 	var n uint
-	for i := range []byte(path) {
-		switch path[i] {
-		case ':', '*':
-			n++
-		}
-	}
+	s := strToBytes(path)
+	n += uint(bytes.Count(s, strColon))
+	n += uint(bytes.Count(s, strStar))
 	return uint16(n)
 }
 
diff --git a/tree_test.go b/tree_test.go
index 1cb4f559..e244e140 100644
--- a/tree_test.go
+++ b/tree_test.go
@@ -93,6 +93,20 @@ func TestCountParams(t *testing.T) {
 	}
 }
 
+var s = strings.Repeat("/:param", 5)
+
+func BenchmarkCountParamsOld(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		countParamsOld(s)
+	}
+}
+
+func BenchmarkCountParams(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		countParamsNew(s)
+	}
+}
+
 func TestTreeAddAndGet(t *testing.T) {
 	tree := &node{}