Optimize compact map field names concatenation

fxamacker · fxamacker · commit 87e6b6b32996 · 2023-10-20T10:47:22.000-05:00
diff --git a/typeinfo.go b/typeinfo.go
@@ -22,6 +22,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"sort"
+	"strings"
 
 	"github.com/fxamacker/cbor/v2"
 )
@@ -418,9 +419,12 @@ func (fn *fieldNameSorter) Swap(i, j int) {
 }
 
 func (fn *fieldNameSorter) join(sep string) string {
-	var s string
-	for _, i := range fn.index {
-		s += sep + fn.names[i].ID()
+	var sb strings.Builder
+	for i, index := range fn.index {
+		if i > 0 {
+			sb.WriteString(sep)
+		}
+		sb.WriteString(fn.names[index].ID())
 	}
-	return s
+	return sb.String()
 }

Original file line number	Diff line number	Diff line change
`@@ -22,6 +22,7 @@ import (`
`22`	`22`	`"encoding/binary"`
`23`	`23`	`"fmt"`
`24`	`24`	`"sort"`
	`25`	`+ "strings"`
`25`	`26`
`26`	`27`	`"github.com/fxamacker/cbor/v2"`
`27`	`28`	`)`
`@@ -418,9 +419,12 @@ func (fn *fieldNameSorter) Swap(i, j int) {`
`418`	`419`	`}`
`419`	`420`
`420`	`421`	`func (fn *fieldNameSorter) join(sep string) string {`
`421`		`- var s string`
`422`		`- for _, i := range fn.index {`
`423`		`- s += sep + fn.names[i].ID()`
	`422`	`+ var sb strings.Builder`
	`423`	`+ for i, index := range fn.index {`
	`424`	`+ if i > 0 {`
	`425`	`+ sb.WriteString(sep)`
	`426`	`+ }`
	`427`	`+ sb.WriteString(fn.names[index].ID())`
`424`	`428`	`}`
`425`		`- return s`
	`429`	`+ return sb.String()`
`426`	`430`	`}`