Merge pull request #55 from nanjj/main

Made `decode` a little fast

strkey.go

@@ -1,4 +1,4 @@
-// Copyright 2018-2022 The NATS Authors
+// Copyright 2018-2023 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -137,22 +137,18 @@ func decode(src []byte) ([]byte, error) {
 	}
 	raw = raw[:n]
 
-	if len(raw) < 4 {
+	if n < 4 {
 		return nil, ErrInvalidEncoding
 	}
 
-	var crc uint16
-	checksum := bytes.NewReader(raw[len(raw)-2:])
-	if err := binary.Read(checksum, binary.LittleEndian, &crc); err != nil {
-		return nil, err
-	}
+	crc := binary.LittleEndian.Uint16(raw[n-2:])
 
 	// ensure checksum is valid
-	if err := validate(raw[0:len(raw)-2], crc); err != nil {
+	if err := validate(raw[0:n-2], crc); err != nil {
 		return nil, err
 	}
 
-	return raw[:len(raw)-2], nil
+	return raw[:n-2], nil
 }
 
 // Decode will decode the base32 string and check crc16 and enforce the prefix is what is expected.

strkey_test.go

@@ -0,0 +1,62 @@
+// Copyright 2023 The NATS Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package nkeys
+
+import (
+	"bytes"
+	"encoding/binary"
+	"testing"
+)
+
+func BenchmarkDecode(b *testing.B) {
+	tcs := []struct {
+		name string
+		f    func([]byte) ([]byte, error)
+	}{
+		{"original", func(src []byte) ([]byte, error) {
+			raw := make([]byte, b32Enc.DecodedLen(len(src)))
+			n, err := b32Enc.Decode(raw, src)
+			if err != nil {
+				return nil, err
+			}
+			raw = raw[:n]
+
+			if len(raw) < 4 {
+				return nil, ErrInvalidEncoding
+			}
+
+			var crc uint16
+			checksum := bytes.NewReader(raw[len(raw)-2:])
+			if err := binary.Read(checksum, binary.LittleEndian, &crc); err != nil {
+				return nil, err
+			}
+
+			// ensure checksum is valid
+			if err := validate(raw[0:len(raw)-2], crc); err != nil {
+				return nil, err
+			}
+			return raw[:len(raw)-2], nil
+		}},
+		{"current", decode},
+	}
+	for _, tc := range tcs {
+		b.Run(tc.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				if _, err := tc.f([]byte("SUAMAR5BIQ2AZCPYRTLLK7UGWMGSG2GWD2VPIXBNO7ZIB6TZAU4QAEJS2Q")); err != nil {
+					b.Fatal(err)
+				}
+			}
+		})
+	}
+}