From: Matt Joiner <anacrolix@gmail.com>
Date: Mon, 23 Jul 2018 00:50:18 +0000 (+1000)
Subject: bencode.Marshal: Get rid of the intermediate buffer
X-Git-Tag: v1.0.0~64
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=2eb98189ff7a313bac8c4fbbddd6b082d3b47917;p=btrtrc.git

bencode.Marshal: Get rid of the intermediate buffer
---

diff --git a/bencode/api.go b/bencode/api.go
index 6c311e11..15687a8c 100644
--- a/bencode/api.go
+++ b/bencode/api.go
@@ -1,7 +1,6 @@
 package bencode
 
 import (
-	"bufio"
 	"bytes"
 	"fmt"
 	"io"
@@ -111,11 +110,11 @@ type Unmarshaler interface {
 	UnmarshalBencode([]byte) error
 }
 
-// Marshal the value 'v' to the bencode form, return the result as []byte and an
-// error if any.
+// Marshal the value 'v' to the bencode form, return the result as []byte and
+// an error if any.
 func Marshal(v interface{}) ([]byte, error) {
 	var buf bytes.Buffer
-	e := Encoder{w: bufio.NewWriter(&buf)}
+	e := Encoder{w: &buf}
 	err := e.Encode(v)
 	if err != nil {
 		return nil, err
@@ -154,5 +153,5 @@ func NewDecoder(r io.Reader) *Decoder {
 }
 
 func NewEncoder(w io.Writer) *Encoder {
-	return &Encoder{w: bufio.NewWriter(w)}
+	return &Encoder{w: w}
 }
diff --git a/bencode/encode.go b/bencode/encode.go
index d6b6334f..2bbf0bad 100644
--- a/bencode/encode.go
+++ b/bencode/encode.go
@@ -17,11 +17,7 @@ func isEmptyValue(v reflect.Value) bool {
 }
 
 type Encoder struct {
-	w interface {
-		Flush() error
-		io.Writer
-		WriteString(string) (int, error)
-	}
+	w       io.Writer
 	scratch [64]byte
 }
 
@@ -42,7 +38,7 @@ func (e *Encoder) Encode(v interface{}) (err error) {
 		}
 	}()
 	e.reflectValue(reflect.ValueOf(v))
-	return e.w.Flush()
+	return nil
 }
 
 type string_values []reflect.Value
@@ -60,9 +56,10 @@ func (e *Encoder) write(s []byte) {
 }
 
 func (e *Encoder) writeString(s string) {
-	_, err := e.w.WriteString(s)
-	if err != nil {
-		panic(err)
+	for s != "" {
+		n := copy(e.scratch[:], s)
+		s = s[n:]
+		e.write(e.scratch[:n])
 	}
 }
 
@@ -129,13 +126,13 @@ func (e *Encoder) reflectValue(v reflect.Value) {
 			e.writeString("i0e")
 		}
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		b := strconv.AppendInt(e.scratch[:0], v.Int(), 10)
 		e.writeString("i")
+		b := strconv.AppendInt(e.scratch[:0], v.Int(), 10)
 		e.write(b)
 		e.writeString("e")
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-		b := strconv.AppendUint(e.scratch[:0], v.Uint(), 10)
 		e.writeString("i")
+		b := strconv.AppendUint(e.scratch[:0], v.Uint(), 10)
 		e.write(b)
 		e.writeString("e")
 	case reflect.String: