Replace MarshalBinary with Encode

This new approach can avoid allocations.

authentication.go

@@ -1,9 +1,10 @@
 package pgproto3
 
 import (
-	"bytes"
 	"encoding/binary"
 	"fmt"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 const (
@@ -36,19 +37,18 @@ func (dst *Authentication) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Authentication) MarshalBinary() ([]byte, error) {
+func (src *Authentication) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'R')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-	buf.WriteByte('R')
+	dst = pgio.AppendInt32(dst, -1)
-	buf.Write(bigEndian.Uint32(0))
+	dst = pgio.AppendUint32(dst, src.Type)
-	buf.Write(bigEndian.Uint32(src.Type))
 
 	switch src.Type {
 	case AuthTypeMD5Password:
-		buf.Write(src.Salt[:])
+		dst = append(dst, src.Salt[:]...)
 	}
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }

backend.go

@@ -32,12 +32,7 @@ func NewBackend(r io.Reader, w io.Writer) (*Backend, error) {
 }
 
 func (b *Backend) Send(msg BackendMessage) error {
-	buf, err := msg.MarshalBinary()
+	_, err := b.w.Write(msg.Encode(nil))
-	if err != nil {
-		return nil
-	}
-
-	_, err = b.w.Write(buf)
 	return err
 }
 

backend_key_data.go

@@ -1,9 +1,10 @@
 package pgproto3
 
 import (
-	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type BackendKeyData struct {
@@ -24,14 +25,12 @@ func (dst *BackendKeyData) Decode(src []byte) error {
 	return nil
 }
 
-func (src *BackendKeyData) MarshalBinary() ([]byte, error) {
+func (src *BackendKeyData) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'K')
-	buf := &bytes.Buffer{}
+	dst = pgio.AppendUint32(dst, 12)
-	buf.WriteByte('K')
+	dst = pgio.AppendUint32(dst, src.ProcessID)
-	buf.Write(bigEndian.Uint32(12))
+	dst = pgio.AppendUint32(dst, src.SecretKey)
-	buf.Write(bigEndian.Uint32(src.ProcessID))
+	return dst
-	buf.Write(bigEndian.Uint32(src.SecretKey))
-	return buf.Bytes(), nil
 }
 
 func (src *BackendKeyData) MarshalJSON() ([]byte, error) {

bind.go

@@ -5,6 +5,8 @@ import (
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Bind struct {
@@ -101,45 +103,40 @@ func (dst *Bind) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Bind) MarshalBinary() ([]byte, error) {
+func (src *Bind) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'B')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('B')
+	dst = append(dst, src.DestinationPortal...)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, 0)
-
+	dst = append(dst, src.PreparedStatement...)
-	buf.WriteString(src.DestinationPortal)
+	dst = append(dst, 0)
-	buf.WriteByte(0)
-	buf.WriteString(src.PreparedStatement)
-	buf.WriteByte(0)
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ParameterFormatCodes))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.ParameterFormatCodes)))
 	for _, fc := range src.ParameterFormatCodes {
-		buf.Write(bigEndian.Int16(fc))
+		dst = pgio.AppendInt16(dst, fc)
 	}
 
-	buf.Write(bigEndian.Uint16(uint16(len(src.Parameters))))
+	dst = pgio.AppendUint16(dst, uint16(len(src.Parameters)))
-
 	for _, p := range src.Parameters {
 		if p == nil {
-			buf.Write(bigEndian.Int32(-1))
+			dst = pgio.AppendInt32(dst, -1)
 			continue
 		}
 
-		buf.Write(bigEndian.Int32(int32(len(p))))
+		dst = pgio.AppendInt32(dst, int32(len(p)))
-		buf.Write(p)
+		dst = append(dst, p...)
 	}
 
-	buf.Write(bigEndian.Uint16(uint16(len(src.ResultFormatCodes))))
+	dst = pgio.AppendUint16(dst, uint16(len(src.ResultFormatCodes)))
-
 	for _, fc := range src.ResultFormatCodes {
-		buf.Write(bigEndian.Int16(fc))
+		dst = pgio.AppendInt16(dst, fc)
 	}
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *Bind) MarshalJSON() ([]byte, error) {

bind_complete.go

@@ -16,8 +16,8 @@ func (dst *BindComplete) Decode(src []byte) error {
 	return nil
 }
 
-func (src *BindComplete) MarshalBinary() ([]byte, error) {
+func (src *BindComplete) Encode(dst []byte) []byte {
-	return []byte{'2', 0, 0, 0, 4}, nil
+	return append(dst, '2', 0, 0, 0, 4)
 }
 
 func (src *BindComplete) MarshalJSON() ([]byte, error) {

close.go

@@ -2,8 +2,9 @@ package pgproto3
 
 import (
 	"bytes"
-	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Close struct {
@@ -31,20 +32,18 @@ func (dst *Close) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Close) MarshalBinary() ([]byte, error) {
+func (src *Close) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'C')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('C')
+	dst = append(dst, src.ObjectType)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, src.Name...)
+	dst = append(dst, 0)
 
-	buf.WriteByte(src.ObjectType)
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
-	buf.WriteString(src.Name)
-	buf.WriteByte(0)
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	return dst
-
-	return buf.Bytes(), nil
 }
 
 func (src *Close) MarshalJSON() ([]byte, error) {

close_complete.go

@@ -16,8 +16,8 @@ func (dst *CloseComplete) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CloseComplete) MarshalBinary() ([]byte, error) {
+func (src *CloseComplete) Encode(dst []byte) []byte {
-	return []byte{'3', 0, 0, 0, 4}, nil
+	return append(dst, '3', 0, 0, 0, 4)
 }
 
 func (src *CloseComplete) MarshalJSON() ([]byte, error) {

command_complete.go

@@ -3,6 +3,8 @@ package pgproto3
 import (
 	"bytes"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type CommandComplete struct {
@@ -22,17 +24,17 @@ func (dst *CommandComplete) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CommandComplete) MarshalBinary() ([]byte, error) {
+func (src *CommandComplete) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'C')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('C')
+	dst = append(dst, src.CommandTag...)
-	buf.Write(bigEndian.Uint32(uint32(4 + len(src.CommandTag) + 1)))
+	dst = append(dst, 0)
 
-	buf.WriteString(src.CommandTag)
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
-	buf.WriteByte(0)
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *CommandComplete) MarshalJSON() ([]byte, error) {

copy_both_response.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type CopyBothResponse struct {
@@ -37,20 +39,19 @@ func (dst *CopyBothResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CopyBothResponse) MarshalBinary() ([]byte, error) {
+func (src *CopyBothResponse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'W')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('W')
-	buf.Write(bigEndian.Uint32(uint32(4 + 1 + 2 + 2*len(src.ColumnFormatCodes))))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ColumnFormatCodes))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.ColumnFormatCodes)))
 	for _, fc := range src.ColumnFormatCodes {
-		buf.Write(bigEndian.Uint16(fc))
+		dst = pgio.AppendUint16(dst, fc)
 	}
 
-	return buf.Bytes(), nil
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
 }
 
 func (src *CopyBothResponse) MarshalJSON() ([]byte, error) {

copy_data.go

@@ -1,9 +1,10 @@
 package pgproto3
 
 import (
-	"bytes"
 	"encoding/hex"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type CopyData struct {
@@ -18,15 +19,11 @@ func (dst *CopyData) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CopyData) MarshalBinary() ([]byte, error) {
+func (src *CopyData) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'd')
-	buf := &bytes.Buffer{}
+	dst = pgio.AppendInt32(dst, int32(4+len(src.Data)))
-
+	dst = append(dst, src.Data...)
-	buf.WriteByte('d')
+	return dst
-	buf.Write(bigEndian.Uint32(uint32(4 + len(src.Data))))
-	buf.Write(src.Data)
-
-	return buf.Bytes(), nil
 }
 
 func (src *CopyData) MarshalJSON() ([]byte, error) {

copy_in_response.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type CopyInResponse struct {
@@ -37,20 +39,19 @@ func (dst *CopyInResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CopyInResponse) MarshalBinary() ([]byte, error) {
+func (src *CopyInResponse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'G')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('G')
-	buf.Write(bigEndian.Uint32(uint32(4 + 1 + 2 + 2*len(src.ColumnFormatCodes))))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ColumnFormatCodes))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.ColumnFormatCodes)))
 	for _, fc := range src.ColumnFormatCodes {
-		buf.Write(bigEndian.Uint16(fc))
+		dst = pgio.AppendUint16(dst, fc)
 	}
 
-	return buf.Bytes(), nil
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
 }
 
 func (src *CopyInResponse) MarshalJSON() ([]byte, error) {

copy_out_response.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type CopyOutResponse struct {
@@ -37,20 +39,19 @@ func (dst *CopyOutResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *CopyOutResponse) MarshalBinary() ([]byte, error) {
+func (src *CopyOutResponse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'H')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('H')
-	buf.Write(bigEndian.Uint32(uint32(4 + 1 + 2 + 2*len(src.ColumnFormatCodes))))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ColumnFormatCodes))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.ColumnFormatCodes)))
 	for _, fc := range src.ColumnFormatCodes {
-		buf.Write(bigEndian.Uint16(fc))
+		dst = pgio.AppendUint16(dst, fc)
 	}
 
-	return buf.Bytes(), nil
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
 }
 
 func (src *CopyOutResponse) MarshalJSON() ([]byte, error) {

data_row.go

@@ -1,10 +1,11 @@
 package pgproto3
 
 import (
-	"bytes"
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type DataRow struct {
@@ -58,28 +59,25 @@ func (dst *DataRow) Decode(src []byte) error {
 	return nil
 }
 
-func (src *DataRow) MarshalBinary() ([]byte, error) {
+func (src *DataRow) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'D')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('D')
-	buf.Write(bigEndian.Uint32(0))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.Values))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.Values)))
 	for _, v := range src.Values {
 		if v == nil {
-			buf.Write(bigEndian.Int32(-1))
+			dst = pgio.AppendInt32(dst, -1)
 			continue
 		}
 
-		buf.Write(bigEndian.Int32(int32(len(v))))
+		dst = pgio.AppendInt32(dst, int32(len(v)))
-		buf.Write(v)
+		dst = append(dst, v...)
 	}
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *DataRow) MarshalJSON() ([]byte, error) {

describe.go

@@ -2,8 +2,9 @@ package pgproto3
 
 import (
 	"bytes"
-	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Describe struct {
@@ -31,20 +32,18 @@ func (dst *Describe) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Describe) MarshalBinary() ([]byte, error) {
+func (src *Describe) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'D')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('D')
+	dst = append(dst, src.ObjectType)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, src.Name...)
+	dst = append(dst, 0)
 
-	buf.WriteByte(src.ObjectType)
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
-	buf.WriteString(src.Name)
-	buf.WriteByte(0)
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	return dst
-
-	return buf.Bytes(), nil
 }
 
 func (src *Describe) MarshalJSON() ([]byte, error) {

empty_query_response.go

@@ -16,8 +16,8 @@ func (dst *EmptyQueryResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *EmptyQueryResponse) MarshalBinary() ([]byte, error) {
+func (src *EmptyQueryResponse) Encode(dst []byte) []byte {
-	return []byte{'I', 0, 0, 0, 4}, nil
+	return append(dst, 'I', 0, 0, 0, 4)
 }
 
 func (src *EmptyQueryResponse) MarshalJSON() ([]byte, error) {

error_response.go

@@ -103,11 +103,11 @@ func (dst *ErrorResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *ErrorResponse) MarshalBinary() ([]byte, error) {
+func (src *ErrorResponse) Encode(dst []byte) []byte {
-	return src.marshalBinary('E')
+	return append(dst, src.marshalBinary('E')...)
 }
 
-func (src *ErrorResponse) marshalBinary(typeByte byte) ([]byte, error) {
+func (src *ErrorResponse) marshalBinary(typeByte byte) []byte {
 	var bigEndian BigEndianBuf
 	buf := &bytes.Buffer{}
 
@@ -193,5 +193,5 @@ func (src *ErrorResponse) marshalBinary(typeByte byte) ([]byte, error) {
 
 	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
 
-	return buf.Bytes(), nil
+	return buf.Bytes()
 }

execute.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Execute struct {
@@ -30,21 +32,19 @@ func (dst *Execute) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Execute) MarshalBinary() ([]byte, error) {
+func (src *Execute) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'E')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('E')
+	dst = append(dst, src.Portal...)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, 0)
 
-	buf.WriteString(src.Portal)
+	dst = pgio.AppendUint32(dst, src.MaxRows)
-	buf.WriteByte(0)
 
-	buf.Write(bigEndian.Uint32(src.MaxRows))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	return dst
-
-	return buf.Bytes(), nil
 }
 
 func (src *Execute) MarshalJSON() ([]byte, error) {

flush.go

@@ -16,8 +16,8 @@ func (dst *Flush) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Flush) MarshalBinary() ([]byte, error) {
+func (src *Flush) Encode(dst []byte) []byte {
-	return []byte{'H', 0, 0, 0, 4}, nil
+	return append(dst, 'H', 0, 0, 0, 4)
 }
 
 func (src *Flush) MarshalJSON() ([]byte, error) {

frontend.go

@@ -42,12 +42,7 @@ func NewFrontend(r io.Reader, w io.Writer) (*Frontend, error) {
 }
 
 func (b *Frontend) Send(msg FrontendMessage) error {
-	buf, err := msg.MarshalBinary()
+	_, err := b.w.Write(msg.Encode(nil))
-	if err != nil {
-		return nil
-	}
-
-	_, err = b.w.Write(buf)
 	return err
 }
 

function_call_response.go

@@ -1,10 +1,11 @@
 package pgproto3
 
 import (
-	"bytes"
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type FunctionCallResponse struct {
@@ -34,21 +35,21 @@ func (dst *FunctionCallResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *FunctionCallResponse) MarshalBinary() ([]byte, error) {
+func (src *FunctionCallResponse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'V')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('V')
-	buf.Write(bigEndian.Uint32(uint32(4 + 4 + len(src.Result))))
 
 	if src.Result == nil {
-		buf.Write(bigEndian.Int32(-1))
+		dst = pgio.AppendInt32(dst, -1)
 	} else {
-		buf.Write(bigEndian.Int32(int32(len(src.Result))))
+		dst = pgio.AppendInt32(dst, int32(len(src.Result)))
-		buf.Write(src.Result)
+		dst = append(dst, src.Result...)
 	}
 
-	return buf.Bytes(), nil
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
 }
 
 func (src *FunctionCallResponse) MarshalJSON() ([]byte, error) {

no_data.go

@@ -16,8 +16,8 @@ func (dst *NoData) Decode(src []byte) error {
 	return nil
 }
 
-func (src *NoData) MarshalBinary() ([]byte, error) {
+func (src *NoData) Encode(dst []byte) []byte {
-	return []byte{'n', 0, 0, 0, 4}, nil
+	return append(dst, 'n', 0, 0, 0, 4)
 }
 
 func (src *NoData) MarshalJSON() ([]byte, error) {

notice_response.go

@@ -8,6 +8,6 @@ func (dst *NoticeResponse) Decode(src []byte) error {
 	return (*ErrorResponse)(dst).Decode(src)
 }
 
-func (src *NoticeResponse) MarshalBinary() ([]byte, error) {
+func (src *NoticeResponse) Encode(dst []byte) []byte {
-	return (*ErrorResponse)(src).marshalBinary('N')
+	return append(dst, (*ErrorResponse)(src).marshalBinary('N')...)
 }

notification_response.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type NotificationResponse struct {
@@ -35,19 +37,19 @@ func (dst *NotificationResponse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *NotificationResponse) MarshalBinary() ([]byte, error) {
+func (src *NotificationResponse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'A')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('A')
+	dst = append(dst, src.Channel...)
-	buf.Write(bigEndian.Uint32(uint32(4 + 4 + len(src.Channel) + len(src.Payload))))
+	dst = append(dst, 0)
+	dst = append(dst, src.Payload...)
+	dst = append(dst, 0)
 
-	buf.WriteString(src.Channel)
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
-	buf.WriteByte(0)
-	buf.WriteString(src.Payload)
-	buf.WriteByte(0)
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *NotificationResponse) MarshalJSON() ([]byte, error) {

parameter_description.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type ParameterDescription struct {
@@ -33,20 +35,19 @@ func (dst *ParameterDescription) Decode(src []byte) error {
 	return nil
 }
 
-func (src *ParameterDescription) MarshalBinary() ([]byte, error) {
+func (src *ParameterDescription) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 't')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('t')
-	buf.Write(bigEndian.Uint32(uint32(4 + 2 + 4*len(src.ParameterOIDs))))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ParameterOIDs))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.ParameterOIDs)))
 	for _, oid := range src.ParameterOIDs {
-		buf.Write(bigEndian.Uint32(oid))
+		dst = pgio.AppendUint32(dst, oid)
 	}
 
-	return buf.Bytes(), nil
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
+
+	return dst
 }
 
 func (src *ParameterDescription) MarshalJSON() ([]byte, error) {

parameter_status.go

@@ -2,8 +2,9 @@ package pgproto3
 
 import (
 	"bytes"
-	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type ParameterStatus struct {
@@ -32,21 +33,19 @@ func (dst *ParameterStatus) Decode(src []byte) error {
 	return nil
 }
 
-func (src *ParameterStatus) MarshalBinary() ([]byte, error) {
+func (src *ParameterStatus) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'S')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('S')
+	dst = append(dst, src.Name...)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, 0)
+	dst = append(dst, src.Value...)
+	dst = append(dst, 0)
 
-	buf.WriteString(src.Name)
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
-	buf.WriteByte(0)
-	buf.WriteString(src.Value)
-	buf.WriteByte(0)
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	return dst
-
-	return buf.Bytes(), nil
 }
 
 func (ps *ParameterStatus) MarshalJSON() ([]byte, error) {

parse.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Parse struct {
@@ -44,27 +46,24 @@ func (dst *Parse) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Parse) MarshalBinary() ([]byte, error) {
+func (src *Parse) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'P')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
+	dst = pgio.AppendInt32(dst, -1)
 
-	buf.WriteByte('P')
+	dst = append(dst, src.Name...)
-	buf.Write(bigEndian.Uint32(0))
+	dst = append(dst, 0)
+	dst = append(dst, src.Query...)
+	dst = append(dst, 0)
 
-	buf.WriteString(src.Name)
+	dst = pgio.AppendUint16(dst, uint16(len(src.ParameterOIDs)))
-	buf.WriteByte(0)
+	for _, oid := range src.ParameterOIDs {
-	buf.WriteString(src.Query)
+		dst = pgio.AppendUint32(dst, oid)
-	buf.WriteByte(0)
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.ParameterOIDs))))
-
-	for _, v := range src.ParameterOIDs {
-		buf.Write(bigEndian.Uint32(v))
 	}
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *Parse) MarshalJSON() ([]byte, error) {

parse_complete.go

@@ -16,8 +16,8 @@ func (dst *ParseComplete) Decode(src []byte) error {
 	return nil
 }
 
-func (src *ParseComplete) MarshalBinary() ([]byte, error) {
+func (src *ParseComplete) Encode(dst []byte) []byte {
-	return []byte{'1', 0, 0, 0, 4}, nil
+	return append(dst, '1', 0, 0, 0, 4)
 }
 
 func (src *ParseComplete) MarshalJSON() ([]byte, error) {

password_message.go

@@ -3,6 +3,8 @@ package pgproto3
 import (
 	"bytes"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type PasswordMessage struct {
@@ -23,14 +25,14 @@ func (dst *PasswordMessage) Decode(src []byte) error {
 	return nil
 }
 
-func (src *PasswordMessage) MarshalBinary() ([]byte, error) {
+func (src *PasswordMessage) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'p')
-	buf := &bytes.Buffer{}
+	dst = pgio.AppendInt32(dst, int32(4+len(src.Password)+1))
-	buf.WriteByte('p')
+
-	buf.Write(bigEndian.Uint32(uint32(4 + len(src.Password) + 1)))
+	dst = append(dst, src.Password...)
-	buf.WriteString(src.Password)
+	dst = append(dst, 0)
-	buf.WriteByte(0)
+
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *PasswordMessage) MarshalJSON() ([]byte, error) {

pgproto3.go

@@ -4,12 +4,13 @@ import "fmt"
 
 // Message is the interface implemented by an object that can decode and encode
 // a particular PostgreSQL message.
-//
-// Decode is allowed and expected to retain a reference to data after
-// returning (unlike encoding.BinaryUnmarshaler).
 type Message interface {
+	// Decode is allowed and expected to retain a reference to data after
+	// returning (unlike encoding.BinaryUnmarshaler).
 	Decode(data []byte) error
-	MarshalBinary() (data []byte, err error)
+
+	// Encode appends itself to dst and returns the new buffer.
+	Encode(dst []byte) []byte
 }
 
 type FrontendMessage interface {

query.go

@@ -3,6 +3,8 @@ package pgproto3
 import (
 	"bytes"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 type Query struct {
@@ -22,14 +24,14 @@ func (dst *Query) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Query) MarshalBinary() ([]byte, error) {
+func (src *Query) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'Q')
-	buf := &bytes.Buffer{}
+	dst = pgio.AppendInt32(dst, int32(4+len(src.String)+1))
-	buf.WriteByte('Q')
+
-	buf.Write(bigEndian.Uint32(uint32(4 + len(src.String) + 1)))
+	dst = append(dst, src.String...)
-	buf.WriteString(src.String)
+	dst = append(dst, 0)
-	buf.WriteByte(0)
+
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *Query) MarshalJSON() ([]byte, error) {

ready_for_query.go

@@ -20,8 +20,8 @@ func (dst *ReadyForQuery) Decode(src []byte) error {
 	return nil
 }
 
-func (src *ReadyForQuery) MarshalBinary() ([]byte, error) {
+func (src *ReadyForQuery) Encode(dst []byte) []byte {
-	return []byte{'Z', 0, 0, 0, 5, src.TxStatus}, nil
+	return append(dst, 'Z', 0, 0, 0, 5, src.TxStatus)
 }
 
 func (src *ReadyForQuery) MarshalJSON() ([]byte, error) {

row_description.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 const (
@@ -64,30 +66,27 @@ func (dst *RowDescription) Decode(src []byte) error {
 	return nil
 }
 
-func (src *RowDescription) MarshalBinary() ([]byte, error) {
+func (src *RowDescription) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	dst = append(dst, 'T')
-	buf := &bytes.Buffer{}
+	sp := len(dst)
-
+	dst = pgio.AppendInt32(dst, -1)
-	buf.WriteByte('T')
-	buf.Write(bigEndian.Uint32(0))
-
-	buf.Write(bigEndian.Uint16(uint16(len(src.Fields))))
 
+	dst = pgio.AppendUint16(dst, uint16(len(src.Fields)))
 	for _, fd := range src.Fields {
-		buf.WriteString(fd.Name)
+		dst = append(dst, fd.Name...)
-		buf.WriteByte(0)
+		dst = append(dst, 0)
 
-		buf.Write(bigEndian.Uint32(fd.TableOID))
+		dst = pgio.AppendUint32(dst, fd.TableOID)
-		buf.Write(bigEndian.Uint16(fd.TableAttributeNumber))
+		dst = pgio.AppendUint16(dst, fd.TableAttributeNumber)
-		buf.Write(bigEndian.Uint32(fd.DataTypeOID))
+		dst = pgio.AppendUint32(dst, fd.DataTypeOID)
-		buf.Write(bigEndian.Uint16(uint16(fd.DataTypeSize)))
+		dst = pgio.AppendInt16(dst, fd.DataTypeSize)
-		buf.Write(bigEndian.Uint32(fd.TypeModifier))
+		dst = pgio.AppendUint32(dst, fd.TypeModifier)
-		buf.Write(bigEndian.Uint16(uint16(fd.Format)))
+		dst = pgio.AppendInt16(dst, fd.Format)
 	}
 
-	binary.BigEndian.PutUint32(buf.Bytes()[1:5], uint32(buf.Len()-1))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *RowDescription) MarshalJSON() ([]byte, error) {

startup_message.go

@@ -5,6 +5,8 @@ import (
 	"encoding/binary"
 	"encoding/json"
 	"fmt"
+
+	"github.com/jackc/pgx/pgio"
 )
 
 const (
@@ -64,22 +66,22 @@ func (dst *StartupMessage) Decode(src []byte) error {
 	return nil
 }
 
-func (src *StartupMessage) MarshalBinary() ([]byte, error) {
+func (src *StartupMessage) Encode(dst []byte) []byte {
-	var bigEndian BigEndianBuf
+	sp := len(dst)
-	buf := &bytes.Buffer{}
+	dst = pgio.AppendInt32(dst, -1)
-	buf.Write(bigEndian.Uint32(0))
+
-	buf.Write(bigEndian.Uint32(src.ProtocolVersion))
+	dst = pgio.AppendUint32(dst, src.ProtocolVersion)
 	for k, v := range src.Parameters {
-		buf.WriteString(k)
+		dst = append(dst, k...)
-		buf.WriteByte(0)
+		dst = append(dst, 0)
-		buf.WriteString(v)
+		dst = append(dst, v...)
-		buf.WriteByte(0)
+		dst = append(dst, 0)
 	}
-	buf.WriteByte(0)
+	dst = append(dst, 0)
 
-	binary.BigEndian.PutUint32(buf.Bytes()[0:4], uint32(buf.Len()))
+	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
 
-	return buf.Bytes(), nil
+	return dst
 }
 
 func (src *StartupMessage) MarshalJSON() ([]byte, error) {

sync.go

@@ -16,8 +16,8 @@ func (dst *Sync) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Sync) MarshalBinary() ([]byte, error) {
+func (src *Sync) Encode(dst []byte) []byte {
-	return []byte{'S', 0, 0, 0, 4}, nil
+	return append(dst, 'S', 0, 0, 0, 4)
 }
 
 func (src *Sync) MarshalJSON() ([]byte, error) {

terminate.go

@@ -16,8 +16,8 @@ func (dst *Terminate) Decode(src []byte) error {
 	return nil
 }
 
-func (src *Terminate) MarshalBinary() ([]byte, error) {
+func (src *Terminate) Encode(dst []byte) []byte {
-	return []byte{'X', 0, 0, 0, 4}, nil
+	return append(dst, 'X', 0, 0, 0, 4)
 }
 
 func (src *Terminate) MarshalJSON() ([]byte, error) {