Refactor pgio and types to append buffers

read.go

@@ -2,103 +2,39 @@ package pgio
 
 import (
 	"encoding/binary"
-	"io"
 )
 
-type Uint16Reader interface {
+func NextByte(buf []byte) ([]byte, byte) {
-	ReadUint16() (n uint16, err error)
+	b := buf[0]
+	return buf[1:], b
 }
 
-type Uint32Reader interface {
+func NextUint16(buf []byte) ([]byte, uint16) {
-	ReadUint32() (n uint32, err error)
+	n := binary.BigEndian.Uint16(buf)
+	return buf[2:], n
 }
 
-type Uint64Reader interface {
+func NextUint32(buf []byte) ([]byte, uint32) {
-	ReadUint64() (n uint64, err error)
+	n := binary.BigEndian.Uint32(buf)
+	return buf[4:], n
 }
 
-// ReadByte reads a byte from r.
+func NextUint64(buf []byte) ([]byte, uint64) {
-func ReadByte(r io.Reader) (byte, error) {
+	n := binary.BigEndian.Uint64(buf)
-	if r, ok := r.(io.ByteReader); ok {
+	return buf[8:], n
-		return r.ReadByte()
-	}
-
-	buf := make([]byte, 1)
-	_, err := r.Read(buf)
-	return buf[0], err
 }
 
-// ReadUint16 reads an uint16 from r in PostgreSQL wire format (network byte order). This
+func NextInt16(buf []byte) ([]byte, int16) {
-// may be more efficient than directly using Read if r provides a ReadUint16
+	buf, n := NextUint16(buf)
-// method.
+	return buf, int16(n)
-func ReadUint16(r io.Reader) (uint16, error) {
-	if r, ok := r.(Uint16Reader); ok {
-		return r.ReadUint16()
-	}
-
-	buf := make([]byte, 2)
-	_, err := io.ReadFull(r, buf)
-	if err != nil {
-		return 0, err
-	}
-
-	return binary.BigEndian.Uint16(buf), nil
 }
 
-// ReadInt16 reads an int16 r in PostgreSQL wire format (network byte order). This
+func NextInt32(buf []byte) ([]byte, int32) {
-// may be more efficient than directly using Read if r provides a ReadUint16
+	buf, n := NextUint32(buf)
-// method.
+	return buf, int32(n)
-func ReadInt16(r io.Reader) (int16, error) {
-	n, err := ReadUint16(r)
-	return int16(n), err
 }
 
-// ReadUint32 reads an uint32 r in PostgreSQL wire format (network byte order). This
+func NextInt64(buf []byte) ([]byte, int64) {
-// may be more efficient than directly using Read if r provides a ReadUint32
+	buf, n := NextUint64(buf)
-// method.
+	return buf, int64(n)
-func ReadUint32(r io.Reader) (uint32, error) {
-	if r, ok := r.(Uint32Reader); ok {
-		return r.ReadUint32()
-	}
-
-	buf := make([]byte, 4)
-	_, err := io.ReadFull(r, buf)
-	if err != nil {
-		return 0, err
-	}
-
-	return binary.BigEndian.Uint32(buf), nil
-}
-
-// ReadInt32 reads an int32 r in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Read if r provides a ReadUint32
-// method.
-func ReadInt32(r io.Reader) (int32, error) {
-	n, err := ReadUint32(r)
-	return int32(n), err
-}
-
-// ReadUint64 reads an uint64 r in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Read if r provides a ReadUint64
-// method.
-func ReadUint64(r io.Reader) (uint64, error) {
-	if r, ok := r.(Uint64Reader); ok {
-		return r.ReadUint64()
-	}
-
-	buf := make([]byte, 8)
-	_, err := io.ReadFull(r, buf)
-	if err != nil {
-		return 0, err
-	}
-
-	return binary.BigEndian.Uint64(buf), nil
-}
-
-// ReadInt64 reads an int64 r in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Read if r provides a ReadUint64
-// method.
-func ReadInt64(r io.Reader) (int64, error) {
-	n, err := ReadUint64(r)
-	return int64(n), err
 }

read_test.go

@@ -0,0 +1,57 @@
+package pgio
+
+import (
+	"testing"
+)
+
+func TestNextByte(t *testing.T) {
+	buf := []byte{42, 1}
+	var b byte
+	buf, b = NextByte(buf)
+	if b != 42 {
+		t.Errorf("NextByte(buf) => %v, want %v", b, 42)
+	}
+	buf, b = NextByte(buf)
+	if b != 1 {
+		t.Errorf("NextByte(buf) => %v, want %v", b, 1)
+	}
+}
+
+func TestNextUint16(t *testing.T) {
+	buf := []byte{0, 42, 0, 1}
+	var n uint16
+	buf, n = NextUint16(buf)
+	if n != 42 {
+		t.Errorf("NextUint16(buf) => %v, want %v", n, 42)
+	}
+	buf, n = NextUint16(buf)
+	if n != 1 {
+		t.Errorf("NextUint16(buf) => %v, want %v", n, 1)
+	}
+}
+
+func TestNextUint32(t *testing.T) {
+	buf := []byte{0, 0, 0, 42, 0, 0, 0, 1}
+	var n uint32
+	buf, n = NextUint32(buf)
+	if n != 42 {
+		t.Errorf("NextUint32(buf) => %v, want %v", n, 42)
+	}
+	buf, n = NextUint32(buf)
+	if n != 1 {
+		t.Errorf("NextUint32(buf) => %v, want %v", n, 1)
+	}
+}
+
+func TestNextUint64(t *testing.T) {
+	buf := []byte{0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0, 1}
+	var n uint64
+	buf, n = NextUint64(buf)
+	if n != 42 {
+		t.Errorf("NextUint64(buf) => %v, want %v", n, 42)
+	}
+	buf, n = NextUint64(buf)
+	if n != 1 {
+		t.Errorf("NextUint64(buf) => %v, want %v", n, 1)
+	}
+}

write.go

@@ -1,97 +1,40 @@
 package pgio
 
-import (
+import "encoding/binary"
-	"encoding/binary"
-	"io"
-)
 
-type Uint16Writer interface {
+func AppendUint16(buf []byte, n uint16) []byte {
-	WriteUint16(uint16) (n int, err error)
+	wp := len(buf)
+	buf = append(buf, 0, 0)
+	binary.BigEndian.PutUint16(buf[wp:], n)
+	return buf
 }
 
-type Uint32Writer interface {
+func AppendUint32(buf []byte, n uint32) []byte {
-	WriteUint32(uint32) (n int, err error)
+	wp := len(buf)
+	buf = append(buf, 0, 0, 0, 0)
+	binary.BigEndian.PutUint32(buf[wp:], n)
+	return buf
 }
 
-type Uint64Writer interface {
+func AppendUint64(buf []byte, n uint64) []byte {
-	WriteUint64(uint64) (n int, err error)
+	wp := len(buf)
+	buf = append(buf, 0, 0, 0, 0, 0, 0, 0, 0)
+	binary.BigEndian.PutUint64(buf[wp:], n)
+	return buf
 }
 
-// WriteByte writes b to w.
+func AppendInt16(buf []byte, n int16) []byte {
-func WriteByte(w io.Writer, b byte) error {
+	return AppendUint16(buf, uint16(n))
-	if w, ok := w.(io.ByteWriter); ok {
-		return w.WriteByte(b)
-	}
-	_, err := w.Write([]byte{b})
-	return err
 }
 
-// WriteUint16 writes n to w in PostgreSQL wire format (network byte order). This
+func AppendInt32(buf []byte, n int32) []byte {
-// may be more efficient than directly using Write if w provides a WriteUint16
+	return AppendUint32(buf, uint32(n))
-// method.
-func WriteUint16(w io.Writer, n uint16) (int, error) {
-	if w, ok := w.(Uint16Writer); ok {
-		return w.WriteUint16(n)
-	}
-	b := make([]byte, 2)
-	binary.BigEndian.PutUint16(b, n)
-	return w.Write(b)
 }
 
-// WriteInt16 writes n to w in PostgreSQL wire format (network byte order). This
+func AppendInt64(buf []byte, n int64) []byte {
-// may be more efficient than directly using Write if w provides a WriteUint16
+	return AppendUint64(buf, uint64(n))
-// method.
-func WriteInt16(w io.Writer, n int16) (int, error) {
-	return WriteUint16(w, uint16(n))
 }
 
-// WriteUint32 writes n to w in PostgreSQL wire format (network byte order). This
+func SetInt32(buf []byte, n int32) {
-// may be more efficient than directly using Write if w provides a WriteUint32
+	binary.BigEndian.PutUint32(buf, uint32(n))
-// method.
-func WriteUint32(w io.Writer, n uint32) (int, error) {
-	if w, ok := w.(Uint32Writer); ok {
-		return w.WriteUint32(n)
-	}
-	b := make([]byte, 4)
-	binary.BigEndian.PutUint32(b, n)
-	return w.Write(b)
-}
-
-// WriteInt32 writes n to w in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Write if w provides a WriteUint32
-// method.
-func WriteInt32(w io.Writer, n int32) (int, error) {
-	return WriteUint32(w, uint32(n))
-}
-
-// WriteUint64 writes n to w in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Write if w provides a WriteUint64
-// method.
-func WriteUint64(w io.Writer, n uint64) (int, error) {
-	if w, ok := w.(Uint64Writer); ok {
-		return w.WriteUint64(n)
-	}
-	b := make([]byte, 8)
-	binary.BigEndian.PutUint64(b, n)
-	return w.Write(b)
-}
-
-// WriteInt64 writes n to w in PostgreSQL wire format (network byte order). This
-// may be more efficient than directly using Write if w provides a WriteUint64
-// method.
-func WriteInt64(w io.Writer, n int64) (int, error) {
-	return WriteUint64(w, uint64(n))
-}
-
-// WriteCString writes s to w followed by a null byte.
-func WriteCString(w io.Writer, s string) (int, error) {
-	n, err := io.WriteString(w, s)
-	if err != nil {
-		return n, err
-	}
-	err = WriteByte(w, 0)
-	if err != nil {
-		return n, err
-	}
-	return n + 1, nil
 }

write_test.go

@@ -0,0 +1,78 @@
+package pgio
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestAppendUint16NilBuf(t *testing.T) {
+	buf := AppendUint16(nil, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 1}) {
+		t.Errorf("AppendUint16(nil, 1) => %v, want %v", buf, []byte{0, 1})
+	}
+}
+
+func TestAppendUint16EmptyBuf(t *testing.T) {
+	buf := []byte{}
+	buf = AppendUint16(buf, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 1}) {
+		t.Errorf("AppendUint16(nil, 1) => %v, want %v", buf, []byte{0, 1})
+	}
+}
+
+func TestAppendUint16BufWithCapacityDoesNotAllocate(t *testing.T) {
+	buf := make([]byte, 0, 4)
+	AppendUint16(buf, 1)
+	buf = buf[0:2]
+	if !reflect.DeepEqual(buf, []byte{0, 1}) {
+		t.Errorf("AppendUint16(nil, 1) => %v, want %v", buf, []byte{0, 1})
+	}
+}
+
+func TestAppendUint32NilBuf(t *testing.T) {
+	buf := AppendUint32(nil, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 1}) {
+		t.Errorf("AppendUint32(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 1})
+	}
+}
+
+func TestAppendUint32EmptyBuf(t *testing.T) {
+	buf := []byte{}
+	buf = AppendUint32(buf, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 1}) {
+		t.Errorf("AppendUint32(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 1})
+	}
+}
+
+func TestAppendUint32BufWithCapacityDoesNotAllocate(t *testing.T) {
+	buf := make([]byte, 0, 4)
+	AppendUint32(buf, 1)
+	buf = buf[0:4]
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 1}) {
+		t.Errorf("AppendUint32(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 1})
+	}
+}
+
+func TestAppendUint64NilBuf(t *testing.T) {
+	buf := AppendUint64(nil, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 0, 0, 0, 0, 1}) {
+		t.Errorf("AppendUint64(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 0, 0, 0, 0, 1})
+	}
+}
+
+func TestAppendUint64EmptyBuf(t *testing.T) {
+	buf := []byte{}
+	buf = AppendUint64(buf, 1)
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 0, 0, 0, 0, 1}) {
+		t.Errorf("AppendUint64(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 0, 0, 0, 0, 1})
+	}
+}
+
+func TestAppendUint64BufWithCapacityDoesNotAllocate(t *testing.T) {
+	buf := make([]byte, 0, 8)
+	AppendUint64(buf, 1)
+	buf = buf[0:8]
+	if !reflect.DeepEqual(buf, []byte{0, 0, 0, 0, 0, 0, 0, 1}) {
+		t.Errorf("AppendUint64(nil, 1) => %v, want %v", buf, []byte{0, 0, 0, 0, 0, 0, 0, 1})
+	}
+}