Refactor variable names for readability in reader.go

Variable names in reader.go have been changed to be more expressive for improved readability. 'buf' and 'off' were renamed to 'buffer' and 'offset' respectively throughout the file. The changes also include corresponding adjustments in code comments and related test cases, contributing to consistent and understandable code.

msg.go

@@ -1087,7 +1087,7 @@ func (m *Msg) NewReader() *Reader {
 	if err != nil {
 		reader.err = fmt.Errorf("failed to write Msg to Reader buffer: %w", err)
 	}
-	reader.buf = buffer.Bytes()
+	reader.buffer = buffer.Bytes()
 	return reader
 }
 
@@ -1097,7 +1097,7 @@ func (m *Msg) UpdateReader(reader *Reader) {
 	buffer := bytes.Buffer{}
 	_, err := m.Write(&buffer)
 	reader.Reset()
-	reader.buf = buffer.Bytes()
+	reader.buffer = buffer.Bytes()
 	reader.err = err
 }
 

reader.go

@@ -10,8 +10,8 @@ import (
 
 // Reader is a type that implements the io.Reader interface for a Msg
 type Reader struct {
-	buf []byte // contents are the bytes buf[off : len(buf)]
-	off int    // read at &buf[off], write at &buf[len(buf)]
+	buffer []byte // contents are the bytes buffer[offset : len(buffer)]
+	offset int    // read at &buffer[offset], write at &buffer[len(buffer)]
 	err    error  // initialization error
 }
 
@@ -21,28 +21,28 @@ func (r *Reader) Error() error {
 }
 
 // Read reads the length of p of the Msg buffer to satisfy the io.Reader interface
-func (r *Reader) Read(p []byte) (n int, err error) {
+func (r *Reader) Read(payload []byte) (n int, err error) {
 	if r.err != nil {
 		return 0, r.err
 	}
-	if r.empty() || r.buf == nil {
+	if r.empty() || r.buffer == nil {
 		r.Reset()
-		if len(p) == 0 {
+		if len(payload) == 0 {
 			return 0, nil
 		}
 		return 0, io.EOF
 	}
-	n = copy(p, r.buf[r.off:])
-	r.off += n
+	n = copy(payload, r.buffer[r.offset:])
+	r.offset += n
 	return n, err
 }
 
 // Reset resets the Reader buffer to be empty, but it retains the underlying storage
 // for use by future writes.
 func (r *Reader) Reset() {
-	r.buf = r.buf[:0]
-	r.off = 0
+	r.buffer = r.buffer[:0]
+	r.offset = 0
 }
 
 // empty reports whether the unread portion of the Reader buffer is empty.
-func (r *Reader) empty() bool { return len(r.buf) <= r.off }
+func (r *Reader) empty() bool { return len(r.buffer) <= r.offset }

reader_test.go

@@ -65,7 +65,7 @@ func TestReader_Read_error(t *testing.T) {
 
 // TestReader_Read_empty tests the Reader.Read method with an empty buffer
 func TestReader_Read_empty(t *testing.T) {
-	r := Reader{buf: []byte{}}
+	r := Reader{buffer: []byte{}}
 	p := make([]byte, 1)
 	p[0] = 'a'
 	_, err := r.Read(p)
@@ -76,7 +76,7 @@ func TestReader_Read_empty(t *testing.T) {
 
 // TestReader_Read_nil tests the Reader.Read method with a nil buffer
 func TestReader_Read_nil(t *testing.T) {
-	r := Reader{buf: nil, off: -10}
+	r := Reader{buffer: nil, offset: -10}
 	p := make([]byte, 0)
 	_, err := r.Read(p)
 	if err != nil && !errors.Is(err, io.EOF) {