codecutil: added ByteLexer struct for configuring buffer size

codec/codecutil/lex.go

@@ -30,11 +30,21 @@ import (
 	"time"
 )
 
-// LexBytes reads n bytes from src and writes them to dst every t seconds.
-func LexBytes(dst io.Writer, src io.Reader, t time.Duration, n int) error {
-	if n <= 0 {
-		return fmt.Errorf("invalid buffer size: %v", n)
+// ByteLexer is used to lex a certain number of bytes per a given delay, the number is configured upon construction.
+type ByteLexer struct {
+	bufSize int
+}
+
+// NewByteLexer returns a pointer to a ByteLexer with the given buffer size.
+func NewByteLexer(bufSize int) (*ByteLexer, error) {
+	if bufSize <= 0 {
+		return nil, fmt.Errorf("invalid buffer size: %v", bufSize)
 	}
+	return &ByteLexer{bufSize: bufSize}, nil
+}
+
+// Lex reads l.bufSize bytes from src and writes them to dst every t seconds.
+func (l *ByteLexer) Lex(dst io.Writer, src io.Reader, t time.Duration) error {
 	if t < 0 {
 		return fmt.Errorf("invalid delay: %v", t)
 	}
@@ -45,7 +55,7 @@ func LexBytes(dst io.Writer, src io.Reader, t time.Duration, n int) error {
 		tick = ticker.C
 	}
 
-	buf := make([]byte, n)
+	buf := make([]byte, l.bufSize)
 	for {
 		if t != 0 {
 			<-tick

codec/codecutil/lex_test.go

@@ -47,15 +47,20 @@ var lexTests = []struct {
 	{[]byte{0x10, 0x00, 0xf3, 0x45, 0xfe, 0xd2, 0xaa, 0x4e}, time.Millisecond, 15, false},
 }
 
-func TestLexBytes(t *testing.T) {
+func TestByteLexer(t *testing.T) {
 	for i, tt := range lexTests {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			dst := bytes.NewBuffer([]byte{})
-			err := LexBytes(dst, bytes.NewReader(tt.data), tt.t, tt.n)
-			if err != nil && err != io.EOF {
+			l, err := NewByteLexer(tt.n)
+			if err != nil {
 				if !tt.fail {
 					t.Errorf("unexpected error: %v", err.Error())
 				}
+				return
+			}
+			err = l.Lex(dst, bytes.NewReader(tt.data), tt.t)
+			if err != nil && err != io.EOF {
+				t.Errorf("unexpected error: %v", err.Error())
 			} else if !bytes.Equal(dst.Bytes(), tt.data) {
 				t.Errorf("data before and after lex are not equal: want %v, got %v", tt.data, dst.Bytes())
 			}