showhex: fix processColor

Author: fcharlie

pkg/zeta/showhex.go

@@ -166,18 +166,20 @@ func processColor(r io.Reader, w io.Writer, size int64, colorMode term.Level) er
 	for {
 		readBytes := min(size, 16)
 		n, err := io.ReadFull(r, input[:readBytes])
-		if err != nil {
+		if err != nil && err != io.ErrUnexpectedEOF {
 			break
 		}
 		if err := b.writeLine(offset, input[:n]); err != nil {
 			return err
 		}
-		offset += 16
 		size -= int64(n)
-		if n != 16 || size <= 0 {
+		if size <= 0 {
+			break
+		}
+		if n != 16 {
 			break
 		}
+		offset += 16
 	}
-
 	return b.writeFooter()
 }

pkg/zeta/showhex_test.go

@@ -18,6 +18,15 @@ func TestProcessColor(t *testing.T) {
 	_ = processColor(bytes.NewReader(b), os.Stdout, int64(len(b)), term.Level16M)
 }
 
+func TestProcessColorOverflow(t *testing.T) {
+	b := make([]byte, 1000)
+	_, err := rand.Read(b[10:])
+	if err != nil {
+		return
+	}
+	_ = processColor(bytes.NewReader(b), os.Stdout, int64(len(b))+8, term.Level16M)
+}
+
 func TestBorder(t *testing.T) {
 	input := make([]byte, 15)
 	_, err := rand.Read(input)