nazabits: new func ReadString, ReadBits32IgnErr, ReadStringIgnErr

pkg/nazabits/bits.go

@@ -12,13 +12,13 @@ import "errors"
 
 var ErrNazaBits = errors.New("nazabits: fxxk")
 
-// 按位流式读取字节切片
+// BitReader 按位流式读取字节切片
 // 从高位向低位读
 // 注意，可以在每次读取后，判断是否发生错误。也可以在多次读取后，判断是否发生错误。
 type BitReader struct {
 	core  []byte
 	avail uint // 还没有读取的bit数量
-	index uint // 从0开始
+	index uint // 从0开始，待读取的字节下标
 	pos   uint // 从左往右，从高位往低位 [0, 7]
 	err   error
 }
@@ -131,6 +131,7 @@ func (br *BitReader) ReadBits64(n uint) (r uint64, err error) {
 	}
 }
 
+// ReadBytes
 // @param n: 读取多少个字节
 func (br *BitReader) ReadBytes(n uint) (r []byte, err error) {
 	// 对常见的pos为0的情况单独做优化
@@ -155,6 +156,16 @@ func (br *BitReader) ReadBytes(n uint) (r []byte, err error) {
 	return
 }
 
+func (br *BitReader) ReadString(n uint) (r string, err error) {
+	var bs []byte
+	bs, err = br.ReadBytes(n)
+	if err != nil {
+		return
+	}
+	r = string(bs)
+	return
+}
+
 func (br *BitReader) ReadGolomb() (v uint32, err error) {
 	return br.ReadUeGolomb()
 }
@@ -196,6 +207,16 @@ func (br *BitReader) ReadSeGolomb() (v int32, err error) {
 	return
 }
 
+func (br *BitReader) ReadBits32IgnErr(n uint) uint32 {
+	r, _ := br.ReadBits32(n)
+	return r
+}
+
+func (br *BitReader) ReadStringIgnErr(n uint) string {
+	r, _ := br.ReadString(n)
+	return r
+}
+
 func (br *BitReader) SkipBytes(n uint) error {
 	if err := br.reserve(n * 8); err != nil {
 		return err

pkg/nazabits/bits_test.go

@@ -253,6 +253,24 @@ func TestBitReader_ReadBytes(t *testing.T) {
 	}
 }
 
+func TestBitReader_ReadString(t *testing.T) {
+	v := []byte{48, 57, 49, 56}
+	{
+		br := nazabits.NewBitReader(v)
+		r, err := br.ReadString(2)
+		assert.Equal(t, nil, err)
+		assert.Equal(t, "09", r)
+		assert.Equal(t, nil, br.Err())
+
+		r = br.ReadStringIgnErr(2)
+		assert.Equal(t, "18", r)
+
+		br.ReadStringIgnErr(1)
+		assert.Equal(t, nazabits.ErrNazaBits, br.Err())
+
+	}
+}
+
 func TestBitReader_ReadGolomb(t *testing.T) {
 	var b []byte
 	var v uint32