91 lines
1.6 KiB
Go
91 lines
1.6 KiB
Go
package spec
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import (
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"bytes"
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"errors"
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"io"
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//"git.hpds.cc/Component/mq_coder/encoding"
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"mq_coder/encoding"
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)
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// L is the Length in a TLV structure
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type L struct {
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buf []byte
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size int
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len int
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}
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// NewL will take an int type len as parameter and return L to
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// represent the size of V in a TLV. an integer will be encoded as
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// a PVarInt32 type to represent the value.
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func NewL(len int) (L, error) {
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var l = L{}
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if len < -1 {
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return l, errors.New("y3.L: len can't less than -1")
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}
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valLen := int32(len)
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l.size = encoding.SizeOfPVarInt32(valLen)
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codec := encoding.VarCodec{Size: l.size}
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tmp := make([]byte, l.size)
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err := codec.EncodePVarInt32(tmp, valLen)
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if err != nil {
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panic(err)
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}
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l.buf = make([]byte, l.size)
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copy(l.buf, tmp)
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l.len = len
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return l, nil
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}
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// Bytes will return the raw bytes of L.
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func (l L) Bytes() []byte {
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return l.buf
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}
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// Size returns how many bytes used to represent this L.
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func (l L) Size() int {
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return l.size
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}
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// VSize returns the size of V.
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func (l L) VSize() int {
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return int(l.len)
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}
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// ReadL read L from bufio.Reader
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func ReadL(r io.Reader) (*L, error) {
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lenBuf := bytes.Buffer{}
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for {
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b, err := readByte(r)
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if err != nil {
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return nil, err
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}
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lenBuf.WriteByte(b)
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if b&msb != msb {
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break
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}
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}
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buf := lenBuf.Bytes()
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// decode to L
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length, err := decodeL(buf)
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if err != nil {
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return nil, err
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}
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return &L{
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buf: buf,
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len: int(length),
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size: len(buf),
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}, nil
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}
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func decodeL(buf []byte) (length int32, err error) {
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codec := encoding.VarCodec{}
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err = codec.DecodePVarInt32(buf, &length)
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return length, err
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}
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