package sarama import ( "encoding/binary" "math" ) var errInvalidArrayLength = PacketDecodingError{"invalid array length"} var errInvalidByteSliceLength = PacketDecodingError{"invalid byteslice length"} var errInvalidStringLength = PacketDecodingError{"invalid string length"} var errInvalidSubsetSize = PacketDecodingError{"invalid subset size"} type realDecoder struct { raw []byte off int stack []pushDecoder } // primitives func (rd *realDecoder) getInt8() (int8, error) { if rd.remaining() < 1 { rd.off = len(rd.raw) return -1, ErrInsufficientData } tmp := int8(rd.raw[rd.off]) rd.off++ return tmp, nil } func (rd *realDecoder) getInt16() (int16, error) { if rd.remaining() < 2 { rd.off = len(rd.raw) return -1, ErrInsufficientData } tmp := int16(binary.BigEndian.Uint16(rd.raw[rd.off:])) rd.off += 2 return tmp, nil } func (rd *realDecoder) getInt32() (int32, error) { if rd.remaining() < 4 { rd.off = len(rd.raw) return -1, ErrInsufficientData } tmp := int32(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 return tmp, nil } func (rd *realDecoder) getInt64() (int64, error) { if rd.remaining() < 8 { rd.off = len(rd.raw) return -1, ErrInsufficientData } tmp := int64(binary.BigEndian.Uint64(rd.raw[rd.off:])) rd.off += 8 return tmp, nil } func (rd *realDecoder) getArrayLength() (int, error) { if rd.remaining() < 4 { rd.off = len(rd.raw) return -1, ErrInsufficientData } tmp := int(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 if tmp > rd.remaining() { rd.off = len(rd.raw) return -1, ErrInsufficientData } else if tmp > 2*math.MaxUint16 { return -1, errInvalidArrayLength } return tmp, nil } // collections func (rd *realDecoder) getBytes() ([]byte, error) { tmp, err := rd.getInt32() if err != nil { return nil, err } n := int(tmp) switch { case n < -1: return nil, errInvalidByteSliceLength case n == -1: return nil, nil case n == 0: return make([]byte, 0), nil case n > rd.remaining(): rd.off = len(rd.raw) return nil, ErrInsufficientData } tmpStr := rd.raw[rd.off : rd.off+n] rd.off += n return tmpStr, nil } func (rd *realDecoder) getString() (string, error) { tmp, err := rd.getInt16() if err != nil { return "", err } n := int(tmp) switch { case n < -1: return "", errInvalidStringLength case n == -1: return "", nil case n == 0: return "", nil case n > rd.remaining(): rd.off = len(rd.raw) return "", ErrInsufficientData } tmpStr := string(rd.raw[rd.off : rd.off+n]) rd.off += n return tmpStr, nil } func (rd *realDecoder) getInt32Array() ([]int32, error) { if rd.remaining() < 4 { rd.off = len(rd.raw) return nil, ErrInsufficientData } n := int(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 if rd.remaining() < 4*n { rd.off = len(rd.raw) return nil, ErrInsufficientData } if n == 0 { return nil, nil } if n < 0 { return nil, errInvalidArrayLength } ret := make([]int32, n) for i := range ret { ret[i] = int32(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 } return ret, nil } func (rd *realDecoder) getInt64Array() ([]int64, error) { if rd.remaining() < 4 { rd.off = len(rd.raw) return nil, ErrInsufficientData } n := int(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 if rd.remaining() < 8*n { rd.off = len(rd.raw) return nil, ErrInsufficientData } if n == 0 { return nil, nil } if n < 0 { return nil, errInvalidArrayLength } ret := make([]int64, n) for i := range ret { ret[i] = int64(binary.BigEndian.Uint64(rd.raw[rd.off:])) rd.off += 8 } return ret, nil } func (rd *realDecoder) getStringArray() ([]string, error) { if rd.remaining() < 4 { rd.off = len(rd.raw) return nil, ErrInsufficientData } n := int(binary.BigEndian.Uint32(rd.raw[rd.off:])) rd.off += 4 if n == 0 { return nil, nil } if n < 0 { return nil, errInvalidArrayLength } ret := make([]string, n) for i := range ret { if str, err := rd.getString(); err != nil { return nil, err } else { ret[i] = str } } return ret, nil } // subsets func (rd *realDecoder) remaining() int { return len(rd.raw) - rd.off } func (rd *realDecoder) getSubset(length int) (packetDecoder, error) { if length < 0 { return nil, errInvalidSubsetSize } else if length > rd.remaining() { rd.off = len(rd.raw) return nil, ErrInsufficientData } start := rd.off rd.off += length return &realDecoder{raw: rd.raw[start:rd.off]}, nil } // stacks func (rd *realDecoder) push(in pushDecoder) error { in.saveOffset(rd.off) reserve := in.reserveLength() if rd.remaining() < reserve { rd.off = len(rd.raw) return ErrInsufficientData } rd.stack = append(rd.stack, in) rd.off += reserve return nil } func (rd *realDecoder) pop() error { // this is go's ugly pop pattern (the inverse of append) in := rd.stack[len(rd.stack)-1] rd.stack = rd.stack[:len(rd.stack)-1] return in.check(rd.off, rd.raw) }