func Unmarshal()

in ssh/messages.go [374:490]
111 lines of code
33 McCabe index (conditional complexity)

func Unmarshal(data []byte, out interface{}) error {
	v := reflect.ValueOf(out).Elem()
	structType := v.Type()
	expectedTypes := typeTags(structType)

	var expectedType byte
	if len(expectedTypes) > 0 {
		expectedType = expectedTypes[0]
	}

	if len(data) == 0 {
		return parseError(expectedType)
	}

	if len(expectedTypes) > 0 {
		goodType := false
		for _, e := range expectedTypes {
			if e > 0 && data[0] == e {
				goodType = true
				break
			}
		}
		if !goodType {
			return fmt.Errorf("ssh: unexpected message type %d (expected one of %v)", data[0], expectedTypes)
		}
		data = data[1:]
	}

	var ok bool
	for i := 0; i < v.NumField(); i++ {
		field := v.Field(i)
		t := field.Type()
		switch t.Kind() {
		case reflect.Bool:
			if len(data) < 1 {
				return errShortRead
			}
			field.SetBool(data[0] != 0)
			data = data[1:]
		case reflect.Array:
			if t.Elem().Kind() != reflect.Uint8 {
				return fieldError(structType, i, "array of unsupported type")
			}
			if len(data) < t.Len() {
				return errShortRead
			}
			for j, n := 0, t.Len(); j < n; j++ {
				field.Index(j).Set(reflect.ValueOf(data[j]))
			}
			data = data[t.Len():]
		case reflect.Uint64:
			var u64 uint64
			if u64, data, ok = parseUint64(data); !ok {
				return errShortRead
			}
			field.SetUint(u64)
		case reflect.Uint32:
			var u32 uint32
			if u32, data, ok = parseUint32(data); !ok {
				return errShortRead
			}
			field.SetUint(uint64(u32))
		case reflect.Uint8:
			if len(data) < 1 {
				return errShortRead
			}
			field.SetUint(uint64(data[0]))
			data = data[1:]
		case reflect.String:
			var s []byte
			if s, data, ok = parseString(data); !ok {
				return fieldError(structType, i, "")
			}
			field.SetString(string(s))
		case reflect.Slice:
			switch t.Elem().Kind() {
			case reflect.Uint8:
				if structType.Field(i).Tag.Get("ssh") == "rest" {
					field.Set(reflect.ValueOf(data))
					data = nil
				} else {
					var s []byte
					if s, data, ok = parseString(data); !ok {
						return errShortRead
					}
					field.Set(reflect.ValueOf(s))
				}
			case reflect.String:
				var nl []string
				if nl, data, ok = parseNameList(data); !ok {
					return errShortRead
				}
				field.Set(reflect.ValueOf(nl))
			default:
				return fieldError(structType, i, "slice of unsupported type")
			}
		case reflect.Ptr:
			if t == bigIntType {
				var n *big.Int
				if n, data, ok = parseInt(data); !ok {
					return errShortRead
				}
				field.Set(reflect.ValueOf(n))
			} else {
				return fieldError(structType, i, "pointer to unsupported type")
			}
		default:
			return fieldError(structType, i, fmt.Sprintf("unsupported type: %v", t))
		}
	}

	if len(data) != 0 {
		return parseError(expectedType)
	}

	return nil
}