testing and improvements to the common data structures

lib/common/string.go

@@ -6,20 +6,66 @@ import (
 
 type String []byte
 
-func ReadString(data []byte) (str String, remainder []byte, err error) {
-	if len(data) == 0 {
-		err = errors.New("no string in empty byte slice")
-		return
+func (str String) Length() (int, error) {
+	if len(str) == 0 {
+		// log
+		return 0, errors.New("error parsing string: zero length")
 	}
-	length := Integer([]byte{data[0]})
-	data = data[1:]
-
-	if len(data) < length {
-		str = data
-		err = errors.New("string longer than provided slice")
-		return
+	length := Integer([]byte{str[0]})
+	inferred_len := length + 1
+	str_len := len(str)
+	if inferred_len > str_len {
+		// log
+		return length, errors.New("string parsing warning: string data is shorter than specified by length")
+	} else if str_len > inferred_len {
+		//log
+		return length, errors.New("string parsing warning: string contains data beyond length")
 	}
-	str = data[:length]
-	remainder = data[length:]
-	return
+	return length, nil
+}
+
+func (str String) Data() ([]byte, error) {
+	length, err := str.Length()
+	if err != nil {
+		switch err.Error() {
+		case "error parsing string: zero length":
+			return make([]byte, 0), err
+		case "string parsing warning: string data is shorter than specified by length":
+			return str[1:], err
+		case "string parsing warning: string contains data beyond length":
+			return str[1 : length+1], err
+		}
+	}
+	return str[1:], nil
+}
+
+func (str String) GoString() (string, error) {
+	content, err := str.Data()
+	return string(content), err
+}
+
+func ToI2PString(data []byte) (String, error) {
+	data_len := len(data)
+	if data_len >= 256 {
+		return make([]byte, 0), errors.New("cannot store that much data in I2P string")
+	}
+	i2p_string := []byte{byte(data_len)}
+	i2p_string = append(i2p_string, data...)
+	return String(i2p_string), nil
+}
+
+func ReadString(data []byte) (String, []byte, error) {
+	str := String(data)
+	length, err := String(data).Length()
+	if err != nil {
+		switch err.Error() {
+		case "error parsing string: zero length":
+			return String{}, make([]byte, 0), err
+		case "string parsing warning: string data is shorter than specified by length":
+			return str, make([]byte, 0), err
+		case "string parsing warning: string contains data beyond length":
+			return String(str[:length+1]), str[length+1:], err
+		}
+	}
+	return str, make([]byte, 0), nil
 }