changing approach to mapping dicts in encoding and decoding

uds/database/text_data_record.py

@@ -1,5 +1,8 @@
 """Definition of TextDataRecord which is class for encode and decode values of data records."""
+import copy
 from typing import Optional, Tuple, Union, Dict
+from uu import decode
+
 from uds.database.abstract_data_record import (AbstractDataRecord, DataRecordType, DataRecordPhysicalValueAlias,
                                                DecodedDataRecord)
 
@@ -15,7 +18,8 @@ def __init__(self, name: str, length: int, mapping: Dict[int, str] = None) -> No
         """
         super().__init__(name)
         self.length = length
-        self.mapping = mapping
+        # self.__reversed_mapping = None ### should it be deleted?
+        self.__mapping = mapping
 
     @property  # noqa: F841
     def length(self) -> int:
@@ -67,6 +71,25 @@ def contains(self) -> Tuple["AbstractDataRecord", ...]:
         """Get Data Records contained by this Data Record."""
         # TODO
 
+    @property
+    def mapping(self):
+        """Get mapping dict."""
+        return self.__mapping
+
+    @mapping.setter
+    def mapping(self, mapping: dict) -> None:
+        """Set the mapping.
+
+        :param mapping: dict contains mapping.
+        """
+        self.__mapping = mapping
+        self.__reversed_mapping = {v: k for k, v in self.__mapping.items()}
+
+    @property
+    def reversed_mapping(self):
+        """Get reversed mapping dict."""
+        return self.__reversed_mapping
+
     def decode(self, raw_value: int) -> DecodedDataRecord:  # noqa: F841
         """
         Decode physical value for provided raw value.
@@ -75,13 +98,13 @@ def decode(self, raw_value: int) -> DecodedDataRecord:  # noqa: F841
 
         :return: Dictionary with physical value for this Data Record.
         """
-        if self.mapping:
-            for k, v in self.mapping.items():
-                if v == raw_value:
-                    return DecodedDataRecord(name=self.name, raw_value=k, physical_value=raw_value)
-            raise ValueError("physical_value not found in provided mapping.")
-        else:
-            return DecodedDataRecord(name=self.name, raw_value=raw_value, physical_value=raw_value)
+        if self.__reversed_mapping:
+            try:
+                decoded_value = self.__reversed_mapping[raw_value]
+                return DecodedDataRecord(name=self.name, raw_value=decoded_value, physical_value=raw_value)
+            except KeyError as error:
+                raise KeyError("raw_value not found in provided mapping.") from error
+        return DecodedDataRecord(name=self.name, raw_value=raw_value, physical_value=raw_value)
 
     def encode(self, physical_value: DataRecordPhysicalValueAlias) -> int:  # noqa: F841
         """
@@ -94,10 +117,10 @@ def encode(self, physical_value: DataRecordPhysicalValueAlias) -> int:  # noqa:
         if isinstance(physical_value, int):
             return physical_value
         elif isinstance(physical_value, str):
-            if self.mapping:
-                for k, v in self.mapping.items():
-                    if v == physical_value:
-                        return k
-                raise ValueError("physical_value not found in provided mapping.")
+            if self.__mapping:
+                try:
+                    return self.__mapping[physical_value]
+                except KeyError as error:
+                    raise KeyError("physical_value not found in provided mapping.") from error
             else:
                 raise TypeError("During encoding of str mapping must be provided.")