From be8103dbbc93255be315c4eb306513cf9e48831c Mon Sep 17 00:00:00 2001
From: Jonathan Wallace <jonmon6691@gmail.com>
Date: Tue, 27 May 2025 16:38:04 -0700
Subject: [PATCH 1/3] Add metadata object type

---
 can/io/blf.py | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/can/io/blf.py b/can/io/blf.py
index e64a2247d..88da1f60e 100644
--- a/can/io/blf.py
+++ b/can/io/blf.py
@@ -77,9 +77,13 @@ class BLFParseError(Exception):
 # group name length, marker name length, description length
 GLOBAL_MARKER_STRUCT = struct.Struct("<LLL3xBLLL12x")
 
+# Metadata object type, 4 context-specific bytes, metadata length, 4 more
+# context-specific bytes
+METADATA_HEADER_STRUCT = struct.Struct("<I4BI4B")
 
 CAN_MESSAGE = 1
 LOG_CONTAINER = 10
+METADATA = 65
 CAN_ERROR_EXT = 73
 CAN_MESSAGE2 = 86
 GLOBAL_MARKER = 96
@@ -142,7 +146,12 @@ class BLFReader(BinaryIOMessageReader):
     Iterator of CAN messages from a Binary Logging File.
 
     Only CAN messages and error frames are supported. Other object types are
-    silently ignored.
+    silently ignored. Metadata objects are parsed into `self.metadata` when
+    they are encountered while iterating.
+
+    Metadata are a list of tuples containing the parsed metadata objects. The
+    interpretation of this data is context-specific and out of scope of the
+    BLFReader class.
     """
 
     file: BinaryIO
@@ -173,6 +182,10 @@ def __init__(
         )
         # Read rest of header
         self.file.read(header[1] - FILE_HEADER_STRUCT.size)
+
+        # Metadata is appended when type 65 is encountered while iterating
+        self.metadata = []
+
         self._tail = b""
         self._pos = 0
 
@@ -230,6 +243,8 @@ def _parse_data(self, data):
         unpack_can_fd_64_msg = CAN_FD_MSG_64_STRUCT.unpack_from
         can_fd_64_msg_size = CAN_FD_MSG_64_STRUCT.size
         unpack_can_error_ext = CAN_ERROR_EXT_STRUCT.unpack_from
+        metadata_header = METADATA_HEADER_STRUCT.unpack_from
+        metadata_header_size = METADATA_HEADER_STRUCT.size
 
         start_timestamp = self.start_timestamp
         max_pos = len(data)
@@ -370,6 +385,24 @@ def _parse_data(self, data):
                     data=msg_data,
                     channel=channel - 1,
                 )
+            elif obj_type == METADATA:
+                # When we encounter a metadata object, parse it and save it in
+                # self.metadata and continue looping for a message to return
+                (
+                    mdobj_type,
+                    b0, b1, b2, b3, 
+                    mdsize, 
+                    b4, b5, b6, b7
+                ) = metadata_header(data, pos)
+                # Context-specific data
+                mdcontext = bytearray([b0, b1, b2, b3, b4, b5, b6, b7])
+                # Read until the end of the block rather than using the
+                # untrusted size bytes
+                mdstring = data[pos + metadata_header_size:next_pos]
+                # Append the metadata block, including the size bytes read
+                # from the header. Caller can determine what to do if there's
+                # a mismatch
+                self.metadata.append((mdobj_type, mdcontext, mdsize, mdstring))
 
             pos = next_pos
 

From 38ffc7c8394a5398af151f2ce1cc35d7512ae78c Mon Sep 17 00:00:00 2001
From: Jonathan Wallace <jonmon6691@gmail.com>
Date: Wed, 28 May 2025 09:43:50 -0700
Subject: [PATCH 2/3] Change metadata to app_text

---
 can/io/blf.py | 46 ++++++++++++++++++++--------------------------
 1 file changed, 20 insertions(+), 26 deletions(-)

diff --git a/can/io/blf.py b/can/io/blf.py
index 88da1f60e..87f6b2724 100644
--- a/can/io/blf.py
+++ b/can/io/blf.py
@@ -77,13 +77,13 @@ class BLFParseError(Exception):
 # group name length, marker name length, description length
 GLOBAL_MARKER_STRUCT = struct.Struct("<LLL3xBLLL12x")
 
-# Metadata object type, 4 context-specific bytes, metadata length, 4 more
-# context-specific bytes
-METADATA_HEADER_STRUCT = struct.Struct("<I4BI4B")
+# APP_TEXT object type, 4 reserved bytes, text length, 4 more
+# reserved bytes
+APP_TEXT_HEADER_STRUCT = struct.Struct("<I4sI4s")
 
 CAN_MESSAGE = 1
 LOG_CONTAINER = 10
-METADATA = 65
+APP_TEXT = 65
 CAN_ERROR_EXT = 73
 CAN_MESSAGE2 = 86
 GLOBAL_MARKER = 96
@@ -146,10 +146,10 @@ class BLFReader(BinaryIOMessageReader):
     Iterator of CAN messages from a Binary Logging File.
 
     Only CAN messages and error frames are supported. Other object types are
-    silently ignored. Metadata objects are parsed into `self.metadata` when
+    silently ignored. APP_TEXT objects are parsed into `self.apt_text` when
     they are encountered while iterating.
 
-    Metadata are a list of tuples containing the parsed metadata objects. The
+    self.app_text is a list of tuples containing the parsed app_text objects. The
     interpretation of this data is context-specific and out of scope of the
     BLFReader class.
     """
@@ -183,8 +183,9 @@ def __init__(
         # Read rest of header
         self.file.read(header[1] - FILE_HEADER_STRUCT.size)
 
-        # Metadata is appended when type 65 is encountered while iterating
-        self.metadata = []
+        # APP_TEXT objects are appended when type 65 is encountered
+        # while iterating
+        self.app_text: list[tuple] = []
 
         self._tail = b""
         self._pos = 0
@@ -243,8 +244,8 @@ def _parse_data(self, data):
         unpack_can_fd_64_msg = CAN_FD_MSG_64_STRUCT.unpack_from
         can_fd_64_msg_size = CAN_FD_MSG_64_STRUCT.size
         unpack_can_error_ext = CAN_ERROR_EXT_STRUCT.unpack_from
-        metadata_header = METADATA_HEADER_STRUCT.unpack_from
-        metadata_header_size = METADATA_HEADER_STRUCT.size
+        app_text_header = APP_TEXT_HEADER_STRUCT.unpack_from
+        app_text_header_size = APP_TEXT_HEADER_STRUCT.size
 
         start_timestamp = self.start_timestamp
         max_pos = len(data)
@@ -385,24 +386,17 @@ def _parse_data(self, data):
                     data=msg_data,
                     channel=channel - 1,
                 )
-            elif obj_type == METADATA:
-                # When we encounter a metadata object, parse it and save it in
-                # self.metadata and continue looping for a message to return
-                (
-                    mdobj_type,
-                    b0, b1, b2, b3, 
-                    mdsize, 
-                    b4, b5, b6, b7
-                ) = metadata_header(data, pos)
-                # Context-specific data
-                mdcontext = bytearray([b0, b1, b2, b3, b4, b5, b6, b7])
+            elif obj_type == APP_TEXT:
+                # When we encounter an app_text object, parse it and save it in
+                # self.app_text and continue looping for a message to return
+                source, reserved1, text_size, reserved2 = app_text_header(data, pos)
                 # Read until the end of the block rather than using the
                 # untrusted size bytes
-                mdstring = data[pos + metadata_header_size:next_pos]
-                # Append the metadata block, including the size bytes read
-                # from the header. Caller can determine what to do if there's
-                # a mismatch
-                self.metadata.append((mdobj_type, mdcontext, mdsize, mdstring))
+                text = data[pos + app_text_header_size : next_pos]
+                # Append the app_text block, including the size bytes read
+                # from the header. Caller may determine what to do if there's
+                # a mismatch in the actual text length
+                self.app_text.append((source, reserved1, text_size, reserved2, text))
 
             pos = next_pos
 

From 84f55bfc7367fe2f29796a32a6d2753c7253a58f Mon Sep 17 00:00:00 2001
From: Jonathan Wallace <jonmon6691@gmail.com>
Date: Wed, 28 May 2025 09:59:40 -0700
Subject: [PATCH 3/3] Fix type annotation

---
 can/io/blf.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/can/io/blf.py b/can/io/blf.py
index 87f6b2724..9bf01745e 100644
--- a/can/io/blf.py
+++ b/can/io/blf.py
@@ -146,7 +146,7 @@ class BLFReader(BinaryIOMessageReader):
     Iterator of CAN messages from a Binary Logging File.
 
     Only CAN messages and error frames are supported. Other object types are
-    silently ignored. APP_TEXT objects are parsed into `self.apt_text` when
+    silently ignored. APP_TEXT objects are parsed into `self.app_text` when
     they are encountered while iterating.
 
     self.app_text is a list of tuples containing the parsed app_text objects. The
@@ -185,7 +185,7 @@ def __init__(
 
         # APP_TEXT objects are appended when type 65 is encountered
         # while iterating
-        self.app_text: list[tuple] = []
+        self.app_text: List[Tuple] = []
 
         self._tail = b""
         self._pos = 0