From 3d1a3eb2c3bbc65e077e835bd2c9806681938f70 Mon Sep 17 00:00:00 2001
From: mvgalen <marijnvangalen@gmail.com>
Date: Wed, 4 Dec 2024 10:26:21 +0100
Subject: [PATCH] Change web based CAN log file format to CANdump (#655)

* Update web page CAN logging to CANdump format
* Improve performance of web based CAN logging by removing unnecessary strcat and strlen calls.
---
 Software/Software.ino              | 46 +++++++++++++-----------------
 Software/src/datalayer/datalayer.h |  1 +
 2 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/Software/Software.ino b/Software/Software.ino
index 1994978f..79e99bf8 100644
--- a/Software/Software.ino
+++ b/Software/Software.ino
@@ -642,44 +642,38 @@ void print_can_frame(CAN_frame frame, frameDirection msgDir) {
 #endif  //#DEBUG_CAN_DATA
 
   if (datalayer.system.info.can_logging_active) {  // If user clicked on CAN Logging page in webserver, start recording
+    char* message_string = datalayer.system.info.logged_can_messages;
+    int offset = datalayer.system.info.logged_can_messages_offset;  // Keeps track of the current position in the buffer
+    size_t message_string_size = sizeof(datalayer.system.info.logged_can_messages);
 
-    char message_string[128];  // Buffer to hold the message string
-    int offset = 0;            // Keeps track of the current position in the buffer
-
+    if (offset + 128 > sizeof(datalayer.system.info.logged_can_messages)) {
+      // Not enough space, reset and start from the beginning
+      offset = 0;
+    }
+    unsigned long currentTime = millis();
     // Add timestamp
-    offset += snprintf(message_string + offset, sizeof(message_string) - offset, "%lu ", millis());
+    offset += snprintf(message_string + offset, message_string_size - offset, "(%lu.%03lu) ", currentTime / 1000,
+                       currentTime % 1000);
 
-    // Add direction
+    // Add direction. The 0 and 1 after RX and TX ensures that SavvyCAN puts TX and RX in a different bus.
     offset +=
-        snprintf(message_string + offset, sizeof(message_string) - offset, "%s ", (msgDir == MSG_RX) ? "RX" : "TX");
+        snprintf(message_string + offset, message_string_size - offset, "%s ", (msgDir == MSG_RX) ? "RX0" : "TX1");
 
     // Add ID and DLC
-    offset += snprintf(message_string + offset, sizeof(message_string) - offset, "%X %u ", frame.ID, frame.DLC);
+    offset += snprintf(message_string + offset, message_string_size - offset, "%X [%u] ", frame.ID, frame.DLC);
 
     // Add data bytes
     for (uint8_t i = 0; i < frame.DLC; i++) {
-      offset += snprintf(message_string + offset, sizeof(message_string) - offset, "%s%X ",
-                         frame.data.u8[i] < 16 ? "0" : "", frame.data.u8[i]);
+      if (i < frame.DLC - 1) {
+        offset += snprintf(message_string + offset, message_string_size - offset, "%02X ", frame.data.u8[i]);
+      } else {
+        offset += snprintf(message_string + offset, message_string_size - offset, "%02X", frame.data.u8[i]);
+      }
     }
     // Add linebreak
-    offset += snprintf(message_string + offset, sizeof(message_string) - offset, "\n");
-
-    // Ensure the string is null-terminated
-    message_string[sizeof(message_string) - 1] = '\0';
-
-    // Append the message string to the system info structure
-    size_t current_len =
-        strnlen(datalayer.system.info.logged_can_messages, sizeof(datalayer.system.info.logged_can_messages));
-    size_t available_space =
-        sizeof(datalayer.system.info.logged_can_messages) - current_len - 1;  // Space left for new data
-
-    if (available_space < strlen(message_string) + 1) {
-      // Not enough space, reset and start from the beginning
-      current_len = 0;
-      datalayer.system.info.logged_can_messages[0] = '\0';
-    }
+    offset += snprintf(message_string + offset, message_string_size - offset, "\n");
 
-    strncat(datalayer.system.info.logged_can_messages, message_string, available_space);
+    datalayer.system.info.logged_can_messages_offset = offset;  // Update offset in buffer
   }
 }
 
diff --git a/Software/src/datalayer/datalayer.h b/Software/src/datalayer/datalayer.h
index 81814336..e6de68ce 100644
--- a/Software/src/datalayer/datalayer.h
+++ b/Software/src/datalayer/datalayer.h
@@ -133,6 +133,7 @@ typedef struct {
   char inverter_protocol[64] = {0};
   /** array with incoming CAN messages, for displaying on webserver */
   char logged_can_messages[15000] = {0};
+  size_t logged_can_messages_offset = 0;
   /** bool, determines if CAN messages should be logged for webserver */
   bool can_logging_active = false;