Update logging format

Separate keys for persistent and periodic
Add device alias map

README.md

@@ -14,6 +14,24 @@ By default, this project builds against the latest WPILib development build. To
 
 ## Data Format
 
+### Revision 2
+
+- "Raw/Persistent"
+  - Buffer Length, Not Published (uint32)
+  - Persistent Messages (8 bytes each)
+    - Short Message ID (uint16)
+    - Data (6 bytes)
+- "Raw/Periodic"
+  - Buffer Length, Not Published (uint32)
+  - Periodic Messages (14 bytes each)
+    - Timestamp MS (uint32)
+    - Short Message ID (uint16)
+    - Data (8 bytes)
+- "Raw/Aliases"
+  - JSON object of (CAN ID string -> alias string)
+
+### Revision 1
+
 - Buffer Size, Not Published (uint32)
 - Persistent Message Count (uint32)
 - Periodic Message Count (uint32)

src/main/driver/cpp/URCLDriver.cpp

@@ -42,7 +42,8 @@ constexpr int periodicMessageId =
 constexpr int periodicMessageIdMask = 0x1ffffc00;
 
 bool running = false;
-char* sharedBuffer;
+char* persistentBuffer;
+char* periodicBuffer;
 int32_t halStatus;
 uint32_t timeOffsetMillis;
 uint32_t firmwareStreamHandle;
@@ -57,16 +58,24 @@ uint64_t devicesModelReceived = 0;
 uint64_t devicesCANReady = 0;
 HAL_CANHandle devicesCANHandles[64];
 
-char* URCLDriver_start() {
-    if (running) return sharedBuffer;
+void URCLDriver_start() {
+    if (running) return;
     running = true;
-    sharedBuffer = (char*) malloc(bufferSize);
+    persistentBuffer = (char*) malloc(persistentSize);
+    periodicBuffer = (char*) malloc(periodicSize);
     uint32_t fpgaMillis = (HAL_GetFPGATime(&halStatus) / 1000ull) & 0xffffffff;
     timeOffsetMillis = fpgaMillis - HAL_GetCANPacketBaseTime();
     HAL_CAN_OpenStreamSession(&firmwareStreamHandle, firmwareMessageId, firmwareMessageIdMask, maxPersistentMessages, &halStatus);
     HAL_CAN_OpenStreamSession(&modelStreamHandle, modelMessageId, modelMessageIdMask, maxPersistentMessages, &halStatus);
     HAL_CAN_OpenStreamSession(&periodicStreamHandle, periodicMessageId, periodicMessageIdMask, maxPeriodicMessages, &halStatus);
-    return sharedBuffer;
+}
+
+char* URCLDriver_getPersistentBuffer() {
+    return persistentBuffer;
+}
+
+char* URCLDriver_getPeriodicBuffer() {
+    return periodicBuffer;
 }
 
 /** 
@@ -76,8 +85,9 @@ void writeMessagePersistent(HAL_CANStreamMessage message) {
     uint16_t messageIdShort = message.messageID & 0xffff;
     uint32_t index = 0;
     while (index < persistentMessageCount) {
-        char* messageBuffer = sharedBuffer + startSize + (index * persistentMessageSize);
-        uint16_t existingMessageId = *messageBuffer;
+        char* messageBuffer = persistentBuffer + 4 + (index * persistentMessageSize);
+        uint16_t existingMessageId;
+        std::memcpy(&existingMessageId, messageBuffer, 2);
         if (messageIdShort == existingMessageId) {
             std::memcpy(messageBuffer + 2, &message.data, 6);
             return;
@@ -87,7 +97,7 @@ void writeMessagePersistent(HAL_CANStreamMessage message) {
 
     if (persistentMessageCount < maxPersistentMessages) {
         persistentMessageCount++;
-        char* messageBuffer = sharedBuffer + startSize + (index * persistentMessageSize);
+        char* messageBuffer = persistentBuffer + 4 + (index * persistentMessageSize);
         std::memcpy(messageBuffer, &messageIdShort, 2);
         std::memcpy(messageBuffer + 2, &message.data, 6);
     }
@@ -97,9 +107,7 @@ void writeMessagePersistent(HAL_CANStreamMessage message) {
  * Write a periodic message to the buffer at the specified index. 
  */
 void writeMessagePeriodic(HAL_CANStreamMessage message, uint32_t index) {
-    char* messageBuffer = sharedBuffer + startSize + 
-        (persistentMessageCount * persistentMessageSize) + 
-        (index * periodicMessageSize);
+    char* messageBuffer = periodicBuffer + 4 + (index * periodicMessageSize);
     uint32_t timestamp = message.timeStamp + timeOffsetMillis;
     uint16_t messageIdShort = message.messageID & 0xffff;
     std::memcpy(messageBuffer + 0, &timestamp, 4);
@@ -166,12 +174,10 @@ void URCLDriver_read() {
     }
 
     // Write sizes
-    uint32_t bufferSize = startSize - 4 + 
-        (persistentMessageCount * persistentMessageSize) + 
-        (messageCount * periodicMessageSize);
-    std::memcpy(sharedBuffer, &bufferSize, 4);
-    std::memcpy(sharedBuffer + 4, &persistentMessageCount, 4);
-    std::memcpy(sharedBuffer + 8, &messageCount, 4);
+    uint32_t persistentSize = persistentMessageCount * persistentMessageSize;
+    uint32_t periodicSize = messageCount * periodicMessageSize;
+    std::memcpy(persistentBuffer, &persistentSize, 4);
+    std::memcpy(periodicBuffer, &periodicSize, 4);
 }
 
 }

src/main/driver/cpp/URCLJNI.cpp

@@ -26,9 +26,19 @@ JNI_OnLoad(JavaVM* vm, void* reserved) {
 JNIEXPORT void JNICALL
 JNI_OnUnload(JavaVM* vm, void* reserved) {}
 
-JNIEXPORT jobject JNICALL
+JNIEXPORT void JNICALL
 Java_org_littletonrobotics_urcl_URCLJNI_start(JNIEnv* env, jclass clazz) {
-  return env->NewDirectByteBuffer(URCLDriver_start(), bufferSize);
+  URCLDriver_start();
+}
+
+JNIEXPORT jobject JNICALL
+Java_org_littletonrobotics_urcl_URCLJNI_getPersistentBuffer(JNIEnv* env, jclass clazz) {
+  return env->NewDirectByteBuffer(URCLDriver_getPersistentBuffer(), persistentSize);
+}
+
+JNIEXPORT jobject JNICALL
+Java_org_littletonrobotics_urcl_URCLJNI_getPeriodicBuffer(JNIEnv* env, jclass clazz) {
+  return env->NewDirectByteBuffer(URCLDriver_getPeriodicBuffer(), periodicSize);
 }
 
 JNIEXPORT void JNICALL

src/main/driver/include/URCLDriver.h

@@ -11,17 +11,18 @@
 extern "C" {
 #endif
 
-constexpr int startSize = 4 + 4 + 4;
 constexpr int persistentMessageSize = 8;
 constexpr int periodicMessageSize = 14;
 constexpr int maxPersistentMessages = 200;
 constexpr int maxPeriodicMessages = 500;
-constexpr int bufferSize = 
-    startSize +
-    (persistentMessageSize * maxPersistentMessages) +
-    (periodicMessageSize * maxPeriodicMessages);
+constexpr int persistentSize = 4 + (persistentMessageSize * maxPersistentMessages);
+constexpr int periodicSize = 4 + (periodicMessageSize * maxPeriodicMessages);
 
-char* URCLDriver_start();
+void URCLDriver_start();
+
+char* URCLDriver_getPersistentBuffer();
+
+char* URCLDriver_getPeriodicBuffer();
 
 void URCLDriver_read();
 

src/main/driver/symbols.txt

@@ -1,6 +1,10 @@
 JNI_OnLoad
 JNI_OnUnload
 URCLDriver_start
+URCLDriver_getPersistentBuffer
+URCLDriver_getPeriodicBuffer
 URCLDriver_read
 Java_org_littletonrobotics_urcl_URCLJNI_start
+Java_org_littletonrobotics_urcl_URCLJNI_getPersistentBuffer
+Java_org_littletonrobotics_urcl_URCLJNI_getPeriodicBuffer
 Java_org_littletonrobotics_urcl_URCLJNI_read

src/main/java/org/littletonrobotics/urcl/URCL.java

@@ -9,6 +9,8 @@
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.nio.charset.Charset;
+import java.util.Map;
 import java.util.function.Supplier;
 
 import edu.wpi.first.networktables.NetworkTableInstance;
@@ -35,28 +37,61 @@ public class URCL {
   private static final double period = 0.02;
 
   private static boolean running = false;
-  private static ByteBuffer buffer;
-  private static RawPublisher publisher;
+  private static ByteBuffer persistentBuffer;
+  private static ByteBuffer periodicBuffer;
+  private static ByteBuffer aliasesBuffer;
+  private static RawPublisher persistentPublisher;
+  private static RawPublisher periodicPublisher;
+  private static RawPublisher aliasesPublisher;
   private static Notifier notifier;
 
   /**
    * Start capturing data from REV motor controllers to NetworkTables. This method
    * should only be called once.
    */
   public static void start() {
+    start(Map.of());
+  }
+
+  /**
+   * Start capturing data from REV motor controllers to NetworkTables. This method
+   * should only be called once.
+   * 
+   * @param aliases The set of aliases mapping CAN IDs to names.
+   */
+  public static void start(Map<Integer, String> aliases) {
     if (running) {
       DriverStation.reportError("URCL cannot be started multiple times", true);
       return;
     }
     running = true;
 
-    buffer = URCLJNI.start();
-    buffer.order(ByteOrder.LITTLE_ENDIAN);
-    publisher = NetworkTableInstance.getDefault()
-        .getRawTopic("/URCL")
-        .publish("URCL");
+    // Update aliases buffer
+    updateAliasesBuffer(aliases);
+
+    // Start driver
+    URCLJNI.start();
+    persistentBuffer = URCLJNI.getPersistentBuffer();
+    periodicBuffer = URCLJNI.getPeriodicBuffer();
+    persistentBuffer.order(ByteOrder.LITTLE_ENDIAN);
+    periodicBuffer.order(ByteOrder.LITTLE_ENDIAN);
 
-    notifier = new Notifier(() -> publisher.set(getData()));
+    // Start publishers
+    persistentPublisher = NetworkTableInstance.getDefault()
+        .getRawTopic("/URCL/Raw/Persistent")
+        .publish("URCLr2_persistent");
+    periodicPublisher = NetworkTableInstance.getDefault()
+        .getRawTopic("/URCL/Raw/Periodic")
+        .publish("URCLr2_periodic");
+    aliasesPublisher = NetworkTableInstance.getDefault()
+        .getRawTopic("/URCL/Raw/Aliases")
+        .publish("URCLr2_aliases");
+    notifier = new Notifier(() -> {
+      var data = getData();
+      persistentPublisher.set(data[0]);
+      periodicPublisher.set(data[1]);
+      aliasesPublisher.set(data[2]);
+    });
     notifier.setName("URCL");
     notifier.startPeriodic(period);
   }
@@ -69,23 +104,72 @@ public static void start() {
    * 
    * @return The log supplier, to be called periodically
    */
-  public static Supplier<ByteBuffer> startExternal() {
+  public static Supplier<ByteBuffer[]> startExternal() {
+    return startExternal(Map.of());
+  }
+
+  /**
+   * Start capturing data from REV motor controllers to an external framework like
+   * <a href=
+   * "https://github.com/Mechanical-Advantage/AdvantageKit">AdvantageKit</a>. This
+   * method should only be called once.
+   * 
+   * @param aliases The set of aliases mapping CAN IDs to names.
+   * @return The log supplier, to be called periodically
+   */
+  public static Supplier<ByteBuffer[]> startExternal(Map<Integer, String> aliases) {
     if (running) {
       DriverStation.reportError("URCL cannot be started multiple times", true);
-      ByteBuffer dummyBuffer = ByteBuffer.allocate(0);
-      return () -> dummyBuffer;
+      ByteBuffer[] emptyOutput = new ByteBuffer[] {
+        ByteBuffer.allocate(0),
+        ByteBuffer.allocate(0),
+        ByteBuffer.allocate(0)
+      };
+      return () -> emptyOutput;
     }
     running = true;
 
-    buffer = URCLJNI.start();
-    buffer.order(ByteOrder.LITTLE_ENDIAN);
+    // Update aliases buffer
+    updateAliasesBuffer(aliases);
+
+    // Start driver
+    URCLJNI.start();
+    persistentBuffer = URCLJNI.getPersistentBuffer();
+    periodicBuffer = URCLJNI.getPeriodicBuffer();
+    persistentBuffer.order(ByteOrder.LITTLE_ENDIAN);
+    periodicBuffer.order(ByteOrder.LITTLE_ENDIAN);
     return URCL::getData;
   }
 
-  /** Refreshes and reads all data from the queue. */
-  private static ByteBuffer getData() {
+  /** Fills the alias data into the aliases buffer as JSON. */
+  private static void updateAliasesBuffer(Map<Integer, String> aliases) {
+    StringBuilder aliasesBuilder = new StringBuilder();
+    aliasesBuilder.append("{");
+    boolean firstEntry = true;
+    for (Map.Entry<Integer, String> entry : aliases.entrySet()) {
+      if (!firstEntry) {
+        aliasesBuilder.append(",");
+      }
+      firstEntry = false;
+      aliasesBuilder.append("\"");
+      aliasesBuilder.append(entry.getKey().toString());
+      aliasesBuilder.append("\":\"");
+      aliasesBuilder.append(entry.getValue());
+      aliasesBuilder.append("\"");
+    }
+    aliasesBuilder.append("}");
+    aliasesBuffer = Charset.forName("UTF-8").encode(aliasesBuilder.toString());
+  }
+
+  /** Refreshes and reads all data from the queues. */
+  private static ByteBuffer[] getData() {
     URCLJNI.read();
-    int size = buffer.getInt(0);
-    return buffer.slice(4, size);
+    int persistentSize = persistentBuffer.getInt(0);
+    int periodicSize = periodicBuffer.getInt(0);
+    return new ByteBuffer[] {
+      persistentBuffer.slice(4, persistentSize),
+      periodicBuffer.slice(4, periodicSize),
+      aliasesBuffer
+    };
   }
 }

src/main/java/org/littletonrobotics/urcl/URCLJNI.java

@@ -75,15 +75,23 @@ public static synchronized void forceLoad() throws IOException {
     libraryLoaded = true;
   }
 
-  /**
-   * Start logging data from all devices.
+  /** Start logging. */
+  public static native void start();
+
+  /** 
+   * Get the shared buffer with persistent data.
    * 
-   * @return The shared memory buffer for transferring data
+   * @return The shared buffer
    */
-  public static native ByteBuffer start();
+  public static native ByteBuffer getPersistentBuffer();
 
-  /**
-   * Reads all data from the queue to the shared memory buffer.
+  /** 
+   * Get the shared buffer with periodic data.
+   * 
+   * @return The shared buffer
    */
+  public static native ByteBuffer getPeriodicBuffer();
+
+  /** Read new data. */
   public static native void read();
 }