new API & coverage

reader/src/main/java/com/rusefi/can/reader/dbc/DbcField.java

@@ -123,4 +123,13 @@ public class DbcField {
         name = niceName;
         isNiceName = true;
     }
+
+    public boolean coversByte(int byteIndex) {
+        int startBit = byteIndex * 8;
+        if (startOffset>startBit)
+            return false;
+        if (startOffset + length < byteIndex + 8)
+            return false;
+        return true;
+    }
 }

reader/src/main/java/com/rusefi/can/reader/dbc/DbcPacket.java

@@ -102,4 +102,11 @@ public class DbcPacket {
         return buf.toString();
     }
 
+    public DbcField getFieldAtByte(int byteIndex) {
+        for (DbcField field : fields) {
+            if (field.coversByte(byteIndex))
+                return field;
+        }
+        return null;
+    }
 }

reader/src/test/java/com/rusefi/can/reader/impl/GetValueFromTrcTest.java

@@ -1,6 +1,7 @@
 package com.rusefi.can.reader.impl;
 
 import com.rusefi.can.CANPacket;
+import com.rusefi.can.reader.dbc.DbcPacket;
 import com.rusefi.mlv.LoggingStrategy;
 import com.rusefi.can.reader.dbc.DbcField;
 import com.rusefi.can.reader.dbc.DbcFile;
@@ -52,7 +53,11 @@ public class GetValueFromTrcTest {
             BufferedReader reader = new BufferedReader(new StringReader(VAG_MOTOR_1));
             dbc.read(reader);
         }
-        assertNotNull(dbc.findPacket(640));
+        DbcPacket packet640 = dbc.findPacket(640);
+        assertNotNull(packet640);
+        DbcField byte1 = packet640.getFieldAtByte(1);
+        assertNotNull(byte1);
+        assertEquals("inneres_Motor_Moment", byte1.getName());
         assertNull(dbc.findPacket(1640));
 
         String trcLine = "  3769)      2117.7  Rx         0280  8  01 1D DF 12 1E 00 1A 1E ";