better API (#4810)

java_console/models/src/main/java/com/rusefi/stream/LogicdataOutputStream.java

@@ -0,0 +1,52 @@
+package com.rusefi.stream;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+public class LogicdataOutputStream {
+    private final OutputStream outputStream;
+
+    public LogicdataOutputStream(OutputStream outputStream) {
+        this.outputStream = outputStream;
+    }
+
+    // This is the main secret of this format! :)
+    public void writeVarLength(long value) throws IOException {
+        if (value < 0 || value > 0xFFFFFFFFL) {
+            writeAs(value, 8);
+        } else if (value == 0) {
+            writeByte(0);
+        } else if (value <= 0xff) {
+            writeAs(value, 1);
+        } else if (value <= 0xffff) {
+            writeAs(value, 2);
+        } else if (value <= 0xffffff) {
+            writeAs(value, 3);
+        } else {
+            writeAs(value, 4);
+        }
+    }
+
+    private void writeAs(long value, int numBytes) throws IOException {
+    	if (value == 0) {
+   			writeByte(0);
+   		} else {
+			writeByte(numBytes);
+			for (int i = 0; i < numBytes; i++) {
+				writeByte((byte)((value >> (i * 8)) & 0xff));
+			}
+		}
+    }
+
+    public void close() throws IOException {
+        outputStream.close();
+    }
+
+    public void flush() throws IOException {
+        outputStream.flush();
+    }
+
+    public void writeByte(int i) throws IOException {
+        outputStream.write(i);
+    }
+}

java_console/models/src/main/java/com/rusefi/stream/LogicdataStreamFile.java

@@ -85,7 +85,7 @@ public class LogicdataStreamFile extends StreamFile {
     	// we need at least 2 records
     	if (events == null || events.size() < 2)
     		return;
-		long firstRecordTs = events.get(1).getTimestamp();
+		long firstRecordTs = events.get(1).getTimestamp(); // huh why not index '0'?
 		long lastRecordTs = events.get(events.size() - 1).getTimestamp();
 	    // we don't know the total duration, so we create a margin after the last record which equals to the duration of the first event
 		// TODO: why do we jump from timestamps to samples?

java_console/models/src/main/java/com/rusefi/stream/StreamFile.java

@@ -6,6 +6,7 @@ import java.io.*;
 import java.util.List;
 
 public abstract class StreamFile {
+    // todo: always write into Writer since it has better API, it's insane to have to references into same stream
     protected OutputStream stream;
     protected Writer writer;
 

java_console/models/src/test/java/com/rusefi/stream/LogicdataStreamFileTest.java

@@ -0,0 +1,22 @@
+package com.rusefi.stream;
+
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+public class LogicdataStreamFileTest {
+    @Test
+    public void testWriteAs() throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        LogicdataOutputStream logicdataOutputStream = new LogicdataOutputStream(baos);
+        logicdataOutputStream.writeVarLength(10);
+
+        byte[] bytes = baos.toByteArray();
+        assertEquals(2, bytes.length);
+        assertEquals(1, bytes[0]);
+        assertEquals(10, bytes[1]);
+    }
+}