Add varint encoding for full data

Closes Merge !93
Thanks Ryan Hitchman!

core/src/test/java/tests/DhFullDataSourceRepoTests.java

@@ -87,16 +87,23 @@ public class DhFullDataSourceRepoTests
             
 			Random seededRandom = new Random(3);
 			
-			for (int i = 0; i < FullDataSourceV2.WIDTH * FullDataSourceV2.WIDTH; i++)
+			for (int arrayIndex = 0; arrayIndex < FullDataSourceV2.WIDTH * FullDataSourceV2.WIDTH; arrayIndex++)
 			{
-				fullDataArray[i] = new LongArrayList(1);
+				fullDataArray[arrayIndex] = new LongArrayList(1);
 				
 				// random column heights so we can differentiate
 				// columns from each other
 				int columnCount = Math.abs(seededRandom.nextInt() % 31) + 1;
-				for (int j = 0; j < columnCount; j++)
+				for (int colIndex = 0; colIndex < columnCount; colIndex++)
 				{
-					fullDataArray[i].add(FullDataPointUtil.encode(j, 1, j, LodUtil.MAX_MC_LIGHT, LodUtil.MAX_MC_LIGHT));
+					long datapoint = FullDataPointUtil.encode(
+							colIndex, // id 
+							1, // height
+							colIndex, // relative min Y
+							(byte)(colIndex % LodUtil.MAX_MC_LIGHT), // block light 
+							(byte)((colIndex + 2) % LodUtil.MAX_MC_LIGHT) // sky light
+					);
+					fullDataArray[arrayIndex].add(datapoint);
 				}
 			}
 			
@@ -113,6 +120,18 @@ public class DhFullDataSourceRepoTests
 			repo.save(originalDto);
 			
 			
+			// also create format-1 encoded version to ensure backwards compatibility
+			long posV1 = DhSectionPos.encode((byte) 6, 2, 3);
+			FullDataSourceV2 dataSourceFormatV1 = FullDataSourceV2.createWithData(posV1, dataMapping, fullDataArray, columnGenStep, columnWorldCompressionMode);
+			FullDataSourceV2DTO dtoFormatV1 = FullDataSourceV2DTO.CreateFromDataSource(dataSourceFormatV1, EDhApiDataCompressionMode.LZMA2);
+			FullDataSourceV2DTO.writeDataSourceDataArrayToBlobV1(
+					dataSourceFormatV1.dataPoints,
+					dtoFormatV1.compressedDataByteArray,
+					EDhApiDataCompressionMode.LZMA2);
+			dtoFormatV1.dataFormatVersion = FullDataSourceV2DTO.DATA_FORMAT.V1_NO_ADJACENT_DATA;
+			repo.save(dtoFormatV1);
+			
+			
 			
 			//=======================//
 			// confirm DTO data is   // 
@@ -152,6 +171,21 @@ public class DhFullDataSourceRepoTests
 				}
 			}
 			
+			// check that we have proper backwards compatability to V1
+			try (FullDataSourceV2 savedDataSource = repo.getByKey(posV1).createUnitTestDataSource())
+			{
+				Assert.assertNotNull("Failed to create DataSource", savedDataSource);
+				assertArraysAreEqual(originalDataSource.columnGenerationSteps, savedDataSource.columnGenerationSteps);
+				assertArraysAreEqual(originalDataSource.columnWorldCompressionMode,
+						savedDataSource.columnWorldCompressionMode);
+				Assert.assertTrue(originalDataSource.dataPoints.length == savedDataSource.dataPoints.length);
+				
+				for (int i = 0; i < FullDataSourceV2.WIDTH * FullDataSourceV2.WIDTH; i++)
+				{
+					assertArraysAreEqual(originalDataSource.dataPoints[i], savedDataSource.dataPoints[i]);
+				}
+			}
+			
 			
 			
 			//==============//

core/src/test/java/tests/VarintTest.java

@@ -0,0 +1,94 @@
+/*
+ *    This file is part of the Distant Horizons mod
+ *    licensed under the GNU LGPL v3 License.
+ *
+ *    Copyright (C) 2020 James Seibel
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU Lesser General Public License as published by
+ *    the Free Software Foundation, version 3.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Lesser General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Lesser General Public License
+ *    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package tests;
+
+import com.seibel.distanthorizons.api.enums.config.EDhApiDataCompressionMode;
+import com.seibel.distanthorizons.core.sql.dto.FullDataSourceV2DTO;
+import com.seibel.distanthorizons.core.sql.dto.util.VarintUtil;
+import com.seibel.distanthorizons.core.util.objects.dataStreams.DhDataInputStream;
+import com.seibel.distanthorizons.core.util.objects.dataStreams.DhDataOutputStream;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+public class VarintTest
+{
+	
+	@Test
+	public void Test()
+	{
+		Assert.assertEquals(0x80, 128);
+		
+		
+		// zig zag encoding is needed for varint handling, so test it first
+		for (int i = -256; i < 256; i++)
+		{
+			//testZigZagEncoding(i);
+		}
+		
+		for (int i = -256; i < 256; i++)
+		{
+			//testSingleVarint(i);
+		}
+	}
+	
+	private static void testZigZagEncoding(int value)
+	{
+		int encodedValue = VarintUtil.zigzagEncode(value);
+		int decodedValue = VarintUtil.zigzagDecode(encodedValue);
+		Assert.assertEquals(value, decodedValue);
+	}
+	
+	private static void testSingleVarint(int value)
+	{
+		// write to stream
+		ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+		try (DhDataOutputStream outputStream = new DhDataOutputStream(byteArrayOutputStream, EDhApiDataCompressionMode.UNCOMPRESSED))
+		{
+			int encodedValue = VarintUtil.zigzagEncode(value);
+			VarintUtil.writeVarint(outputStream, encodedValue); // varint requires zig-zag encoding to function
+		}
+		catch (IOException e)
+		{
+			e.printStackTrace();
+			Assert.fail("Fail writing varint ["+value+"], error: ["+e.getMessage()+"]");
+		}
+		
+		
+		// read stream
+		byte[] byteArray = byteArrayOutputStream.toByteArray();
+		ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArray);
+		try (DhDataInputStream inputStream = new DhDataInputStream(byteArrayInputStream, EDhApiDataCompressionMode.UNCOMPRESSED))
+		{
+			int encodedValue = VarintUtil.readVarint(inputStream);
+			int decodedValue = VarintUtil.zigzagDecode(encodedValue);
+			Assert.assertEquals(value, decodedValue);
+		}
+		catch (IOException e)
+		{
+			e.printStackTrace();
+			Assert.fail("Fail reading varint ["+value+"], error: ["+e.getMessage()+"]");
+		}
+	}
+	
+}