added test for write read bits in different modes

Author: raydac

jbbp/src/test/java/com/igormaznitsa/jbbp/io/JBBPBitOrderTest.java

@@ -0,0 +1,86 @@
+package com.igormaznitsa.jbbp.io;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.BitSet;
+import java.util.Random;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.EnumSource;
+
+public class JBBPBitOrderTest {
+
+  @ParameterizedTest
+  @EnumSource(JBBPBitOrder.class)
+  void testBitWriteRead(final JBBPBitOrder bitOrder) throws Exception {
+    final int bits = 10_000_000;
+
+    final Random rnd = new Random(1232345L);
+
+    final BitSet bitSet = new BitSet(bits * 5);
+    for (int i = 0; i < bits; i++) {
+      bitSet.set(rnd.nextInt(bitSet.size()));
+    }
+
+    final byte[] array = bitSet.toByteArray();
+
+    final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+
+    final JBBPBitOutputStream bitOutputStream = new JBBPBitOutputStream(outputStream, bitOrder);
+
+    final ByteArrayOutputStream portions = new ByteArrayOutputStream();
+    int dataIndex = 0;
+    while (dataIndex < array.length) {
+      int bitsLeft = 8;
+      int acc = array[dataIndex++] & 0xFF;
+      while (bitsLeft > 0) {
+        final int portion = Math.min(bitsLeft, rnd.nextInt(8) + 1);
+        bitsLeft -= portion;
+
+        final JBBPBitNumber bitNumber = JBBPBitNumber.decode(portion);
+
+        bitOutputStream.writeBits(acc, JBBPBitNumber.decode(portion));
+        acc >>>= portion;
+        portions.write(portion);
+      }
+    }
+    bitOutputStream.close();
+    outputStream.close();
+
+    final byte[] portionsArray = portions.toByteArray();
+    final byte[] dataArray = outputStream.toByteArray();
+
+    final JBBPBitInputStream inputStream =
+        new JBBPBitInputStream(new ByteArrayInputStream(dataArray), bitOrder);
+
+    final ByteArrayOutputStream restoredDataStream = new ByteArrayOutputStream();
+
+    for (int i = 0; i < portionsArray.length; ) {
+      int readBits = 0;
+      int acc = 0;
+      while (readBits < 8) {
+        final int portion = portionsArray[i++];
+        final JBBPBitNumber bitNumber = JBBPBitNumber.decode(portion);
+        final int data = inputStream.readBits(bitNumber);
+        acc |= ((data & bitNumber.getMask()) << readBits);
+
+        readBits += portion;
+        if (readBits > 8) {
+          throw new Error("unexpected");
+        }
+        if (readBits == 8) {
+          restoredDataStream.write(acc);
+        }
+      }
+    }
+    restoredDataStream.close();
+
+    final byte[] readData = restoredDataStream.toByteArray();
+
+    assertEquals(array.length, readData.length);
+    assertArrayEquals(array, readData);
+  }
+
+}