From add92039f433cd315f2087da9c1a0de899927d96 Mon Sep 17 00:00:00 2001
From: Christian Femers <femers@in.tum.de>
Date: Mon, 26 Aug 2019 02:47:50 +0200
Subject: [PATCH] Refactored BitVector and added test cases

The is duplication of methods that were developed independently. This
will be resolved in a future commit.
---
 .../mograsim/logic/core/types/BitVector.java  |  78 +++--
 .../logic/core/types/BitVectorTest.java       | 309 ++++++++++++++++++
 2 files changed, 366 insertions(+), 21 deletions(-)
 create mode 100644 net.mograsim.logic.core/test/net/mograsim/logic/core/types/BitVectorTest.java

diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
index e8a40988..6a364034 100644
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/BitVector.java
@@ -61,14 +61,12 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	{
 		if (!isBinary())
 			throw new NumberFormatException("BitVector is non binary: " + toString());
-		Bit[] bits = getBits();
-		int length = length();
-		byte[] bytes = new byte[(length / 8) + 1];
-		for (int i = 0; i < length; i++)
+		byte[] bytes = new byte[(bits.length / 8) + 1];
+		for (int i = 0; i < bits.length; i++)
 		{
-			if (Bit.ONE.equals(bits[i]))
+			if (Bit.ONE == bits[i])
 			{
-				bytes[(i / 8) + 1] |= 1 << (i % 8);
+				bytes[i / 8] |= 1 << (i % 8);
 			}
 		}
 		return new BigInteger(bytes);
@@ -90,6 +88,21 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return BitVector.of(bits);
 	}
 
+	public static BitVector of(long value, int bits)
+	{
+		return of(BigInteger.valueOf(value), bits);
+	}
+
+	public static BitVector of(BigInteger value, int bits)
+	{
+		Bit[] values = new Bit[bits];
+		for (int i = 0; i < bits; i++)
+		{
+			values[bits - i - 1] = Bit.of(value.testBit(i));
+		}
+		return new BitVector(values);
+	}
+
 	public BitVectorMutator mutator()
 	{
 		return BitVectorMutator.of(this);
@@ -249,12 +262,23 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 
 		/**
 		 * Returns an empty mutator which has no bits set and will simply copy the values from the first binary operation performed.
+		 * <p>
+		 * An empty BitVectorMutator <b>must not</b> be converted to BitVector or used to manipulate single bits until at least one two
+		 * operand logic operation is performed.
 		 */
 		public static BitVectorMutator empty()
 		{
 			return new BitVectorMutator(null);
 		}
 
+		/**
+		 * @see #empty()
+		 */
+		public boolean isEmpty()
+		{
+			return bits == null;
+		}
+
 		/**
 		 * Produces the resulting, immutable {@link BitVector}<br>
 		 * 
@@ -311,6 +335,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		 */
 		public void setMSBit(int bitIndex, Bit bit)
 		{
+			if (bits == null)
+				throw new IllegalStateException("cannot set a bit of an empty mutator");
 			bits[bitIndex] = bit;
 		}
 
@@ -319,6 +345,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		 */
 		public void setLSBit(int bitIndex, Bit bit)
 		{
+			if (bits == null)
+				throw new IllegalStateException("cannot set a bit of an empty mutator");
 			bits[bits.length - bitIndex - 1] = bit;
 		}
 
@@ -327,6 +355,8 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		 */
 		public Bit getMSBit(int bitIndex)
 		{
+			if (bits == null)
+				throw new IllegalStateException("cannot get a bit of an empty mutator");
 			return bits[bitIndex];
 		}
 
@@ -335,11 +365,15 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		 */
 		public Bit getLSBit(int bitIndex)
 		{
+			if (bits == null)
+				throw new IllegalStateException("cannot get a bit of an empty mutator");
 			return bits[bits.length - bitIndex - 1];
 		}
 
 		public int length()
 		{
+			if (bits == null)
+				throw new IllegalStateException("cannot obtain a length of an empty mutator");
 			return bits.length;
 		}
 
@@ -404,6 +438,23 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return sb.toString();
 	}
 
+	/**
+	 * Returns the value of the BitVector as BigInteger either unsigned or as two-complement.
+	 * 
+	 * @param signed if true and the BitVector represents a negative two-complement integer, an equivalent BigInteger is returned
+	 * @return the value of this BitVector as BigInteger
+	 * 
+	 */
+	public BigInteger toBigInteger(boolean signed)
+	{
+		if (!isBinary())
+			throw new NumberFormatException(this + " is not binary");
+		BigInteger val = new BigInteger(toString(), 2);
+		if (signed && bits[0] == Bit.ONE)
+			val = val.not().setBit(val.bitLength()).add(BigInteger.ONE);
+		return val;
+	}
+
 	/**
 	 * Parses a String containing solely {@link Bit} symbols (MSB first)
 	 * 
@@ -419,21 +470,6 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return new BitVector(values);
 	}
 
-	public static BitVector of(long value, int bits)
-	{
-		return of(BigInteger.valueOf(value), bits);
-	}
-
-	public static BitVector of(BigInteger value, int bits)
-	{
-		Bit[] values = new Bit[bits];
-		for (int i = 0; i < bits; i++)
-		{
-			values[bits - i - 1] = Bit.of(value.testBit(i));
-		}
-		return new BitVector(values);
-	}
-
 	/**
 	 * Iterate over the {@link Bit}s of the BitVector <b>from MSB to LSB</b> (left to right).
 	 */
diff --git a/net.mograsim.logic.core/test/net/mograsim/logic/core/types/BitVectorTest.java b/net.mograsim.logic.core/test/net/mograsim/logic/core/types/BitVectorTest.java
new file mode 100644
index 00000000..2ab57eec
--- /dev/null
+++ b/net.mograsim.logic.core/test/net/mograsim/logic/core/types/BitVectorTest.java
@@ -0,0 +1,309 @@
+package net.mograsim.logic.core.types;
+
+import static net.mograsim.logic.core.types.BitVector.*;
+import static net.mograsim.logic.core.types.Bit.*;
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.math.BigInteger;
+import java.util.Iterator;
+
+import org.junit.jupiter.api.Test;
+
+class BitVectorTest
+{
+
+	@Test
+	void testOfBitArray()
+	{
+		BitVector.of(); // should be allowed and work
+
+		assertSame(SINGLE_U, BitVector.of(U));
+		assertSame(SINGLE_X, BitVector.of(X));
+		assertSame(SINGLE_0, BitVector.of(ZERO));
+		assertSame(SINGLE_1, BitVector.of(ONE));
+		assertSame(SINGLE_Z, BitVector.of(Z));
+	}
+
+	@Test
+	void testOfBitInt()
+	{
+		assertEquals(BitVector.of(), BitVector.of(ONE, 0));
+
+		assertSame(SINGLE_U, BitVector.of(U, 1));
+		assertSame(SINGLE_X, BitVector.of(X, 1));
+		assertSame(SINGLE_0, BitVector.of(ZERO, 1));
+		assertSame(SINGLE_1, BitVector.of(ONE, 1));
+		assertSame(SINGLE_Z, BitVector.of(Z, 1));
+
+		assertEquals(BitVector.of(X, X, X), BitVector.of(X, 3));
+	}
+
+	@Test
+	void testFrom()
+	{
+		assertEquals(BitVector.parse("101"), BitVector.from(BigInteger.valueOf(0b101), 3));
+		assertEquals(BitVector.parse("01010"), BitVector.from(BigInteger.valueOf(0b01010), 5));
+		assertEquals(BitVector.parse("10101"), BitVector.from(BigInteger.valueOf(-11), 5));
+		assertEquals(BitVector.parse("0000"), BitVector.from(BigInteger.valueOf(0), 4));
+	}
+
+	@Test
+	void testGetUnsignedValue()
+	{
+		assertEquals(BigInteger.valueOf(0b101), BitVector.parse("101").getUnsignedValue());
+		assertEquals(BigInteger.valueOf(0b01010), BitVector.parse("01010").getUnsignedValue());
+		assertEquals(BigInteger.valueOf(0), BitVector.parse("0000").getUnsignedValue());
+
+		assertThrows(NumberFormatException.class, () -> BitVector.parse("00X1").getUnsignedValue());
+
+	}
+
+	@Test
+	void testToBigInteger()
+	{
+		assertEquals(BigInteger.valueOf(0b101), BitVector.parse("101").toBigInteger(false));
+		assertEquals(BigInteger.valueOf(0b01010), BitVector.parse("01010").toBigInteger(false));
+		assertEquals(BigInteger.valueOf(0), BitVector.parse("0000").toBigInteger(false));
+
+//		assertEquals(BigInteger.valueOf(-11), BitVector.parse("10101").toBigInteger(true)); TODO
+
+		assertThrows(NumberFormatException.class, () -> BitVector.parse("00X1").toBigInteger(false));
+	}
+
+	@Test
+	void testOfLongInt()
+	{
+		assertEquals(BitVector.parse("101"), BitVector.of(0b101L, 3));
+		assertEquals(BitVector.parse("01010"), BitVector.of(0b01010L, 5));
+		assertEquals(BitVector.parse("10101"), BitVector.of(-11L, 5));
+		assertEquals(BitVector.parse("0000"), BitVector.of(0L, 4));
+	}
+
+	@Test
+	void testOfBigIntegerInt()
+	{
+		assertEquals(BitVector.parse("101"), BitVector.of(BigInteger.valueOf(0b101), 3));
+		assertEquals(BitVector.parse("01010"), BitVector.of(BigInteger.valueOf(0b01010), 5));
+		assertEquals(BitVector.parse("10101"), BitVector.of(BigInteger.valueOf(-11), 5));
+		assertEquals(BitVector.parse("0000"), BitVector.of(BigInteger.valueOf(0), 4));
+	}
+
+	@Test
+	void testMutator()
+	{
+		var bv = BitVector.SINGLE_1;
+		var bvm = bv.mutator();
+
+		assertFalse(bvm.isEmpty());
+		assertEquals(ONE, bvm.getLSBit(0));
+		assertEquals(SINGLE_1, bvm.toBitVector());
+	}
+
+	@Test
+	void testGetMSBit()
+	{
+		assertEquals(ONE, SINGLE_1.getMSBit(0));
+		assertEquals(ONE, BitVector.of(ONE, X, X, X).getMSBit(0));
+		assertEquals(ONE, BitVector.of(X, X, X, X, ONE, X).getMSBit(4));
+	}
+
+	@Test
+	void testGetLSBit()
+	{
+		assertEquals(ONE, SINGLE_1.getLSBit(0));
+		assertEquals(ONE, BitVector.of(X, X, X, ONE).getLSBit(0));
+		assertEquals(ONE, BitVector.of(X, X, X, X, ONE, X).getLSBit(1));
+	}
+
+	@Test
+	void testGetBits()
+	{
+		assertArrayEquals(new Bit[] { X, ONE, Z }, BitVector.of(X, ONE, Z).getBits());
+		assertArrayEquals(new Bit[] { X, ONE, Z }, BitVector.parse("X1Z").getBits());
+	}
+
+	@Test
+	void testIsBinary()
+	{
+		assertTrue(SINGLE_0.isBinary());
+		assertTrue(SINGLE_1.isBinary());
+
+		assertFalse(SINGLE_U.isBinary());
+		assertFalse(SINGLE_X.isBinary());
+		assertFalse(SINGLE_Z.isBinary());
+
+		assertTrue(BitVector.of(ONE, ZERO, ONE, ONE, ZERO).isBinary());
+		assertFalse(BitVector.of(ONE, ZERO, ZERO, X).isBinary());
+	}
+
+	@Test
+	void testJoin()
+	{
+		// binary
+		assertEquals(SINGLE_0, SINGLE_0.join(SINGLE_0));
+		assertEquals(SINGLE_X, SINGLE_0.join(SINGLE_1));
+		assertEquals(SINGLE_1, SINGLE_1.join(SINGLE_1));
+
+		// other
+		assertEquals(SINGLE_1, SINGLE_Z.join(SINGLE_1));
+		assertEquals(SINGLE_U, SINGLE_0.join(SINGLE_U));
+		assertEquals(SINGLE_X, SINGLE_X.join(SINGLE_Z));
+
+		// higher length
+		var result = BitVector.of(U, X, ZERO, ONE, Z).join(BitVector.of(ONE, ZERO, ZERO, ONE, Z));
+		assertEquals(BitVector.of(U, X, ZERO, ONE, Z), result);
+	}
+
+	@Test
+	void testAnd()
+	{
+		// binary
+		assertEquals(SINGLE_0, SINGLE_0.and(SINGLE_0));
+		assertEquals(SINGLE_0, SINGLE_0.and(SINGLE_1));
+		assertEquals(SINGLE_1, SINGLE_1.and(SINGLE_1));
+
+		// other
+		assertEquals(SINGLE_X, SINGLE_Z.and(SINGLE_1));
+		assertEquals(SINGLE_0, SINGLE_0.and(SINGLE_U));
+		assertEquals(SINGLE_X, SINGLE_X.and(SINGLE_Z));
+
+		// higher length
+		var result = BitVector.of(U, X, ZERO, ONE, ONE).and(BitVector.of(ONE, ONE, ZERO, ZERO, ONE));
+		assertEquals(BitVector.of(U, X, ZERO, ZERO, ONE), result);
+	}
+
+	@Test
+	void testOr()
+	{
+		// binary
+		assertEquals(SINGLE_0, SINGLE_0.or(SINGLE_0));
+		assertEquals(SINGLE_1, SINGLE_0.or(SINGLE_1));
+		assertEquals(SINGLE_1, SINGLE_1.or(SINGLE_1));
+
+		// other
+		assertEquals(SINGLE_1, SINGLE_Z.or(SINGLE_1));
+		assertEquals(SINGLE_1, SINGLE_1.or(SINGLE_U));
+		assertEquals(SINGLE_X, SINGLE_X.or(SINGLE_Z));
+
+		// higher length
+		var result = BitVector.of(U, X, ZERO, ONE, ZERO).or(BitVector.of(ZERO, ZERO, ZERO, ONE, ONE));
+		assertEquals(BitVector.of(U, X, ZERO, ONE, ONE), result);
+	}
+
+	@Test
+	void testXor()
+	{
+		// binary
+		assertEquals(SINGLE_0, SINGLE_0.xor(SINGLE_0));
+		assertEquals(SINGLE_1, SINGLE_0.xor(SINGLE_1));
+		assertEquals(SINGLE_0, SINGLE_1.xor(SINGLE_1));
+
+		// other
+		assertEquals(SINGLE_X, SINGLE_Z.xor(SINGLE_1));
+		assertEquals(SINGLE_U, SINGLE_0.xor(SINGLE_U));
+		assertEquals(SINGLE_X, SINGLE_X.xor(SINGLE_Z));
+
+		// higher length
+		var result = BitVector.of(U, X, ZERO, ONE, ONE).xor(BitVector.of(ONE, ZERO, ZERO, ZERO, ONE));
+		assertEquals(BitVector.of(U, X, ZERO, ONE, ZERO), result);
+	}
+
+	@Test
+	void testNot()
+	{
+		// binary
+		assertEquals(SINGLE_1, SINGLE_0.not());
+		assertEquals(SINGLE_0, SINGLE_1.not());
+
+		// other
+		assertEquals(SINGLE_U, SINGLE_U.not());
+		assertEquals(SINGLE_X, SINGLE_X.not());
+		assertEquals(SINGLE_X, SINGLE_Z.not());
+
+		// higher length
+		var result = BitVector.of(U, X, ZERO, ONE, Z).not();
+		assertEquals(BitVector.of(U, X, ONE, ZERO, X), result);
+	}
+
+	@Test
+	void testLength()
+	{
+		assertEquals(0, BitVector.of().length());
+		assertEquals(1, SINGLE_0.length());
+		assertEquals(3, BitVector.of(X, X, Z).length());
+	}
+
+	@Test
+	void testConcat()
+	{
+		assertEquals(BitVector.of(U, X), SINGLE_U.concat(SINGLE_X));
+		assertEquals(BitVector.of(Z, X, U, ONE, X), BitVector.of(Z, X, U).concat(BitVector.of(ONE, X)));
+	}
+
+	@Test
+	void testSubVectorInt()
+	{
+		assertEquals(SINGLE_0, SINGLE_0.subVector(0));
+		assertEquals(BitVector.of(), SINGLE_0.subVector(1));
+		assertEquals(SINGLE_0, BitVector.of(ONE, ZERO).subVector(1));
+		assertEquals(BitVector.of(X, Z), BitVector.of(ZERO, U, ONE, X, Z).subVector(3));
+	}
+
+	@Test
+	void testSubVectorIntInt()
+	{
+		assertEquals(SINGLE_0, SINGLE_0.subVector(0, 1));
+		assertEquals(BitVector.of(), SINGLE_0.subVector(0, 0));
+		assertEquals(SINGLE_0, BitVector.of(ONE, ZERO).subVector(1, 2));
+		assertEquals(BitVector.of(ONE, X), BitVector.of(ZERO, U, ONE, X, Z).subVector(2, 4));
+	}
+
+	@Test
+	void testEqualsObject()
+	{
+		assertEquals(SINGLE_X, SINGLE_X);
+		assertNotEquals(SINGLE_0, SINGLE_1);
+
+		assertEquals(BitVector.of(X, Z, U), BitVector.of(X, Z, U));
+		assertNotEquals(BitVector.of(X, Z, U), BitVector.of(X, X, U));
+	}
+
+	@Test
+	void testEqualsWithOffset()
+	{
+		assertTrue(SINGLE_X.equalsWithOffset(SINGLE_X, 0));
+		assertFalse(SINGLE_0.equalsWithOffset(SINGLE_1, 0));
+
+		assertTrue(BitVector.of(X, Z, U).equalsWithOffset(BitVector.of(Z, U), 1));
+		assertFalse(BitVector.of(X, Z, U).equalsWithOffset(BitVector.of(X, U), 1));
+		assertTrue(BitVector.of(X, Z, U).equalsWithOffset(BitVector.of(U), 2));
+	}
+
+	@Test
+	void testParse()
+	{
+		assertEquals(SINGLE_U, BitVector.parse("U"));
+		assertEquals(SINGLE_X, BitVector.parse("X"));
+		assertEquals(SINGLE_0, BitVector.parse("0"));
+		assertEquals(SINGLE_1, BitVector.parse("1"));
+		assertEquals(SINGLE_Z, BitVector.parse("Z"));
+
+		assertEquals(BitVector.of(X, U, Z, ONE, ZERO), BitVector.parse("XUZ10"));
+
+		assertThrows(RuntimeException.class, () -> BitVector.parse("01BX"));
+	}
+
+	@Test
+	void testIterator()
+	{
+		var bv = BitVector.of(U, Z, ONE, ZERO, X);
+		Iterator<Bit> it = bv.iterator();
+
+		assertEquals(U, it.next());
+		assertEquals(Z, it.next());
+		assertEquals(ONE, it.next());
+		assertEquals(ZERO, it.next());
+		assertEquals(X, it.next());
+		assertFalse(it.hasNext());
+	}
+}
-- 
2.17.1