From 91969fbb8e1a846c21cdfe6dc7e2b20534d86119 Mon Sep 17 00:00:00 2001
From: Christian Femers <femers@in.tum.de>
Date: Mon, 26 Aug 2019 03:28:58 +0200
Subject: [PATCH] My proposal for resolving
 add92039f433cd315f2087da9c1a0de899927d96

The choice was made based on functionality (and a bit performance) and
mostly readability.
---
 .../net/mograsim/logic/core/types/Bit.java    |  5 ++
 .../mograsim/logic/core/types/BitVector.java  | 63 ++++++-------------
 .../logic/core/types/BitVectorTest.java       | 37 +++--------
 .../am2900/am2910/TestableAm2910Impl.java     |  2 +-
 4 files changed, 34 insertions(+), 73 deletions(-)

diff --git a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/Bit.java b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/Bit.java
index 8bff357a..da7b8c91 100644
--- a/net.mograsim.logic.core/src/net/mograsim/logic/core/types/Bit.java
+++ b/net.mograsim.logic.core/src/net/mograsim/logic/core/types/Bit.java
@@ -18,6 +18,11 @@ public enum Bit implements StrictLogicType<Bit>
 		this.symbol = symbol;
 	}
 
+	/**
+	 * Returns if the Bit is binary, this is only true for <code>ZERO</code> and <code>ONE</code>.
+	 * 
+	 * @return true if and only if <code>this == ONE || this == ZERO</code>
+	 */
 	public boolean isBinary()
 	{
 		return this == ONE || this == ZERO;
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 6a364034..e17ae6e1 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
@@ -57,43 +57,12 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return new BitVector(bit.makeArray(length));
 	}
 
-	public BigInteger getUnsignedValue()
-	{
-		if (!isBinary())
-			throw new NumberFormatException("BitVector is non binary: " + toString());
-		byte[] bytes = new byte[(bits.length / 8) + 1];
-		for (int i = 0; i < bits.length; i++)
-		{
-			if (Bit.ONE == bits[i])
-			{
-				bytes[i / 8] |= 1 << (i % 8);
-			}
-		}
-		return new BigInteger(bytes);
-	}
-
-	public static BitVector from(BigInteger b, int length)
+	public static BitVector from(long value, int bits)
 	{
-		int bitLength = b.bitLength();
-		int actualLength = Integer.min(bitLength, length);
-		Bit[] bits = new Bit[length];
-		for (int i = 0; i < actualLength; i++)
-			bits[i] = b.testBit(i) ? Bit.ONE : Bit.ZERO;
-		if (b.signum() < 0)
-			for (int i = actualLength; i < length; i++)
-				bits[i] = Bit.ONE;
-		else
-			for (int i = actualLength; i < length; i++)
-				bits[i] = Bit.ZERO;
-		return BitVector.of(bits);
+		return from(BigInteger.valueOf(value), bits);
 	}
 
-	public static BitVector of(long value, int bits)
-	{
-		return of(BigInteger.valueOf(value), bits);
-	}
-
-	public static BitVector of(BigInteger value, int bits)
+	public static BitVector from(BigInteger value, int bits)
 	{
 		Bit[] values = new Bit[bits];
 		for (int i = 0; i < bits; i++)
@@ -129,6 +98,11 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return bits.clone();
 	}
 
+	/**
+	 * Checks if all bits are {@link Bit#isBinary() binary}.
+	 * 
+	 * @see Bit#isBinary()
+	 */
 	public boolean isBinary()
 	{
 		for (int i = 0; i < bits.length; i++)
@@ -439,20 +413,23 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 	}
 
 	/**
-	 * 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
+	 * Returns the value of the BitVector as BigInteger.
 	 * 
+	 * @throws NumberFormatException if the BitVector is not {@link #isBinary() binary}.
 	 */
-	public BigInteger toBigInteger(boolean signed)
+	public BigInteger getUnsignedValue()
 	{
 		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;
+		byte[] bytes = new byte[(bits.length / 8) + 1];
+		for (int i = 0; i < bits.length; i++)
+		{
+			if (Bit.ONE == bits[i])
+			{
+				bytes[i / 8] |= 1 << (i % 8);
+			}
+		}
+		return new BigInteger(bytes);
 	}
 
 	/**
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
index 6c4670f5..11b5febf 100644
--- 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
@@ -38,15 +38,6 @@ class BitVectorTest
 		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()
 	{
@@ -58,34 +49,22 @@ class BitVectorTest
 
 	}
 
-	@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));
+		assertEquals(BitVector.parse("101"), BitVector.from(0b101L, 3));
+		assertEquals(BitVector.parse("01010"), BitVector.from(0b01010L, 5));
+		assertEquals(BitVector.parse("10101"), BitVector.from(-11L, 5));
+		assertEquals(BitVector.parse("0000"), BitVector.from(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));
+		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
diff --git a/net.mograsim.logic.model.am2900/test/net/mograsim/logic/model/am2900/am2910/TestableAm2910Impl.java b/net.mograsim.logic.model.am2900/test/net/mograsim/logic/model/am2900/am2910/TestableAm2910Impl.java
index 1695eae3..f3686aa2 100644
--- a/net.mograsim.logic.model.am2900/test/net/mograsim/logic/model/am2900/am2910/TestableAm2910Impl.java
+++ b/net.mograsim.logic.model.am2900/test/net/mograsim/logic/model/am2900/am2910/TestableAm2910Impl.java
@@ -54,7 +54,7 @@ public class TestableAm2910Impl implements TestableAm2910
 	@Override
 	public void setInstruction(Am2910_Inst inst)
 	{
-		I.setState(BitVector.of(inst.ordinal(), 4));
+		I.setState(BitVector.from(inst.ordinal(), 4));
 	}
 
 	@Override
-- 
2.17.1