X-Git-Url: https://mograsim.net/gitweb/?a=blobdiff_plain;f=net.mograsim.logic.core%2Fsrc%2Fnet%2Fmograsim%2Flogic%2Fcore%2Ftypes%2FBitVector.java;h=e17ae6e1a233cbf7af23c3c68ac52cf37e002e13;hb=91969fbb8e1a846c21cdfe6dc7e2b20534d86119;hp=e8a40988c62c92ec89efda689875d593c878c7b6;hpb=faa90c5086c9be5550b6696cb47d976ccea66906;p=Mograsim.git

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..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
@@ -57,37 +57,19 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return new BitVector(bit.makeArray(length));
 	}
 
-	public BigInteger getUnsignedValue()
+	public static BitVector from(long value, int bits)
 	{
-		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++)
-		{
-			if (Bit.ONE.equals(bits[i]))
-			{
-				bytes[(i / 8) + 1] |= 1 << (i % 8);
-			}
-		}
-		return new BigInteger(bytes);
+		return from(BigInteger.valueOf(value), bits);
 	}
 
-	public static BitVector from(BigInteger b, int length)
+	public static BitVector from(BigInteger 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);
+		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()
@@ -116,6 +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++)
@@ -249,12 +236,23 @@ 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 +309,8 @@ 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 +319,8 @@ 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 +329,8 @@ 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 +339,15 @@ 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 +412,26 @@ public final class BitVector implements StrictLogicType<BitVector>, Iterable<Bit
 		return sb.toString();
 	}
 
+	/**
+	 * Returns the value of the BitVector as BigInteger.
+	 * 
+	 * @throws NumberFormatException if the BitVector is not {@link #isBinary() binary}.
+	 */
+	public BigInteger getUnsignedValue()
+	{
+		if (!isBinary())
+			throw new NumberFormatException(this + " is not binary");
+		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);
+	}
+
 	/**
 	 * Parses a String containing solely {@link Bit} symbols (MSB first)
 	 * 
@@ -419,21 +447,6 @@ 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).
 	 */