[Archive-access-cvs] SF.net SVN: archive-access:[3106] trunk/archive-access/projects/wayback/ wayba

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Revision: 3106
          http://archive-access.svn.sourceforge.net/archive-access/?rev=3106&view=rev
Author:   bradtofel
Date:     2010-05-18 22:56:23 +0000 (Tue, 18 May 2010)

Log Message:
-----------
INITIAL REV: simple class for manipulating bits within a byte array.

Added Paths:
-----------
    trunk/archive-access/projects/wayback/wayback-core/src/main/java/org/archive/wayback/util/BitArray.java
    trunk/archive-access/projects/wayback/wayback-core/src/test/java/org/archive/wayback/util/BitArrayTest.java

Added: trunk/archive-access/projects/wayback/wayback-core/src/main/java/org/archive/wayback/util/BitArray.java
===================================================================

--- trunk/archive-access/projects/wayback/wayback-core/src/main/java/org/archive/wayback/util/BitArray.java	                        (rev 0)
+++ trunk/archive-access/projects/wayback/wayback-core/src/main/java/org/archive/wayback/util/BitArray.java	2010-05-18 22:56:23 UTC (rev 3106)
@@ -0,0 +1,109 @@
+/* BitArray
+ *
+ * $Id$:
+ *
+ * Created on Apr 27, 2010.
+ *
+ * Copyright (C) 2006 Internet Archive.
+ *
+ * This file is part of Wayback.
+ *
+ * Wayback is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * any later version.
+ *
+ * Wayback 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 Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser Public License
+ * along with Wayback; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+package org.archive.wayback.util;
+
+/**
+ * @author brad
+ *
+ */
+public class BitArray {
+	private static final int MASKS[] = {
+		0x01,
+		0x02,
+		0x04,
+		0x08,
+		0x10,
+		0x20,
+		0x40,
+		0x80
+	};
+	private static final int MASKSR[] = {
+		~0x01,
+		~0x02,
+		~0x04,
+		~0x08,
+		~0x10,
+		~0x20,
+		~0x40,
+		~0x80
+	};
+	private byte array[] = null;
+	
+	/**
+	 * Construct a new BitArray holding at least n bits
+	 * @param n number of bits to hold
+	 */
+	public BitArray(int n) {
+		int bytes = n / 8;
+		int bits = n % 8;
+		if(bits > 0) {
+			bytes++;
+		}
+		this.array = new byte[bytes];
+	}
+	/**
+	 * Construct a new BitArray using argument as initial values.
+	 * @param array byte array of initial values
+	 */
+	public BitArray(byte array[]) {
+		this.array = array;
+	}
+	/**
+	 * @return the byte array backing this bit array.
+	 */
+	public byte[] getBytes() {
+		return array;
+	}
+	/**
+	 * @param i index of bit to test
+	 * @return true if the i'th bit is set, false otherwise
+	 */
+	public boolean get(int i) {
+		int idx = i / 8;
+		if(idx >= array.length) {
+			throw new IndexOutOfBoundsException();
+		}
+		int bit = 7 - (i % 8);
+		return ((array[idx] & MASKS[bit]) == MASKS[bit]);
+	}
+	/**
+	 * set the i'th bit to 1 or 0
+	 * @param i bit number to set
+	 * @param value if true, the bit is set to 1, otherwise it is set to 0
+	 */
+	public void set(int i, boolean value) {
+		int idx = i / 8;
+		if(idx >= array.length) {
+			throw new IndexOutOfBoundsException();
+		}
+		int bit = 7 - (i % 8);
+		if(value) {
+			array[idx] = (byte) (array[idx] | MASKS[bit]);
+		} else {
+			array[idx] = (byte) (array[idx] & MASKSR[bit]);
+		}
+	}
+}


Property changes on: trunk/archive-access/projects/wayback/wayback-core/src/main/java/org/archive/wayback/util/BitArray.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Revision Id

Added: trunk/archive-access/projects/wayback/wayback-core/src/test/java/org/archive/wayback/util/BitArrayTest.java
===================================================================
--- trunk/archive-access/projects/wayback/wayback-core/src/test/java/org/archive/wayback/util/BitArrayTest.java	                        (rev 0)
+++ trunk/archive-access/projects/wayback/wayback-core/src/test/java/org/archive/wayback/util/BitArrayTest.java	2010-05-18 22:56:23 UTC (rev 3106)
@@ -0,0 +1,84 @@
+/* BitArrayTest
+ *
+ * $Id$:
+ *
+ * Created on May 14, 2010.
+ *
+ * Copyright (C) 2006 Internet Archive.
+ *
+ * This file is part of Wayback.
+ *
+ * Wayback is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * any later version.
+ *
+ * Wayback 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 Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser Public License
+ * along with Wayback; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+package org.archive.wayback.util;
+
+import junit.framework.TestCase;
+
+/**
+ * @author brad
+ *
+ */
+public class BitArrayTest extends TestCase {
+
+	/**
+	 * Test method for {@link org.archive.wayback.util.BitArray#get(int)}.
+	 */
+	public void testGet() {
+		byte bytes[] = "Here is some data!".getBytes();
+		byte bytes2[] = "Here is some data!".getBytes();
+		int bits = bytes.length * 8;
+		sun.security.util.BitArray sba = 
+			new sun.security.util.BitArray(bits, bytes);
+		org.archive.wayback.util.BitArray wba = 
+			new org.archive.wayback.util.BitArray(bytes2);
+		for(int i = 0; i < bits; i++) {
+			boolean want = sba.get(i);
+			boolean got = wba.get(i);
+			if(want != got) {
+				got = wba.get(i);
+			}
+			assertEquals(want,got);
+		}
+	}
+
+	/**
+	 * Test method for {@link org.archive.wayback.util.BitArray#set(int, boolean)}.
+	 */
+	public void testSet() {
+		byte bytes[] = "Here is some data!".getBytes();
+		byte bytes2[] = "Here is some data!".getBytes();
+		int bits = bytes.length * 8;
+		sun.security.util.BitArray sba = 
+			new sun.security.util.BitArray(bits, bytes);
+		org.archive.wayback.util.BitArray wba = 
+			new org.archive.wayback.util.BitArray(bytes2);
+		for(int i = 0; i < bits; i++) {
+			boolean want = sba.get(i);
+			boolean got = wba.get(i);
+			boolean not = !want;
+			assertTrue(ByteOp.cmp(sba.toByteArray(), wba.getBytes()));
+			sba.set(i,not);
+			wba.set(i,not);
+			assertTrue(ByteOp.cmp(sba.toByteArray(), wba.getBytes()));
+			assertEquals(not,wba.get(i));
+			sba.set(i,got);
+			wba.set(i,got);
+			assertEquals(sba.get(i),wba.get(i));			
+			assertTrue(ByteOp.cmp(sba.toByteArray(), wba.getBytes()));
+		}
+		
+	}
+}


Property changes on: trunk/archive-access/projects/wayback/wayback-core/src/test/java/org/archive/wayback/util/BitArrayTest.java
___________________________________________________________________
Added: svn:keywords
   + Author Date Revision Id


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[Archive-access-cvs] SF.net SVN: archive-access:[3106] trunk/archive-access/projects/wayback/ wayba

[Archive-access-cvs] SF.net SVN: archive-access:[3106] trunk/archive-access/projects/wayback/ wayback-core/src