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From: Bryan T. <tho...@us...> - 2007-07-10 16:13:04
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Update of /cvsroot/cweb/lgpl-utils/src/test/it/unimi/dsi/mg4j/compression In directory sc8-pr-cvs4.sourceforge.net:/tmp/cvs-serv14570/src/test/it/unimi/dsi/mg4j/compression Added Files: HuffmanCodecTest.java TestHuTuckerCodec.java Log Message: Commit incorporates some clases from the mg4j project that I am trying out for order preserving (alphabetic) compression. I am in the process of writing test cases for the HuTuckerCodec that verify its use and order preserving properties. A minimal set of classes from mg4j has been imported to support compression. A fastutils jar has also been incorporated, but it can doubtless be prunned down even further. The import is from the 1.x version of mg4j. I should really re-import from 2.0 now that it has been released. --- NEW FILE: TestHuTuckerCodec.java --- package it.unimi.dsi.mg4j.compression; import junit.framework.TestCase; /** * Test suite for the {@link HuTuckerCodec}. * * @author <a href="mailto:tho...@us...">Bryan Thompson</a> * @version $Id$ */ public class TestHuTuckerCodec extends TestCase { /** * */ public TestHuTuckerCodec() { // TODO Auto-generated constructor stub } /** * @param arg0 */ public TestHuTuckerCodec(String arg0) { super(arg0); // TODO Auto-generated constructor stub } } --- NEW FILE: HuffmanCodecTest.java --- package it.unimi.dsi.mg4j.compression; import it.unimi.dsi.fastutil.booleans.BooleanArrayList; import it.unimi.dsi.fastutil.booleans.BooleanIterator; import it.unimi.dsi.mg4j.compression.Decoder; import it.unimi.dsi.mg4j.compression.HuffmanCodec; import it.unimi.dsi.mg4j.compression.PrefixCodec; import java.util.Random; import junit.framework.TestCase; import cern.colt.bitvector.BitVector; public class HuffmanCodecTest extends TestCase { public void testOneSymbol() { HuffmanCodec coder = new HuffmanCodec( new int[] { 1 } ); assertEquals( 1, coder.codeWord.length ); assertEquals( new BitVector( 0 ), coder.codeWord[ 0 ] ); } public void testTwoEquiprobableSymbols() { HuffmanCodec coder = new HuffmanCodec( new int[] { 1, 1 } ); assertEquals( 2, coder.codeWord.length ); assertEquals( new BitVector( 1 ), coder.codeWord[ 0 ] ); BitVector v = new BitVector( 1 ); v.set( 0 ); assertEquals( v, coder.codeWord[ 1 ] ); } public void testThreeNonequiprobableSymbols() { HuffmanCodec coder = new HuffmanCodec( new int[] { 1, 2, 4 } ); assertEquals( 3, coder.codeWord.length ); assertEquals( new BitVector( 2 ), coder.codeWord[ 0 ] ); BitVector v = new BitVector( 2 ); v.set( 1 ); assertEquals( v, coder.codeWord[ 1 ] ); v = new BitVector( 1 ); v.set( 0 ); assertEquals( v, coder.codeWord[ 2 ] ); } public void testRandomFrequencies() { long seed = System.currentTimeMillis(); System.err.println( seed ); Random r = new Random( seed ); int[] frequency = new int[ 100 ]; for( int i = 0; i < frequency.length; i++ ) frequency[ i ] = r.nextInt( 1000 ); HuffmanCodec codec = new HuffmanCodec( frequency ); checkPrefixCodec( codec, r ); } private void checkPrefixCodec( PrefixCodec codec, Random r ) { int[] symbol = new int[ 100 ]; BooleanArrayList bits = new BooleanArrayList(); for( int i = 0; i < symbol.length; i++ ) symbol[ i ] = r.nextInt( codec.size ); for( int i = 0; i < symbol.length; i++ ) { BitVector word = codec.codeWord[ symbol[ i ] ]; for( int j = 0; j < word.size(); j++ ) bits.add( word.get( j ) ); } BooleanIterator booleanIterator = bits.iterator(); Decoder decoder = codec.getDecoder(); for( int i = 0; i < symbol.length; i++ ) { assertEquals( decoder.decode( booleanIterator ), symbol[ i ] ); } } private void checkLengths( int[] frequency, int[] codeLength, BitVector[] codeWord ) { for( int i = 0; i < frequency.length; i++ ) assertEquals( Integer.toString( i ), codeLength[ i ], codeWord[ i ].size() ); } public void testRandomCodeLengths() { int[] frequency = { 805, 1335, 6401, 7156, 7333, 10613, 10951, 11708, 12710, 12948, 13237, 13976, 20355, 20909, 22398, 26303, 26400, 28380, 28865, 30152, 31693, }; int[] codeLength = { 7, 7, 6, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 3, 3 }; HuffmanCodec codec = new HuffmanCodec( frequency ); checkLengths( frequency, codeLength, codec.codeWord ); checkPrefixCodec( codec, new Random() ); } public void testExponentialCodeLengths() { int[] frequency = { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824 }; int[] codeLength = { 30, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 }; HuffmanCodec codec = new HuffmanCodec( frequency ); checkLengths( frequency, codeLength, codec.codeWord ); checkPrefixCodec( codec, new Random() ); } } |