Download Homework 4 - UW

Homework4
HuffmanCoding
Due11:59PMMondayMarch27
HuffmanCoding
•  ImplementHuffmanEncodingandDecoding
andtheclassesshownonthefollowingslides.
YouwillalsoneedtousetheStackclassandthe
LinkedListorArrayListclass.
•  HuffmanEncodeexpects2commandline
arguments:thenameofthesourcefile(thefile
tobecompressed)andthenameofthe
desOnaOonfile(thefiletowhichthe
compressedfilemustbewriPen)
HuffmanCoding
•  HuffmanDecodeexpects2commandline
arguments:thenameofthesourcefile(afile
thatcontainsacompressedfilecreatedby
yourencoder)andthenameofthe
desOnaOonfile(thefiletowhichthe
uncompressedfilemustbewriPen)
•  Ifyourprogramsworkthecontentsof
decoder’sdesOnaOonfileshouldbeexactly
thesameastheoriginalsourcefileusedby
encoder
HuffmanCoding
•  Iwillpostsomelargefilesforyoutotestwith
butyoushouldfirsttestwithsmallfilesyou
create
•  YouwilldemonstrateyourimplementaOonto
me.
HuffmanCoding
importjava.io.*;
publicabstractclassBitInputStream{
protectedDataInputStreamd;
publicBitInputStream(Stringfilename){
try{
d=newDataInputStream(newFileInputStream(filename));
}
catch(IOExcepOone){
}
}
publicabstractintreadBit();
publicabstractvoidclose();
}
HuffmanCoding
importjava.io.*;
publicabstractclassBitOutputStream{
protectedDataOutputStreamd;
publicBitOutputStream(Stringfilename){
try{
d=newDataOutputStream(newFileOutputStream(filename));
}
catch(IOExcepOone){
}
}
publicabstractvoidwriteBit(intbit);
publicabstractvoidclose();
}
HuffmanCoding
importjava.io.*;
publicclassHuffmanInputStreamextendsBitInputStream{
privateStringtree;
privateinttotalChars;
publicHuffmanInputStream(Stringfilename){
super(filename);
try{
tree=d.readUTF();
totalChars=d.readInt();
}
catch(IOExcepOone){}
}
}
HuffmanCoding
HuffmanInputStream(conOnued)
publicintreadBit(){
}
}
publicStringgetTree(){
}
publicinttotalChars(){
}
publicvoidclose(){
}
HuffmanCoding
importjava.io.*;
publicclassHuffmanOutputStreamextendsBitOutputStream{
publicHuffmanOutputStream(Stringfilename,Stringtree,inttotalChars){
super(filename);
try{
d.writeUTF(tree);
d.writeInt(totalChars);
}
catch(IOExcepOone){
}
}
publicvoidwriteBit(intbit){
//PREbit==0||bit==1
}
publicvoidclose(){
}
}
HuffmanCoding
importjava.uOl.*;
publicclassHuffmanTree{
privateclassNode{
privateNodeled;
privatechardata;
privateNoderight;
privateNode(NodeL,chard,NodeR){
led=L;
data=d;
right=R;
}
}
privateNoderoot;
privateNodecurrent;
HuffmanCoding
HuffmanTree(conOnued)
publicHuffmanTree(){
root=null;
current=null;
}
publicHuffmanTree(chard){
}
publicHuffmanTree(Stringt,charnonLeaf){
//AssumestrepresentsapostorderrepresentaOonofthetree
//whereanodeiseitheraleaforhastwochildren.nonLeaf
//isthecharvalueofthedatainthenon-leafnodes
}
publicHuffmanTree(HuffmanTreeb1,HuffmanTreeb2,chard){
}
HuffmanCoding
HuffmanTree(conOnued)
//Thefollowingmethodsallowauserobjecttofollowapathinthetree.
//EachmethodexceptatLeafandcurrentchangesthevalueofcurrent
//atLeafreturnstrueofthecurrentposiOonisaleaf,otherwiseitreturnsfalse
//currentreturnsthedatavalueinthecurrentNode
publicvoidmoveRoot(){
}
publicvoidmoveLed(){
}
publicvoidmoveRight(){
}
publicbooleanatLeaf(){
}
publiccharcurrent(){
}
HuffmanCoding
HuffmanTree(conOnued)
//Innerclasstocreateaniterator.Theiteratorallowstheuserclasstofindallpathsfrom
//theroottoaleaf.Thepathsareseqeuncesof0sand1s.0meansledand1meansright
//Youwillfinditeasiertofindallthepathswhentheiteratoriscreated.
publicclassPathIteratorimplementsIterator<String>{
publicPathIterator(){
}
}
publicbooleanhasNext(){
}
publicStringnext(){
}
publicvoidremove(){
//opOonalmethodnotimplemented
}
HuffmanCoding
HuffmanTree(conOnued)
publicIterator<String>iterator(){
//returnaPathIteratorobject
}
publicStringtoString(){
}
}
HuffmanCoding
importjava.io.*;
importjava.uOl.*;
publicclassHuffmanEncode{
publicHuffmanEncode(Stringin,Stringout){
//Implementsthehuffmanencodingalgorithm
//Addprivatemethodsasneeded
}
publicstaOcvoidmain(Stringargs[]){
newHuffmanEncode(args[0],args[1]);
}
}
HuffmanCoding
importjava.io.*;
importjava.uOl.*;
publicclassHuffmanDecode{
publicHuffmanDecode(Stringin,Stringout){
//Implementsthehuffmandecodingalgorithm
//Addprivatemethodsasneeded
}
publicstaOcvoidmain(Stringargs[]){
newHuffmanDecode(args[0],args[1]);
}
}
HuffmanCoding
•  InaddiOontotheclassesontheprevious
slidesyoushouldmodifytheBinaryHeapclass
Idiscussedinclasssoitcanbeusedasa
priorityqueuetobuildtheHuffmantree.
Homework4Submission
•  Youwilldemonstrateyourprogramtomeeitheron
yourownmachineoronamachineintheCSlab
•  IfyoudemobetweenMondayMar.27andThursday
Mar.30theprogramisonOme.Iwillnotbeableto
dodemosforeveryoneonthelastdaysoyoushould
notwaitunOlthelastdaytodemo.
•  YoucandemofromFridayMar.31unOlThursday
Apr.6forupto50%ofthepoints.