entry
Kulesi sihloko ngizokhuluma nge-algorithm edumile ye-Huffman, kanye nokusetshenziswa kwayo ekucindezelweni kwedatha.
Ngenxa yalokho, sizobhala i-archiver elula. Lokhu sekuxoxiwe ngakho , kodwa ngaphandle kokuqaliswa okungokoqobo. Izinto ezithiyori zokuthunyelwe kwamanje zithathwe ezifundweni zesayensi yekhompyutha yesikole kanye nencwadi kaRobert Laforet ethi "Data Structures and Algorithms in Java". Ngakho, yonke into isikiwe!
Imicabango embalwa
Efayelini lombhalo elivamile, uhlamvu olulodwa lubhalwe ngekhodi ngamabhithi angu-8 (ASCII encoding) noma 16 (Unicode encoding). Okulandelayo sizocubungula umbhalo we-ASCII. Isibonelo, thatha umugqa s1 = “USUSIE UTHI KULULA”. Kunengqikithi yezinhlamvu ezingu-22 emgqeni, ngokwemvelo, kuhlanganise nezikhala kanye nohlamvu olusha lomugqa - 'n'. Ifayela eliqukethe lo mugqa lizoba nesisindo esingu-22*8 = 176 bits. Umbuzo uphakama ngokushesha: ingabe kunengqondo ukusebenzisa wonke amabhithi ayi-8 ukufaka ikhodi engu-1? Asizisebenzisi zonke izinhlamvu ze-ASCII. Ngisho noma bekwenzile, bekuyoba okunengqondo ngokwengeziwe ukuba uhlamvu oluvame kakhulu - S - lunikezwe ikhodi emfushane kakhulu, futhi uhlamvu olungavamile - T (noma u-U, noma u-'n') - lunikezwe ikhodi ende. Yilokhu okuqukethe i-algorithm ye-Huffman: kuyadingeka ukuthola inketho yombhalo wekhodi efanele lapho ifayela lizoba nesisindo esincane. Kuyinto evamile ukuthi ubude bekhodi buzohluka ngezimpawu ezahlukene - lokhu yilokho i-algorithm esekelwe kuyo.
Ukubhala amakhodi
Kungani unganiki umlingisi u-'S' ikhodi, isibonelo, ubude obuyibhithi elilodwa: 1 noma 0. Makube ngu-1. Bese kuba uhlamvu lwesibili oluvame kakhulu - '' (isikhala) - nikeza u-1. Ake sithi uqale ukuqopha umlayezo wakho - iyunithi yezinhlamvu enekhodi s0 - futhi uyabona ukuthi ikhodi iqala ngo-1. Ngakho, wenzani: ingabe lolu uhlamvu S, noma omunye uhlamvu, isibonelo A? Ngakho-ke, kuphakama umthetho obalulekile:
Ayikho ikhodi okufanele ibe isiqalo yenye
Lo mthetho ubalulekile ku-algorithm. Ngakho-ke, ukudala ikhodi kuqala ngetafula lemvamisa, elibonisa imvamisa (inombolo yezenzeko) zophawu ngalunye:
Izinhlamvu ezinezenzeko eziningi kufanele zibhalwe ngekhodi okungenani kungenzeka inani lamabhithi. Ngizonikeza isibonelo selinye lamathebula ekhodi okungenzeka:
Ngakho-ke umlayezo ofakwe ikhodi uzobukeka kanje:
10 01111 10 110 1111 00 10 010 1110 10 00 110 0110 00 110 10 00 1111 010 10 1110 01110
Ngihlukanise ikhodi yohlamvu ngalunye ngesikhala. Lokhu ngeke kwenzeke kufayela elicindezelwe ngempela!
Umbuzo uphakama: le nsizwa yaqhamuka kanjani nekhodi yokwakha itafula lamakhodi? Lokhu kuzoxoxwa ngakho ngezansi.
Ukwakha isihlahla se-Huffman
Yilapho izihlahla zokusesha ezinambambili zisiza khona. Ungakhathazeki, ngeke udinge ukusesha, ukufaka, noma ukususa izindlela lapha. Nasi isakhiwo sesihlahla ku-java:
public class Node {
private int frequence;
private char letter;
private Node leftChild;
private Node rightChild;
...
}
class BinaryTree {
private Node root;
public BinaryTree() {
root = new Node();
}
public BinaryTree(Node root) {
this.root = root;
}
...
}
Lena akuyona ikhodi ephelele, ikhodi egcwele izoba ngezansi.
Nansi i-algorithm yokwakha isihlahla:
- Dala into ye-Node yohlamvu ngalunye olusuka kumlayezo (umugqa s1). Esimeni sethu kuzoba namanodi ayi-9 (Izinto zeNode). I-node ngayinye inezinkambu zedatha ezimbili: uphawu kanye nemvamisa
- Dala into Yesihlahla (BinaryTree) kuNode ngayinye. I-node iba impande yesihlahla.
- Faka lezi zihlahla kulayini obalulekile. Lapho i-frequency iphansi, iphezulu ukubaluleka kwayo. Ngakho, lapho ukhipha, i-dervo ene-frequency ephansi ihlale ikhethiwe.
Okulandelayo udinga ukwenza okulandelayo ngomjikelezo:
- Susa izihlahla ezimbili kulayini obalulekile futhi uzenze izingane zenodi entsha (i-node esanda kwakhiwa ngaphandle kohlamvu). Imvamisa yenodi entsha ilingana nesamba samafrikhwensi ezihlahla ezimbili ezizalayo.
- Kule nodi, dala isihlahla esinempande kule nodi. Faka lesi sihlahla emuva kulayini obalulekile. (Njengoba isihlahla sinobuningi obusha, cishe sizovela endaweni entsha kulayini)
- Qhubeka izinyathelo 1 kanye ne-2 kuze kube yilapho sekusele isihlahla esisodwa kuphela emgqeni - isihlahla sika-Huffman
Cabangela le-algorithm kumugqa s1:
Lapha uphawu “lf” (linefeed) lusho umugqa omusha, “sp” (isikhala) yisikhala.
Yini elandelayo?
Sithole isihlahla se-Huffman. KULUNGILE. Futhi wenzeni ngakho? Ngeke baze bakuthathe mahhala. Bese, udinga ukulandelela zonke izindlela ezingenzeka kusukela empandeni kuya emaqabunga esihlahla. Masivumelane ukusho unqenqema 0 uma luholela enganeni yesokunxele futhi 1 uma luholela kwekwesokudla. Uma sikhuluma ngokuqinile, kulokhu kuphawulwa, ikhodi yophawu yindlela esuka empandeni yesihlahla iye eqabungeni eliqukethe lona kanye lolu phawu.
Le yindlela ithebula lamakhodi elivele ngayo. Qaphela ukuthi uma sicabangela leli thebula, singaphetha ngokuthi "isisindo" sophawu ngalunye - lokhu ubude bekhodi yalo. Khona-ke, ngefomu elicindezelwe, ifayela lokuqala lizoba nesisindo: 2 * 3 + 2*4 + 3 * 3 + 6 * 2 + 1 * 4 + 1 * 5 + 2 * 4 + 4 * 2 + 1 * 5 = 65 bits . Ekuqaleni yayinesisindo esingamabhithi angu-176. Ngenxa yalokho, sinciphise izikhathi ezingu-176/65 = 2.7! Kodwa lokhu kuyi-utopia. I-coefficient enjalo cishe ayinakwenzeka. Kungani? Lokhu kuzoxoxwa ngakho kamuva.
Ukuqopha
Hhayi-ke, mhlawumbe into elula esele ukuqopha. Ngicabanga ukuthi abaningi benu baqagele ukuthi asikwazi ukumane sidale ifayela elicindezelwe ngaphandle kokusikisela ukuthi lafakwa kanjani ikhodi - ngeke sikwazi ukulihlukanisa! Yebo, yebo, bekunzima kimina ukuqaphela lokhu, kodwa kuzodingeka ngidale ithebula lefayela lombhalo elinethebula lokuminyanisa:
01110
00
A010
E1111
I110
S10
T0110
U01111
Y1110
Ukufakwa kwethebula ngendlela 'yophawu' 'ikhodi yomlingiswa'. Kungani u-01110 engenalo uphawu? Eqinisweni, inophawu, amathuluzi e-java nje engiwasebenzisayo lapho ngikhiphela ifayela, uhlamvu olusha lomugqa - 'n' - luguqulwa lube umugqa omusha (noma ngabe kuzwakala kuwubuwula kangakanani). Ngakho-ke, umugqa ongenalutho phezulu uhlamvu lwekhodi 01110. Kwikhodi 00, uhlamvu yisikhala ekuqaleni komugqa. Ngizosho zisuka nje ukuthi ku-Khan yethu, le ndlela yokugcina itafula ingasho ukuthi ayinangqondo kakhulu. Kodwa kulula ukuyiqonda nokuyisebenzisa. Ngizojabula ukuzwa izincomo zakho kumazwana mayelana nokwenza kahle.
Ukuba naleli thebula kwenza kube lula kakhulu ukuqopha. Masikhumbule ukuthi yimuphi umthetho esiwulandele lapho sidala umbhalo wekhodi:
Ayikho ikhodi okufanele ibe isiqalo yenye
Yilapho idlala khona indima yokusiza. Sifunda ngokulandelana kancane kancane futhi, ngokushesha nje lapho umucu ophumayo u-d, ohlanganisa izingcezu ezifundiwe, ufana nombhalo wekhodi ohambisana nomlingiswa womlingiswa, ngokushesha sazi ukuthi uhlamvu lomlingiswa (futhi lona kuphela!) lufakwe ikhodi. Okulandelayo, sibhala uhlamvu emugqeni wokukhipha amakhodi (umugqa oqukethe umyalezo okhishwe), setha kabusha umugqa d, bese ufunda ifayela elibhalwe ngekhodi.
Ukuqaliswa
Isikhathi sokululaza ikhodi yami futhi ngibhale i-archiver. Masiyibize ngeCompressor.
Qala phansi. Okokuqala, sibhala isigaba se-Node:
public class Node {
private int frequence;//частота
private char letter;//буква
private Node leftChild;//левый потомок
private Node rightChild;//правый потомок
public Node(char letter, int frequence) { //собственно, конструктор
this.letter = letter;
this.frequence = frequence;
}
public Node() {}//перегрузка конструтора для безымянных узлов(см. выше в разделе о построении дерева Хаффмана)
public void addChild(Node newNode) {//добавить потомка
if (leftChild == null)//если левый пустой=> правый тоже=> добавляем в левый
leftChild = newNode;
else {
if (leftChild.getFrequence() <= newNode.getFrequence()) //в общем, левым потомком
rightChild = newNode;//станет тот, у кого меньше частота
else {
rightChild = leftChild;
leftChild = newNode;
}
}
frequence += newNode.getFrequence();//итоговая частота
}
public Node getLeftChild() {
return leftChild;
}
public Node getRightChild() {
return rightChild;
}
public int getFrequence() {
return frequence;
}
public char getLetter() {
return letter;
}
public boolean isLeaf() {//проверка на лист
return leftChild == null && rightChild == null;
}
}
Manje isihlahla:
class BinaryTree {
private Node root;
public BinaryTree() {
root = new Node();
}
public BinaryTree(Node root) {
this.root = root;
}
public int getFrequence() {
return root.getFrequence();
}
public Node getRoot() {
return root;
}
}
Umugqa Obalulekile:
import java.util.ArrayList;//да-да, очередь будет на базе списка
class PriorityQueue {
private ArrayList<BinaryTree> data;//список очереди
private int nElems;//кол-во элементов в очереди
public PriorityQueue() {
data = new ArrayList<BinaryTree>();
nElems = 0;
}
public void insert(BinaryTree newTree) {//вставка
if (nElems == 0)
data.add(newTree);
else {
for (int i = 0; i < nElems; i++) {
if (data.get(i).getFrequence() > newTree.getFrequence()) {//если частота вставляемого дерева меньше
data.add(i, newTree);//чем част. текущего, то cдвигаем все деревья на позициях справа на 1 ячейку
break;//затем ставим новое дерево на позицию текущего
}
if (i == nElems - 1)
data.add(newTree);
}
}
nElems++;//увеличиваем кол-во элементов на 1
}
public BinaryTree remove() {//удаление из очереди
BinaryTree tmp = data.get(0);//копируем удаляемый элемент
data.remove(0);//собственно, удаляем
nElems--;//уменьшаем кол-во элементов на 1
return tmp;//возвращаем удаленный элемент(элемент с наименьшей частотой)
}
}
Ikilasi elidala isihlahla se-Huffman:
public class HuffmanTree {
private final byte ENCODING_TABLE_SIZE = 127;//длина кодировочной таблицы
private String myString;//сообщение
private BinaryTree huffmanTree;//дерево Хаффмана
private int[] freqArray;//частотная таблица
private String[] encodingArray;//кодировочная таблица
//----------------constructor----------------------
public HuffmanTree(String newString) {
myString = newString;
freqArray = new int[ENCODING_TABLE_SIZE];
fillFrequenceArray();
huffmanTree = getHuffmanTree();
encodingArray = new String[ENCODING_TABLE_SIZE];
fillEncodingArray(huffmanTree.getRoot(), "", "");
}
//--------------------frequence array------------------------
private void fillFrequenceArray() {
for (int i = 0; i < myString.length(); i++) {
freqArray[(int)myString.charAt(i)]++;
}
}
public int[] getFrequenceArray() {
return freqArray;
}
//------------------------huffman tree creation------------------
private BinaryTree getHuffmanTree() {
PriorityQueue pq = new PriorityQueue();
//алгоритм описан выше
for (int i = 0; i < ENCODING_TABLE_SIZE; i++) {
if (freqArray[i] != 0) {//если символ существует в строке
Node newNode = new Node((char) i, freqArray[i]);//то создать для него Node
BinaryTree newTree = new BinaryTree(newNode);//а для Node создать BinaryTree
pq.insert(newTree);//вставить в очередь
}
}
while (true) {
BinaryTree tree1 = pq.remove();//извлечь из очереди первое дерево.
try {
BinaryTree tree2 = pq.remove();//извлечь из очереди второе дерево
Node newNode = new Node();//создать новый Node
newNode.addChild(tree1.getRoot());//сделать его потомками два извлеченных дерева
newNode.addChild(tree2.getRoot());
pq.insert(new BinaryTree(newNode);
} catch (IndexOutOfBoundsException e) {//осталось одно дерево в очереди
return tree1;
}
}
}
public BinaryTree getTree() {
return huffmanTree;
}
//-------------------encoding array------------------
void fillEncodingArray(Node node, String codeBefore, String direction) {//заполнить кодировочную таблицу
if (node.isLeaf()) {
encodingArray[(int)node.getLetter()] = codeBefore + direction;
} else {
fillEncodingArray(node.getLeftChild(), codeBefore + direction, "0");
fillEncodingArray(node.getRightChild(), codeBefore + direction, "1");
}
}
String[] getEncodingArray() {
return encodingArray;
}
public void displayEncodingArray() {//для отладки
fillEncodingArray(huffmanTree.getRoot(), "", "");
System.out.println("======================Encoding table====================");
for (int i = 0; i < ENCODING_TABLE_SIZE; i++) {
if (freqArray[i] != 0) {
System.out.print((char)i + " ");
System.out.println(encodingArray[i]);
}
}
System.out.println("========================================================");
}
//-----------------------------------------------------
String getOriginalString() {
return myString;
}
}
Ikilasi eliqukethe ukuthi yimaphi amakhodi/amakhodi:
public class HuffmanOperator {
private final byte ENCODING_TABLE_SIZE = 127;//длина таблицы
private HuffmanTree mainHuffmanTree;//дерево Хаффмана (используется только для сжатия)
private String myString;//исходное сообщение
private int[] freqArray;//частотаная таблица
private String[] encodingArray;//кодировочная таблица
private double ratio;//коэффициент сжатия
public HuffmanOperator(HuffmanTree MainHuffmanTree) {//for compress
this.mainHuffmanTree = MainHuffmanTree;
myString = mainHuffmanTree.getOriginalString();
encodingArray = mainHuffmanTree.getEncodingArray();
freqArray = mainHuffmanTree.getFrequenceArray();
}
public HuffmanOperator() {}//for extract;
//---------------------------------------compression-----------------------------------------------------------
private String getCompressedString() {
String compressed = "";
String intermidiate = "";//промежуточная строка(без добавочных нулей)
//System.out.println("=============================Compression=======================");
//displayEncodingArray();
for (int i = 0; i < myString.length(); i++) {
intermidiate += encodingArray[myString.charAt(i)];
}
//Мы не можем писать бит в файл. Поэтому нужно сделать длину сообщения кратной 8=>
//нужно добавить нули в конец(можно 1, нет разницы)
byte counter = 0;//количество добавленных в конец нулей (байта в полне хватит: 0<=counter<8<127)
for (int length = intermidiate.length(), delta = 8 - length % 8;
counter < delta ; counter++) {//delta - количество добавленных нулей
intermidiate += "0";
}
//склеить кол-во добавочных нулей в бинарном предаствлении и промежуточную строку
compressed = String.format("%8s", Integer.toBinaryString(counter & 0xff)).replace(" ", "0") + intermidiate;
//идеализированный коэффициент
setCompressionRatio();
//System.out.println("===============================================================");
return compressed;
}
private void setCompressionRatio() {//посчитать идеализированный коэффициент
double sumA = 0, sumB = 0;//A-the original sum
for (int i = 0; i < ENCODING_TABLE_SIZE; i++) {
if (freqArray[i] != 0) {
sumA += 8 * freqArray[i];
sumB += encodingArray[i].length() * freqArray[i];
}
}
ratio = sumA / sumB;
}
public byte[] getBytedMsg() {//final compression
StringBuilder compressedString = new StringBuilder(getCompressedString());
byte[] compressedBytes = new byte[compressedString.length() / 8];
for (int i = 0; i < compressedBytes.length; i++) {
compressedBytes[i] = (byte) Integer.parseInt(compressedString.substring(i * 8, (i + 1) * 8), 2);
}
return compressedBytes;
}
//---------------------------------------end of compression----------------------------------------------------------------
//------------------------------------------------------------extract-----------------------------------------------------
public String extract(String compressed, String[] newEncodingArray) {
String decompressed = "";
String current = "";
String delta = "";
encodingArray = newEncodingArray;
//displayEncodingArray();
//получить кол-во вставленных нулей
for (int i = 0; i < 8; i++)
delta += compressed.charAt(i);
int ADDED_ZEROES = Integer.parseInt(delta, 2);
for (int i = 8, l = compressed.length() - ADDED_ZEROES; i < l; i++) {
//i = 8, т.к. первым байтом у нас идет кол-во вставленных нулей
current += compressed.charAt(i);
for (int j = 0; j < ENCODING_TABLE_SIZE; j++) {
if (current.equals(encodingArray[j])) {//если совпало
decompressed += (char)j;//то добавляем элемент
current = "";//и обнуляем текущую строку
}
}
}
return decompressed;
}
public String getEncodingTable() {
String enc = "";
for (int i = 0; i < encodingArray.length; i++) {
if (freqArray[i] != 0)
enc += (char)i + encodingArray[i] + 'n';
}
return enc;
}
public double getCompressionRatio() {
return ratio;
}
public void displayEncodingArray() {//для отладки
System.out.println("======================Encoding table====================");
for (int i = 0; i < ENCODING_TABLE_SIZE; i++) {
//if (freqArray[i] != 0) {
System.out.print((char)i + " ");
System.out.println(encodingArray[i]);
//}
}
System.out.println("========================================================");
}
}
Ikilasi elenza kube lula ukubhala ifayela:
import java.io.File;
import java.io.PrintWriter;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.Closeable;
public class FileOutputHelper implements Closeable {
private File outputFile;
private FileOutputStream fileOutputStream;
public FileOutputHelper(File file) throws FileNotFoundException {
outputFile = file;
fileOutputStream = new FileOutputStream(outputFile);
}
public void writeByte(byte msg) throws IOException {
fileOutputStream.write(msg);
}
public void writeBytes(byte[] msg) throws IOException {
fileOutputStream.write(msg);
}
public void writeString(String msg) {
try (PrintWriter pw = new PrintWriter(outputFile)) {
pw.write(msg);
} catch (FileNotFoundException e) {
System.out.println("Неверный путь, или такого файла не существует!");
}
}
@Override
public void close() throws IOException {
fileOutputStream.close();
}
public void finalize() throws IOException {
close();
}
}
Ikilasi elenza kube lula ukufunda efayeleni:
import java.io.FileInputStream;
import java.io.EOFException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
public class FileInputHelper implements Closeable {
private FileInputStream fileInputStream;
private BufferedReader fileBufferedReader;
public FileInputHelper(File file) throws IOException {
fileInputStream = new FileInputStream(file);
fileBufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));
}
public byte readByte() throws IOException {
int cur = fileInputStream.read();
if (cur == -1)//если закончился файл
throw new EOFException();
return (byte)cur;
}
public String readLine() throws IOException {
return fileBufferedReader.readLine();
}
@Override
public void close() throws IOException{
fileInputStream.close();
}
}
Yebo, kanye nekilasi eliyinhloko:
import java.io.File;
import java.nio.charset.MalformedInputException;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Paths;
import java.util.List;
import java.io.EOFException;
public class Main {
private static final byte ENCODING_TABLE_SIZE = 127;
public static void main(String[] args) throws IOException {
try {//указываем инструкцию с помощью аргументов командной строки
if (args[0].equals("--compress") || args[0].equals("-c"))
compress(args[1]);
else if ((args[0].equals("--extract") || args[0].equals("-x"))
&& (args[2].equals("--table") || args[2].equals("-t"))) {
extract(args[1], args[3]);
}
else
throw new IllegalArgumentException();
} catch (ArrayIndexOutOfBoundsException | IllegalArgumentException e) {
System.out.println("Неверный формат ввода аргументов ");
System.out.println("Читайте Readme.txt");
e.printStackTrace();
}
}
public static void compress(String stringPath) throws IOException {
List<String> stringList;
File inputFile = new File(stringPath);
String s = "";
File compressedFile, table;
try {
stringList = Files.readAllLines(Paths.get(inputFile.getAbsolutePath()));
} catch (NoSuchFileException e) {
System.out.println("Неверный путь, или такого файла не существует!");
return;
} catch (MalformedInputException e) {
System.out.println("Текущая кодировка файла не поддерживается");
return;
}
for (String item : stringList) {
s += item;
s += 'n';
}
HuffmanOperator operator = new HuffmanOperator(new HuffmanTree(s));
compressedFile = new File(inputFile.getAbsolutePath() + ".cpr");
compressedFile.createNewFile();
try (FileOutputHelper fo = new FileOutputHelper(compressedFile)) {
fo.writeBytes(operator.getBytedMsg());
}
//create file with encoding table:
table = new File(inputFile.getAbsolutePath() + ".table.txt");
table.createNewFile();
try (FileOutputHelper fo = new FileOutputHelper(table)) {
fo.writeString(operator.getEncodingTable());
}
System.out.println("Путь к сжатому файлу: " + compressedFile.getAbsolutePath());
System.out.println("Путь к кодировочной таблице " + table.getAbsolutePath());
System.out.println("Без таблицы файл будет невозможно извлечь!");
double idealRatio = Math.round(operator.getCompressionRatio() * 100) / (double) 100;//идеализированный коэффициент
double realRatio = Math.round((double) inputFile.length()
/ ((double) compressedFile.length() + (double) table.length()) * 100) / (double)100;//настоящий коэффициент
System.out.println("Идеализированный коэффициент сжатия равен " + idealRatio);
System.out.println("Коэффициент сжатия с учетом кодировочной таблицы " + realRatio);
}
public static void extract(String filePath, String tablePath) throws FileNotFoundException, IOException {
HuffmanOperator operator = new HuffmanOperator();
File compressedFile = new File(filePath),
tableFile = new File(tablePath),
extractedFile = new File(filePath + ".xtr");
String compressed = "";
String[] encodingArray = new String[ENCODING_TABLE_SIZE];
//read compressed file
//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!check here:
try (FileInputHelper fi = new FileInputHelper(compressedFile)) {
byte b;
while (true) {
b = fi.readByte();//method returns EOFException
compressed += String.format("%8s", Integer.toBinaryString(b & 0xff)).replace(" ", "0");
}
} catch (EOFException e) {
}
//--------------------
//read encoding table:
try (FileInputHelper fi = new FileInputHelper(tableFile)) {
fi.readLine();//skip first empty string
encodingArray[(byte)'n'] = fi.readLine();//read code for 'n'
while (true) {
String s = fi.readLine();
if (s == null)
throw new EOFException();
encodingArray[(byte)s.charAt(0)] = s.substring(1, s.length());
}
} catch (EOFException ignore) {}
extractedFile.createNewFile();
//extract:
try (FileOutputHelper fo = new FileOutputHelper(extractedFile)) {
fo.writeString(operator.extract(compressed, encodingArray));
}
System.out.println("Путь к распакованному файлу " + extractedFile.getAbsolutePath());
}
}
Kuzodingeka uzibhalele wena ifayela le-readme.txt :)
isiphetho
Ngicabanga ukuthi yilokho kuphela ebengifuna ukukusho. Uma unokuthile ongakusho mayelana nokungabi namakhono kwami ekuthuthukiseni ikhodi, i-algorithm, nanoma yikuphi ukuthuthukiswa ngokuvamile, zizwe ukhululekile ukubhala. Uma ngingakachazi lutho ngicela ubhale nami. Ngingathanda ukuzwa kuwe kumazwana!
PS
Yebo, yebo, ngisekhona, ngoba angizange ngikhohlwe mayelana ne-coefficient. Ngochungechunge s1, ithebula lombhalo wekhodi linesisindo samabhayithi angu-48 - likhulu kakhulu kunefayela elingumthombo, futhi asizange sikhohlwe ngoziro abengeziwe (inani loziro abangeziwe ngu-7) => isilinganiso sokucindezela sizoba ngaphansi kweyodwa: 176/ (65 + 48*8 + 7) = 0.38. Uma nawe ukubonile lokhu, akubona nje ubuso bakho obuhle. Yebo, lokhu kuqaliswa ngeke kusebenze kahle kakhulu kumafayela amancane. Kodwa kwenzekani kumafayela amakhulu? Osayizi bamafayela bakhulu kakhulu kunosayizi wethebula lombhalo wekhodi. Yilapho i-algorithm isebenza khona njengoba kufanele! Ngokwesibonelo, for I-archiver ikhiqiza i-coefficient yangempela (hhayi ekahle) engu-1.46 - cishe isikhathi esisodwa nesigamu! Futhi yebo, ifayela bekufanele libe ngesiNgisi.
Source: www.habr.com