private ArrayList<Symbol> getSymbolTable(byte[] encodedFileAsBytes) {
// Finding the Divider in the file & separate the SymbolTable
System.out.println("\nFileContent: ");
System.out.println(Arrays.toString(encodedFileAsBytes));
int i = getDividerIndexInArray(encodedFileAsBytes);
// Reading the String of symbol table from the byteArray
String symbolTableString = "";
for (int j = 0; j < i; j++) {
symbolTableString += String.valueOf((char) encodedFileAsBytes[j]);
}
// Generating the ArrayList<Symbol>
String[] splitSymbolsAndCodes = symbolTableString.split(",");
ArrayList<Symbol> symbols = new ArrayList<Symbol>();
for (int j = 0; j < splitSymbolsAndCodes.length; j++) {
String[] symbolCodePair = splitSymbolsAndCodes[j].split(":");
Symbol symbol = new Symbol(0, symbolCodePair[0]);
symbol.setCode(symbolCodePair[1]);
symbols.add(symbol);
}
// Logging the Symbol List
System.out.println("\nSymbol Table Retrived from the File");
System.out.println(Symbol.symbolListToString(symbols));
return symbols;
}
public void decodeFile(String encodedFileName, String decodedFileName) {
try {
byte[] encodedFileAsBytes = getFileAsByteArray(encodedFileName);
// Generating the Symbol & Code ArrayList
ArrayList<Symbol> symbols = getSymbolTable(encodedFileAsBytes);
// // Generating CodeTree
// Node codeTree = CodeTree.makeCodeTree(symbols);
// // Logging the CodeTree whether it have been generated correctly or not.
// String code = "";
// CodeTree.getCodeOfSymbol(CodeTree.Node.ROOT, symbols.get(2).getIdentifier(),
// code);
// System.out.println("Symbol: " + symbols.get(2) + " Code_Retrived: " + code);
// Decoding the content
int dividerIndex = getDividerIndexInArray(encodedFileAsBytes);
byte[] encodedMessage = new byte[encodedFileAsBytes.length - dividerIndex];
for (int j = 0, i = dividerIndex + 1; i < encodedFileAsBytes.length; i++) {
encodedMessage[j++] = encodedFileAsBytes[i];
}
String message = ByteUtils.toBinary(encodedMessage);
System.out.println("Encoded Message In File: " + message);
Symbol.symbolListToString(symbols);
StringBuilder decodedMessage = new StringBuilder("");
while (message.length() != 0) {
// Loggin the Messages
// System.out.println("");
// logger.info("Meesage: " + message);
// logger.info("Message Decoded: " + decodedMessage);
boolean flag = false;
for (Symbol symbol : symbols) {
if (message.startsWith(symbol.getCode())) {
decodedMessage.append(symbol.getIdentifier());
message = message.substring(symbol.getCode().length(), message.length());
flag = true;
break;
}
}
/*
* We are checking that if no symbol is there in the symbol list
* then it is the EOF as some padding is done by the String to
* Byte & Byte to String conversion
*/
if (!flag) {
break;
}
}
System.out.println("Decoded Message: " + decodedMessage);
// Writing the decoded Message in the Output File
File file = new File(decodedFileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(decodedMessage.toString().getBytes());
} catch (Exception ex) {
logger.log(Level.WARNING, ex.toString());
ex.printStackTrace();
}
}