Can anybody solve this in Java ? input output need to be same.

Question

//this code is giving wrong result.
//there is a code in C and that is working good. below link.
// https://code.sololearn.com/chtXRPxR0yTk/#cpp

//java code

public class Program
{
public static void main(String[] args) {
byte[] input = { 1, 2, 0xA, 0xF, 5, 0xC };
System.out.println("Original Array: ");
for (int i = 0; i < input.length; i++) {
System.out.println(String.format("%02X",input[i]));
}

byte[] compressed = new byte[3];
for (int i = 0; i < 3; ++i) {
// get always two bytes from the original array
int idx = 2 * i;
byte a1 = input[idx];
byte a2 = input[idx + 1];
// now shift the first byte 4 binary digits to the left
a1 <<= 4; //or a1*=16
// add then add the bitwise OR of both bytes to our compressed array
compressed[i] = (byte) (a1 | a2);

}

System.out.println("Compressed Array: ");
for (int i = 0; i < 3; ++i) {
System.out.println(String.format("%02X",compressed[i]));
}

//now uncompress the compressed again
byte[] uncompressed= new byte[6];
for(int i = 0; i< 3; ++i)
{
int idx = 2*i;
//get the first bits
uncompressed[idx] = (byte) (compressed[i]>>4);
//get the last bits
uncompressed[idx+1] = (byte) (compressed[i] & 0x0F);
}

//print uncompressed
System.out.println("Uncompressed Array: ");
for(int i = 0; i < 6; ++i)
{
System.out.println(String.format("%02X",uncompressed[i]));
}

}
}

Answer 1

Brother, Thanks a lots for your valuable reply.
Problem not solved.
followed your instruction but result same as before.

Test Result:

Original Array:
01020A0F050C

Compressed Array:
12 AF 5C

Uncompressed Array: 0102FA0F050C
NOTE: bit just changed. { FA, it should give 0A }
Test Link: https://code.sololearn.com/c27nQ35yE5ZF

Answer 2

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Answer 3

// 6 bytes of input works fine but if i increase bytes, then its giving wrong result again.
// code is dynamic now
// inputs will be bytes packets. input packet size is (32767 * 2)
// i actually want to use it in a vpn app.

compiler: https://code.sololearn.com/c27nQ35yE5ZF/#java

public class Program {

public static void main(String[] args) {
byte[] input = { 1, 2, 0xA, 0xF, 5, 0xC };

uncompressed(compressed(input));

}

public static byte[] compressed(byte[] bytes) {
System.out.println("Original Array: ");
for (int i = 0; i < bytes.length; i++) {
System.out.print(String.format("%02X ", bytes[i]));
}

byte[] compressed = new byte[bytes.length / 2];
for (int i = 0; i < compressed.length; ++i) {
// get always two bytes from the original array
int idx = 2 * i;
byte a1 = bytes[idx];
byte a2 = bytes[idx + 1];
// now shift the first byte 4 binary digits to the left
a1 <<= compressed.length + 1; // or a1*=16
// add then add the bitwise OR of both bytes to our compressed array
compressed[i] = (byte) (a1 | a2);

}
System.out.println("\n");
System.out.println("Compressed Array: ");
for (int i = 0; i < compressed.length; ++i) {
System.out.print(String.format("%02X ", compressed[i]));
// System.out.println("\n");
}
System.out.println("\n");
System.out.println("Size:" + compressed.length);
return compressed;
}

private static byte[] uncompressed(byte[] compressed) {
// now uncompress the compressed again
byte[] uncompressed = new byte[compressed.length * 2];
for (int i = 0; i < uncompressed.length / 2; ++i) {
int idx = 2 * i;
// get the first bits
uncompressed[idx] = (byte) (compressed[i] >> uncompressed.length / 2 + 1 & 0x0F);
// get the last bits
uncompressed[idx + 1] = (byte) (compressed[i] & 0x0F);
}

// print uncompressed
System.out.print("Uncompressed Array: ");
System.out.println("\n");
for (int i = 0; i < uncompressed.length; ++i) {
System.out.print(Str

Answer 4

thanks a lot. i solved this code.

public class Program {
public static void main(String[] args) {
byte[] input = { 1, 2, 0xA, 0xF, 5, 0xC, 6, 0xD, 7, 0xE, 7, 0xE };

uncompressed(compressed(input));

}

public static byte[] compressed(byte[] bytes) {
System.out.println("Original Array: ");
for (int i = 0; i < bytes.length; i++) {
System.out.print(String.format("%02X ", bytes[i]));
}
System.out.println("\nSize:" + bytes.length);

byte[] compressed = new byte[bytes.length / 2];
for (int i = 0; i < compressed.length; ++i) {
// get always two bytes from the original array
int idx = 2 * i;
byte a1 = bytes[idx];
byte a2 = bytes[idx + 1];
// now shift the first byte 4 binary digits to the left
a1 <<= 4; // or a1*=16
// add then add the bitwise OR of both bytes to our compressed array
compressed[i] = (byte) (a1 | a2);
}
System.out.println("\n");
System.out.println("Compressed Array: ");

for (int i = 0; i < compressed.length; ++i) {
System.out.print(String.format("%02X ", compressed[i]));
// System.out.println("\n");
}
System.out.println("\nSize:" + compressed.length);
System.out.println("\n");
return compressed;
}

private static byte[] uncompressed(byte[] compressed) {
// now uncompress the compressed again
byte[] uncompressed = new byte[compressed.length * 2];
for (int i = 0; i < uncompressed.length / 2; ++i) {
int idx = 2 * i;
// get the first bits
uncompressed[idx] = (byte) (compressed[i] >> 4 & 0x0F);
// get the last bits
uncompressed[idx + 1] = (byte) (compressed[i] & 0x0F);
}

// print uncompressed
System.out.print("Uncompressed Array: \n");
//System.out.println("\n");
for (int i = 0; i < uncompressed.length; ++i) {