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| public class Crc1 {
public static int[] convertStringArraytoIntArray(String[] sarray) throws Exception {
if (sarray != null) {
int intarray[] = new int[sarray.length];
for (int i = 0; i < sarray.length; i++) {
intarray[i] = Integer.parseInt(sarray[i].toString());
}
return intarray;
}
return null;
}
public static void main(String[] args) throws IOException {
int a=0;
System.out.println("taper votre chaine");
BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));
String s = buff.readLine();
String binaire;
byte[] bytes = s.getBytes();
StringBuilder binary = new StringBuilder();
for (byte b : bytes) {
int val = b;
for (int i = 0; i < 8; i++) {
binary.append((val & 128) == 0 ? 0 : 1);
val <<= 1;
a = a + 1;
}
}
System.out.println(binary);
//System.out.println("le nombre de bit est :" binary.length());
binaire=binary.toString();
System.out.println(binaire);
String[] result = binaire.split("");
int [] data;
int [] resultat;
int data_bits=result.length;
data= new int [data_bits];
resultat =convertStringArraytoIntArray(result);
for(int i=0;i<result.length;i++){
data[i]=resultat[i];
}
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
int[] div;
int[] divisor;
int[] rem;
int[] crc;
int divisor_bits, tot_length;
System.out.println("entre le nombre de bits a diviser : ");
divisor_bits=Integer.parseInt(br.readLine());
divisor=new int[divisor_bits];
System.out.println("entre la suite a diviser : ");
for(int i=0; i<divisor_bits; i++)
divisor[i]=Integer.parseInt(br.readLine());
tot_length=data_bits+divisor_bits-1;
div=new int[tot_length];
rem=new int[tot_length];
crc=new int[tot_length];
/*------------------ CRC GENERATION-----------------------*/
for(int i=0;i<data.length;i++)
div[i]=data[i];
System.out.print("Dividend (after appending 0's) are : ");
for(int i=0; i< div.length; i++)
System.out.print(div[i]);
System.out.println();
for(int j=0; j<div.length; j++){
rem[j] = div[j];
}
rem=divide(div, divisor, rem);
for(int i=0;i<div.length;i++)
{
crc[i]=(div[i]^rem[i]);
}
System.out.println();
System.out.println("CRC code : ");
for(int i=0;i<crc.length;i++)
System.out.print(crc[i]);
}
static int[] divide(int div[],int divisor[], int rem[])
{
int cur=0;
while(true)
{
for(int i=0;i<divisor.length;i++)
rem[cur+i]=(rem[cur+i]^divisor[i]);
while(rem[cur]==0 && cur!=rem.length-1)
cur++;
if((rem.length-cur)<divisor.length)
break;
}
return rem;
}
} |
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