C Program help I am trying to complete a C program that does C R C calculation .

ID: 3604205 • Letter: C

Question

C Program help I am trying to complete a C program that does C R C calculation . I got everyting to work except a function to display binary difference at each X O R step .

the program compiles using two comand line arguments .

programName c [input Hex] : for calculation

programName v [input Hex] : for virification

The polynomial is always the same

here is how the output should look like :

Here is my code so far :

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
int i_temp=0;
char* pointer_stop;
int val =0;
char binary[50000][12];
char binary_string[50000];
int length=0;
int error=0;
char input[50000];
char lowercase[50000];
char chksm[50000];
char tester[50000];
char string_end[50000];
char *polynomial;

//HEX-BINARY
void HEXA_BIN(char *hexaDecimal)
{
long int i=0;
char block[5];
while(hexaDecimal[i])
{
switch(hexaDecimal[i])
{
case '0':
strcpy(block, "0000");
break;
case '1':
strcpy(block, "0001");
break;
case '2':
strcpy(block, "0010");
break;
case '3':
strcpy(block, "0011");
break;
case '4':
strcpy(block, "0100");
break;
case '5':
strcpy(block, "0101");
break;
case '6':
strcpy(block, "0110");
break;
case '7':
strcpy(block, "0111");
break;
case '8':
strcpy(block, "1000");
break;
case '9':
strcpy(block, "1001");
break;
case 'a':
strcpy(block, "1010");
break;
case 'b':
strcpy(block, "1011");
break;
case 'c':
strcpy(block, "1100");
break;
case 'd':
strcpy(block, "1101");
break;
case 'e':
strcpy(block, "1110");
break;
case 'f':
strcpy(block, "1111");
break;
}
i++;
strcat(binary_string, block);
}
}
void CrcChecker()
{
int i,p;
int c;
for(i=0; i<strlen(polynomial); i++)
chksm[i]= binary_string[i];
do
{
if(chksm[0]=='1')
{
for(c = 1; c < strlen(polynomial); c++)
{
if (chksm[c] == polynomial[c])
{
chksm[c] = '0';
}else chksm[c] = '1';
}
}
for(p=0; p<strlen(polynomial)-1; p++)
chksm[p]=chksm[p+1];
chksm[p]=binary_string[i++];
}
while(i<=length+strlen(polynomial)-1);
}

//BINARY-HEX
void BIN_HEXA(char *binary)
{
long int dec;
long int rm;
long int qt;
int i=1,j,temp;
char hx[50000];
dec = strtol (binary,NULL,2);
qt = dec;
while(qt!=0)
{
temp = qt % 16;
if( temp < 10)
{
temp =temp + 48;
}else temp = temp + 55;
hx[i++]= temp;
qt = qt / 16;
}
for(j = i -1 ; j> 0; j--)
printf("%c",hx[j]);
printf(" (hex)");

}

//MAIN
int main(int argc, char *argv[])
{
int i=0,e=0;
int i_line=0;
polynomial="1101";
polynomial="1100110110101";
int spacer=0;

strcpy(input, argv[2]);
printf("----------------------------------------------------------------------- ");

//CHOOSE CALC MODE
if (strcmp(argv[1], "c") == 0)
{
printf("The input string (hex): %s ", input);

for(i = 0; i<strlen(input); i++)
{
lowercase[i] = tolower(input[i]);
}
HEXA_BIN(lowercase);
printf("The input string (bin): " );

for(i=0; i<strlen(input)*4; i++)
{
printf("%c" , binary_string[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf(" ");
printf(" ");
printf("The polynomial that was used (binary bit string): ");
for(i=0; i<strlen(polynomial); i++)
{
printf("%c" , polynomial[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf(" ");
printf("Mode of operation: calculate ");
printf(" ");
printf("Number of zeroes that will be appended to the binary input : 12 ");
printf(" ");
printf("The binary string difference after each XOR step of the CRC calculation: ");
length = strlen(binary_string);
for(i=strlen(binary_string); i<(strlen(polynomial) + length) - 1; i++)
{
binary_string[i]='0';
}
//Calculate(binary_string, polynomial);
CrcChecker();
printf(" ");
i_line=0;
if (strlen(chksm) % 4 == 0)
{
printf("The CRC computed from the input : ");
for(i=0; i<strlen(chksm); i++)
{
printf("%c" , chksm[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf("(bin) = ");
BIN_HEXA(chksm);
printf(" ");
}
else
{
i_line=0;
printf("The CRC computed for the input is: 0");
for(i=0; i<strlen(chksm); i++)
{
printf("%c" , chksm[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf("(bin) = ");
BIN_HEXA(chksm);
printf(" ");
}
printf(" ");
}

//CHOOSE VERIFY MODE
else if (strcmp(argv[1], "v") == 0)
{
printf("The input string (hex): %s ", input);
for(i = 0; i<strlen(input); i++)
{
lowercase[i] = tolower(input[i]);
}
HEXA_BIN(lowercase);
printf("The input string (bin): " );
for(i=0; i<strlen(input)*4; i++)
{
printf("%c" , binary_string[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf(" ");
printf(" ");
printf("The polynomial that was used (binary bit string): ");
for(i=0; i<strlen(polynomial); i++)
{
printf("%c" , polynomial[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf(" ");
printf(" ");
printf(" Mode of operation: verification ");
printf(" The CRC observed at the end of the input: ");
i_line=0;
i_temp=0;
for(i=strlen(binary_string) - 12; i<strlen(binary_string); i++)
{
printf("%c" , binary_string[i]);
string_end[i_temp]=binary_string[i];
i_temp++;
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf("(bin) = ");
BIN_HEXA(string_end);
printf(" ");

length = strlen(binary_string);
for(i=strlen(binary_string) - 12; i<strlen(binary_string); i++)
{
binary_string[i]='0';
}
length = strlen(binary_string)-12;
CrcChecker();
printf(" ");

printf("The binary string difference after each XOR step of the CRC calculation: ");
i_line=0;
if (strlen(chksm) % 4 == 0)
{
printf("The CRC computed for the input : ");
for(i=0; i<strlen(chksm); i++)
{
printf("%c" , chksm[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf("(bin) = ");
BIN_HEXA(chksm);
printf(" ");
}
else
{
i_line=0;
printf("The CRC computed for the input : 0");
for(i=0; i<strlen(chksm); i++)
{
printf("%c" , chksm[i]);
i_line++;
if(i_line == 4)
{
i_line = 0;
printf(" ");
}
}
printf("(bin) = ");
BIN_HEXA(chksm);
printf(" ");
}
printf(" ");
if(strcmp(chksm,string_end) == 0)
{
printf("Did the CRC check pass? (Yes or No): Yes ");
}
else
{
printf("Did the CRC check pass? (Yes or No): No ");
}
}
}

CIS3360 Fall 2017 Integrity Checking Using CRC Author: [Your_name or names] The input string (hex): 5AE The input string (bin): 0101 1010 1110 The polynomial used (binary bit string): 1100 1101 1010 1 Mode of operation: calculation Number of zeroes that will be appended to the binary input: 12 The binary string difference after each XOR step of the CRC calculation: 0101 1010 1110 0000 0000 000 0011 1100 0011 0100 0000 0000 0000 1111 0101 11100000 0000 0000 0011 1000 0100 1000 0000 0000 0000 1011 0010 0010 0000 0000 0000 0111 1111 1000 1000 0000 0000 0001 1001 0101 1100 0000 0000 0000 0000 1110 1001 The CRC computed from the input: 0000 1110 1001 (bin) - 0E9 (hex)

Explanation / Answer

}

//MAIN
int main(int argc, char *argv[])
{
int i=0,e=0;
int i_line=0;
polynomial="1101";
polynomial="1100110110101";
int spacer=0;

strcpy(input, argv[2]);
printf("----------------------------------------------------------------------- ");

//CHOOSE CALC MODE
if (strcmp(argv[1], "c") == 0)
{
printf("The input string (hex): %s ", input);

for(i = 0; i<strlen(input); i++)
{
lowercase[i] = tolower(input[i]);
}
HEXA_BIN(lowercase);
printf("The input string (bin): " );

length = strlen(binary_string);
for(i=strlen(binary_string) - 12; i<strlen(binary_string); i++)
{
binary_string[i]='0';
}
length = strlen(binary_string)-12;
CrcChecker();
printf(" ");

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