What does the function calculate_modified do? What problems or issues, if any, d

Question

What does the function calculate_modified do?

What problems or issues, if any, do you see with it?

How could you improve the function, and what benefits would your improvements make?

What other additional improvements could you make to the rest of the code?

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

#include <sys/time.h>

typedef int int32;

typedef char int8;

static void unite_arrays(int8 *output, int8 *input_1, const int8 *input_2, int32 length)

{

int32 i = 0;   

for(i=0; i<length; i++)

{

output[i] = (int8)(input_1[i] ^ input_2[i]);

}

return;

}

static void itoa( int32 num, int8 *alpha, int32 radix )

{

if( radix == 10 )

{

sprintf(alpha, "%i", num);

}

else if( radix == 16 )

{

sprintf(alpha, "%X", num);

}

}

int8 *calculate_modified(int8 modifier, const int8 *input_1, int32 length)

{

int8 leading[3];

int32 i_leading;

int8 * temp_string = NULL;

int8 * ret;

int32 i = 0;

itoa(modifier/2, leading, 10);

i_leading = atoi(leading);

temp_string = (int8 *) malloc(8);

ret = (int8 *) malloc(length);

memset(temp_string, 0, 8);

temp_string[0] = 0;

if( (modifier+1)%2 == 0 )

{

temp_string[0] = (int8)((i_leading<<4) + 8);

}

else

{

temp_string[0] = (int8)(i_leading<<4);

}   

for(i=0; i<(length>>3); i++)

{

unite_arrays(ret+i*8, temp_string, input_1+i*8, 8);

}

free(temp_string);

return ret;

}

// Do not change anything in main

// main only contains example input

// Change anything else

int main(int argc, char **argv)

{

int8 data[] = {0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,

0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,

0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57};

int8 *resp = calculate_modified(0x10, data, sizeof(data));

free(resp);

}

Explanation / Answer

calculate_modified function converts string argument to integer argument by reverse order.

Please find below updated code.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/time.h>

typedef int int32;
typedef char int8;

static void unite_arrays(int8 *output, int8 *input_1, const int8 *input_2, int32 length)
{
int32 i = 0;
for(i=0; i<length; i++)
{
output[i] = (int8)(input_1[i] ^ input_2[i]);
}
return;
}

static void itoa( int32 num, int8 *alpha, int32 radix )
{
if( radix == 10 )
{
sprintf(alpha, "%i", num);
}
else if( radix == 16 )
{
sprintf(alpha, "%X", num);
}
}

int8 *calculate_modified(int8 modifier, const int8 *input_1, int32 length)
{
int8 leading[3];
int32 i_leading;
int8 * temp_string = NULL;
int8 * ret;
int32 i = 0;
  
itoa(modifier/2, leading, 10);
i_leading = atoi(leading);
temp_string = (int8 *) malloc(8);
ret = (int8 *) malloc(length);
memset(temp_string, 0, 8);
temp_string[0] = 0;
  
if( (modifier+1)%2 == 0 )
{
temp_string[0] = (int8)((i_leading<<4) + 8);
}
else
{
temp_string[0] = (int8)(i_leading<<4);
}
for(i=0; i<(length>>3); i++)
{
unite_arrays(ret+i*8, temp_string, input_1+i*8, 8);
}
free(temp_string);
return ret;
}

int main(int argc, char **argv)
{
int8 data[] = {0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57};
  
int8 *resp = calculate_modified(0x10, data, sizeof(data));
free(resp);
}

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