Thread: coding problem

Hey I got this code and I just wanted to know what this code do and where the error is located:

Code:

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

typedef int int32;
typedef char int8;

void xorStringRounds(int8  *output, int8  *pbDataOne, const int8  *pbDataTwo, int32 length)
{
	int32 i = 0;

	for(i=0; i<length; i++)
	{
		output[i] = (int8)(pbDataOne[i] ^ pbDataTwo[i]);
	}

	return;
}

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

int8 *oldModString(int32 modifier, const int8  *pbDataOne, int32 length)
{
	int8  leading[3];
	int32 ileading;
	int8 * tempStr = NULL;
	int8 * ret;
	int32 i = 0;

	itoa(modifier/2, leading, 10);
	ileading = atoi(leading);
	tempStr = (int8 *) malloc(8);
	ret = (int8 *) malloc(length);
	memset(tempStr, 0, 8);
	tempStr[0] = 0;

	if( (modifier+1)%2 == 0 ) {
		tempStr[0] = (int8)((ileading<<4) + 8);
	}
	else {
		tempStr[0] = (int8)(ileading<<4);
	}

	for(i=0; i<(length>>3); i++)
	{
		xorStringRounds(ret+i*8, tempStr, pbDataOne+i*8, 8);
	}
	free(tempStr);
	return ret;
}

int main(int argc, char **argv) {
	int8 data[32];

	memset(data, 0x0A, sizeof(data));
	int8 *resp = oldModString(0xFF, data, sizeof(data));

	free(resp);

	return 0;
}

And I kind of don't want to download the linux mostly because I am afraid to
If you could help me that would be great and thanks

I agree with quantumpete. The key point is to break down this complicated issue you are dealing with into smaller pieces. Then concentrate on the issue you want to solve. Much better this way. Also if you are afraid of installing Linux, then what have you used to compile this, better yet what compiler are you using, have you even tried to compile this?

When you post such open ended questions like this, you bound to get a bunch more thrown at you.

Originally Posted by Elysia

But why would you need Linux in the first place?

Lol, you don't really. I was just commenting against their statement.

So Learner87 did you get the exact errors and its issues in the code. If yes, please post it so that it could help others too...

korn

Originally Posted by vart

why not just

ileading = modifier/2;
at least youwill not have memory overrun in this case

Hello,

After changing the name of itoa function to my_itoa, the code runs fine. Its because of the itoa() also defined in stdlib.h
However I have a question here,
What exactly does oldModString() do? Is it just masking the values?

--
korn

The code learner87 attached was a test for a local encryption programmer position.

I guess learner87 was not so learned87 after all.

@ jesseutsa
The code learner87 attached was a test for a local encryption programmer position.

I guess learner87 was not so learned87 after all.

Thats really funny. I mean posting interview questions so that you can send the answer back and claim it as your own.