ASCII string to hexadecimal integers conversion - c

Question

I want to convert an ascii string of 16 bytes into 16 bytes hexadecimal integers. Kindly help. Here is my code:
uint stringToByteArray(char *str,uint **array)
{
uint i, len=strlen(str) >> 1;
*array=(uint *)malloc(len*sizeof(uint));
//Conversion of str (string) into *array (hexadecimal)
return len;
}

Answer 1

If you are looking for printing integer numbers in hexadecimal form, this might help:
#include <stdio.h>
int main() {
/* define ASCII string */
/* note that char is an integer number type */
char s[] = "Hello World";
/* iterate buffer */
char *p;
for (p = s; p != s+sizeof(s); p++) {
/* print each integer in its hex representation */
printf("%02X", (unsigned char)(*p));
}
printf("\n");
return 0;
}
If all you want is to turn a char array to an array of 1-byte integer numbers, then you are already done. char already is an integral number type. You can use the buffer you already have, or use malloc/memcpy to copy the data to a new one.
You might want to have a look at the explicit width integer types defined in stdint.h, e.g., uint8_t for a one byte unsigned integer.

Answer 2

A C-"string" of 16 characters length is 16bytes!
To have it converted to a "byte"-array (of 16 entries lenght) you might like to do the following:
#include <unistd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
/* Copies all characters of str into a freshly allocated array pointed to by *parray. */
/* Returns the number of characters bytes copied and -1 on error. Sets errno accordingly. */
size_t stringToByteArray(const char * str, uint8_t **parray)
{
if (NULL == str)
{
errno = EINVAL;
return -1;
}
{
size_t size = strlen(str);
*parray = malloc(size * sizeof(**parray));
if (NULL == *parray)
{
errno = ENOMEM;
return -size;
}
for (size_t s = 0; s < size; ++s)
{
(*parray)[s] = str[s];
}
return size;
}
}
int main()
{
char str[] = "this is 16 bytes";
uint8_t * array = NULL;
ssize_t size = stringToByteArray(str, &array);
if (-1 == size)
{
perror("stringToByteArray() failed");
return EXIT_FAILURE;
}
/* Do what you like with array. */
free(array);
return EXIT_SUCCESS;
}