Question

I have a program returning data in the following format:

<CFData 0x1001219c0 [0x7fff7027aee0]>{length = 20, capacity = 20, bytes = 0x8deead13b8ae7057f6a629fdaae5e1200bcb8cf5}

I need to extract 8deead13b8ae7057f6a629fdaae5e1200bcb8cf5 (yes, minus the 0x). I tried using sscanf and passing some regular expressions but I have no clue on that.

Any idea how to do this? Code snippets are appreciated.

Answer 1

You could use strstr() to locate “bytes = 0x” in the input string and copy the remainder of the string (from the end of “bytes = 0x”) except for the last character:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    char* s = "<CFData 0x1001219c0 [0x7fff7027aee0]>{length = 20, "
              "capacity = 20, "
              "bytes = 0x8deead13b8ae7057f6a629fdaae5e1200bcb8cf5}";
    char* value = 0;
    const char* begin = strstr(s, "bytes = 0x");

    if (begin)
    {
        begin += 10; /* Move past "bytes = 0x" */
        value = malloc(strlen(begin)); /* Don't need 1 extra for NULL as not
                                          copy last character from 'begin'. */
        if (value)
        {
            memcpy(value, begin, strlen(begin) - 1);
            *(value + strlen(begin) - 1) = 0;
            printf("%s\n", value);
            free(value);
        }
    }
    return 0;
}