svcomp_cstrncmp_true-termination.c

contents

/*
 * Date: 17.12.2013
 * Author: Thomas Ströder
 */
#include <stdlib.h>

extern int __VERIFIER_nondet_int(void);

/* Returns some null-terminated string. */
char* __VERIFIER_nondet_String(void) {
    int length = __VERIFIER_nondet_int();
    if (length < 1) {
        length = 1;
    }
    char* nondetString = (char*) malloc(length * sizeof(char));
    nondetString[length-1] = '\0';
    return nondetString;
}





int (cstrncmp)(const char *s1, const char *s2, int n)
 {
     unsigned char uc1, uc2;
     /* Nothing to compare?  Return zero.  */
     if (n == 0)
         return 0;
     /* Loop, comparing bytes.  */
     while (n-- > 0 && *s1 == *s2) {
         /* If we've run out of bytes or hit a null, return zero
            since we already know *s1 == *s2.  */
         if (n == 0 || *s1 == '\0')
             return 0;
         s1++;
         s2++;
     }
     uc1 = (*(unsigned char *) s1);
     uc2 = (*(unsigned char *) s2);
     return ((uc1 < uc2) ? -1 : (uc1 > uc2));
 }

int main() {
    return cstrncmp(__VERIFIER_nondet_String(),__VERIFIER_nondet_String(),__VERIFIER_nondet_int());
}

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