/* strcmpn.c - string compare between a string and a number of characters */
/* PUBLIC DOMAIN - Jon Mayo - October 11, 2006 */

/*!
 * description: compares a with b[0..b_len]. 
 * parameters:
 * a - the first string, must be null terminated
 * b - second string. no null termination (series of characters)
 * b_len - length of b.
 * returns:
 * negative if a<b, zero a==b, else positive.
 */
int strcmpn(const char *a, const char *b, unsigned b_len) {
        while(b_len--) {
                if(!*a) return -*b;
                if(*a!=*b) return *a-*b;
                a++; b++;
        }
        return *a;
}

#ifdef STAND_ALONE
/* the STAND_ALONE mode is a unit test for the function strcmpn */
#include <stdio.h>
#include <string.h>
static void test(const char *a, const char *b, unsigned b_len) {
    int r;
    r=strcmpn(a, b, b_len);
    printf("\"%s\" %c \"%.*s\"\n", a, r<0?'<':r>0?'>':'=', b_len, b);
}

int main(int argc, char **argv) {
    int i;
    if(argc<2) {
        /* default test */
        test("Hello", "Worldasdfkadsf", 5);
        test("Hello", "World", 5);
        test("Hello", "World", 1);
        test("Hello", "Hello", 5);
        test("Hello", "Helloaskdjfkadsf", 5);
        test("World", "World", 5);
        test("Hello", "Hello", 1);
        test("World", "Hello", 5);
        test("Hello", "Hello", 0);
    }

    /* compares the first parameter with all the other parameters */
    for(i=2;i<argc;i++) {
        test(argv[1], argv[i], strlen(argv[i]));
    }
    return 0;
}
#endif