string_fns.c

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

#include "string_fns.h"

/* The following function signatures will be used for
 * sets containing strings, where all void * pointers
 * are really char *s.
 */

/* Test two strings for equality */
int string_equals(void *arg1, void *arg2) {
    if (!arg1 || !arg2)
        return !arg1 && !arg2;
    else
        return !strcmp((char *)arg1, (char *)arg2);
}

/* Create a dynamically-allocated copy of the
 * given string, and return a pointer to it */
void *string_copy(void *arg) {
    char *str = (char *)arg;
    if (str) {
        size_t len = strlen(str);
        char *kopje = (char *)malloc(len + 1);
        strncpy(kopje, str, len + 1);
        return kopje;
    } else {
        return NULL;
    }
}

/* Free the given string */
void string_delete(void *arg) { free(arg); }

/* Print a representation of the given string
 * to the given stream */
void string_print(FILE *stream, void *arg) {
    if (arg == NULL)
        fprintf(stream, "null ");
    else
        fprintf(stream, "\"%s\" ", (char *)arg);
}