#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <gc.h>


const char *BLANKS = " \t";
const char *TEXT = "hi there  fr  [[]  ie]nd]  []    23    ";
/*                  01234567890123456789
                       ^     ^
*/

char *
trim_leading_blanks(char *str)
{
        size_t offset = strspn(str, BLANKS);
        if (offset == strlen(str)) {
                /* All blanks. */
                return NULL;
        }
        return str + offset;
}

int
main(void)
{
	char *rest, *text, *snip;
	ptrdiff_t diff;

        text = trim_leading_blanks((char *)TEXT);
	rest = strpbrk(text, " []");
	while (NULL != rest) {
                /* How many chars have we got? */
		diff = rest - text;

                if (diff) {
                        /* Allocate space and copy out the substring. */
                        snip = (char *)GC_malloc(diff + 1);
                        strncat(snip, text, diff);
                        printf("%s\n", snip);
                }

                /* The next char is a space or '[' or ']'. */
                if ('[' == rest[0] || ']' == rest[0]) {
                        printf("%c\n", rest[0]);
                }

                /*  */
                text = trim_leading_blanks(++rest);
                /*printf(">>>%s\n\n", text);*/

                /* calling strpbrk on NULL caused segfault! */
                rest = (NULL != text) ? strpbrk(text, " []") : text;
	}
        if (text) {
                printf("%s\n", text);
        }
}