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

typedef struct RE RE;
RE*	RE_compile(char *);
int	RE_match(RE *, char *);
char	*RE_start(RE *);
char	*RE_end(RE *);
void	RE_free(RE *);

int yes(char *, char *, char *);
int no(char *, char *);
int err(char *);

RE *lre;	/* last regular expression; used by yes, no, err */

int main(int argc, char *argv[]) 
{
	char buf[1000], regexp[1000], str[1000], result[1000];
	char *p;
	int nfail = 0, line, nf, stat, ntest = 0;

/* input:
x	axb	a[x]b
x	abc
x*	""	[]
x*a	abxab	[a]bxab

conventions:
	literal "" is replaced by empty string so empty fields can be used
	literal @ is replaced by ' ' so \s and \S can be tested
*/

	for (line = 1; fgets(buf, sizeof buf, stdin) != NULL; line++) {
		buf[strlen(buf)-1] = 0;	/* kill \n */
		if (strlen(buf) == 0) /* skip blank lines */
			continue;
		stat = 0;
		lre = 0;
		regexp[0] = str[0] = result[0] = 0;
		nf = sscanf(buf, "%s %s %s", regexp, str, result);
		if (strcmp(regexp, "\"\"") == 0)
			regexp[0] = 0;
		if (strcmp(str, "\"\"") == 0)
			str[0] = 0;
		if (strcmp(result, "\"\"") == 0)
			result[0] = 0;
		for (p = result; (p = strchr(result, '@')) != NULL; )
			*p = ' ';
		for (p = str; (p = strchr(str, '@')) != NULL; )
			*p = ' ';
		for (p = result; (p = strchr(result, '@')) != NULL; )
			*p = ' ';
		switch (nf) {
		case 3: /* should match */
			stat = yes(regexp, str, result);
			if (stat > 0) {
				char *start, *end;
				start = RE_start(lre);
				end = RE_end(lre);
				if (start == NULL) {
					printf("start == NULL\n");
				} else if (end == NULL) {
					printf("end == NULL\n");
				} else if (start >= str && start <= end 
				    && end >= str+strlen(str)) {
					printf("start = '%s', end = '%s'\n", start, end);
				} else {
					printf("start or end invalid\n");
				}
			}
			RE_free(lre);
			break;
		case 2: /* should not match */
			stat = no(regexp, str);
			RE_free(lre);
			break;
		default: /* die?? */
			printf("bad test %3d:   %s\n", line, buf);
			break;
		}
		if (stat > 0)
			printf("failure at line %3d   %s\n", line, buf);
		nfail += stat;
		ntest++;
	}
	printf("%d fail   %d tests\n", nfail, ntest);
	return nfail;
}

int yes(char *regexp, char *str, char *result) {
	lre = RE_compile(regexp);
	if (lre == NULL)
		return 1;
	if (!RE_match(lre, str))
		return 1;
	if (RE_start(lre) > RE_end(lre))
		return 1;

	if (RE_start(lre) == NULL)	/* if there's a match, should be a string */
		return 1;
	if (RE_end(lre) == NULL)	/* these tests not fully thought out */
		return 1;

	if (result[RE_start(lre)-str] != '[') {
		printf("bad [\n");
		return 1;
	}
	if (result[RE_end(lre)-str+1] != ']') {
		printf("bad ]\n");
		return 1;
	}

	return 0;
}

int no(char *regexp, char *str) {
	lre = RE_compile(regexp);
	if (lre == NULL)
		return 1;
	if (RE_match(lre, str))
		return 1;
	return 0;
}

int err(char *regexp) {
	lre = RE_compile(regexp);
	if (lre != NULL)
		return 1;
	return 0;
}