libpsyc/src/match.c

#include "psyc/lib.h"

int PSYC_inherits(char* sho, size_t slen,
		  char* lon, size_t llen) {

	// this allows to pass zero-terminated strings instead of providing
	// the length.. but we would be faster here if we expected the callee
	// to always use the PSYC_C2ARG() macro instead. additionally, the
	// empty string would then be fully supported (in case you want that)
	if (!slen) slen = strlen(sho);
	if (!llen) llen = strlen(lon);

	if (slen == 0 || *sho != '_' ||
	    llen == 0 || *lon != '_') {
		P1(("Please use long format keywords (compact ones would be faster, I know..)\n"))
		return -2;
	}

	if (slen > llen) {
		P1(("The long string is shorter than the short one.\n"))
		return -3;
	}

	if (!strncmp(sho, lon, slen)) {
		/* according to PSYC spec we have hereby already proved
		 * inheritance. the following check is optional!
		 */
		if (llen > slen && lon[slen] != '_') {
			/* It is illegal to introduce a keyword family
			 * that starts just like an existing one. Since
			 * _failure exists, you can't use _fail. But
			 * implementations are not required to recognize
			 * that.
			 */
			P1(("Illegal choice of keyword names!\n"))
			return -4;
		}
		return 0;
	}
	P4(("%*s does not inherit from %*s.\n", llen, lon, slen, sho))
	return 1;
}

int PSYC_matches(char* sho, size_t slen,
		 char* lon, size_t llen) {
	char *s, *l, *se, *le;

	if (!slen) slen = strlen(sho);
	if (!llen) llen = strlen(lon);

	if (slen == 0 || *sho != '_' ||
	    llen == 0 || *lon != '_') {
		P1(("Please use long format keywords (compact ones would be faster, I know..)\n"))
		return -2;
	}

	if (slen > llen) {
		P1(("The long string is shorter than the short one.\n"))
		return -3;
	}

	if (slen == llen) {
		if (!strncmp(sho, lon, slen)) {
			P1(("Identical arguments.\n"))
			return 0;
		}
		P1(("Same length but different.\nNo match, but they could be related or have a common type.\n"))
		return -4;
	}
	P3(("# PSYC_matches short '%*s' in long '%*s' ?\n", slen, sho, llen, lon))

	se = sho+slen;
	le = lon+llen;
	sho++; lon++; slen--; llen--;
	while(*sho && sho < se) {
		P3(("# comparing short '%*s' (%d)\n", slen, sho, slen))
		unless (s = memchr(sho, '_', slen)) s = se;
		P4(("# sho goes '%c' and lon goes '%c'\n", *sho, *lon))
		while(*lon && lon < le) {
			P3(("# against long '%*s' (%d)\n", llen, lon, llen))
			unless (l = memchr(lon, '_', llen)) l = le;
			P3(("# %d == %d && !strncmp '%*s', '%*s'\n", s-sho, l-lon, s-sho, sho, s-sho, lon))
			if (l-lon == s-sho && !strncmp(sho, lon, s-sho)) goto foundone;
			P4(("# failed\n"))
			llen -= l-lon + 1;
			lon = ++l;
		}
		goto failed;
foundone:
		P3(("# found %d of short '%*s' and long '%*s'\n", s-sho, s-sho, sho, s-sho, lon))
		llen -= l-lon;
		slen -= s-sho;
		sho = ++s;
		lon = ++l;
	}
	return 0;
failed:
	P4(("No, they don't match.\n"))
	return 1;
}

#ifdef CMDTOOL
int main(int argc, char **argv) {
	if (argc != 3) {
		printf("Usage: %s <short> <long>\n\nExample: %s _failure_delivery _failure_unsuccessful_delivery_death\n", argv[0], argv[0]);
		return -1;
	}
	if (PSYC_matches(argv[1], 0, argv[2], 0) == 0)
	    printf("Yes, %s matches %s!\n", argv[1], argv[2]);
	if (PSYC_inherits(argv[1], 0, argv[2], 0) == 0)
	    printf("Yes, %s inherits from %s!\n", argv[2], argv[1]);
}
#endif