libpsyc/src/match.c

/*
  This file is part of libpsyc.
  Copyright (C) 2011,2012 Carlo v. Loesch, Gabor X Toth, Mathias L. Baumann,
  and other contributing authors.

  libpsyc is free software: you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free
  Software Foundation, either version 3 of the License, or (at your option) any
  later version. As a special exception, libpsyc is distributed with additional
  permissions to link libpsyc libraries with non-AGPL works.

  libpsyc is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
  details.

  You should have received a copy of the GNU Affero General Public License and
  the linking exception along with libpsyc in a COPYING file.
*/

#include "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)
    // Disabled this, let's use that macro rather.
    //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", (int) llen, lon, (int) 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", (int) slen, sho,
	(int) llen, lon));

    se = sho + slen;
    le = lon + llen;
    sho++;
    lon++;
    slen--;
    llen--;
    while (*sho && sho < se) {
	P3(("# comparing short '%.*s' (%d)\n", (int) slen, sho, (int) slen));
	unless(s = memchr(sho, '_', slen)) s = se;
	P4(("# sho goes '%c' and lon goes '%c'\n", *sho, (int) *lon));
	while (*lon && lon < le) {
	    P3(("# against long '%.*s' (%d)\n", (int) llen, lon, (int) llen));
	    unless(l = memchr(lon, '_', llen)) l = le;
	    P3(("# %ld == %ld && !strncmp '%.*s', '%.*s'\n", s - sho, l - lon,
		(int) (s - sho), sho, (int) (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 %ld of short '%.*s' and long '%.*s'\n", s - sho,
	    (int) (s - sho), sho, (int) (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;
}

/**
 * Look up value associated with a key in a map.
 */
void *
psyc_map_lookup(const PsycMap * map, size_t size,
		const char *key, size_t keylen, PsycBool inherit)
{
    //size_t cursor = 1;
    size_t c = 0;
    uint8_t i, match = 0;

    if (keylen < 2 || key[0] != '_')
	return 0;

    //for (c = 0, i = 0; c < keylen && i < size; c++) {
    for (i = 0; i < size; i++) {
	if (!(keylen == map[i].key.length
	      || (inherit && keylen > map[i].key.length
		  && key[map[i].key.length] == '_')))
	    continue;

	match = 1;
	for (c = 0; c < keylen; c++) {
	    if (c < map[i].key.length && map[i].key.data[c] == key[c])
		continue;
	    else if (c == map[i].key.length && key[c] == '_')
		return map[i].value;	// after the end of a matching prefix
	    else if (map[i].key.data[c] > key[c])
		return NULL;

	    match = 0;
	    break;
	}
	if (match)
	    return map[i].value;
    }

    return NULL;
}

extern inline intptr_t
psyc_map_lookup_int (const PsycMapInt *map, size_t size,
		     const char *key, size_t keylen, PsycBool inherit);

#ifdef CMDTOOL
int
main(int argc, char **argv)
{
    if (argc != 3) {
	printf("Usage: %s <short> <long>\n\n"
	       "Example: %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