2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2011, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * nstr.c: compile and execute the item selections on sectors
29 * Known contributors to this file:
32 * Markus Armbruster, 2004-2008
42 #include "prototypes.h"
44 static char *nstr_parse_val(char *, struct valstr *);
45 static int nstr_match_ca(struct valstr *, struct castr *);
46 static int nstr_is_name_of_ca(struct valstr *, struct castr *, int);
47 static int nstr_ca_comparable(struct castr *, int, int);
48 static int nstr_match_val(struct valstr *, struct castr *, int);
49 static struct valstr *nstr_resolve_id(struct valstr *, struct castr *, int);
50 static struct valstr *nstr_resolve_val(struct valstr *, int, struct castr *);
51 static int nstr_optype(enum nsc_type, enum nsc_type);
54 * Compile conditions into array NP[LEN].
55 * Return number of conditions, or -1 on error.
56 * It is an error if there are more than LEN conditions.
57 * TYPE is the context type, a file type.
58 * STR is the condition string, in Empire syntax, without the leading
62 nstr_comp(struct nscstr *np, int len, int type, char *str)
64 struct castr *ca = ef_cadef(type);
69 int lft_caidx, rgt_caidx;
74 for (i = 0; ; ++i, ++np) {
79 tail = nstr_parse_val(cond, &np->lft);
80 lft_caidx = nstr_match_ca(&np->lft, ca);
83 if (*tail != '<' && *tail != '=' && *tail != '>' && *tail != '#') {
85 pr("%s -- expected condition operator\n", cond);
87 pr("%s -- missing condition operator\n", cond);
94 tail = nstr_parse_val(tail, &np->rgt);
95 rgt_caidx = nstr_match_ca(&np->rgt, ca);
100 * If just one operand is an identifier, it names a selector.
101 * If both operands are identifiers, things get complicated:
102 * either can then name a selector or a symbolic value for the
103 * selector named by the other operand.
105 if (np->lft.val_cat == NSC_ID && np->rgt.val_cat == NSC_ID) {
106 lft_val = nstr_match_val(&np->lft, ca, rgt_caidx);
107 rgt_val = nstr_match_val(&np->rgt, ca, lft_caidx);
108 two_sels = nstr_ca_comparable(ca, lft_caidx, rgt_caidx);
110 * If lft_val >= 0 interpreting rgt as a selector and lft
111 * as one of its values works. Likewise for rgt_val >= 0.
112 * If two_sels, interpreting both lft and rgt as selector
115 switch ((lft_val >= 0) + (rgt_val >= 0) + !!two_sels) {
116 case 0: /* no interpretation */
117 if (lft_caidx >= 0 && rgt_caidx >= 0) {
119 * Both identifiers name selectors. Since
120 * !two_sels, they can't be comparable.
121 * Example: type=civil.
123 pr("%.*s -- not comparable\n", (int)(tail-cond), cond);
127 * At least one identifier doesn't name a selector,
128 * and nstr_resolve_id() will fail for it below
131 case 1: /* one unambigous interpretation */
133 default: /* multiple interpretations */
135 * Last-resort disambiguation: if the identifier is
136 * the unabbreviated name of a selector, discard
137 * value, else discard selector interpretation.
138 * Example: resolve wing=g to wing='g', not wing=group
141 if (nstr_is_name_of_ca(&np->lft, ca, lft_caidx))
145 if (nstr_is_name_of_ca(&np->rgt, ca, rgt_caidx))
149 if ((lft_val >= 0) + (rgt_val >= 0) + !!two_sels == 1)
150 break; /* last-resort disambiguation worked */
152 * Example: n<n for sectors could mean newdes<n or
155 pr("%.*s -- condition ambiguous\n", (int)(tail-cond), cond);
158 /* resolve identifiers naming values */
160 nstr_resolve_val(&np->lft, lft_val, &ca[rgt_caidx]);
162 nstr_resolve_val(&np->rgt, rgt_val, &ca[lft_caidx]);
164 /* remaining identifiers name selectors */
165 if (!nstr_resolve_id(&np->lft, ca, lft_caidx))
167 if (!nstr_resolve_id(&np->rgt, ca, rgt_caidx))
170 /* find operator type */
171 np->optype = nstr_optype(np->lft.val_type, np->rgt.val_type);
172 if (np->optype == NSC_NOTYPE) {
173 pr("%.*s -- not comparable\n", (int)(tail-cond), cond);
177 /* another condition? */
181 pr("%s -- expected `&'\n", cond);
188 /* could just return I and let caller gripe or enlarge buffer */
189 pr("%s -- too many conditions\n", str);
196 /* Like strcmp(S1, S2), but limit length of S1 to SZ1 and of S2 to SZ2. */
198 strnncmp(char *s1, size_t sz1, char *s2, size_t sz2)
202 return strncmp(s1, s2, sz2);
204 return -strnncmp(s2, sz2, s1, sz1);
205 res = strncmp(s1, s2, sz2);
206 return res ? res : s1[sz2];
209 #define EVAL(op, lft, rgt) \
210 ((op) == '<' ? (lft) < (rgt) \
211 : (op) == '=' ? (lft) == (rgt) \
212 : (op) == '>' ? (lft) > (rgt) \
213 : (op) == '#' ? (lft) != (rgt) \
217 * Evaluate compiled conditions in array NP[NCOND].
218 * Return non-zero iff they are all true.
219 * PTR points to a context object of the type that was used to compile
223 nstr_exec(struct nscstr *np, int ncond, void *ptr)
225 int i, op, optype, cmp;
226 struct valstr lft, rgt;
228 for (i = 0; i < ncond; ++i) {
230 optype = np[i].optype;
231 if (np[i].lft.val_cat == NSC_NOCAT || np[i].rgt.val_cat == NSC_NOCAT)
234 nstr_exec_val(&lft, player->cnum, ptr, optype);
236 nstr_exec_val(&rgt, player->cnum, ptr, optype);
239 if (!EVAL(op, lft.val_as.lng, rgt.val_as.lng))
243 if (!EVAL(op, lft.val_as.dbl, rgt.val_as.dbl))
247 cmp = strnncmp(lft.val_as.str.base, lft.val_as.str.maxsz,
248 rgt.val_as.str.base, rgt.val_as.str.maxsz);
249 if (!EVAL(op, cmp, 0))
262 * Parse a value in STR into VAL.
263 * Return a pointer to the first character after the value.
264 * Value is either evaluated into NSC_STRING, NSC_DOUBLE or NSC_LONG,
268 nstr_parse_val(char *str, struct valstr *val)
275 if (str[0] == '\'') {
276 for (tail = str + 1; *tail && *tail != '\''; ++tail) ;
277 /* FIXME implement \ quoting */
278 val->val_type = NSC_STRING;
279 val->val_cat = NSC_VAL;
280 val->val_as.str.base = str + 1;
281 val->val_as.str.maxsz = tail - (str + 1);
284 /* FIXME else unclosed string */
289 if (isalpha(str[0])) {
290 for (tail = str+1; isalnum(*tail) || *tail == '_'; ++tail) ;
291 val->val_type = NSC_NOTYPE;
292 val->val_cat = NSC_ID;
293 val->val_as.str.base = str;
294 val->val_as.str.maxsz = tail - str;
299 l = strtol(str, &tail, 0);
300 d = strtod(str, &tail2);
302 val->val_type = NSC_DOUBLE;
303 val->val_cat = NSC_VAL;
308 val->val_type = NSC_LONG;
309 val->val_cat = NSC_VAL;
314 /* funny character, interpret as identifier */
316 val->val_type = NSC_NOTYPE;
317 val->val_cat = NSC_ID;
318 val->val_as.str.base = str;
319 val->val_as.str.maxsz = tail - str;
324 * Match VAL in table of selector descriptors CA, return index.
325 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
327 * A VAL that is not an identifier doesn't match anything. A null CA
328 * is considered empty.
331 nstr_match_ca(struct valstr *val, struct castr *ca)
335 if (val->val_cat != NSC_ID || val->val_as.str.maxsz >= sizeof(id))
341 memcpy(id, val->val_as.str.base, val->val_as.str.maxsz);
342 id[val->val_as.str.maxsz] = 0;
344 return stmtch(id, ca, offsetof(struct castr, ca_name),
345 sizeof(struct castr));
349 * Is identifier VAL the name of the selector given by CA and IDX?
350 * Return non-zero if and only if IDX is non-negative and VAL is the
352 * IDX must have been obtained from nstr_match_ca(VAL, CA).
355 nstr_is_name_of_ca(struct valstr *val, struct castr *ca, int idx)
357 if (CANT_HAPPEN(val->val_cat != NSC_ID && idx >= 0))
359 return idx >= 0 && strlen(ca[idx].ca_name) == val->val_as.str.maxsz;
363 * Do we have two comparable selectors?
364 * Check selector descriptors CA[LFT_IDX] (unless LFT_IDX is negative)
365 * and CA[RGT_IDX] (unless RGT_IDX is negative). CA may be null when
369 nstr_ca_comparable(struct castr *ca, int lft_idx, int rgt_idx)
371 if (lft_idx < 0 || rgt_idx < 0)
373 if (ca[lft_idx].ca_table != ca[rgt_idx].ca_table)
374 return 0; /* Example: land type=spy */
375 return nstr_optype(ca[lft_idx].ca_type, ca[rgt_idx].ca_type)
376 != NSC_NOTYPE; /* Example: ship name=effic */
380 * Match VAL in a selector's values, return its (non-negative) value.
381 * Match values of selector descriptor CA[IDX], provided IDX is not
382 * negative. CA may be null when IDX is negative.
383 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
387 nstr_match_val(struct valstr *val, struct castr *ca, int idx)
392 if (val->val_cat != NSC_ID || idx < 0)
395 type = nstr_promote(ca[idx].ca_type);
396 if (type == NSC_STRING)
399 if (ca[idx].ca_table == EF_BAD || CANT_HAPPEN(type != NSC_LONG))
402 if (val->val_as.str.maxsz >= sizeof(id))
404 memcpy(id, val->val_as.str.base, val->val_as.str.maxsz);
405 id[val->val_as.str.maxsz] = 0;
406 return ef_elt_byname(ca[idx].ca_table, id);
410 * Change VAL to resolve identifier to selector.
411 * Return VAL on success, NULL on error.
412 * No change if VAL is not an identifier.
413 * Else change VAL into symbolic value for selector CA[IDX] if IDX >=
414 * 0, and error if not.
416 static struct valstr *
417 nstr_resolve_id(struct valstr *val, struct castr *ca, int idx)
419 if (val->val_cat != NSC_ID)
422 if (idx == M_NOTUNIQUE) {
423 pr("%.*s -- ambiguous name\n",
424 (int)val->val_as.str.maxsz, val->val_as.str.base);
425 val->val_cat = NSC_NOCAT;
429 if (idx == M_NOTFOUND) {
430 pr("%.*s -- unknown name\n",
431 (int)val->val_as.str.maxsz, val->val_as.str.base);
432 val->val_cat = NSC_NOCAT;
436 if ((ca[idx].ca_flags & NSC_DEITY) && !player->god) {
437 pr("%.*s -- not accessible to mortals\n",
438 (int)val->val_as.str.maxsz, val->val_as.str.base);
439 val->val_cat = NSC_NOCAT;
443 return nstr_mksymval(val, &ca[idx], 0);
447 * Change VAL to resolve identifier to value SELVAL for selector CA.
449 * VAL must be an identifier, and SELVAL must have been obtained from
450 * nstr_match_val(VAL, CA0, IDX), where CA = &CA0[IDX].
452 static struct valstr *
453 nstr_resolve_val(struct valstr *val, int selval, struct castr *ca)
455 enum nsc_type type = nstr_promote(ca->ca_type);
457 if (CANT_HAPPEN(val->val_cat != NSC_ID)) {
458 val->val_cat = NSC_NOCAT;
462 if (type == NSC_STRING) {
463 val->val_type = NSC_STRING;
464 val->val_cat = NSC_VAL;
465 /* map identifier ~ to empty string, like some commands do */
466 if (val->val_as.str.maxsz == 1 && val->val_as.str.base[0] == '~')
467 val->val_as.str.maxsz = 0;
471 if (CANT_HAPPEN(type != NSC_LONG || ca->ca_table == EF_BAD)) {
472 val->val_type = NSC_NOTYPE;
473 val->val_cat = NSC_NOCAT;
477 val->val_type = type;
478 val->val_cat = NSC_VAL;
479 val->val_as.lng = selval;
484 * Return operator type for operand types LFT, RGT.
487 nstr_optype(enum nsc_type lft, enum nsc_type rgt)
489 lft = nstr_promote(lft);
490 rgt = nstr_promote(rgt);
493 if (lft == NSC_DOUBLE && rgt == NSC_LONG)
495 if (rgt == NSC_DOUBLE && lft == NSC_LONG)
501 * Compile a value in STR into VAL.
502 * Return a pointer to the first character after the value on success,
504 * TYPE is the context type, a file type.
505 * If STR names an array, VAL simply refers to the element with index
509 nstr_comp_val(char *str, struct valstr *val, int type)
511 struct castr *ca = ef_cadef(type);
512 char *tail = nstr_parse_val(str, val);
513 if (!nstr_resolve_id(val, ca, nstr_match_ca(val, ca)))