/*
* Empire - A multi-player, client/server Internet based war game.
- * Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
- * Ken Stevens, Steve McClure
+ * Copyright (C) 1986-2011, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ * Ken Stevens, Steve McClure, Markus Armbruster
*
- * This program is free software; you can redistribute it and/or modify
+ * Empire is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* ---
*
* ---
*
* nstr.c: compile and execute the item selections on sectors
- *
+ *
* Known contributors to this file:
* Dave Pare, 1989
* Steve McClure, 1997
- * Markus Armbruster, 2004-2006
+ * Markus Armbruster, 2004-2008
*/
#include <config.h>
static char *nstr_parse_val(char *, struct valstr *);
static int nstr_match_ca(struct valstr *, struct castr *);
+static int nstr_is_name_of_ca(struct valstr *, struct castr *, int);
+static int nstr_ca_comparable(struct castr *, int, int);
static int nstr_match_val(struct valstr *, struct castr *, int);
-static int nstr_string_ok(struct castr *ca, int idx);
-static struct valstr *nstr_resolve_sel(struct valstr *, struct castr *);
-static struct valstr *nstr_mkselval(struct valstr *, int, struct castr *);
-static struct valstr *nstr_resolve_id(struct valstr *, struct castr *, int, int);
+static struct valstr *nstr_resolve_id(struct valstr *, struct castr *, int);
+static struct valstr *nstr_resolve_val(struct valstr *, int, struct castr *);
+static int nstr_optype(enum nsc_type, enum nsc_type);
/*
* Compile conditions into array NP[LEN].
struct nscstr dummy;
int lft_caidx, rgt_caidx;
int lft_val, rgt_val;
- int lft_type, rgt_type;
+ int two_sels;
cond = str;
for (i = 0; ; ++i, ++np) {
/*
* Resolve identifiers
*
- * An identifier can name a selector or, if the other operand
- * is a selector, a value for that. The condition is
- * ambiguous if both selector x value and value x selector are
- * possible. Example: n<n for sectors could mean newdes<n or
- * n<newdes.
- */
- lft_val = nstr_match_val(&np->lft, ca, rgt_caidx);
- rgt_val = nstr_match_val(&np->rgt, ca, lft_caidx);
- /*
- * if lft_val >= 0, then rhs names a selector and lhs names
- * one of its values. Likewise for rgt_val.
+ * If just one operand is an identifier, it names a selector.
+ * If both operands are identifiers, things get complicated:
+ * either can then name a selector or a symbolic value for the
+ * selector named by the other operand.
*/
- if (lft_val >= 0 && rgt_val >= 0) {
- pr("%.*s -- condition ambiguous\n", (int)(tail-cond), cond);
- return -1;
- } else if (rgt_val >= 0) {
- /* selector x value */
- if (!nstr_resolve_sel(&np->lft, &ca[lft_caidx]))
- return -1;
- nstr_mkselval(&np->rgt, rgt_val, &ca[lft_caidx]);
- } else if (lft_val >= 0) {
- /* value x selector */
- nstr_mkselval(&np->lft, lft_val, &ca[rgt_caidx]);
- if (!nstr_resolve_sel(&np->rgt, &ca[rgt_caidx]))
- return -1;
- } else {
+ if (np->lft.val_cat == NSC_ID && np->rgt.val_cat == NSC_ID) {
+ lft_val = nstr_match_val(&np->lft, ca, rgt_caidx);
+ rgt_val = nstr_match_val(&np->rgt, ca, lft_caidx);
+ two_sels = nstr_ca_comparable(ca, lft_caidx, rgt_caidx);
/*
- * Neither side works as selector value; any identifiers
- * must name selectors.
+ * If lft_val >= 0 interpreting rgt as a selector and lft
+ * as one of its values works. Likewise for rgt_val >= 0.
+ * If two_sels, interpreting both lft and rgt as selector
+ * works.
*/
- if (!nstr_resolve_id(&np->lft, ca, lft_caidx,
- nstr_string_ok(ca, rgt_caidx)))
- return -1;
- if (!nstr_resolve_id(&np->rgt, ca, rgt_caidx,
- nstr_string_ok(ca, lft_caidx)))
+ switch ((lft_val >= 0) + (rgt_val >= 0) + !!two_sels) {
+ case 0: /* no interpretation */
+ if (lft_caidx >= 0 && rgt_caidx >= 0) {
+ /*
+ * Both identifiers name selectors. Since
+ * !two_sels, they can't be comparable.
+ * Example: type=civil.
+ */
+ pr("%.*s -- not comparable\n", (int)(tail-cond), cond);
+ return -1;
+ }
+ /*
+ * At least one identifier doesn't name a selector,
+ * and nstr_resolve_id() will fail for it below
+ */
+ break;
+ case 1: /* one unambigous interpretation */
+ break;
+ default: /* multiple interpretations */
+ /*
+ * Last-resort disambiguation: if the identifier is
+ * the unabbreviated name of a selector, discard
+ * value, else discard selector interpretation.
+ * Example: resolve wing=g to wing='g', not wing=group
+ * or 'wing'=group.
+ */
+ if (nstr_is_name_of_ca(&np->lft, ca, lft_caidx))
+ lft_val = -1;
+ else
+ two_sels = 0;
+ if (nstr_is_name_of_ca(&np->rgt, ca, rgt_caidx))
+ rgt_val = -1;
+ else
+ two_sels = 0;
+ if ((lft_val >= 0) + (rgt_val >= 0) + !!two_sels == 1)
+ break; /* last-resort disambiguation worked */
+ /*
+ * Example: n<n for sectors could mean newdes<n or
+ * n<newdes.
+ */
+ pr("%.*s -- condition ambiguous\n", (int)(tail-cond), cond);
return -1;
+ }
+ /* resolve identifiers naming values */
+ if (lft_val >= 0)
+ nstr_resolve_val(&np->lft, lft_val, &ca[rgt_caidx]);
+ if (rgt_val >= 0)
+ nstr_resolve_val(&np->rgt, rgt_val, &ca[lft_caidx]);
}
+ /* remaining identifiers name selectors */
+ if (!nstr_resolve_id(&np->lft, ca, lft_caidx))
+ return -1;
+ if (!nstr_resolve_id(&np->rgt, ca, rgt_caidx))
+ return -1;
- /* find operator type, coerce operands */
- lft_type = nstr_promote(np->lft.val_type);
- rgt_type = nstr_promote(np->rgt.val_type);
- np->optype = NSC_NOTYPE;
- if (lft_type == NSC_STRING) {
- if (!nstr_coerce_val(&np->rgt, NSC_STRING, str))
- np->optype = NSC_STRING;
- } else if (rgt_type == NSC_STRING) {
- if (!nstr_coerce_val(&np->lft, NSC_STRING, str))
- np->optype = NSC_STRING;
- } else if (lft_type == NSC_DOUBLE) {
- if (!nstr_coerce_val(&np->rgt, NSC_DOUBLE, str))
- np->optype = NSC_DOUBLE;
- } else if (rgt_type == NSC_DOUBLE) {
- if (!nstr_coerce_val(&np->lft, NSC_DOUBLE, str))
- np->optype = NSC_DOUBLE;
- } else {
- if (!nstr_coerce_val(&np->lft, NSC_LONG, str)
- && !nstr_coerce_val(&np->rgt, NSC_LONG, str))
- np->optype = NSC_LONG;
- }
- if (np->optype == NSC_NOTYPE)
+ /* find operator type */
+ np->optype = nstr_optype(np->lft.val_type, np->rgt.val_type);
+ if (np->optype == NSC_NOTYPE) {
+ pr("%.*s -- not comparable\n", (int)(tail-cond), cond);
return -1;
+ }
/* another condition? */
if (*tail == 0)
strnncmp(char *s1, size_t sz1, char *s2, size_t sz2)
{
int res;
- if (sz1 == sz2) return strncmp(s1, s2, sz2);
- if (sz1 < sz2) return -strnncmp(s2, sz2, s1, sz1);
+ if (sz1 == sz2)
+ return strncmp(s1, s2, sz2);
+ if (sz1 < sz2)
+ return -strnncmp(s2, sz2, s1, sz1);
res = strncmp(s1, s2, sz2);
return res ? res : s1[sz2];
}
val->val_cat = NSC_VAL;
val->val_as.str.base = str + 1;
val->val_as.str.maxsz = tail - (str + 1);
- if (*tail) ++tail;
+ if (*tail)
+ ++tail;
/* FIXME else unclosed string */
return tail;
}
sizeof(struct castr));
}
+/*
+ * Is identifier VAL the name of the selector given by CA and IDX?
+ * Return non-zero if and only if IDX is non-negative and VAL is the
+ * name of CA[IDX].
+ * IDX must have been obtained from nstr_match_ca(VAL, CA).
+ */
+static int
+nstr_is_name_of_ca(struct valstr *val, struct castr *ca, int idx)
+{
+ if (CANT_HAPPEN(val->val_cat != NSC_ID && idx >= 0))
+ return 0;
+ return idx >= 0 && strlen(ca[idx].ca_name) == val->val_as.str.maxsz;
+}
+
+/*
+ * Do we have two comparable selectors?
+ * Check selector descriptors CA[LFT_IDX] (unless LFT_IDX is negative)
+ * and CA[RGT_IDX] (unless RGT_IDX is negative). CA may be null when
+ * both are negative.
+ */
+static int
+nstr_ca_comparable(struct castr *ca, int lft_idx, int rgt_idx)
+{
+ if (lft_idx < 0 || rgt_idx < 0)
+ return 0;
+ if (ca[lft_idx].ca_table != ca[rgt_idx].ca_table)
+ return 0; /* Example: land type=spy */
+ return nstr_optype(ca[lft_idx].ca_type, ca[rgt_idx].ca_type)
+ != NSC_NOTYPE; /* Example: ship name=effic */
+}
+
/*
* Match VAL in a selector's values, return its (non-negative) value.
* Match values of selector descriptor CA[IDX], provided IDX is not
nstr_match_val(struct valstr *val, struct castr *ca, int idx)
{
char id[32];
+ enum nsc_type type;
- if (val->val_cat != NSC_ID || val->val_as.str.maxsz >= sizeof(id))
+ if (val->val_cat != NSC_ID || idx < 0)
return M_NOTFOUND;
- if (idx < 0 || ca[idx].ca_table == EF_BAD)
- return M_NOTFOUND;
- if (CANT_HAPPEN(nstr_promote(ca[idx].ca_type) != NSC_LONG))
+ type = nstr_promote(ca[idx].ca_type);
+ if (type == NSC_STRING)
+ return 0;
+
+ if (ca[idx].ca_table == EF_BAD || CANT_HAPPEN(type != NSC_LONG))
return M_NOTFOUND;
+ if (val->val_as.str.maxsz >= sizeof(id))
+ return M_NOTFOUND;
memcpy(id, val->val_as.str.base, val->val_as.str.maxsz);
id[val->val_as.str.maxsz] = 0;
-
return ef_elt_byname(ca[idx].ca_table, id);
}
/*
- * Can CA[IDX] be compared to a string?
- * Return 0 for negative IDX.
- */
-static int
-nstr_string_ok(struct castr *ca, int idx)
-{
- return idx >= 0 && nstr_promote(ca[idx].ca_type) == NSC_STRING;
-}
-
-/*
- * Change VAL to resolve identifier to selector or string.
+ * Change VAL to resolve identifier to selector.
* Return VAL on success, NULL on error.
- * No change if VAL is not an identifier. Otherwise, change it as
- * follows.
- * Error if IDX == M_NOTUNIQUE or IDX == M_NOTFOUND and !STRING_OK.
- * Change into string if IDX == M_NOTFOUND and STRING_OK.
- * Change into selector CA[IDX] if IDX >= 0.
+ * No change if VAL is not an identifier.
+ * Else change VAL into symbolic value for selector CA[IDX] if IDX >=
+ * 0, and error if not.
*/
static struct valstr *
-nstr_resolve_id(struct valstr *val, struct castr *ca, int idx, int string_ok)
+nstr_resolve_id(struct valstr *val, struct castr *ca, int idx)
{
if (val->val_cat != NSC_ID)
return val;
- if (idx == M_NOTUNIQUE && !string_ok) {
+ if (idx == M_NOTUNIQUE) {
pr("%.*s -- ambiguous name\n",
(int)val->val_as.str.maxsz, val->val_as.str.base);
val->val_cat = NSC_NOCAT;
return NULL;
}
- if (idx == M_NOTFOUND && !string_ok) {
+ if (idx == M_NOTFOUND) {
pr("%.*s -- unknown name\n",
(int)val->val_as.str.maxsz, val->val_as.str.base);
val->val_cat = NSC_NOCAT;
return NULL;
}
- if (idx < 0) {
- CANT_HAPPEN(!string_ok);
- /* interpret unresolvable identifier as string */
- val->val_type = NSC_STRING;
- val->val_cat = NSC_VAL;
- /* map identifier ~ to empty string, like some commands do */
- if (val->val_as.str.maxsz == 1 && val->val_as.str.base[0] == '~')
- val->val_as.str.maxsz = 0;
- return val;
+ if ((ca[idx].ca_flags & NSC_DEITY) && !player->god) {
+ pr("%.*s -- not accessible to mortals\n",
+ (int)val->val_as.str.maxsz, val->val_as.str.base);
+ val->val_cat = NSC_NOCAT;
+ return NULL;
}
- return nstr_resolve_sel(val, &ca[idx]);
+ return nstr_mksymval(val, &ca[idx], 0);
}
/*
- * Change VAL to resolve identifier to selector CA.
- * Return VAL on success, NULL if the player is denied access to the
- * selector.
- * VAL must be an identifier.
+ * Change VAL to resolve identifier to value SELVAL for selector CA.
+ * Return VAL.
+ * VAL must be an identifier, and SELVAL must have been obtained from
+ * nstr_match_val(VAL, CA0, IDX), where CA = &CA0[IDX].
*/
static struct valstr *
-nstr_resolve_sel(struct valstr *val, struct castr *ca)
+nstr_resolve_val(struct valstr *val, int selval, struct castr *ca)
{
+ enum nsc_type type = nstr_promote(ca->ca_type);
+
if (CANT_HAPPEN(val->val_cat != NSC_ID)) {
val->val_cat = NSC_NOCAT;
return val;
}
- if ((ca->ca_flags & NSC_DEITY) && !player->god) {
- pr("%.*s -- not accessible to mortals\n",
- (int)val->val_as.str.maxsz, val->val_as.str.base);
- val->val_cat = NSC_NOCAT;
- return NULL;
+ if (type == NSC_STRING) {
+ val->val_type = NSC_STRING;
+ val->val_cat = NSC_VAL;
+ /* map identifier ~ to empty string, like some commands do */
+ if (val->val_as.str.maxsz == 1 && val->val_as.str.base[0] == '~')
+ val->val_as.str.maxsz = 0;
+ return val;
}
- return nstr_mksymval(val, ca, 0);
-}
-
-/*
- * Initialize VAL to value SELVAL for selector CA, return VAL.
- */
-static struct valstr *
-nstr_mkselval(struct valstr *val, int selval, struct castr *ca)
-{
- if (CANT_HAPPEN(nstr_promote(ca->ca_type) != NSC_LONG
- || ca->ca_table == EF_BAD)) {
+ if (CANT_HAPPEN(type != NSC_LONG || ca->ca_table == EF_BAD)) {
val->val_type = NSC_NOTYPE;
val->val_cat = NSC_NOCAT;
return val;
}
- val->val_type = ca->ca_type;
+ val->val_type = type;
val->val_cat = NSC_VAL;
val->val_as.lng = selval;
return val;
}
+/*
+ * Return operator type for operand types LFT, RGT.
+ */
+static int
+nstr_optype(enum nsc_type lft, enum nsc_type rgt)
+{
+ lft = nstr_promote(lft);
+ rgt = nstr_promote(rgt);
+ if (lft == rgt)
+ return lft;
+ if (lft == NSC_DOUBLE && rgt == NSC_LONG)
+ return NSC_DOUBLE;
+ if (rgt == NSC_DOUBLE && lft == NSC_LONG)
+ return NSC_DOUBLE;
+ return NSC_NOTYPE;
+}
+
/*
* Compile a value in STR into VAL.
* Return a pointer to the first character after the value on success,
{
struct castr *ca = ef_cadef(type);
char *tail = nstr_parse_val(str, val);
- if (!nstr_resolve_id(val, ca, nstr_match_ca(val, ca), 0))
+ if (!nstr_resolve_id(val, ca, nstr_match_ca(val, ca)))
return NULL;
return tail;
}
-
-static int
-cond_type_mismatch(char *str)
-{
- if (str)
- pr("%s -- condition operand type mismatch\n", str);
- return -1;
-}
-
-/*
- * Coerce VAL to promoted value type TO.
- * Return 0 on success, -1 on error.
- * If VAL is evaluated, convert it, else only check.
- * STR is the condition text to be used for error messages. Suppress
- * messages if it is a null pointer.
- */
-int
-nstr_coerce_val(struct valstr *val, nsc_type to, char *str)
-{
- /* FIXME get rid of promotion? */
- nsc_type from = nstr_promote(val->val_type);
-
- if (from == NSC_NOTYPE)
- return 0;
-
- if (from != to) {
- switch (to) {
- case NSC_STRING:
- return cond_type_mismatch(str); /* FIXME implement */
- case NSC_DOUBLE:
- if (from == NSC_LONG) {
- if (val->val_cat == NSC_VAL)
- val->val_as.dbl = val->val_as.lng;
- } else
- return cond_type_mismatch(str);
- break;
- case NSC_LONG:
- return cond_type_mismatch(str);
- default:
- CANT_REACH();
- to = from;
- }
- }
-
- if (val->val_cat == NSC_VAL) {
- /* unimplemented conversions; don't currently occur here */
- CANT_HAPPEN(val->val_type == NSC_XCOORD
- || val->val_type == NSC_YCOORD
- || val->val_type == NSC_HIDDEN);
- val->val_type = to;
- }
-
- return 0;
-}
projects / empserver / blobdiff