2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Cimarron D. Taylor of the University of California, Berkeley.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93";
41 #include <sys/types.h>
51 * destructively removes the top from the plan
55 PLAN **planp; /* pointer to top of plan (modified) */
57 PLAN *node; /* top node removed from the plan */
59 if ((node = (*planp)) == NULL)
61 (*planp) = (*planp)->next;
68 * Removes one expression from the plan. This is used mainly by
69 * paren_squish. In comments below, an expression is either a
70 * simple node or a N_EXPR node containing a list of simple nodes.
74 PLAN **planp; /* pointer to top of plan (modified) */
76 register PLAN *next; /* temp node holding subexpression results */
77 PLAN *node; /* pointer to returned node or expression */
78 PLAN *tail; /* pointer to tail of subplan */
79 PLAN *subplan; /* pointer to head of ( ) expression */
82 /* first pull the top node from the plan */
83 if ((node = yanknode(planp)) == NULL)
87 * If the node is an '(' then we recursively slurp up expressions
88 * until we find its associated ')'. If it's a closing paren we
89 * just return it and unwind our recursion; all other nodes are
90 * complete expressions, so just return them.
92 if (node->type == N_OPENPAREN)
93 for (tail = subplan = NULL;;) {
94 if ((next = yankexpr(planp)) == NULL)
95 err(1, "(: missing closing ')'");
97 * If we find a closing ')' we store the collected
98 * subplan in our '(' node and convert the node to
99 * a N_EXPR. The ')' we found is ignored. Otherwise,
100 * we just continue to add whatever we get to our
103 if (next->type == N_CLOSEPAREN) {
105 errx(1, "(): empty inner expression");
106 node->p_data[0] = subplan;
112 tail = subplan = next;
125 * replaces "parentheisized" plans in our search plan with "expr" nodes.
129 PLAN *plan; /* plan with ( ) nodes */
131 register PLAN *expr; /* pointer to next expression */
132 register PLAN *tail; /* pointer to tail of result plan */
133 PLAN *result; /* pointer to head of result plan */
135 result = tail = NULL;
138 * the basic idea is to have yankexpr do all our work and just
139 * collect it's results together.
141 while ((expr = yankexpr(&plan)) != NULL) {
143 * if we find an unclaimed ')' it means there is a missing
146 if (expr->type == N_CLOSEPAREN)
147 errx(1, "): no beginning '('");
149 /* add the expression to our result plan */
151 tail = result = expr;
163 * compresses "!" expressions in our search plan.
167 PLAN *plan; /* plan to process */
169 register PLAN *next; /* next node being processed */
170 register PLAN *node; /* temporary node used in N_NOT processing */
171 register PLAN *tail; /* pointer to tail of result plan */
172 PLAN *result; /* pointer to head of result plan */
174 tail = result = next = NULL;
176 while ((next = yanknode(&plan)) != NULL) {
178 * if we encounter a ( expression ) then look for nots in
181 if (next->type == N_EXPR)
182 next->p_data[0] = not_squish(next->p_data[0]);
185 * if we encounter a not, then snag the next node and place
186 * it in the not's subplan. As an optimization we compress
187 * several not's to zero or one not.
189 if (next->type == N_NOT) {
192 node = yanknode(&plan);
193 while (node != NULL && node->type == N_NOT) {
195 node = yanknode(&plan);
198 errx(1, "!: no following expression");
199 if (node->type == N_OR)
200 errx(1, "!: nothing between ! and -o");
202 * If we encounter ! ( expr ) then look for nots in
205 if (node->type == N_EXPR)
206 node->p_data[0] = not_squish(node->p_data[0]);
207 if (notlevel % 2 != 1)
210 next->p_data[0] = node;
213 /* add the node to our result plan */
215 tail = result = next;
227 * compresses -o expressions in our search plan.
231 PLAN *plan; /* plan with ors to be squished */
233 register PLAN *next; /* next node being processed */
234 register PLAN *tail; /* pointer to tail of result plan */
235 PLAN *result; /* pointer to head of result plan */
237 tail = result = next = NULL;
239 while ((next = yanknode(&plan)) != NULL) {
241 * if we encounter a ( expression ) then look for or's in
244 if (next->type == N_EXPR)
245 next->p_data[0] = or_squish(next->p_data[0]);
247 /* if we encounter a not then look for or's in the subplan */
248 if (next->type == N_NOT)
249 next->p_data[0] = or_squish(next->p_data[0]);
252 * if we encounter an or, then place our collected plan in the
253 * or's first subplan and then recursively collect the
254 * remaining stuff into the second subplan and return the or.
256 if (next->type == N_OR) {
258 errx(1, "-o: no expression before -o");
259 next->p_data[0] = result;
260 next->p_data[1] = or_squish(plan);
261 if (next->p_data[1] == NULL)
262 errx(1, "-o: no expression after -o");
266 /* add the node to our result plan */
268 tail = result = next;