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.
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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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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
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24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93";
41 static const char rcsid[] =
46 #include <sys/types.h>
56 * destructively removes the top from the plan
60 PLAN **planp; /* pointer to top of plan (modified) */
62 PLAN *node; /* top node removed from the plan */
64 if ((node = (*planp)) == NULL)
66 (*planp) = (*planp)->next;
73 * Removes one expression from the plan. This is used mainly by
74 * paren_squish. In comments below, an expression is either a
75 * simple node or a N_EXPR node containing a list of simple nodes.
79 PLAN **planp; /* pointer to top of plan (modified) */
81 register PLAN *next; /* temp node holding subexpression results */
82 PLAN *node; /* pointer to returned node or expression */
83 PLAN *tail; /* pointer to tail of subplan */
84 PLAN *subplan; /* pointer to head of ( ) expression */
87 /* first pull the top node from the plan */
88 if ((node = yanknode(planp)) == NULL)
92 * If the node is an '(' then we recursively slurp up expressions
93 * until we find its associated ')'. If it's a closing paren we
94 * just return it and unwind our recursion; all other nodes are
95 * complete expressions, so just return them.
97 if (node->type == N_OPENPAREN)
98 for (tail = subplan = NULL;;) {
99 if ((next = yankexpr(planp)) == NULL)
100 err(1, "(: missing closing ')'");
102 * If we find a closing ')' we store the collected
103 * subplan in our '(' node and convert the node to
104 * a N_EXPR. The ')' we found is ignored. Otherwise,
105 * we just continue to add whatever we get to our
108 if (next->type == N_CLOSEPAREN) {
110 errx(1, "(): empty inner expression");
111 node->p_data[0] = subplan;
117 tail = subplan = next;
130 * replaces "parentheisized" plans in our search plan with "expr" nodes.
134 PLAN *plan; /* plan with ( ) nodes */
136 register PLAN *expr; /* pointer to next expression */
137 register PLAN *tail; /* pointer to tail of result plan */
138 PLAN *result; /* pointer to head of result plan */
140 result = tail = NULL;
143 * the basic idea is to have yankexpr do all our work and just
144 * collect it's results together.
146 while ((expr = yankexpr(&plan)) != NULL) {
148 * if we find an unclaimed ')' it means there is a missing
151 if (expr->type == N_CLOSEPAREN)
152 errx(1, "): no beginning '('");
154 /* add the expression to our result plan */
156 tail = result = expr;
168 * compresses "!" expressions in our search plan.
172 PLAN *plan; /* plan to process */
174 register PLAN *next; /* next node being processed */
175 register PLAN *node; /* temporary node used in N_NOT processing */
176 register PLAN *tail; /* pointer to tail of result plan */
177 PLAN *result; /* pointer to head of result plan */
179 tail = result = next = NULL;
181 while ((next = yanknode(&plan)) != NULL) {
183 * if we encounter a ( expression ) then look for nots in
186 if (next->type == N_EXPR)
187 next->p_data[0] = not_squish(next->p_data[0]);
190 * if we encounter a not, then snag the next node and place
191 * it in the not's subplan. As an optimization we compress
192 * several not's to zero or one not.
194 if (next->type == N_NOT) {
197 node = yanknode(&plan);
198 while (node != NULL && node->type == N_NOT) {
200 node = yanknode(&plan);
203 errx(1, "!: no following expression");
204 if (node->type == N_OR)
205 errx(1, "!: nothing between ! and -o");
207 * If we encounter ! ( expr ) then look for nots in
210 if (node->type == N_EXPR)
211 node->p_data[0] = not_squish(node->p_data[0]);
212 if (notlevel % 2 != 1)
215 next->p_data[0] = node;
218 /* add the node to our result plan */
220 tail = result = next;
232 * compresses -o expressions in our search plan.
236 PLAN *plan; /* plan with ors to be squished */
238 register PLAN *next; /* next node being processed */
239 register PLAN *tail; /* pointer to tail of result plan */
240 PLAN *result; /* pointer to head of result plan */
242 tail = result = next = NULL;
244 while ((next = yanknode(&plan)) != NULL) {
246 * if we encounter a ( expression ) then look for or's in
249 if (next->type == N_EXPR)
250 next->p_data[0] = or_squish(next->p_data[0]);
252 /* if we encounter a not then look for or's in the subplan */
253 if (next->type == N_NOT)
254 next->p_data[0] = or_squish(next->p_data[0]);
257 * if we encounter an or, then place our collected plan in the
258 * or's first subplan and then recursively collect the
259 * remaining stuff into the second subplan and return the or.
261 if (next->type == N_OR) {
263 errx(1, "-o: no expression before -o");
264 next->p_data[0] = result;
265 next->p_data[1] = or_squish(plan);
266 if (next->p_data[1] == NULL)
267 errx(1, "-o: no expression after -o");
271 /* add the node to our result plan */
273 tail = result = next;