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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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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39 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93";
41 static const char rcsid[] =
46 #include <sys/types.h>
54 static PLAN *yanknode __P((PLAN **));
55 static PLAN *yankexpr __P((PLAN **));
59 * destructively removes the top from the plan
63 PLAN **planp; /* pointer to top of plan (modified) */
65 PLAN *node; /* top node removed from the plan */
67 if ((node = (*planp)) == NULL)
69 (*planp) = (*planp)->next;
76 * Removes one expression from the plan. This is used mainly by
77 * paren_squish. In comments below, an expression is either a
78 * simple node or a f_expr node containing a list of simple nodes.
82 PLAN **planp; /* pointer to top of plan (modified) */
84 PLAN *next; /* temp node holding subexpression results */
85 PLAN *node; /* pointer to returned node or expression */
86 PLAN *tail; /* pointer to tail of subplan */
87 PLAN *subplan; /* pointer to head of ( ) expression */
89 /* first pull the top node from the plan */
90 if ((node = yanknode(planp)) == NULL)
94 * If the node is an '(' then we recursively slurp up expressions
95 * until we find its associated ')'. If it's a closing paren we
96 * just return it and unwind our recursion; all other nodes are
97 * complete expressions, so just return them.
99 if (node->execute == f_openparen)
100 for (tail = subplan = NULL;;) {
101 if ((next = yankexpr(planp)) == NULL)
102 err(1, "(: missing closing ')'");
104 * If we find a closing ')' we store the collected
105 * subplan in our '(' node and convert the node to
106 * a f_expr. The ')' we found is ignored. Otherwise,
107 * we just continue to add whatever we get to our
110 if (next->execute == f_closeparen) {
112 errx(1, "(): empty inner expression");
113 node->p_data[0] = subplan;
114 node->execute = f_expr;
118 tail = subplan = next;
131 * replaces "parentheisized" plans in our search plan with "expr" nodes.
135 PLAN *plan; /* plan with ( ) nodes */
137 PLAN *expr; /* pointer to next expression */
138 PLAN *tail; /* pointer to tail of result plan */
139 PLAN *result; /* pointer to head of result plan */
141 result = tail = NULL;
144 * the basic idea is to have yankexpr do all our work and just
145 * collect its results together.
147 while ((expr = yankexpr(&plan)) != NULL) {
149 * if we find an unclaimed ')' it means there is a missing
152 if (expr->execute == f_closeparen)
153 errx(1, "): no beginning '('");
155 /* add the expression to our result plan */
157 tail = result = expr;
169 * compresses "!" expressions in our search plan.
173 PLAN *plan; /* plan to process */
175 PLAN *next; /* next node being processed */
176 PLAN *node; /* temporary node used in f_not processing */
177 PLAN *tail; /* pointer to tail of result plan */
178 PLAN *result; /* pointer to head of result plan */
180 tail = result = NULL;
182 while ((next = yanknode(&plan))) {
184 * if we encounter a ( expression ) then look for nots in
187 if (next->execute == f_expr)
188 next->p_data[0] = not_squish(next->p_data[0]);
191 * if we encounter a not, then snag the next node and place
192 * it in the not's subplan. As an optimization we compress
193 * several not's to zero or one not.
195 if (next->execute == f_not) {
198 node = yanknode(&plan);
199 while (node != NULL && node->execute == f_not) {
201 node = yanknode(&plan);
204 errx(1, "!: no following expression");
205 if (node->execute == f_or)
206 errx(1, "!: nothing between ! and -o");
208 * If we encounter ! ( expr ) then look for nots in
211 if (node->execute == f_expr)
212 node->p_data[0] = not_squish(node->p_data[0]);
213 if (notlevel % 2 != 1)
216 next->p_data[0] = node;
219 /* add the node to our result plan */
221 tail = result = next;
233 * compresses -o expressions in our search plan.
237 PLAN *plan; /* plan with ors to be squished */
239 PLAN *next; /* next node being processed */
240 PLAN *tail; /* pointer to tail of result plan */
241 PLAN *result; /* pointer to head of result plan */
243 tail = result = next = NULL;
245 while ((next = yanknode(&plan)) != NULL) {
247 * if we encounter a ( expression ) then look for or's in
250 if (next->execute == f_expr)
251 next->p_data[0] = or_squish(next->p_data[0]);
253 /* if we encounter a not then look for or's in the subplan */
254 if (next->execute == f_not)
255 next->p_data[0] = or_squish(next->p_data[0]);
258 * if we encounter an or, then place our collected plan in the
259 * or's first subplan and then recursively collect the
260 * remaining stuff into the second subplan and return the or.
262 if (next->execute == f_or) {
264 errx(1, "-o: no expression before -o");
265 next->p_data[0] = result;
266 next->p_data[1] = or_squish(plan);
267 if (next->p_data[1] == NULL)
268 errx(1, "-o: no expression after -o");
272 /* add the node to our result plan */
274 tail = result = next;