2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
8 * Cimarron D. Taylor of the University of California, Berkeley.
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13 * 1. Redistributions of source code must retain the above copyright
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37 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93";
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/types.h>
52 static PLAN *yanknode(PLAN **);
53 static PLAN *yankexpr(PLAN **);
57 * destructively removes the top from the plan
60 yanknode(PLAN **planp)
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 f_expr node containing a list of simple nodes.
78 yankexpr(PLAN **planp)
80 PLAN *next; /* temp node holding subexpression results */
81 PLAN *node; /* pointer to returned node or expression */
82 PLAN *tail; /* pointer to tail of subplan */
83 PLAN *subplan; /* pointer to head of ( ) expression */
85 /* first pull the top node from the plan */
86 if ((node = yanknode(planp)) == NULL)
90 * If the node is an '(' then we recursively slurp up expressions
91 * until we find its associated ')'. If it's a closing paren we
92 * just return it and unwind our recursion; all other nodes are
93 * complete expressions, so just return them.
95 if (node->execute == f_openparen)
96 for (tail = subplan = NULL;;) {
97 if ((next = yankexpr(planp)) == NULL)
98 errx(1, "(: missing closing ')'");
100 * If we find a closing ')' we store the collected
101 * subplan in our '(' node and convert the node to
102 * a f_expr. The ')' we found is ignored. Otherwise,
103 * we just continue to add whatever we get to our
106 if (next->execute == f_closeparen) {
108 errx(1, "(): empty inner expression");
109 node->p_data[0] = subplan;
110 node->execute = f_expr;
114 tail = subplan = next;
127 * replaces "parenthesized" plans in our search plan with "expr" nodes.
130 paren_squish(PLAN *plan)
132 PLAN *expr; /* pointer to next expression */
133 PLAN *tail; /* pointer to tail of result plan */
134 PLAN *result; /* pointer to head of result plan */
136 result = tail = NULL;
139 * the basic idea is to have yankexpr do all our work and just
140 * collect its results together.
142 while ((expr = yankexpr(&plan)) != NULL) {
144 * if we find an unclaimed ')' it means there is a missing
147 if (expr->execute == f_closeparen)
148 errx(1, "): no beginning '('");
150 /* add the expression to our result plan */
152 tail = result = expr;
164 * compresses "!" expressions in our search plan.
167 not_squish(PLAN *plan)
169 PLAN *next; /* next node being processed */
170 PLAN *node; /* temporary node used in f_not processing */
171 PLAN *tail; /* pointer to tail of result plan */
172 PLAN *result; /* pointer to head of result plan */
174 tail = result = NULL;
176 while ((next = yanknode(&plan))) {
178 * if we encounter a ( expression ) then look for nots in
181 if (next->execute == f_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->execute == f_not) {
192 node = yanknode(&plan);
193 while (node != NULL && node->execute == f_not) {
195 node = yanknode(&plan);
198 errx(1, "!: no following expression");
199 if (node->execute == f_or)
200 errx(1, "!: nothing between ! and -o");
202 * If we encounter ! ( expr ) then look for nots in
205 if (node->execute == f_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.
230 or_squish(PLAN *plan)
232 PLAN *next; /* next node being processed */
233 PLAN *tail; /* pointer to tail of result plan */
234 PLAN *result; /* pointer to head of result plan */
236 tail = result = next = NULL;
238 while ((next = yanknode(&plan)) != NULL) {
240 * if we encounter a ( expression ) then look for or's in
243 if (next->execute == f_expr)
244 next->p_data[0] = or_squish(next->p_data[0]);
246 /* if we encounter a not then look for or's in the subplan */
247 if (next->execute == f_not)
248 next->p_data[0] = or_squish(next->p_data[0]);
251 * if we encounter an or, then place our collected plan in the
252 * or's first subplan and then recursively collect the
253 * remaining stuff into the second subplan and return the or.
255 if (next->execute == f_or) {
257 errx(1, "-o: no expression before -o");
258 next->p_data[0] = result;
259 next->p_data[1] = or_squish(plan);
260 if (next->p_data[1] == NULL)
261 errx(1, "-o: no expression after -o");
265 /* add the node to our result plan */
267 tail = result = next;