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
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36 * $FreeBSD: src/usr.bin/find/operator.c,v 1.5.6.1 2001/05/06 09:53:22 phk Exp $
37 * $DragonFly: src/usr.bin/find/operator.c,v 1.4 2004/07/09 19:11:20 drhodus Exp $
39 * @(#)operator.c 8.1 (Berkeley) 6/6/93
42 #include <sys/types.h>
52 * destructively removes the top from the plan
54 /* planp: pointer to top of plan (modified) */
56 yanknode(PLAN **planp)
58 PLAN *node; /* top node removed from the plan */
60 if ((node = (*planp)) == NULL)
62 (*planp) = (*planp)->next;
69 * Removes one expression from the plan. This is used mainly by
70 * paren_squish. In comments below, an expression is either a
71 * simple node or a f_expr node containing a list of simple nodes.
73 /* planp: pointer to top of plan (modified) */
75 yankexpr(PLAN **planp)
77 register PLAN *next; /* temp node holding subexpression results */
78 PLAN *node; /* pointer to returned node or expression */
79 PLAN *tail; /* pointer to tail of subplan */
80 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->execute == f_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 f_expr. The ')' we found is ignored. Otherwise,
100 * we just continue to add whatever we get to our
103 if (next->execute == f_closeparen) {
105 errx(1, "(): empty inner expression");
106 node->p_data[0] = subplan;
107 node->execute = f_expr;
111 tail = subplan = next;
124 * replaces "parentheisized" plans in our search plan with "expr" nodes.
126 /* plan: plan with ( ) nodes */
128 paren_squish(PLAN *plan)
130 register PLAN *expr; /* pointer to next expression */
131 register PLAN *tail; /* pointer to tail of result plan */
132 PLAN *result; /* pointer to head of result plan */
134 result = tail = NULL;
137 * the basic idea is to have yankexpr do all our work and just
138 * collect its results together.
140 while ((expr = yankexpr(&plan)) != NULL) {
142 * if we find an unclaimed ')' it means there is a missing
145 if (expr->execute == f_closeparen)
146 errx(1, "): no beginning '('");
148 /* add the expression to our result plan */
150 tail = result = expr;
162 * compresses "!" expressions in our search plan.
164 /* plan: plan to process */
166 not_squish(PLAN *plan)
168 register PLAN *next; /* next node being processed */
169 register PLAN *node; /* temporary node used in f_not processing */
170 register PLAN *tail; /* pointer to tail of result plan */
171 PLAN *result; /* pointer to head of result plan */
173 tail = result = NULL;
175 while ((next = yanknode(&plan))) {
177 * if we encounter a ( expression ) then look for nots in
180 if (next->execute == f_expr)
181 next->p_data[0] = not_squish(next->p_data[0]);
184 * if we encounter a not, then snag the next node and place
185 * it in the not's subplan. As an optimization we compress
186 * several not's to zero or one not.
188 if (next->execute == f_not) {
191 node = yanknode(&plan);
192 while (node != NULL && node->execute == f_not) {
194 node = yanknode(&plan);
197 errx(1, "!: no following expression");
198 if (node->execute == f_or)
199 errx(1, "!: nothing between ! and -o");
201 * If we encounter ! ( expr ) then look for nots in
204 if (node->execute == f_expr)
205 node->p_data[0] = not_squish(node->p_data[0]);
206 if (notlevel % 2 != 1)
209 next->p_data[0] = node;
212 /* add the node to our result plan */
214 tail = result = next;
226 * compresses -o expressions in our search plan.
228 /* plan: plan with ors to be squished */
230 or_squish(PLAN *plan)
232 register PLAN *next; /* next node being processed */
233 register 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;