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Diffstat (limited to 'shell_cmds/find/operator.c')
| -rw-r--r-- | shell_cmds/find/operator.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/shell_cmds/find/operator.c b/shell_cmds/find/operator.c new file mode 100644 index 0000000..1aa851e --- /dev/null +++ b/shell_cmds/find/operator.c @@ -0,0 +1,273 @@ +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Cimarron D. Taylor of the University of California, Berkeley. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93"; +#endif +#endif /* not lint */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: src/usr.bin/find/operator.c,v 1.17 2010/12/11 08:32:16 joel Exp $"); + +#include <sys/types.h> + +#include <err.h> +#include <fts.h> +#include <stdio.h> + +#include "find.h" + +static PLAN *yanknode(PLAN **); +static PLAN *yankexpr(PLAN **); + +/* + * yanknode -- + * destructively removes the top from the plan + */ +static PLAN * +yanknode(PLAN **planp) +{ + PLAN *node; /* top node removed from the plan */ + + if ((node = (*planp)) == NULL) + return (NULL); + (*planp) = (*planp)->next; + node->next = NULL; + return (node); +} + +/* + * yankexpr -- + * Removes one expression from the plan. This is used mainly by + * paren_squish. In comments below, an expression is either a + * simple node or a f_expr node containing a list of simple nodes. + */ +static PLAN * +yankexpr(PLAN **planp) +{ + PLAN *next; /* temp node holding subexpression results */ + PLAN *node; /* pointer to returned node or expression */ + PLAN *tail; /* pointer to tail of subplan */ + PLAN *subplan; /* pointer to head of ( ) expression */ + + /* first pull the top node from the plan */ + if ((node = yanknode(planp)) == NULL) + return (NULL); + + /* + * If the node is an '(' then we recursively slurp up expressions + * until we find its associated ')'. If it's a closing paren we + * just return it and unwind our recursion; all other nodes are + * complete expressions, so just return them. + */ + if (node->execute == f_openparen) + for (tail = subplan = NULL;;) { + if ((next = yankexpr(planp)) == NULL) + errx(1, "(: missing closing ')'"); + /* + * If we find a closing ')' we store the collected + * subplan in our '(' node and convert the node to + * a f_expr. The ')' we found is ignored. Otherwise, + * we just continue to add whatever we get to our + * subplan. + */ + if (next->execute == f_closeparen) { + if (subplan == NULL) + errx(1, "(): empty inner expression"); + node->p_data[0] = subplan; + node->execute = f_expr; + break; + } else { + if (subplan == NULL) + tail = subplan = next; + else { + tail->next = next; + tail = next; + } + tail->next = NULL; + } + } + return (node); +} + +/* + * paren_squish -- + * replaces "parenthesized" plans in our search plan with "expr" nodes. + */ +PLAN * +paren_squish(PLAN *plan) +{ + PLAN *expr; /* pointer to next expression */ + PLAN *tail; /* pointer to tail of result plan */ + PLAN *result; /* pointer to head of result plan */ + + result = tail = NULL; + + /* + * the basic idea is to have yankexpr do all our work and just + * collect its results together. + */ + while ((expr = yankexpr(&plan)) != NULL) { + /* + * if we find an unclaimed ')' it means there is a missing + * '(' someplace. + */ + if (expr->execute == f_closeparen) + errx(1, "): no beginning '('"); + + /* add the expression to our result plan */ + if (result == NULL) + tail = result = expr; + else { + tail->next = expr; + tail = expr; + } + tail->next = NULL; + } + return (result); +} + +/* + * not_squish -- + * compresses "!" expressions in our search plan. + */ +PLAN * +not_squish(PLAN *plan) +{ + PLAN *next; /* next node being processed */ + PLAN *node; /* temporary node used in f_not processing */ + PLAN *tail; /* pointer to tail of result plan */ + PLAN *result; /* pointer to head of result plan */ + + tail = result = NULL; + + while ((next = yanknode(&plan))) { + /* + * if we encounter a ( expression ) then look for nots in + * the expr subplan. + */ + if (next->execute == f_expr) + next->p_data[0] = not_squish(next->p_data[0]); + + /* + * if we encounter a not, then snag the next node and place + * it in the not's subplan. As an optimization we compress + * several not's to zero or one not. + */ + if (next->execute == f_not) { + int notlevel = 1; + + node = yanknode(&plan); + while (node != NULL && node->execute == f_not) { + ++notlevel; + node = yanknode(&plan); + } + if (node == NULL) + errx(1, "!: no following expression"); + if (node->execute == f_or) + errx(1, "!: nothing between ! and -o"); + /* + * If we encounter ! ( expr ) then look for nots in + * the expr subplan. + */ + if (node->execute == f_expr) + node->p_data[0] = not_squish(node->p_data[0]); + if (notlevel % 2 != 1) + next = node; + else + next->p_data[0] = node; + } + + /* add the node to our result plan */ + if (result == NULL) + tail = result = next; + else { + tail->next = next; + tail = next; + } + tail->next = NULL; + } + return (result); +} + +/* + * or_squish -- + * compresses -o expressions in our search plan. + */ +PLAN * +or_squish(PLAN *plan) +{ + PLAN *next; /* next node being processed */ + PLAN *tail; /* pointer to tail of result plan */ + PLAN *result; /* pointer to head of result plan */ + + tail = result = next = NULL; + + while ((next = yanknode(&plan)) != NULL) { + /* + * if we encounter a ( expression ) then look for or's in + * the expr subplan. + */ + if (next->execute == f_expr) + next->p_data[0] = or_squish(next->p_data[0]); + + /* if we encounter a not then look for or's in the subplan */ + if (next->execute == f_not) + next->p_data[0] = or_squish(next->p_data[0]); + + /* + * if we encounter an or, then place our collected plan in the + * or's first subplan and then recursively collect the + * remaining stuff into the second subplan and return the or. + */ + if (next->execute == f_or) { + if (result == NULL) + errx(1, "-o: no expression before -o"); + next->p_data[0] = result; + next->p_data[1] = or_squish(plan); + if (next->p_data[1] == NULL) + errx(1, "-o: no expression after -o"); + return (next); + } + + /* add the node to our result plan */ + if (result == NULL) + tail = result = next; + else { + tail->next = next; + tail = next; + } + tail->next = NULL; + } + return (result); +} |