freebsd-skq/usr.bin/find/operator.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

276 lines
7.4 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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.
* 3. 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("$FreeBSD$");
#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);
}