/* $OpenBSD: operator.c,v 1.10 2009/10/27 23:59:38 deraadt Exp $ */ /*- * 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. */ #include <sys/types.h> #include <sys/stat.h> #include <err.h> #include <fts.h> #include <stdio.h> #include "find.h" #include "extern.h" /* * yanknode -- * destructively removes the top from the plan */ static PLAN * yanknode(PLAN **planp) /* pointer to top of plan (modified) */ { 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 N_EXPR node containing a list of simple nodes. */ static PLAN * yankexpr(PLAN **planp) /* pointer to top of plan (modified) */ { 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 */ extern int f_expr(PLAN *, FTSENT *); /* 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->type == N_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 N_EXPR. The ')' we found is ignored. Otherwise, * we just continue to add whatever we get to our * subplan. */ if (next->type == N_CLOSEPAREN) { if (subplan == NULL) errx(1, "(): empty inner expression"); node->p_data[0] = subplan; node->type = N_EXPR; node->eval = f_expr; break; } else { if (subplan == NULL) tail = subplan = next; else { tail->next = next; tail = next; } tail->next = NULL; } } return (node); } /* * paren_squish -- * replaces "parentheisized" plans in our search plan with "expr" nodes. */ PLAN * paren_squish(PLAN *plan) /* plan with ( ) nodes */ { 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 it's results together. */ while ((expr = yankexpr(&plan)) != NULL) { /* * if we find an unclaimed ')' it means there is a missing * '(' someplace. */ if (expr->type == N_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 to process */ { PLAN *next; /* next node being processed */ PLAN *node; /* temporary node used in N_NOT processing */ 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 nots in * the expr subplan. */ if (next->type == N_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->type == N_NOT) { int notlevel = 1; node = yanknode(&plan); while (node != NULL && node->type == N_NOT) { ++notlevel; node = yanknode(&plan); } if (node == NULL) errx(1, "!: no following expression"); if (node->type == N_OR) errx(1, "!: nothing between ! and -o"); if (node->type == N_EXPR) node = not_squish(node); 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 with ors to be squished */ { 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->type == N_EXPR) next->p_data[0] = or_squish(next->p_data[0]); /* if we encounter a not then look for not's in the subplan */ if (next->type == N_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->type == N_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); }
